24 hour variability of ventricular premature beats coupling interval in patients with ischemic heart disease

The study was designed to analyse the diurnal variations of coupling interval of ventricular premature beats (VPBs) in 12 patients with ischemic heart disease and frequent VPBs. 24 hour ECG recordings and analyses were performed using commercially available system and software. Data were compared in six epochs of 4 hour period each. In total 72 epochs were analysed. The coupling interval of VPBS varied throughout 24 hours and reflected those of RR interval. Greater differences were found in 5% values of PVBs-CI ranged from 435±46 ms at 10 AM to 484±61 ms at 10 PM (p<0.001). Standard deviation of PVBs-CI ranged from 73.8±47.7 ms at 6 AM to 52.3±22.8 at 2 PM (ns). Longer PVBS-CI, as well as greater standard deviation of CI were found in patients with low ejection fraction, non-sustained VT or in those, who subsequently died. It is concluded that evaluation of variability of coupling interval of PVBS from 24 hour ECG recodings may be a novel tool for quantifying ventricular arrhythmia