The chameleon on the electrocardiogram

Introduction: Differentiation between ventricular tachycardia and supraventricular aberrant tachycardia remains an old dilemma and nevertheless a current challenge in current clinical practice. The therapeutic decision is closely related with the differentiation of the two entities, since misinterpretation of ventricular tachycardia as supraventricular may be fatal.
Case presentation: We present the case of a 60-year-old, smoker, hypertensive, diabetic, with ischemic heart disease (inferior myocardial infarction, quadruple co-ronary artery bypass graft and mitral valvuloplasty for severe ischemic mitral regurgitation – 2005), presenting in the emergency department for anterior chest pain highly suggestive of angina, on the electrocardiogram a broad complex tachycardia being registered.
Methods: On admission, the patient had angina, BP=170/80 mmHg. The electrocardiogram showed re-gular wide complex tachycardia 225 bpm, right bundle branch block morphology, interpreted as ventricular tachycardia. The presence of angina required the administration of an external electric shock with return to sinus rhythm. On echocardiography the left ventricle had akinesia of the inferior and lateral walls, achieving a moderately depressed global systolic function (EF=38%). The emergency coronary angiography revealed the occlusion of the four bypasses, but with the native right and anterior descending coronary arteries without significant stenosis and without indication of revascularization. We chose Amiodarone loading and electrophysiological study in order to ablate the broad complex tachycardia. In the electrophysiological study, non-sustained ventricular tachycardia with two different morphologies (right and left bundle branch block) was induced by programmed ventricular stimulation. The surprise element occurred at programmed atrial stimulation when atrial tachycardia with 1: 1 atrioventricular conduction was induced, with the same morphology as broad complex tachycardia for which the patient was addressed. We mention that on the re-sting electrocardiogram the patient has preexisting right bundle branch block. The first depolarization was at the upper right atrium level in the anterolateral region, where a fragmented, split potential, suggestive of postoperative atrial scarring was documented. Radio-frequency ablation at that level interrupted the reentrant microcircuit.
Conclusions: In most of the cases, a wide complex tachycardia in a patient with known ischemic heart disease, who presented in the emergency department for ongoing chest pain and cardiac enzyme rise, should be foremost interpreted as ventricular tachycardia in the setting of an acute coronary syndrome, rather than paroxysmal supraventricular tachycardia with aberrant conduction that precipitates angina.
Particularity of the case: T he incision made for mitral valvuloplasty in 2005 was correlated with the scar described at the ablation procedure and also with the myocardial strain of the right atrium.

ISSN – online: 2734 – 6382
ISSN-L 1220-658X
ISSN – print: 1220-658X
The Romanian Journal of Cardiology is indexed by:
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CODE: 379
CME Credits: 10 (Romanian College of Physicians)