Atrial Fibrillation - PDF - PDF by ravenms

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									Atrial fibrillation

    Janet Wong, M.D.




                       1
       Emergent/urgent Cardioversion       Atrial fibrillation is the most frequently occurring cardiac arrhythmia,
                                           and it is the main problem that we have to deal with when it comes
                                           to cardiac arrhythmias. There is a 2% risk of atrial fibrillation over
€ Poorly tolerated atrial ablation:        20 years, and the risk increases with age. By the time people reach
                                           75, there is a high prevalence of atrial fibrillation. The risk also
   •   Significant hypotension
                                           increases with other associated diseases like hypertension, coro-
   •   Pulmonary edema                     nary disease, and diabetes.
   •   Significant ischemia
                                           The main thing we worry about is the risk of stroke in people with
€ DC cardioversion:                        atrial fibrillation. People can be very symptomatic and have func-
                                           tional limitations due to rapid ventricular rate, loss of AV synchrony,
   •   Minimum 200 J. synchronized shock
                                           variability of ventricular response, and tachycardia-induced
                                           cardiomyopathy.

                                           Poorly tolerated atrial fibrillation is characterized by significant
                                           hypotension. If their BP is 50, you are going to want to treat it as an
                                           emergency. So you have someone that comes in, their blood
                                           pressure is maintained, but they are developing severe pulmonary
                                           edema or they are complaining of crushing chest pain with ECG
                                           changes, I think you are not wrong in that case to urgently DC
                                           cardiovert those people.

                                           Atrial fibrillation is probably the most difficult arrhythmia to electri-
                                           cally cardiovert. Certainly harder than ventricular tachycardia, often
                                           harder than ventricular fibrillation. It usually takes high energy.

                                           There are two reasons to start with a higher energy. A shock of 50
                                           joules externally stimulates skeletal muscle and that's what makes
                                           it painful. A shock of 200 joules or 300 joules or even 360 joules
                                           hurts just as much. It doesn't hurt any more. So, you are not saving
                                           your patient any discomfort by using a lower energy. When you
                                           shock somebody, you should always recharge the defibrillator
                                           immediately because when you shock somebody there is always
                                           the risk you are going to put them into VF. The risk of causing VF
                                           with the shock is related to the energy. The lower the energy, the
                                           higher the risk of VF because you have incompletely depolarized
                                           the heart.

                                           You can decrease the number of shocks if you use a higher energy
                                           and you can also reduce the risk of causing VF. I routinely start at
                                           200 to 300 joules, and if I have a big barrel-chested person or an
                                           obese person, I just start with 360.




                                                                                                                       2
                 Acute Rate Control
                                                                What if the person is stable and you want to just control them
                                                                medically when they come in? The rate can be controlled with a
€   IV calcium channel blockers                                 variety of agents. One group of agents is the IV calcium channel
                                                                blockers. IV diltiazem is the drug of choice because of the ease of
    • Diltiazem 20 - 25 mg bolus, then 10-15 mg/hour infusion
                                                                use. After you have loaded the patient with a bolus, which is usually
    • Verapamil 2.5 - 5 mg bolus                                20 to 25 mg, you can start the patient on an infusion of 10 to 15
                                                                mg/hour, and you can titrate the infusion rate to achieve the appro-
€   IV Digoxin
                                                                priate heart rate. This strategy is very effective in the short term at
                                                                controlling ventricular rate. You want to convert people over that
                                                                can take p.o. medications early on if you are going to continue to
                                                                need to rate control them.

                                                                IV beta blockers work very well. IV Inderal, IV metoprolol; the short-
                                                                acting one is esmolol which is difficult to dose. Diltiazem is easier
                                                                for that reason.

                                                                IV digoxin is not usually recommended for acute rate control be-
                                                                cause the onset of action is very long; it can take hours before you
                                                                rate control someone. Digoxin is not good at rate control in some-
                                                                body with a high catecholamine state. IV digoxin is no longer used
                                                                for acute rate control. There is no difference in conversion rate with
                                                                IV digoxin.

