BACKGROUND
The etiology of frequent premature ventricular complexes (PVCs) induced left ventricular dysfunction (LVD) is unclear. The speculative mechanisms of LVD are alteration in calcium homeostasis and/or ventricular dyssynchrony, however, the electrophysiologic factors resulting in LVD remains to be clarified.
OBJECTIVES
The purpose of this study was to determine the electrophysiologic characteristics of frequent PVCs associated with LVD.
METHODS
161 consecutive patients with frequent PVCs (PVCs burden≥10%) without significant structural heart disease were studied. The characteristics of PVCs were assessed by surface ECG, 24-or 48-hour Holter monitoring and exercise ECG. Transthoracic echocardiography was used to assess LV function and dimension.
RESULTS
LVD [ejection fraction (EF), 44.0 ± 5.8%)] was present in 39 of 161 patients (24.2%). A subgroup of patients with LVD demonstrated significantly enlarged LVEDd and LVESd as compared with normal LV function group (55 ± 5mm vs. 49 ± 4mm, 38 ± 7mm vs. 29 ± 4mm, respectively, P<0.001). There was a significant difference in mean PVC burden (27 ± 12% vs. 20 ± 9%, P<0.01), the presence of nonsustained ventricular tachycardia (VT, 61.5% vs. 36.9%, P<0.01) and presence of retrograde p wave (64.1% vs. 30.3%, P<0.01) between LVD and normal LV function group. There were no significant differences in PVCs morphology, coupling interval, QRS width and emergence pattern during exercise ECG between two groups. Catheter ablation (CA) was attempted in higher number of the patients in LVD group than normal LV function group (28/39, 71.8% vs. 65/122, 53.3%, P=0.04). There were, however, no significant differences in the origin site of PVCs and success rate of CA (89.3% vs. 92.3%, NS) between those underwent CA in each group.
CONCLUSIONS
A higher PVC burden (≥27% per day), the presence of nonsustained VT and retrograde p wave were associated with PVCs-induced LVD, in which catheter ablation was found to be equally effective as in normal LV. Further study to verify their mechanisms responsible for LVD is required.
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