Atrial activity and ventricular tachycardia

Patient

67-year-old patient with dilated cardiomyopathy, ejection fraction of 40%, hospitalized for palpitations;

Trace

This tracing of wide QRS tachycardia illustrates the difficulty in locating and identifying the atrial activity in order to arrive at the diagnosis based on the relationship between atria and ventricles; the positive concordance in the precordium (QRS complexes all positive from V1 to V6) is highly suggestive of the diagnosis of ventricular tachycardia (low probability of having a left bundle branch block type aberration with a positive V1; low probability of having a of right bundle branch block without wide S waves in V6);

Trace

Young patient of 27 years of age, with no prior history, presenting palpitations; on this tracing, we find the characteristics of a typical fascicular ventricular tachycardia (relatively narrow QRS, left delay, left axis); the ventricular rhythm is not very rapid and the atrial sinus activity can be clearly identified (positive P wave in leads II, III, aVF) which is dissociated during tachycardia (slower than the ventricular activity);

Trace

76-year-old patient with ischemic cardiomyopathy implanted with a defibrillator, presenting recurrences of tachycardia; on this first tracing, there is a wide QRS tachycardia, the atrial activity being difficult to pinpoint; the tachycardia is of the right delay type, left axis; the pattern in V6 (in the absence of any antiarrhythmic treatment) is highly suggestive of ventricular tachycardia;

Trace

The patient underwent an antitachycardia pacing burst delivered by the defibrillator; this allows the interruption of the tachycardia and reveals a very wide spontaneous QRS (different from that observed in tachycardia) and an atrial fibrillation; this patient therefore had a bitachycardia (atrial fibrillation + ventricular tachycardia); in this setting, only the QRS pattern allows making the differential diagnosis;

Trace

Patient with surgically-repaired tetralogy of Fallot; wide QRS tachycardia, left delay with 1:1 retrograde conduction (negative P' wave clearly visible behind each QRS in lead II);

Trace

69-year-old patient with ischemic cardiomyopathy; wide QRS tachycardia, left delay, extreme-left axis (not compatible with a conduction aberration) with 2:1 retrograde conduction

Trace

24-year-old man with no prior cardiovascular history; palpitations; tachycardia with moderately widened QRS complexes, right delay, left axis; benign fascicular tachycardia; probable retrograde conduction; there are 3 echoes on this tracing which confirm the diagnosis of ventricular tachycardia: wide QRS complex, retrograde conduction and ventricular capture (complex slightly premature compared to the tachycardia cycle with narrow QRS);

Exergue

During a ventricular tachycardia, there may be an atrioventricular dissociation (most common case), a 1:1 retrograde conduction, a 2:1 retrograde conduction or with Wenckebach pattern, a bitachycardia (VT + SVT).