213 Does continuous assessment of heart rate variability by devices provide prognostic information in cardiac resynchronization therapy patients?

Abstract

Heart failure remains a severe disease with high mortality despite pharmologic treatment and new successful therapy options such as cardiac resynchronization therapy (CRT). Heart rate variability (HRV), which reflects autonomic nervous system function, is a prognostic marker in chronic heart failure. It can be easily and continuously assessed by CRT devices but its prognostic value is not well known in these patients. The relationship between HRV and morbimortality was examined in a retrospective study concerning 34 patients who received CRT devices between july 2002 and february 2008. HRV footprint and standard deviation of averaged normal R to R intervals (SDANN) was continuously measured by devices. The study showed an overall improvement in SDANN (71,8 ± 18,3 to 87,6 ± 29 ms, p=0,002) and HRV footprint (33,5 ± 9,2 to 37,5 ± 9%, p=0,013) after resynchronization. During a median of 17,7 months of follow up, 26% (9/34) patients died or were hospitalised for acute heart failure. SDANN and HRV foorprint at the time of device implantation were not predictors of morbimortality. Improvement of SDANN > 5% after resynchronization was predictor of survival free from event (p<0,0001). Continuous assessment of SDANN by devices may be a useful tool for risk stratification in CRT patients.