Circumferential myocardial contraction patterns in patients with idiopathic frequent premature ventricular complexes from the right ventricular outflow tract.

BACKGROUND

The pathogenesis of frequent premature ventricular complexes (PVCs) in patients without overt cardiovascular disease is considered idiopathic. Idiopathic PVCs are predominantly from the right ventricular outflow tract (RVOT) and considered a reversible cause of left ventricular (LV) dysfunction.

OBJECTIVES

We investigated whether alternations in LV contraction patterns exist in patients with idiopathic frequent PVCs originating from the RVOT.

METHODS

Segmental myocardial circumferential strain (CS)-time curves were acquired from 29 patients with idiopathic frequent RVOT-PVCs and 30 healthy subjects. Peak CS and the time to peak CS (TPcs) of each segment were analyzed, with the standard deviation of TPcs for 18 LV segments (SDtpcs) calculated. All values of patients with RVOT-PVCs were recorded during both sinus beats (PVC-S) and ventricular extrasystoles (PVC-V), respectively.

RESULTS

The distribution of peak CS and TPcs in the PVC-V was opposite that of the healthy subjects. The distribution of TPcs of PVC-S within the different layers differed from that of healthy subjects. These patients had significantly greater dyssynchrony compared with the healthy subjects assessed by SDtpcs (healthy subjects: 6.7%±1.9%, PVC-S: 8.1%±3.1%, PVC-V: 9.7%±3.4%, healthy subjects vs. PVC-S p=0.04; healthy subjects vs. PVC-V p=0.001). Furthermore, a positive correlation was observed between PVC frequency and SDtpcs of PVC-S (r=0.44, p=0.02).

CONCLUSIONS

Idiopathic frequent RVOT-PVCs can induce alterations in the LV myocardial contractile pattern during both sinus beats and ventricular extrasystoles. Circumferential contraction dyssynchrony of patients during sinus beats relates to PVC frequency. Therefore, attention should be paid to patients with frequent RVOT-PVCs, especially those with a high prevalence of PVCs.