Analysis of the QRS pattern for diagnosing ventricular tachycardia

Patient

62-year-old man with severe dilated cardiomyopathy; syncopal episode;

Trace

Wide QRS tachycardia; highly fragmented QRS, extreme-right axis; the negative concordance in the precordium (QRS all negative from V1 to V6) is strongly suggestive of the diagnosis of ventricular tachycardia (low probability of having a left bundle branch block-type aberration with a negative QRS in V6; low probability of having a right bundle branch block with negative QRS in V1);

Trace

67-year-old patient with dilated cardiomyopathy, ejection fraction of 40% hospitalized for palpitations; on this tracing, the identification of the atria is difficult; the positive concordance in the precordium (QRS all positive from V1 to V6) is suggestive of the diagnosis of ventricular tachycardia (low probability of having an left bundle branch block-type aberration with a positive V1; low probability of having a right bundle branch block without wide S waves in V6);

Trace

81-year-old patient with severe ischemic cardiomyopathy; the electrocardiogram shows a wide QRS tachycardia; left delay, right axis; certain elements of this tracing are suggestive of a ventricular tachycardia: right axis, interval of 100 ms between the beginning of the QRS and nadir of the S wave in V2;

Trace

64-year-old man with ischemic cardiomyopathy; wide QRS tachycardia with right delay, left axis; in the setting of a tachycardia with left delay, certain elements are suggestive of a ventricular tachycardia: monophasic pattern (exclusive R) in V1, S wave taller than R wave in V6, left axis deviation; analysis of atrial activation shows a 1:1 retrograde conduction;

Trace

71-year-old patient with an extensive anterior infarction ten years prior with major alteration of left ventricular ejection fraction and apical aneurysm; syncope; the electrocardiogram shows a wide QRS tachycardia; left delay, left axis; certain elements of this tracing are suggestive of a ventricular tachycardia: q wave and qR pattern in V6; greater negative deflection in V2 and V3 than in V1; slow notched intrinsicoid deflection in V1; notch present in the descending branch of the S wave in V1; interval between the beginning of the QRS and nadir of the S wave > 80 ms in V1; a 2:1 retrograde conduction confirms the diagnosis of ventricular tachycardia (P' wave present in 1 QRS out of 2);

Trace

The sinus rhythm electrocardiogram recorded in this patient shows extensive anterior necrosis with persistent elevation (inferior territory and anterior territory) attesting to the left ventricular aneurysm;

Exergue

In the presence of a wide QRS tachycardia, various electrocardiographic criteria can be used to differentiate ventricular tachycardia from supraventricular tachycardia with conduction aberration: an identical QRS pattern in sinus rhythm and in tachycardia is suggestive of a supraventricular origin; the detection of capture or fusion complexes confirms the diagnosis of ventricular tachycardia; the presence of atrioventricular dissociation is quasi-pathognomonic of ventricular tachycardia. In absence of these criteria, analysis of the QRS pattern may allow discriminating the origin of the arrhythmia (typical bundle branch block pattern indicative of a supraventricular origin, distant pattern of a bundle branch block indicative of a ventricular origin).