Direct discrimination and full-day disclosure of ventricular parasystole on new heart rate tachograms

Tachographic Discrimination of Parasystole. Introduction: To discriminate v entricular parasystole from fixed coupling interval ventricular premature c omplexes (VPCs), we developed a new diagnostic method using a dot distribut ion pattern corresponding to VPCs recorded on a heart rate tachogram using ambulatory ECG monitoring data. We tested our hypothesis that widely scatte red VPC dots on instantaneous heart rate tachograms indicate a constant VPC -VPC interval compatible with parasystole, Methods and Results: Patients with frequent VPCs > 5,000/day were divided i nto two groups depending on the tachogram dot distribution patterns: group S (n = 10, aged 61 a 16 years) showed widely scattered VPC dot distribution , whereas group F (n = 10, 60 +/- 17 years) showed fixed VPC dot distributi on limited to a narrow zone. Using digitized R-R interval data, full-day he art rate tachograms and VPC-VPC intervals were depicted simultaneously. Gro up S demonstrated constant basic VPC-VPC intervals (1,285 to 2,052 msec, me an 1,738 +/- 219), with a coefficient of variation (CV) of 0.061 +/- 0.018. Their VPC coupling intervals were markedly variable (651 +/- 113 msec; CV = 0.193 +/- 0.034), Each patient's basic VPC-VPC intervals showed small diu rnal alterations (minimum -13% +/- 3% to maximum +15% +/- 6%), VPC-VPC inte rvals in group F were not constant and showed marked variation. Group F VPC coupling intervals were shorter and constant (480 +/- 30 msec, P = 0.0002; with CV = 0.076 +/- 0.013, P < 0.0001). Conclusion: Ventricular parasystole with constant VPC-VPC intervals consist ently became evident based on VPC dot patterns recorded on heart rate tacho grams.