MD, FESC, FSCAI FHRS
Time : 10:25-10: 45 AM
Head EP unit, Director of Heart Rhythm Service, Egyptian National Heart Institute, Cairo.Consultant of cardiology and critical care. Member of Egyptian Fellowship Board of EP. Member of EHRA and Fellow of Heart Rhythm society. Secretary of Egyptian Cardiac Rhythm Association ECRA. Coordinator of teaching and scientific committee Egyptian National Heart Institute. Goodwill Ambassador Arab Republic Relations Association, Cairo.
Premature ventricular contractions (PVCs) are early repolarizations originating from the myocardium of the ventricles. Pvcs are common phenomenon and they are present in 1% to 4% on standard 12 lead ECG and 40% to 75% on Holter monitoring. PVCs appear in cardiomyopathies, but also in structurally normal heart. While they might represent a risk factor of sudden cardiac death in cardiomyopathy, PVCs in structurally normal heart usually have a begnin course. However, PVC-induced cardiomyopathy has been a subject of great interest in the last decade. This concept was proposed by Duffee et al. in 1998 when pharmacological suppression of PVCs in patients with presumed idiopathic dilated CMP subsequently improved LV systolic dysfunction. Several factors are identified as risk for developement of PVC-induced CMP and include: PVC burden where several authors put a cut-off value of >10% for PVCs originating from RV, and >20% for PVCs originating from LV. PVCs from RV induce CMP at a lower threshold than PVCs from LV and this is due more dyssynchrony. Also fascicular PVCs can cause more CMP. Longer PVC QRS duration was also associated with more EF deterioration. The mechanism by which PVCs induce CMP is multifactorial and my include: ventricular dyssynchrony, increased oxygen consumption, intracellular calcium abnormalities and several other factors (fig.1). The treatment strategy depends on the symptoms of the patient and the extent of systolic dysfunction: while in asymptomatic patient with preserved systolic function, reassurance and follow-up is enough; in symptomatic patient and/or CMP the first line of treatment is pharmacological suppression of PVCs by the mean of anti-arrhythmic drugs (B-blockers, Verapamil, Class III…). In drug refractory PVCs, ablation has become an effective and alternative therapeutic option, with success rate reaching >85%. Ablation can also be performed as first line of treatment according to the wish of patient.