                                                                Rate control that in atrial fibrillation in the setting of the WPW
                                                                syndrome. In WPW, there is an accessory pathway connecting the
                                                                atrium to the ventricle which bypasses the AV node. The problem
                                                                with that is that the AV node limits the number of impulses that can
                                                                reach the atrium from the ventricle, maybe in a young healthy
                                                                person, to 200 to 220 beats per minute. The accessory pathway
                                                                doesn't have that same function and can let 250, even 300, beats
                                                                per minute through to the ventricle. The hallmarks of WPW in atrial
                                                                fibrillation are a wide QRS complex that is an irregular tachycardia,
                                                                and you have changing amounts of preexcitation. So, the QRS is
                                                                almost changing beat to beat by the amount of excitation of the
                                                                ventricle.

                                                                If you give typical AV node blocking drugs in these patients, they
                                                                will block the AV node fine, but the ventricle is still going to be
                                                                activated rapidly over the accessory pathway. If you give a drug like
                                                                verapamil, you may increase conduction over the accessory path-
                                                                way. If you give these patients, digoxin, verapamil, or beta blockers,
                                                                you can degenerate them to ventricular fibrillation.

                                                                The treatment of choice for atrial fibrillation in the setting of WPW
                                                                is electrical cardioversion if the patient is unstable. Procainamide is
                                                                the drug of choice given intravenously because it may convert the
                                                                atrial fibrillation, and it suppresses conduction over the accessory
                                                                pathway, and it will limit the number of impulses getting to the
                                                                ventricle. A potentially life-threatening complication may occur with
                                                                the usual rate control medications.




                                                                                                                                        3
               Elective Cardioversion
                                                                 Patients who have been in atrial fibrillation for less than 48 hours
                                                                 can be safely cardioverted without anticoagulation. Elective cardio-
€ > 24 - 48 hours                                                version can be accomplished pharmacologically with either intrave-
                                                                 nous procainamide or ibutilide. Or you can use oral loading of
€ Pharmacologic
                                                                 quinidine or disopyramide (Norpace). External electrical cardiover-
   •   Intravenous: procainamide/ibutilide                       sion can be used. Internal cardioversions may also be effective in
                                                                 the patients who are resistant to external DC cardioversions.
   •   Oral loading
€ Electrical                                                     In atrial fibrillation that has been present for more than 48 hours,
                                                                 after you cardiovert them, you need to maintain anticoagulation due
   •   External
                                                                 to the high risk of embolic events during that period. Patients that
   •   Internal                                                  have been in chronic atrial fibrillation, the atria are stunned and
                                                                 they don't contract very well. Patients are at continued risk for
                                                                 stroke even though they are in sinus rhythm for a period of three
Anticoagulation for three months after cardioversion is recom-   months after conversion from atrial fibrillation.
mended because of high-risk of embolic events during this
                                                                 The standard approach is you put them on Coumadin and wait four
period.                                                          to six weeks and then bring them in for an elective cardioversion.
                                                                 The down side is there is a delay in cardioversion. You also end up
                                                                 having more prolonged anticoagulation with the risks attendant with
                                                                 warfarin and you delay the recovery of atrial function. The longer
                                                                 you leave somebody in atrial fibrillation, the longer it takes the
                                                                 atrium to recover. The quicker you get somebody out of atrial
                                                                 fibrillation, the longer they will stay out of fibrillation.

                                                                 Transesophageal echo should be used to select candidates for
                                                                 early cardioversion. Heparin therapy should be instituted and the
                                                                 rate should be controlled, and you do a TEE and you look for
                                                                 thrombus. In patients who do not have a thrombus, you can go
                                                                 ahead and cardiovert. So, you have an overall shorter duration of
                                                                 warfarin therapy--four to six weeks less–and a more rapid return of
                                                                 atrial function, and fewer incidents of thromboembolism. In patients
                                                                 in whom left atrial thrombi was excluded, you can safely cardiovert
                                                                 these people.

                                                                 If you decide to cardiovert somebody you don't always have to
                                                                 shock them right off. What we do in our hospital is often bring them
                                                                 in for elective cardioversion, we will give them a load of intravenous
                                                                 procainamide, and if they don't convert then we go ahead and do
                                                                 the DC cardioversion. The standard dose of procainamide, 15
                                                                 mg/kg over 20 to 30 minutes. It is probably more effective at this
                                                                 faster rate because you get a higher peak plasma level of the
                                                                 procainamide, and that is probably what accounts for the acute
                                                                 conversions. The patient should be monitored for hypotension,
                                                                 QRS widening and QT prolongation.

