Results
Figure 1 illustrates that out of the 692 patients who intended to undergo CA from May 2019 to July 2022, 606 patients qualified for inclusion in the present analysis: 451 were in the control group and 155 were in the ICE group. As detailed in Table 1, there were no significant differences in baseline characteristics between the two groups, except for sex distribution and potassium levels. Approximately 60% of patients had a PVC burden of 20% or more; a majority of patients (89.6%) experienced symptoms related to PVCs or VT; 11.1% of patients exhibited a LVEF of less than 55%, and 15.5% had an abnormal LVEDD.
In comparing the control group, it was observed that the origin sites of the condition were more frequently detected outside RVOT in the ICE group, as shown in Figure 2. The ICE group experienced a longer procedural duration; however, they benefited from reduced fluoroscopy times and lower X-ray exposure. The acute success rates between the two groups were similar. In the control group, four significant complications were documented: two instances of transient ischemic attacks, one case of ischemic stroke, and one episode of ventricular fibrillation that transpired during the procedure. Notably, there were no reports of cardiac tamponade or any other severe complications in either group. While the rates of complications varied, the differences did not reach statistical significance, with a p-value of 0.072, as presented in Table 2.
The follow-up duration was considerably longer for the control group. More than 85% of the patients underwent at least one 24-hour Holter monitoring session. The use of antiarrhythmic drugs was less frequent. CA led to a significant increase in LVEF and a decrease in LVEDD during the follow-up period. Notably, the LVEF improvement was more pronounced in the control group. The rate of cardiovascular rehospitalization was similar between the groups throughout the follow-up, and there were no reported deaths (as detailed in Table 1). As depicted in Figure 3A, the long-term success rates were comparable between the control and the ICE groups, with success rates of 89.6% and 87.1%, respectively. Success rates for RVOT origins exceeded 90% in both groups. As shown in Figure 3B, there was no significant difference in the long-term success rates from various ablation sites between the groups.
Table 3 presents the univariable logistic regression analysis, which identified cardiovascular comorbidities, abnormal LV function and size, papillary muscle involvement, and ablation origins from the epicardium or summit as factors associated with lower acute success rates. Conversely, being female and having an RVOT origin of the arrhythmia were associated with higher acute success rates. The multivariable logistic regression analysis, adjusted for age and gender, revealed that RVOT and epicardium or summit origins were independent predictors of acute success (as shown in Figure 4A). Regarding long-term outcomes (Table 4), having an RVOT origin and achieving immediate success were significant predictors of better outcomes, as illustrated in Figure 4B.