Impact of right ventricular apical pacing on left ventricle and right ventricular function – Case series

Introduction: Idiopathic VTs commonly arise from outflow tract of right and left ventricle.We have diagnosed Cardiac Sarcoidosis (CS) among this subset of patients presenting as outflow-tract ventricular tachycardias (OTVT).Objective: To evaluate if ECG abnormalities in sinus rhythm (SR) among patients presenting with OTVT and structurally normal heart(on Echocardiography) predicts underlying CS.Methods: We analyzed the SR ECG of 42 pts with OTVT/VPC with normal echo.All underwent advanced imaging with cardiac MR(CMR)/ PET-CT.22 patients had biopsy proven CS (Gr A, cases).20 patients had idiopathic OTVT (Gr B, controls)[ imaging -negative].Twelve lead ECG of each patients were analyzed by 2 independent observers who were blinded to the clinical diagnosis.Results: Among the ECG features analysed -fascicular or bundle branch block(BBB) were present in 9/22 of cases vs. 1/20 controls (p¼0.006).Among the rest, fractionated QRS (fQRS) was present in 9/13 patients of CS whereas 0/19 of controls (p<0.001).Low voltage of QRS were more often seen among pts with CS (Gr A 14/22 vs. 3/20 in Gr B, ¼0.001).R wave amplitude in V1 were similar (p¼0.88).A simple algorithm based on these ECG findings help to diagnose CS with good accuracy (PPV and NPV 90 % and 88% respectively).Conclusions: Fragmented QRS, fascicular block/BBB and low QRS amplitude in sinus rhythm ECG were more often seen among patients with OTVT having underlying CS.Minor abnormalities in SR ECG may help to suspect / diagnose underlying CS among patients with "idiopathic" OTVT and warrant upfront imaging with CMR/PET.