Fusion CRT pacing: septal flash significance in super responder patients

Abstract

Background LV only CRT pacing is an option that may be considered to maximize response to CRT and at least as an alternative in non-responders to biventricular (BiV) pacing. However, criteria to best titrate therapy on an individual basis are lacking in fusion pacing. On the other hand, septal flash (SF) is a strong predictor of favorable response for patients (pts) with BiV pacing. Purpose To analyze the relationship between SF and the response to fusion CRT pacing. Methods Consecutive pts with exclusive fusion CRT-P were included. Right atrium/left ventricle leads DDD CRT pacing system were used in all patients. Prospective data were collected at every 6 months follow-up visits: device interrogation, exercise test, echocardiographic parameters. Exercise tests, device reprogramming and medication optimization were performed regular in order to maximize CRT response. Patients were divided in 2 groups: super-responders (SR) and responders (R). SRs were defined those with left ventricular end-systolic volume (LVESV) improvement ≥30% and stable ejection fraction (LVEF) ≥45%. Results 69 pts with NYHA II–III heart failure and non-ischemic dilated cardiomyopathy were initially included. 5 pts were non responders and excluded (non LBBB, spontaneous QRS <149 ms). Final analyzed group had 64 pts (35 male) aged 60±12 y.o. The mean follow-up was 54±19 months; 22 pts (34%) were SRs. At baseline, SF was found in all SR pts and in 55% of R pts. SF was corrected post CRT in all patients, except one. For this patient (LV lead in a posterior branch of the coronary sinus – CS) the strategy included an upgrade to triple chamber device with a second lead in a lateral branch of the CS and became SR from R. Mitral regurgitation decreased in 38 patients (all SR, 40% R). Interesting, baseline left atrium volume and pulmonary sistolic artery pressure were smaller in SR versus R group, however SF did not corelate with LA volume/diastolic dysfunction. Conclusions Septal flash seems to be a strong predictor of super-response in patients with fusion CRT pacing. This finding could improve the selection of candidates for fusion CRT-P, however larger studies are needed to assess SF in this categories of patients. Funding Acknowledgement Type of funding sources: None.