                                                                 A new class III antiarrhythmic drug called ibutilide (Corvert) works
                                                                 by prolonging the action potential duration. It works well for up to
                                                                 50%. With atrial fibrillation, with a 30% conversion rate. There is a
                                                                 significant risk of torsades de pointes with ibutilide. It is much
                                                                 easier to give than procainamide - you can give it quicker. Patients
                                                                 develop polymorphic VTs, sustained in almost 2%, 2.5% non-
                                                                 sustained. Some people even developed monomorphic VT. You
                                                                 can see a 9% incidence of ventricular proarrhythmia in these pa-
                                                                 tients. It is okay to use it; you just have to be aware of this and use
                                                                 it in the proper setting. So, if you give this in the ER, patients have
                                                                 to be monitored closely for 4 hours after you use it. If you use it in
                                                                 the hospital, they have to be in a telemetry setting where you are
                                                                 comfortable with the people on your telemetry floors that they can
                                                                 recognize this and treat it very rapidly.

                                                                 How do you convert somebody electrically? When external cardio-
                                                                 version fails, internal cardioversion with a catheter may be success-

                                                                                                                                           4
       Treatment of Atrial Fibrillation              ful. The catheter has a platinum electrode on it is floated into the
                                                     right atrium, and then you shock between the tip of the catheter and
                                                     the back patch. So, you are actually shocking from inside the heart.
                                                     The results have been really encouraging. Significantly more people
€ Treat underlying cause if present                  were cardioverted with internal cardioversion than with external.
                                                     The long-term outcomes were no different. It is useful in the pa-
€ Rate control
                                                     tients who will benefit from sinus rhythm, but you can't get into
€ Anticoagulating                                    sinus rhythm with external shocks.
€ Maintenance of sinus rhythm in selected patients
                                                     Treatment of atrial fibrillation includes treatment of underlying
                                                     causes. The most common disorders are thyrotoxicosis and
                                                     pericarditis.




                                                                                                                         5
   Anticoagulation Recommendations                                  People who have atrial fibrillation have a 6-fold increased risk of
                                                                    stroke. The very high risk patients tend to be the older patients with
                                                                    diabetes, hypertension, previous strokes and TIAs, CHF, coronary
                                                                    disease, and mitral valve disease. High risk patients greater than
€ Strong contraindication to warfarin: Aspirin 325 mg per day       65, with one of these risk factors have a 5% per year risk. The low
                                                                    risk patients are the patients less than 60 with normal hearts, with
€ Lone atrial fibrillation, less than 65: No treatment or aspirin
                                                                    normal blood pressures and glucoses, and the risk is probably even
€ Low-risk: Aspirin                                                 less than 1% per year.
€ One or more risk factors: Warfarin (INR 2.0-3.0)
                                                                    With Coumadin there is an overall 65% reduction in stroke presen-
€ $70, low-risk: Warfarin (INR 2.0) or aspirin                      tations with atrial fibrillation. Anticoagulation is important in atrial
                                                                    fibrillation.

                                                                    There is a significant reduction in the risk of stroke with Coumadin
                                                                    over platelet inhibitors. So, in the general population, including the
                                                                    high-risk patients, Coumadin is clearly better than aspirin alone. In
                                                                    patients that are low-risk, who have essentially structural normal
                                                                    hearts, that have no hypertension, no LV dysfunction, no prior
                                                                    embolic events, even if they are older, aspirin is probably better
                                                                    than warfarin in those patients. High risk patients should be on
                                                                    Coumadin.

                                                                    With strong contraindications to warfarin, you need to put them on
                                                                    aspirin. In patients with lone atrial fibrillation that are relatively
                                                                    young, either nothing or aspirin is recommended. If it is a male
                                                                    patient that is 55 years old, having him take an aspirin a day may
                                                                    have some added benefit in coronary disease, so I like to tell them
                                                                    to take an aspirin anyway.

                                                                    Low-risk patients can be treated with aspirin alone. If they have one
                                                                    or more risk factors, warfarin is recommended with an INR between
                                                                    2 and 3, usually shooting between 2 to 2.5. Greater than 70 puts
                                                                    them in high-risk; however, those are the people that have a higher
                                                                    incidence of bleeding. What I tend to do in people that have rela-
                                                                    tively normal hearts even if they are older than 70, I will often use
                                                                    aspirin alone, or if I do use Coumadin I will tend to shoot on the
                                                                    lower side of the INR. You have to individualize it for each patient.




