Extrasystolic stimulation with bi-ventricular pacing: an acute haemodynamic evaluation.

Aims: Cardiac resynchronization therapy (CRT) by means of biventricular pacing (BiVP) is well established as a treatment for patients with heart failure (HF). Post-extrasystolic potentiation, (PESP) which involves a transient increase in myocardial contractility following a ventricular extrasystole, can be achieved using extrasystolic stimulation (ESS). On this basis, ESS has been proposed as a therapeutic. We assessed acute haemodynamic effects of ESS in the context of BiVP.

Methods And Results: Patients (n = 15, left ventricular ejection fraction < 40%, QRS ≥ 125 ms) with HF, received BiVP in combination with right ventricular (RV) ESS (single stimulus or pulse train). Left ventricular (LV) and peripheral arterial pressures were recorded and dP/dt was monitored. Addition of RV ESS to BiVP pacing led to a 21% increase in maximum (max) dP/dt (P < 0.001) and an 8.5 mm Hg increase in a systolic arterial pressure (P < 0.001). The modest fall in end-diastolic pressure (3.3 mmHg, P < 0.001) observed during ESS and BiVP was prevented by maintaining baseline sinus rate. Varying ESS modes or pacing outputs was not associated with differences in haemodynamic parameters.

Conclusions: Biventricular pacing in combination with ESS, with maintenance of sinus rate, improves myocardial contractility in patients undergoing CRT.