Electrocardiogram features of premature ventricular contractions/ventricular tachycardia originating from the left ventricular outflow tract and the treatment outcome of radiofrequency catheter ablation

Abstract

BackgroundRadiofrequency catheter ablation (RFCA) has been used for the ablation of premature ventricular contractions (PVCs) or ventricular tachycardia (VT). To date, the mapping and catheter ablation of the arrhythmias originating from the left ventricular outflow tract (LVOT) has not been specified. This study investigates the electrocardiogram (ECG) feature of PVCs or VT originating from the LVOT. Moreover, the treatment outcome of RFCA is analyzed.MethodsMapping and ablation were performed on the supravalvular or subvalvular aorta in 52 cases with PVCs/VT originating from the LVOT. The data were compared with those from 104 patients with PVCs/VT originating from the right ventricular outflow tract (RVOT). A differential procedure was prepared based on the comparison of the ECG features of PVCs/VT originating from the RVOT, LVOT, and their different parts.ResultsAmong 52 cases with PVCs originating from the LVOT, 47 were successfully treated by RFCA, with a success rate of 90.38%. Several differences among the 12-lead ECG features were observed from the RVOT and LVOT in the left and right coronary sinus groups, as well as under the left coronary sinus group (left fibrous trigone): (1) If the precordial leads transition <V3 plus the precordial leads transitional index >0 are considered as the diagnostic parameters of PVCs/VT originating from the LVOT, then the sensitivity, specificity, as well as positive and negative predictive values are 94.12%, 93.00%, 87.27%, and 96.88%, respectively; (2) The analysis of different subgroups of the LVOT are as follows: (a) A mainly positive wave of r or m pattern was recorded in the lead I in 72.73% of patients in the right coronary sinus group, versus 12.90% of patients in the left coronary sinus group, and 0% in the under left coronary sinus group. (b) All patients in the right coronary sinus group presented waves of RII>RIII and QSaVR>QSaVL, whereas most patients in the other two groups showed waves of RIII>RII and QSaVL>QSaVR. (c) Most patients in the under left coronary sinus group in lead V1 had a mainly positive wave (R) (77.78%), whereas those in the right (81.82%) and left (62.50%) coronary sinus groups had mainly negative waves (rS).ConclusionsRFCA is a safe and effective curative therapy for PVCs/VT originating from the LVOT. The 12-lead ECG features of the LVOT from different origins exhibit certain distinctions.

Reversal of premature ventricular complexes induced cardiomyopathy. Influence of concomitant structural heart disease

“…While few recent studies have defined cutoff values for PVCs burden before as previously discussed, a cut off value of <8% for PVCs burden after ablation was defined by our group as an independent predictor of LV function improvement. No definite cut off value was reported in the previous studies but instead the term sustained successful ablation was used which is variable among different investigators while some defined it as complete disappearance others used reduction by >75%, or 80% by the remaining 9, 12, 17. Absolute PVCs% reduction may underestimate the hazardous effect of high residual PVCs burden in some patients, though they met criteria of successful ablation.…”

“…Initial success was defined as complete elimination of PVCs or residual PVCs ≤ 10 beats/30 min while long term success was defined as reduction in PVCs burden >80% 9 …”

Origins location of the outflow tract ventricular arrhythmias exhibiting qrS pattern or QS pattern with a notch on the descending limb in lead V1

“…Activation mapping and pace mapping were performed in both right ventricle and left ventricle to locate the origin of VAs with the application of 7F, 4-mm-tip ablation catheters. The method of activation mapping and pace mapping have been described in detail in our previous work [ 1 , 4 – 8 ]. When clinical PVCs/VT did not appear spontaneously at the beginning of the electrophysiology study, burst pacing from right ventricular apex (set at basic cycle lengths of 600, 500, 430 ms respectively) with the intravenous isoproterenol infusion(2–4 μg/min) was initiated to induce the arrhythmias.…”

Outflow tract ventricular premature beats ablation in the presence or absence of structural heart disease: Technical considerations and clinical outcomes

“…Acute success was considered when PVBs completely disappeared or when residual sporadic PVBs ≤ 1 beats/min or ≤10 beats/30 min after RF ablation, while long-term success was defined as complete disappearance or marked reduction by more than 75% in the PVBs absolute number on 24 h holter monitoring done 3–6 months after RF ablation together with improvement in symptoms. 10 …”