                                                                                                                                               6
                  Treatment Goals
                                                             Treatment goals in treating atrial fibrillation include alleviation of
                                                             symptoms, prevention of ischemia with high heart rates. Some
€ Alleviate symptoms                                         patients with atrial fibrillation due to the loss of AV synchrony and
                                                             the irregularness of their rate have more CHF and keeping them in
€ Prevent ischemia
                                                             sinus will improve hemodynamics. You would like to prolong life
€ Improve hemodynamics                                       and prevent sequelae.
€ Prolonge life in prevent sequelae
                                                             There is no data at present that supports reduction in stroke or
Maintenance of sinus rhythm with an antiarrhythmic has not   prolongation of life with antiarrhythmic maintenance of sinus
                                                             rhythm.
been proven to reduce risk of stroke or prolong life
                                                             Antiarrhythmics in patients that had no history of CHF did not
                                                             cause a significant increase in mortality. Patients with a history of
                                                             CHF and no antiarrhythmics, clearly they did less well than those
                                                             patients that had no history of CHF, but the surprising finding was
                                                             that if you looked at the survival curve for the patients that both had
                                                             a history of CHF and were receiving antiarrhythmics to maintain
                                                             sinus rhythm, their survival is much worse than the other groups.




                                                                                                                                       7
                      Rate Control
                                                 Rate control in chronic atrial fibrillation. There are pharmacologic
                                                 agents, digitalis, beta blockers, calcium channel blockers and even
€ Pharmacological                                amiodarone for rate control and there are some non-pharmacologic
                                                 approaches such as AV node modification or ablation of the AV
  •   Calcium blockers
                                                 node and physiologic pacing.
  •   Beta-blockers
  •   Digitalis
  •   Amiodarone
€ Non-pharmacological
  •   AV node modification
  •   AV node ablation plus physiologic pacing




                                                                                                                    8
         Pharmacologic Rate Control
                                                                If you are going to go ahead with pharmacologic rate control it is
                                                                important to confirm that the patient is rate controlled. A significant
€ Digitalis is indicated if history of CHF                      number of patients who their physicians thought were adequately
                                                                rate-controlled were in atrial fibrillation with rates of 140 to 150 at
   •   Poor choice in active patients                           rest. Before people leave the hospital, I will get them up and put
   •   Excessive slowing during sinus rate or at rest           them on the stairs while they are still on telemetry and see what
                                                                their heart rate does. After I send them out, I will either get a tread-
€ Beta-blockers                                                 mill test, or it is even better to send them home with a Holter moni-
   •   Excellent in active patients                             tor and tell them, "I want you to go do all of the things that you are
                                                                normally going to do." You really want to do surveillance Holters
   •   Using combination with and antiarrhythmics               when they are back doing the things that they do because when
   •   First choice in thyrotoxicosis                           these people get active, their heart rates often shoot up much
                                                                higher than you thought.
   •   First choice in ischemic patients
   •   May not be tolerated in patients with CHF or lung dis-   Beta blockers are an excellent choice for active patients. Use in
                                                                combination with antiarrhythmics is well tolerated. It is the first
       ease                                                     choice in patients with thyrotoxicosis. It is the first choice in patients
   •   ISA in patients with tachy-bradycardia syndrome          with ischemia. It may not be tolerated in patients with moderate
                                                                CHF or lung disease, although patients with mild CHF should be
€ Calcium channel blockers                                      put on beta blockers. A beta blocker like Pindolol, with intrinsic
   •   Good in active patients                                  sympathomimetic activity, may be advantageous in patients with
                                                                tachy-bradycardia syndrome, where you could avoid a pacemaker.
   •   First choice in patients with lung disease               But I am not sure how good that is.
   •   Acceptable in patients with ischemia
                                                                Calcium channel blockers, I think, are very good agents for rate
   •   May not be tolerated in patients with CHF                control. They are good in the active patients. They are the first
€ Amiodarone                                                    choice of patients with lung disease who can't use beta blockers. I
                                                                think they are the first choice of patients with atrial fibrillation and
   •   May work when nothing else does                          LVH because of the beneficial effects of calcium channel blockers
   •   Good in patients with enhanced AV conviction             in these patients and the regression of LVH. It may not be tolerated
                                                                in patients with CHF. Negative inotropic effects.
   •   May be beneficial in patients with LV dysfunction
       and/or Nonsustained ventricular tachycardia              Digitalis is only recommended in patients with a history of CHF
                                                                because you have the added benefit in those patients. It is very
                                                                poor in active patients. The problem with digoxin is that you have
                                                                excessive slowing of the sinus rate at rest but not good control
                                                                during exertion. So, you push the dig to a point where someone has
                                                                a heart rate of 60 at rest and then they get up and start doing things
                                                                like climbing stairs and stuff and their heart rate goes up to 170 or
                                                                140. Digoxin, especially in the active patient, is not recomended.

