Lower than expected burden of premature ventricular contractions impairs myocardial function

Abstract

AimsWe aimed to explore the burden of frequent premature ventricular contractions (PVCs) associated with myocardial dysfunction in patients with outflow tract arrhythmia (OTA). We hypothesized that this threshold is lower than the previously suggested threshold of 24 000 PVCs/24 h (24%PVC) when systolic function is assessed by strain echocardiography. Furthermore, we aimed to characterize OTA patients with malignant arrhythmic events.Methods and resultsWe included 52 patients referred for OTA ablation (46 ± 12 years, 58% female). Left ventricular global longitudinal strain (GLS) and mechanical dispersion were assessed by speckle tracking echocardiography. A subset underwent cardiac magnetic resonance imaging. PVC burden (%PVC) was assessed by Holter recording. Sinus rhythm QRS duration and PVC QRS duration were recorded from electrocardiogram, and the ratio was calculated (PVC QRS duration / sinus rhythm QRS duration). Median %PVC was 7.2 (0.2–60.0%). %PVC correlated with GLS (R = 0.44, P = 0.002) and with mechanical dispersion (R = 0.48, P < 0.001), but not with ejection fraction (R = 0.22, P = 0.12). %PVC was higher in patients with impaired systolic function by GLS (worse than −18%) compared with patients with normal function (22% vs. 5%, P = 0.001). Greater than 8%PVC optimally identified patients with abnormal GLS (area under the curve 0.79). Serious arrhythmic events occurred in 11/52 (21%) patients characterized by high QRS ratios (1.56 vs. 1.91, P < 0.001).ConclusionsMore than 8%PVC was associated with impaired systolic function by GLS, which is a lower threshold than previously reported. Patients with serious arrhythmic events had higher QRS ratios, which may represent a more malignant phenotype of OTA.

Detection of concealed structural heart disease by imaging in patients with apparently idiopathic premature ventricular complexes: A review of current literature

“…A daily PVC burden between 16% and 24% of all heartbeats have been associated to progressive LV dysfunction . However, subtle myocardial mechanical dysfunction detected by speckle tracking echocardiography has been reported also in patients with a PVC burden as low as 4% . Left bundle‐branch block (LBBB) PVC‐QRS morphology and longer PVC‐QRS duration (>150 ms) as well as an epicardial origin of PVCs require a lower arrhythmic burden to develop LV dysfunction, thus corroborating the hypothesis of mechanical dyssynchrony as the main mechanism of PVC‐induced cardiomyopathy .…”

“…16 However, subtle myocardial mechanical dysfunction detected by speckle tracking echocardiography has been reported also in patients with a PVC burden as low as 4%. 17 (AADs) or CA. 19 In this regard, several factors have been linked with reversible cardiomyopathy after successful treatment of PVCs including a pre-treatment PVC burden of at least 10% and absence of myocardial scar detectable by late gadolinium enhancement (LGE) CMR.…”

Management of asymptomatic arrhythmias: a European Heart Rhythm Association (EHRA) consensus document, endorsed by the Heart Failure Association (HFA), Heart Rhythm Society (HRS), Asia Pacific Heart Rhythm Society (APHRS), Cardiac Arrhythmia Society of Southern Africa (CASSA), and Latin America Heart Rhythm Society (LAHRS)

“…166,168 A recent study measuring subtle degrees of LV impairment by using speckle tracking echocardiography (measuring LV global longitudinal strain and mechanical dispersion) showed mild impairment of myocardial function with a PVC burden >8%. 169 The wide range reported in studies may be partly explained by the singleday Holter monitoring used. A wide daily variation in PVC burden is well recognized.…”

Impaired left ventricular global longitudinal strain improves with radiofrequency catheter ablation in patients with PVC‐induced cardiomyopathy

“…14 In several studies in the literature, it was reported that LV-GLS value obtained with STE significantly decreased in patients with normal LVEF with frequent PVCs. 16,17,[23][24][25] In addition to LV-GLS, the LA-GLS was also evaluated, and it was reported that both LA-GLS and LV-GLS values decreased in PVCs patients with normal LVEF. 24 Although LVEF reduction in PVCs patients is more common in patients with PVCs burden ≥20%, less frequent PVCs burden >8% are reported to be sufficient to reduce LV-GLS.…”

“…19,21,22 In a limited number of recent studies, LV-GLS evaluation has been performed in patients with PVCs and preserved LVEF. 16,[23][24][25] In these studies, there is evidence that LV-GLS decreases in patients with PVCs and preserved LVEF. 16,[23][24][25] As far as we have investigated, there is no clear information about the evaluation of LA-GLS in patients with PVCs and reduced LVEF and the effect of RFA treatment on LV-GLS in these patients.…”