Pre-ectopic vagal tone affects heart rate turbulence slope in heart failure

Cardiovascular oscillations following spontaneous ventricular premature complexes (VPC) are described by the so-called heart rate turbulence (HRT) onset (TO) and slope (TS). Since HRT is a marker of baroreflex sensitivity, it can be hypothesized to be affected by the preceding VPC sympatovagal balance (pHF). The aim of this study is to investigate the relationship between HRT parameters and pHF in heart failure (HF) patients. We studied 75 24h ECG Holter recording of HF patients (62±9 years) performing a Spearman correlation analysis between TO, TS and pHF values. According to risk stratification standards, each post-VPC response was classified in 0-normal type or 1-abnormal category. Results showed a 53%, 27%,5%,6% of post-VPC respectively 0, 1a, 1b, 2-category, and a remaining 9% unclassified T0=0 values. pHF showed a moderate to good significant (p<;0.0001) positive correlation with TS, ranging from r=0.5 to 0.6 in 0- and 1a-category, weaker correlations has been found between pHF and T0. Conclusions demonstrated that while the early HRT phase do not seem to depend on preceding VPC sympathovagal balance, pre-ectopic vagal tone affects HR late recovery slope in HF, with correlation patterns related to different post-VPC response type.