                                                                Amiodarone may work when nothing else can control the heart rate.
                                                                It is good in patients that have enhanced AV nodal conduction is a
                                                                very rare entity where people go into atrial fibrillation and go very
                                                                rapidly up to 250 or 350 beats per minute. It may be beneficial in
                                                                patients with LV dysfunction and/or nonsustained VT where you get
                                                                the added benefit of reducing the risk of sudden death.

                                                                AV junctional ablation for rate control of atrial fibrillation. The
                                                                response of patients is really dramatic, and people do really well
                                                                with this procedure. Indications include failure of the multiple AV
                                                                nodal blocking drugs. So, patients that you just can't rate control no
                                                                matter what you use. Patients in whom even though their rate is
                                                                controlled the irregularity of the atrial fibrillation still bothers them.
                                                                Drug intolerance. Patients that when they take the drugs that rate
                                                                control, they get admitted five times a year with CHF and their heart
                                                                rate is 150 because they never take their medications. Also, patient
                                                                preference.

                                                                What do we do with patients with atrial fibrillation and heart failure?
                                                                Twenty five percent of patients with heart failure may also have
                                                                atrial fibrillation. These are the patients that are at highest risk of
                                                                proarrhythmia from antiarrhythmic drugs. Congestive heart failure

                                                                                                                                           9
              Chemical Cardioversion                      can lead to atrial fibrillation, and atrial fibrillation can lead to and
                                                          worsen congestive heart failure. Chronic tachycardia is associated
                                                          with the development of a cardiomyopathy and it appears to be
                                                          reversible.
€ Procainamide
                                                          Ablation and pacing results in an improvement in EF from 25% to
  •   15 mg/kg IV over 20-30 minutes (750-1500 mg)        52%. Dramatic increases in injection fraction. With severe LV
  •   Watch for hypotension, QRS widening, QT prolonga-   dysfunction, after you ablate their AV node and put in a pacemaker;
                                                          it is almost back to normal. I think that is a really important point
      tion.                                               that people don't fully understand yet. Patients with mean heart
                                                          rates of 60 to 100 beats per minute on a Holter that had depressed
                                                          LV function underwent AV junctional ablation and showed a signifi-
                                                          cant improvement in function after this.

                                                          Regularization of ventricular response. Even if you have somebody
                                                          rate controlled, the ventricle is being activated very irregularly.
                                                          Regularization of rhythm provides significant hemodynamic bene-
                                                          fits. In patients with AF, an increase in pulmonary capillary wedge
                                                          pressure were seen with irregular rhythm as opposed to regular
                                                          rhythm; therefore, both rapid rate and irregularity leads to de-
                                                          creased LV function.

                                                          If you have patients that are difficult to manage and are having
                                                          repeated visits to the hospital with CHF and have chronic atrial
                                                          fibrillation, AV junctional ablation with pacing is something to
                                                          consider. It may help you manage their CHF.




                                                                                                                                 10
       Maintenance of Sinus to Rhythm
                                        Maintenance of sinus rhythm. There is a subset of patients in whom
                                        we are going to want to try and maintain sinus rhythm. There are
€ Pharmacologic                         pharmacologic approaches, preventative pacing, implantable
                                        defibrillators and ablative therapy.
€ Preventive pacing
€ Implantable defibrillator
€ Ablative therapy
   •   Surgical
   •   Catheter




