Comparison of the predictive accuracy of four different ECG algorithms in identification of true ablation site for the idiopathic right ventricular outflow tract tachycardias.

BACKGROUND: We aimed to investigate the accuracy of four algorithms in prediction of right ventricular outflow tract (RVOT) tachycardias in patients who successfully underwent radiofrequency catheter ablation. METHODS: Four algorithms; two with easy-applicability and having a memorable design (Dixit and Joshi), and two with more complex and detailed design (Ito and Zhang) were compared according to the predictive accuracy. RESULTS: Among 99 patients (mean age 36.5 ± 8.5 years, 39.4% male), there were 51 (51.5%) septal-located and 48 (48.5%) free-wall located RVOT tachycardia. Comparison of the predictive accuracy of the algorithms showed that Zhang (91.9%) was the best algorithm for prediction of either septal or free-wall located tachycardia. The second best algorithm was the Ito (77.7%) compared to Dixit (75.8%) and Joshi (70.7%). CONCLUSION: In patients with RVOT tachycardia, algorithms with a detailed design may predict the arrhythmia location better than the easy-applicable algorithms.

The short-term impact of the catheter ablation on noninvasive autonomic nervous system parameters in patients with paroxysmal atrial fibrillation.

BACKGROUND: The autonomic nervous system (ANS) is a potentially potent modulator of the initiation and perpetuation of atrial fibrillation (AF), whereas the presence of AF can activate and alter the ANS. The catheter ablation of AF (AFCA) may cause the cardiac ANS dysfunction, whereas restoration of sinus rhythm or sympathovagal imbalance by AFCA can reverse this process. Our principal goal was to investigate the short-term effect of AFCA on ANS functions evaluated by noninvasive chronotropic (CI), resting heart rate (RHR), and heart rate recovery (HRR) indices. METHOD: A total of 45 patients were enrolled with symptomatic, drug refractory paroxysmal AF undergoing first cryoballoon (CB) pulmonary vein antrum isolation (PVAI) with one 28-mm CB using single 3-minute freeze techniques without bonus applications. All patients underwent symptom-limited exercise treadmill testing to evaluate noninvasive parameters of ANS before PVAI. For those patients who remained in sinus rhythm, an additional exercise test was repeated after 1 and 3 months after discharge. RESULTS: The autonomic CI and RHR/HRR indices were impaired after PVAI and persisted post-PVAI 3 months. However, these parameters were not different in patients with and without recurrence. CONCLUSION: This study demonstrated that the successful AFCA might concurrently impair the ANS parameters. The autonomic imbalance between the sympathetic and parasympathetic activity after AFCA could either become antiarrhythmic and/or proarrhythmic based on which of the two components was going to prevail after successful AFCA. The impaired ANS balance after PVAI might also be another hypothetical mechanism for AF recurrence particularly in the absence of PV reconnection.