Catheter Ablation Of Scar-related Ventricular Tachycardia Research Articles

Comparison of the arrhythmogenic substrate for ventricular tachycardia in patients with ischemic vs non-ischemic cardiomyopathy - insights from high-density, multi-electrode catheter mapping.

The purpose of this study was to compare the differences of arrhythmogenic substrate using high-density mapping in ventricular tachycardia (VT) patients with ischemic (ICM) vs non-ischemic cardiomyopathy (NICM). Data from patients presenting for VT ablation from December 2016 to December 2020 at Westmead Hospital were reviewed. Sixty consecutive patients with structural heart disease (ICM 57%, NICM 43%, mean age 66years) having catheter ablation of scar-related VT with pre-dominant left ventricular involvement were included. ICM was associated with larger proportion of dense scar area (bipolar; 19 [12-29]% vs 6 [3-10]%, P < 0.001, unipolar; 20 [12-32]% vs 11 [7-19]%, P = 0.01) compared with NICM. However, the scar ratio (unipolar dense scar [%]/bipolar dense scar [%]) was significantly higher in NICM patients (1.2 [0.8-1.7] vs 1.7 [1.3-2.3], P = 0.003). Larger scar area in ICM was paralleled by higher proportion of complex electrograms (6 [2-13] % vs 3 [1-5] %, P = 0.01), longer and wider voltage based conducting channels, higher incidence of late potential-based conducting channels, longer VT cycle-length (399 ± 80ms vs 359 ± 68ms, P = 0.04) and greater maximal stimulation-QRS interval among sites with good pace-map correlation (75 [51-99]ms vs 48 [31-73]ms, P = 0.02). Ventricular arrhythmia (VA) storm was more highly prevalent in ICM than NICM (50% vs 23%, P = 0.03). During the follow-up period, NICM had a significantly higher cumulative incidence for the VA recurrence than ICM (P = 0.03). High-density multi-electrode catheter mapping of left ventricular arrhythmogenic substrate of NICM tends to show smaller dense scar area and higher scar ratio, compared with ICM, suggestive the extent of epicardial/intramural substrate, with paucity of substrate targets for ablation, which results in the worse outcomes with ablation.

Accuracy of automatic abnormal potential annotation for substrate identification in scar-related ventricular tachycardia.

Ultrahigh-density mapping for ventricular tachycardia (VT) is increasingly used. However, manual annotation of local abnormal ventricular activities (LAVAs) is challenging in this setting. Therefore, we assessed the accuracy of the automatic annotation of LAVAs with the Lumipoint algorithm of the Rhythmia system (Boston Scientific). One hundred consecutive patients undergoing catheter ablation of scar-related VT were studied. Areas with LAVAs and ablation sites were manually annotated during the procedure and compared with automatically annotated areas using the Lumipoint features for detecting late potentials (LP), fragmented potentials (FP), and double potentials (DP). The accuracy of each automatic annotation feature was assessed by re-evaluating local potentials within automatically annotated areas. Automatically annotated areas matched with manually annotated areas in 64 cases (64%), identified an area with LAVAs missed during manual annotation in 15 cases (15%), and did not highlight areas identified with manual annotation in 18 cases (18%). Automatic FP annotation accurately detected LAVAs regardless of the cardiac rhythm or scar location; automatic LP annotation accurately detected LAVAs in sinus rhythm, but was affected by the scar location during ventricular pacing; automatic DP annotation was not affected by the mapping rhythm, but its accuracy was suboptimal when the scar was located on the right ventricle or epicardium. The Lumipoint algorithm was as/more accurate than manual annotation in 79% of patients. FP annotation detected LAVAs most accurately regardless of mapping rhythm and scar location. The accuracy of LP and DP annotations varied depending on mapping rhythm or scar location.

Early Mortality After Catheter Ablation of Ventricular Tachycardia in Patients With Structural Heart Disease

BackgroundIn patients referred for radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) in the setting of structural heart disease, early post-procedural mortality (EM) has not been previously investigated. ObjectivesThe purpose of this study was to evaluate EM after catheter ablation of scar-related VT. MethodsAssociations between clinical and procedural variables and EM (within 31 days of the procedure) were tested in patients with structural heart disease undergoing RFCA of VT at 12 international centers. ResultsOf 2,061 patients (mean age 62 ± 13 years; left ventricular ejection fraction [LVEF] 34 ± 13%; 53% ischemic etiology), EM occurred in 100 (5%; 95% confidence interval [CI]: 4% to 6%). A total of 54 (3%) patients died before hospital discharge (median 9 days after the procedure; 25% for refractory VT), including 12 (0.6%) after a major procedure-related complication. In multivariable analysis, the following factors were found to be significantly associated with EM: LVEF (odds ratio [OR] per percent decrease: 1.12; 95% CI: 1.05 to 1.20; p < 0.001), chronic kidney disease (OR: 2.73; 95% CI: 1.10 to 6.80; p = 0.030), presentation with VT storm (OR: 3.61; 95% CI: 1.37 to 9.48; p = 0.009), and presence of unmappable VTs (OR: 5.69; 95% CI: 1.37 to 23.69; p = 0.017). Recurrent VT was also associated with an increased risk of subsequent death (hazard ratio: 7.19; 95% CI: 5.57 to 9.28; p < 0.001) and EM (hazard ratio: 11.45; 95% CI: 7.47 to 17.59; p < 0.001). ConclusionsIn a contemporary cohort of patients with scar-related VT undergoing RFCA, EM occurred in 5% of cases. Clinical and procedural variables indicating poorer clinical status (low LVEF, chronic kidney disease, VT storm, and unmappable VTs) and post-procedural VT recurrence may predict EM. Identification of such features may prompt early consideration for hemodynamic support or other care to help mitigate later potential complications.