                                                                                                        11
 Pharmacologic Maintenance of Sinus
                                                           Pharmacologic agents. The class-I agents are sodium channel
                       to Rhythm                           blockers. There is quinidine, procainamide, disopyramide.
                                                           Quinidine is a drug that has been used for years and years, but 40
                                                           to 50% of patients can't take it because of the diarrhea.
€ Class IA                                                 Procainamide maintenance is not recommended because of arthri-
                                                           tis, rash, and lupus-like syndromes. Disopyramide (Norpace) is not
   •   Quinidine: diarrhea                                 good in older men because of urinary retention, but it is very well-
   •   Procainamide: arthritis/rash/lupus                  tolerated in younger patients, and in patients with vagally mediated
                                                           atrial fibrillation.
   •   Disopyramide: urinary retention
                                                           The class 1C agents. Flecainide got a very bad name because of
€ Class IC
                                                           the excess mortality in patients post MI. But I think in patients with
   •   Flecainide: avoided in ischemia/poor LV function    structurally normal hearts, it is probably one of the most effective
                                                           agents that we have for controlling atrial fibrillation. It should be
   •   Propafenone: avoided in ischemia/poor LV function
                                                           avoided it in patients with ischemia or poor LV function. The same
€ Class III                                                thing with propafenone (Rythmol). A newer agent, Sotalol can be
                                                           very effective because it offers both rate control and an
   •   Sotalol: CHF, asthma, bradycardia
                                                           antiarrhythmic properties, but the beta blocking properties can
€ Amiodarone: end organ toxicity                           cause problems in patients with CHF, asthma, and it can cause
                                                           bradycardia.

                                                           Amiodarone is a very good drug for controlling atrial fibrillation, but
                                                           the end organ toxicities are something to be concerned about. Over
                                                           one year's time on quinidine, about 50% are maintained in sinus
                                                           rhythm. Propafenone and Sotalol, 50%. With the exception of
                                                           amiodarone, the antiarrhythmic drugs are all about 50% effective at
                                                           one year. Amiodarone appears to be the most effective
                                                           antiarrhythmic at maintaining sinus rhythm. It is 78% effective at
                                                           maintaining sinus rhythm in people who had failed a type-I
                                                           antiarrhythmic. Amiodarone versus quinidine, again right around
                                                           50% versus 79%. Same thing for amiodarone versus Norpace.

                                                           Amiodarone is the best drug available for maintaining sinus rhythm.
                                                           We have had a lot of good success with using amiodarone, and we
                                                           use it in a lot of patients. Toxicity tends to be dose related. So, in
                                                           the doses we use in ventricular tachycardia, 400 to 600 mg/day,
                                                           there is a significant incidence of pulmonary fibrosis and other end
                                                           organ toxicities. At the dose we use for atrial fibrillation, it is 200
                                                           mg/day, which is one pill, or even 200 mg every other day, the
                                                           incidence of these side effects are very low. The side effects are
                                                           reversible. In patients that have failed other drugs and patients that
                                                           have LV dysfunction, amiodarone is the drug of choice.

                                                           Amiodarone is a very unique drug. The half-life is one month to five
                                                           months. It is a very lipophilic drug so when you give it to people it
                                                           immediately gets sucked up into their fat stores. Start with a much
                                                           higher dose and then we cut the dose back. Start them on 800
                                                           mg/day for about two weeks, then I will put them on 400 mg/day for
                                                           about a month, then cut them back down to 200 mg/day. Results
                                                           have been very good. Patients have tolerated it well and it clearly
                                                           works much better than other agents. Anybody over 70 who pres-
                                                           ents with atrial fibrillation or who has any LV dysfunction, should be
                                                           started on amiodarone as a first line agent.




                                                                                                                                12
         No Structural Heart Disease
                                                       If you have a patient that has no structural heart disease with lone
                                                       AF, they are very symptomatic, you don't want to leave these
€ First-line agents                                    people in AF all the time and make them take aspirin and have
                                                       them in atrial fibrillation. You can give them drugs to try to maintain
   •   Class IC (flecainide, propafenone)
                                                       sinus rhythm. We have had a lot of success with flecainide in this
   •   Disopyramide (especially if vagally mediated)   population. Norpace is very good especially in vagally mediated AF.
                                                       There is a group of patients who get atrial fibrillation after they eat
€ Second-line
                                                       big meals or they wake up in the middle of the night. Vagal surges
   •   Sotalol                                         change the electrophysiologic properties of the atrium and make it
                                                       more susceptible to atrial fibrillation. Norpace has some vagolytic
€ Third line
                                                       effects and may be effective in those patients. Second line, Sotalol
   •   Amiodarone                                      is often good in these patients, and you can use amiodarone.




