Permanent left atrial pacing therapy may improve symptoms in heart failure patients with preserved ejection fraction and atrial dyssynchrony: a pilot study prior to a national clinical research programme

Aims Our group has recently shown that in some patients, heart failure with preserved ejection fraction (HFPEF) may be explained by ‘atrial dyssynchrony syndrome’ (ADS) due to interatrial conduction delay (IACD), a short left atrioventricular interval (LAVI), and increased left atrial (LA) stiffness. Our primary objective was to evaluate LA pacing therapy as a new treatment to restore left ventricular active filling in patients with no other known causes for HF than ADS. Methods and results Six patients with severe HFPEF with IACD (P wave duration >120 ms in lead II), short LAVI during electrophysiological studies ( 15), and no standard indication for a pacemaker were implanted with a lead screwed inside the coronary sinus for active LA pacing. After 3 months of active pacing, a 2 week randomized double-blind crossover phase compared active vs. inactive LA pacing. After 3 months of pacing, the mean distance walked in 6 min (6MWD) was 21% greater (240 ± 25 m vs. 190 ± 15m, P < 0.05), mitral A wave duration was longer (104 ± 8 vs. 158 ± 25 ms, P = 0.002), and E/A and E/e' ratios were smaller (3.4 ± 1.3 vs. 1.8 ± 0.9, P = 0.009, and 22.6 ± 4.6 vs. 15.3 ± 4.3, P = 0.006, respectively). Inactivation of pacing for 1 week led to a significant reduction in the 6MWD, with an on/off response. Conclusion The beneficial effects of LA pacing observed in this pilot study will have to be confirmed by the randomized, controlled crossover ‘LEAD’ study.