Catheter Ablation of Ventricular Arrhythmia in Nonischemic Cardiomyopathy

Abstract

Background-The aim was to relate distinct scar distributions found in nonischemic cardiomyopathy with ventricular tachycardia (VT) morphology, late potential distribution, ablation strategy, and outcome. Methods and Results-Eighty-seven patients underwent catheter ablation for drug-refractory VT. Based on endocardial unipolar voltage, 44 were classified as predominantly anteroseptal and 43 as inferolateral. Anteroseptal patients more frequently fulfilled diagnostic criteria for dilated cardiomyopathy (64% versus 36%), associated with more extensive endocardial unipolar scar (41 [22-83] versus 9 [1-29] cm 2 ; P<0.001). Left inferior VT axis was predictive of anteroseptal scar (positive predictive value, 100%) and right superior axis for inferolateral (positive predictive value, 89%). Late potentials were infrequent in the anteroseptal group (11% versus 74%; P<0.001). Epicardial late potentials were common in the inferolateral group (81% versus 4%; P<0.001) and correlated with VT termination sites (κ=0.667; P=0.014), whereas no anteroseptal patient had an epicardial VT termination (P<0.001). VT recurred in 44 patients (51%) during a median follow-up of 1.5 years. Anteroseptal scar was associated with higher VT recurrence (74% versus 25%; log-rank P<0.001) and redo procedure rates (59% versus 7%; log-rank P<0.001). After multivariable analysis, clinical predictors of VT recurrence were electrical storm (hazard ratio, 3.211; P=0.001) and New York Heart Association class (hazard ratio, 1.608; P=0.018); the only procedural predictor of VT recurrence was anteroseptal scar pattern (hazard ratio, 5.547; P<0.001). Conclusions-Unipolar low-voltage distribution in nonischemic cardiomyopathy allows categorization of scar pattern as inferolateral, often requiring epicardial ablation mainly based on late potentials, and anteroseptal, which frequently involves an intramural septal substrate, leading to a higher VT recurrence. (Circ Arrhythm Electrophysiol. 2014;7:414-423.)

Ventricular arrhythmias in nonischemic cardiomyopathy

“…The Prospective Heart Centre of Leipzig VT study echoed that the long‐term outcomes in NICM patients were significantly worse than those in ICM patients (40% and 57% freedom from VT at 1‐year follow‐up for NICM and ICM patients, respectively),49 which was echoed by a substrate‐based approach 79. Additionally, patients with scar involving the inferolateral aspect of the LV, which frequently requires an epicardial approach, usually have a better prognosis than those with anteroseptal scar 80. The progressive disease entities and involvement of intramural and epicardial substrates might contribute to a worse prognosis in certain groups of patients.…”

Twelve-Lead ECG of Ventricular Tachycardia in Structural Heart Disease

“…Epicardial mapping was not hampered by overlying structures like the left atrial appendage, a thick fat layer, or coronary arteries in these patients; however, radiofrequency delivery may need to be withheld if damage of the coronary arteries or the phrenic nerve cannot be excluded. Oloriz et al 26 confirmed subsequently these findings in a larger cohort of patients.…”

Epicardial Catheter Ablation Using High-Intensity Ultrasound

“…If endocardial lesions are similar to the epicardial lesions demonstrated here, HIU ablation may also allow ablation of deep septal VTs, which are currently challenging to ablate using radiofrequency from either side of the interventricular septum. 20,21 In conclusion, we have developed an internally irrigated, side-facing, epicardial HIU catheter, capable of making large, deep lesions with sparing of epicardial tissue. Dose ranging studies showed that 20-W lesions had the best balance of depth of penetration and epicardial sparing.…”