                                                                                                                           13
            Ischemic Heart Disease
                                     In patients with ischemic heart disease, the class 1C drugs should
                                     be avoided. Sotalol may be a good drug. The beta blocking proper-
€ First-line:                        ties are good for the ischemic patient, and amiodarone is a good
                                     agent in those patients.
   •   Sotalol
€ Second-line:
   •   Amiodarone
€ Avoid class IC




                                                                                                     14
                CHF/LV Dysfunction
                                        In the patients with CHF and LV dysfunction, you have to avoid
                                        those drugs that are proarrhythmic. Amiodarone may be the best
€ First-line:                           drug in these patients because you get the added protection from
                                        sudden death. You should also consider the non-pharmacologic
   •   Amiodarone
                                        approach in these patients because you may see an increase in LV
€ Consider non-pharmacologic approach   function after you control their rate with ablation and regularize their
                                        ventricular response with pacing.
€ Avoid class IC




                                                                                                              15
                       LVH/HCM
                                               In patients that have left ventricular hypertrophy or hypertrophic
                                               cardiomyopathy, class 1C agents are also good. Disopyramide is
€ First-line                                   specifically good in patients with hypertrophic cardiomyopathy
                                               because of the negative inotropic effects. It may decrease the
   •   Class 1C (flecainide, propafenone)
                                               gradient. Sotalol also is very good in these patients, and
€ Second-line:                                 amiodarone is good. In patients with hypertrophic cardiomyopathy,
                                               you should consider non-pharmacologic management, such as
   •   Sotalol
                                               ablation, because dual-chamber pacing will decrease the pressure
   •   Amiodarone                              gradient so you get the added benefit of those two things.
€ Consider nonpharmacologic management (HCM)




                                                                                                                16
Outpatient loading of antiarrhythmic medications utilizing a monitoring device is probably safe and cost-effective. Patients get their
first dose of the drug in the hospital, and then were sent out with a loop recorder for 10 days. Every day they transmit a tracing of
their heart rate and their QT interval and they also transmit any palpitations or any adverse effects that they had.

Prophylactic pacing for atrial fibrillation. It is thought that atrial fibrillation is due to multiple re-entrant wave fronts throughout the
atria. Excitation and therefore prolongation of the refractoriness of the tissue in the critical regions of the atrium may prevent the
initiation or maintenance of atrial fibrillation. If you stimulate the heart in more than one place, you may be able to prevent these re-
entrant wave fronts and prevent atrial fibrillation. There are trials that have looked at patients with sick sinus syndrome that got either
dual chamber pacers or ventricular pacers alone. The studies showed that in patients that had atrial pacing, it was a significantly
much lower incidence of atrial fibrillation that had active atrial pacing suggesting that somehow pacing the atrium will decrease the
incidence of atrial fibrillation.

Implantable ventricular defibrillators. This is a device that goes in the pectoral region, has two leads in the right atrium. One in the
right atrium, one in the coronary sinus and one for R-wave synchronization in the RV apex. It is used to cardiovert people out of atrial
fibrillation. It can be done when you have two leads inside the heart like this and you are not shocking externally and you are not
stimulating skeletal muscle. The amount of energy required is only in some patients 0.5 Joule or 1 or 2 Joule. So, although in some
patients that causes a fair amount of discomfort, in some patients it doesn't and the idea of atrial defibrillators are being tested right
now. The big questions are safety. The first patient that has an atrial defibrillator that gets shocked or it fails and they get put into VF
and then dies, that will be the end of the whole idea.

Surgical treatment of atrial fibrillation. The Maze procedure consists of multiple atriotomies which interrupt all the potential re-entrant
circuits. This will restore control of the heartbeat to the atrial pacemaker, which is the sinus node, and it allows activation of the entire
atrial myocardium. The long term results are unclear.

Atrial flutter. Typical atrial flutter is characterized by the typical saw-tooth flutter wave in the inferior leads beneath the positive flutter
wave in lead V1. It is a macroreentrant electrical rhythm confined to the right atrium. So, the electrical wave front goes around the
right atrium, up the septum, down the lateral wall and through this isthmus of tissue between the opening of the IVC and the tricuspid
annulus and the coronary sinus. If we can create a line of conduction block, the patient should not have atrial flutter anymore.

We are now able to terminate atrial flutter and cure people that have typical atrial flutter in about 95% of cases. Antiarrhythmic drugs
are not very effective for atrial flutter, and rate control is much more difficult in atrial flutter than atrial fibrillation because it is hard to
get a reasonable rate control. When somebody presents with atrial flutter for the first time, cardioversion is recommended, and then
the patients are discharged and observed to determine what the natural history is going to be. If they are not going to have atrial
flutter for the next five years, no treatment is necessary. The first time they return with atrial flutter, if it is early on, the first line of
therapy now is ablative therapy and our success rate is very good and the risk is low.




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