Objective: Evaluation of the significance of the Wedensky Modulation (WM) examination for ventricular tachyarrhythmias (VT) in patients with coronary artery disease and implantable cardioverter-defibrillator therapy (ICD).
Design: Prospective, single-centre study conducted from 2004 to 2006.
Setting: University of Bonn, Department of Medicine - Cardiology, Bonn, Germany.
Patients: 37 consecutive patients with coronary artery disease receiving an ICD for primary or secondary prevention.
Main outcome measures: Correlation of a positive WM-Index (WMI) with established non-invasive Holter parameter, the occurrence of VT after ICD implantation with regard to primary or secondary prevention, and inducibility of VT during electrophysiological (EP) studies.
Results: The WMI was positive in 15 patients (67 (SD 8) years, 31% (SD 12%) EF) and showed significant correlation with heart rate variability (standard deviation of normal to normal intervals (SDNN): 143 (SD 80) ms vs 102 (SD 29) ms, p = 0.04, r = 0.45; total power (TP). 11 885 (SD 19 674) ms(2) vs 2229 (SD 1779) ms(2), p = 0.03, r = 0.384; very low frequency component (VLF): 2777 (SD 3039) ms(2) vs 1184 (SD 565) ms(2), p = 0.03; low frequency component (LF): 2955 (SD 5734) ms(2) vs 468 (SD 725) ms(2), p = 0.05, r = 0.375; high frequency component (HF): 4885 (SD 9939) ms(2) vs 382 (SD 609) ms(2), p = 0.05, r = 0.315) and turbulence (turbulence onset (TO): -0.002 (SD 0.008) vs +0.005 (SD 0.01), p = 0.05, r = 0.301; turbulence slope (TS): 3.4 (SD 3.1) vs 1.7 (SD 1.5), p = 0.04, r = 0.419). The positive predictive value of the WMI considering the inducibility of VT during EP testing was 100%. Those patients who received an ICD for primary prevention showed a higher WMI (p = 0.049) than the secondary prevention group. With respect to the occurrence of adequate VT episodes, a negative WM test result demonstrated a negative predictive value of 95%.
Conclusion: The data presented show that the WM-Index predicts VT inducibility during EP testing and indicates a high negative predictive value regarding the occurrence of VT.