Entrainment Mapping.

Mapping during ventricular tachycardia (VT) aims to elucidate mechanism, describe myocardial propagation, and identify the origin and critical regions of VT that can be targeted for ablation, most commonly with radiofrequency ablation. Most VTs in structural heart disease are due to macro-reentry in and around scar. A combination of mapping techniques, including mapping to identify the arrhythmia substrate, activation sequence mapping, pace-mapping, and entrainment mapping, may be used to identify putative ablation targets. This review describes the principles of entrainment mapping as it pertains to catheter ablation of scar-related VT.

Freedom from recurrent ventricular tachycardia after catheter ablation is associated with improved survival in patients with structural heart disease: An International VT Ablation Center Collaborative Group study

The impact of catheter ablation of ventricular tachycardia (VT) on all-cause mortality remains unknown. The purpose of this study was to examine the association between VT recurrence after ablation and survival in patients with scar-related VT. Analysis of 2061 patients with structural heart disease referred for catheter ablation of scar-related VT from 12 international centers was performed. Data on clinical and procedural variables, VT recurrence, and mortality were analyzed. Kaplan-Meier analysis was used to estimate freedom from recurrent VT, transplant, and death. Cox proportional hazards frailty models were used to analyze the effect of risk factors on VT recurrence and mortality. One-year freedom from VT recurrence was 70% (72% in ischemic and 68% in nonischemic cardiomyopathy). Fifty-seven patients (3%) underwent cardiac transplantation, and 216 (10%) died during follow-up. At 1 year, the estimated rate of transplant and/or mortality was 15% (same for ischemic and nonischemic cardiomyopathy). Transplant-free survival was significantly higher in patients without VT recurrence than in those with recurrence (90% vs 71%, P<.001). In multivariable analysis, recurrence of VT after ablation showed the highest risk for transplant and/or mortality [hazard ratio 6.9 (95% CI 5.3-9.0), P<.001]. In patients with ejection fraction <30% and across all New York Heart Association functional classes, improved transplant-free survival was seen in those without VT recurrence. Catheter ablation of VT in patients with structural heart disease results in 70% freedom from VT recurrence, with an overall transplant and/or mortality rate of 15% at 1 year. Freedom from VT recurrence is associated with improved transplant-free survival, independent of heart failure severity.

Acute hemodynamic decompensation during catheter ablation of scar-related ventricular tachycardia: incidence, predictors, and impact on mortality.

The occurrence of periprocedural acute hemodynamic decompensation (AHD) in patients undergoing radiofrequency catheter ablation of scar-related ventricular tachycardia (VT) has not been previously investigated. We identified univariate predictors of periprocedural AHD in 193 consecutive patients undergoing radiofrequency catheter ablation of scar-related VT. AHD was defined as persistent hypotension despite vasopressors and requiring mechanical support or procedure discontinuation. AHD occurred in 22 (11%) patients. Compared with the rest of the population, patients with AHD were older (68.5±10.7 versus 61.6±15.0 years; P=0.037); had a higher prevalence of diabetes mellitus (36% versus 18%; P=0.045), ischemic cardiomyopathy (86% versus 52%; P=0.002), chronic obstructive pulmonary disease (41% versus 13%; P=0.001), and VT storm (77% versus 43%; P=0.002); had more severe heart failure (New York Heart Association class III/IV: 55% versus 15%, P<0.001; left ventricular ejection fraction: 26±10% versus 36±16%, P=0.003); and more often received periprocedural general anesthesia (59% versus 29%; P=0.004). At 21±7 months follow-up, the mortality rate was higher in the AHD group compared with the rest of the population (50% versus 11%, log-rank P<0.001). AHD occurs in 11% of patients undergoing radiofrequency catheter ablation of scar-related VT and is associated with increased risk of mortality over follow-up. AHD may be predicted by clinical factors, including advanced age, ischemic cardiomyopathy, more severe heart failure status (New York Heart Association class III/IV, lower ejection fraction), associated comorbidities (diabetes mellitus and chronic obstructive pulmonary disease), presentation with VT storm, and use of general anesthesia.