Copyright © 1994 by the European Society of Cardiology.
© 1994 The European Society of Cardiology
Late Potentials and Heart Rate Variability in Heart Muscle Disease
Medical clinic and policlinic B of the Heinrich-Heine-University Düsseldorf, Germany
* Computing center of the Heinrich-Heine-University Düsseldorf, Germany
Correspondence: Ernst Günter Vester, MD Medizinische Klinik und Poliklinik B, Abteilung für Kardiologie, Pneumologie und Angiolgie der Heinrich-Heine-Universität Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf 1, Germany
To elucidate the incidence and clinical significance of ventricular late potentials (LP) and reduced heart rate variability (HRV) in primary and secondary heart muscle disease, 157 patients with dilated cardiomyopathy (DCM, n = 19), chronic myocarditis (MC, n = 50), hypertrophic cardiomyopathy (HCM, n = 27) and systemic hypertension (HT, n = 61) were studied. LP measured by the signal averaging technique were found in 24% of the total study group—47% of the patients with DCM, 28% with MC, 29% with HCM and 10% with HT. Complex ventricular arrhythmias were detected during Holter monitoring in 56% of patients with DCM, in 41% with MC, in 21% with HT and in 16% with HCM. An electrophysiological study was performed in a total of 75 patients. Non-sustained or sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) were inducible during programmed ventricular stimulation in 32% of patients with MC, in 30% with HT, in 20% with DCM and in 17% with HCM. The total duration of the signal-averaged, filtered QRS complex was the only independent predictive factor for severe arrhythmic events and sudden cardiac death. HRV measured in 39 patients were most reduced in patients with DCM (RR interval standard deviation (HRV-SD) 39 ± 23 ms), followed by 44 ± 16 ms in patients with HCM, 45 ± 28 ms in patients with HCM and 67 ± 51 ms in patients with HT. A significant reduction in the HRV-SD below 30 ms was recorded in 24% of patients measured. There was only a non-significant trend towards a higher occurrence of LP and a more pronounced reduction of HRV-SD with decreased LV ejection fraction and increased LV muscle mass. End-systolic LV volume was significantly increased in patients with a HRV-SD below 30 ms. A longer sigmlaveraged QRS duration was associated with a lower HRV-SD. Spontaneous sustained ventricular tachycardia or aborted sudden cardiac death due to ventricular fibrillation occurred in 17patients (11% of the cohort). Sustained VT or VF were inducible during programmed ventricular stimulation in 7/79 (9%) patients tested. The sensitivity of LP amlysis in spontaneous and in inducible severe ventricular tachyarrhythmias was 53% and 86%, the specificity 80% and 57%, the positive predictive value 24% and 16% and the negative predictive value 93% and 98%, respectively. In conclusion, the incidence of LP is higher in patients with DCM than in patients with MC, HCM or HT, independent of LV function and mass. LP have a weak positive predictive value and a strong negative predictive value for spontaneous and inducible arrhythmias. In contrast, HRV is more predictive of LV failure and enlargement than of ventricular ectopy. The value of impaired HRV for predicting sudden cardiac death remains to be determined.
Key Words: Ventricular late potentials • heart rate variability • dilated cardiomyopathy • myocarditis • hypertrophic cardiomyopathy • hypertension • ventricular arrhythmias • sudden cardiac death