Clinical and echocardiographic outcomes of sync-atrioventricular versus nominal optimization in correlation with QRS narrowing among CRT patients.

BACKGROUND

Cardiac resynchronization therapy (CRT) has been established as a key component in the management of patients with heart failure (HF) with reduced ejection fraction in addition to pharmacologic therapy. Several automatic algorithms have been developed to optimize the timing cycle settings in CRT, especially AV delay which was associated with improvement of the response to CRT. The present study aims to investigate whether the novel device-based SyncAV algorithm could elicit better synchrony and acute hemodynamic response.

METHODS

Thirty-six patients (age 52.81 ± 14.45 years; 69% male; 27% with ischemic cardiomyopathy; LV ejection fraction 24.81 ± 5.87%; QRS duration173.64 ± 15.99 ms) with intact atrioventricular conduction (PR interval 184.69 ± 15.43, range 150-210 ms), left bundle branch block, undergoing CRT implantation were prospectively studied. The device was programmed to two biventricular (BiV) pacing modes after the procedure: Nominal AV delay (140/110 ms) optimization (Group A), and SyncAV algorithm with optimized offset minimizing QRS duration (QRSd) (Group B). After each setting, clinical electrocardiographic, and echocardiographic data were collected at 1- and 6-months post implantation.

RESULTS

The intrinsic QRSd (171.50 ± 16.32 ms) was reduced to161.17 ± 19.89 ms after 1 month and to 157.44 ± 24.51ms after 6 months among group A, However, intrinsic QRSd ( 175.78 ± 15.82 ms ) was reduced to 154.00 ± 14.62 ms after 1 month and to 141.00 ± 16.45 ms after 6 months among group B [P < 0.001 versus nominal mode]) with significant improvement in clinical and echo criteria and without QRSd prolongation in any patient.

CONCLUSION

Post-implant electrical optimization in already well-selected patients with left bundle branch block and optimized LV lead position is facilitated by patient-tailored BiV pacing adjusted to intrinsic atrioventricular timing using an automatic device- based algorithm.