Dr. [Andrew Healey, MD] and colleagues suggest that "one still ought to avoid adenosine in these instances." As quoted by the correspondents, adenosine may be dangerous in WPW syndrome patients with pre-excited atrial fibrillation by increasing the frequency of accessory connection conduction of atrial fibrillation, thereby predisposing the patient to the development of ventricular fibrillation (VF). In the cases cited by Dr.
LETTERS • CORRESPONDANCE Safety first — sedate and this is VT. Although not polymorphic, has grave risks associated with its use. shock the addition of sotalol would increase the We suggest that when an article is pub- pretest likelihood of VT as well. lished one should concern themselves To the editor: Mitchell and Lazarenko If indeed the authors’ logic is correct with the message that is delivered to recently authored a diagnostic challenge and the remaining differential includes the typical emergency physician, and in the November 2008 issue of CJEM.1 supraventricular tachycardia (SVT) therefore should project a message that We thank the authors for providing this with aberrancy by way of an accessory is safe and effective. worthy topic for discussion and con- pathway, one still ought to avoid aden- In this case, no one should close the gratulate them on their publication. osine in these instances. There are sev- journal thinking that through cannon However, with due respect, we take eral reports of ventricular fibrillation atrial waves associated with beat-to- considerable issue with several of the associated with adenosine therapy, beat systolic variability and Brugada conclusions reached in this article and in both Wolff–Parkinson–White syn- criteria that they can differentiate these ultimately with the answer to the diag- drome2–4 and in the treatment of VT.5 2 entities in the chaos of the emergency nostic challenge. Although it is alluded The safest approach in this setting department. Let us put the safety of our to as a possible treatment twice in the would be electrical cardioversion or, in patients first and the vanity of superior discussion, we assert that the safest ap- a stable patient, procainamide.6 academic skills second. proach for the emergency physician is We thank the authors for their com- Sedate and shock this rhythm — be to treat all wide complex tachycardia as ments regarding the application of the safe. ventricular tachycardia (VT). Brugada criteria. The originally re- As with many situations in emer- ported sensitivity and specificity were Andrew Healey, MD gency medicine, when a patient pre- 95.7% and 96.5%,7 which have never PGY5, Emergency Medicine/Critical Care Resident, McMaster University, sents with an unstable wide complex been externally reproduced. Two re- Hamilton, Ont. dysrhythmia, we are forced to make de- ports have failed to replicate these Mark Mensour, MD, FCFP cisions without the benefit of much of numbers in the hands of cardiologists Assistant Professor, Emergency the information referenced within the or emergency physicians, suggesting Medicine, Northern Ontario School article. The assessment for the presence even less broad applicability in the of Medicine, Huntsville, Ont. of cannon atrial waves or variability of emergency setting.8,9 These numbers Thomas Marshall, MD the first heart sound requires clinical are not sufficient to exclude VT, partic- Staff Emergency Physician, acumen well beyond even the expert ularly when considering verapamil or St. Joseph’s Healthcare, Hamilton, Ont. emergency physician. In fact, the addi- diltiazem as a potential therapy. tional criterion of variability in beat-to- Even if these numbers were accept- References beat systolic blood pressure requires able to some practitioners (which is 1. Mitchell J, Lazarenko G. Wide QRS the placement of an arterial catheter, where our concerns lie), life-threaten- complex tachycardia. CJEM 2008;6: 572-3. which is impractical and unnecessary in ing consequences of misdiagnosing 2. Gupta AK, Shah CP, Maheshwari A, many instances. VT as SVT with aberrancy are unac- et al. Adenosine induced ventricular Electrolytes are rarely available and ceptable when the therapy of choice fibrillation in Wolff-Parkinson-White toxicology screens are rarely helpful. for VT works equally well for SVT syndrome. Pacing Clin Electrophysiol 2002;25:477-80. The authors state that the toxicology with aberrancy with very little added 3. Gallagher JJ, Sealy WC, Kasell J, et al. screen was negative, which we believe potential for harm. The authors cor- Multiple accessory pathways in patients to be relatively un
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