Acute Effects of Biventricular Pacing in Heart Failure Patients with a Normal Ejection Fraction and Mechanical Dyssynchrony

Abstract

Objectives: We tested the acute effects of resynchronization in heart failure patients with a normal (>50%) left ventricular (LV) ejection fraction (HFNEF) and mechanical dyssynchrony. Methods: Twenty-four HFNEF patients (72 ± 6 years, 5 male) with mechanical dyssynchrony (standard deviation of electromechanical time delay among 12 LV segments >35 ms) were studied with temporary pacing catheters in the right atrium, LV, and right ventricle (RV), and high-fidelity catheters for pressure recording. Using selected atrioventricular (AV) intervals of 60, 90, 120, 150, and 180 ms to optimize transmitral flow during simultaneous biventricular pacing, the RV-LV (VV) interval was then evaluated at RV30, RV15, 0, LV15, LV30, and LV45 (RV or LV indicates which ventricle was paced first, the number indicates by how many ms). Results: During simultaneous pacing, longer AV intervals were associated with improved LV pressure-derivative minimums and increased aortic pressures (p < 0.05 vs. normal sinus rhythm). In the VV interval from RV30 to LV45, there was a graded increase in the aortic velocity time integral and a decrease in dyssynchrony during simultaneous or LV-first pacing (p < 0.05 vs. normal sinus rhythm). Conclusions: For HFNEF patients with mechanical dyssynchrony, acute simultaneous biventricular or LV-first pacing with longer AV intervals reduced mechanical dyssynchrony and improved diastolic and systolic hemodynamics.

Clinical outcomes according to QRS duration and morphology in the irbesartan in patients with heart failure and preserved systolic function (I‐PRESERVE) trial

“…This intervention, however, has recently been tested in a small trial involving 24 participants with HF‐PEF, normal QRS duration on electrocardiography and features of mechanical dyssynchrony on echocardiography. The results showed signs of improved ventricular relaxation accompanied by a small but significant improvement in diastolic and systolic haemodynamics at longer atrioventricular pacing intervals during biventricular, or isolated left ventricular pacing . It is therefore possible that CRT might be beneficial in patients with interventricular dyssynchrony, as demonstrated by QRS prolongation .…”

“…The results showed signs of improved ventricular relaxation accompanied by a small but significant improvement in diastolic and systolic haemodynamics at longer atrioventricular pacing intervals during biventricular, or isolated left ventricular pacing. 25 It is therefore possible that CRT might be beneficial in patients with interventricular dyssynchrony, as demonstrated by QRS prolongation. 7 Clearly, however, this hypothesis would need to be tested in a randomized clinical trial.…”