Biventricular pacing

Patient

74-year-old man with severe dilated cardiomyopathy and complete atrioventricular block with implanted Medtronic triple chamber defibrillator; right ventricular pacing lead in septo-apical position and left ventricular pacing lead in lateral wall; significant improvement in symptoms and ejection fraction;

Trace

The patient is paced at the ventricular level with synchronization on spontaneous atrial activity; this therefore entails either a DDD or VDD mode (ability to detect the atrium and to trigger an AV delay in order to pace the ventricle or ventricles); the QRS is relatively narrow with a negative pattern in lead I and positive pattern in V1 which suggests effective left ventricular capture (not compatible with right septo-apical ventricular capture alone and no possibility of fusion with spontaneous activation in this patient presenting an atrioventricular block);

Trace

Tracing recorded after the programming of left ventricular pacing only; QRS aspect much wider than during biventricular pacing with clear negative deflection in lead I and positive deflection in V1 compatible with the lateral position of the pacing lead;

Trace

Tracing recorded after the programming of right ventricle only pacing; QRS pattern wider than during biventricular pacing with clear negative deflection in the inferior leads compatible with the apical position of the pacing lead;

Exergue

During biventricular pacing, a positive pattern in V1 and/or negative pattern in lead I is very suggestive of effective left ventricular capture when the right ventricular pacing lead is positioned at the apex. A single high or outflow right septal pacing can also yield this particular pattern thus limiting the effectiveness of these criteria in determining a loss of left ventricular capture.