Prevalence and Predictors of Tachyarrhythmia Induction in Patients Undergoing PSVT Ablation

Atrial tachyarrhythmias, especially in association with thromboembolism, may have catastrophic consequences in paroxysmal supraventricular tachycardia (PSVT). This study was performed to evaluate the prevalence of tachyarrhythmias in patients seen for PSVT. One hundred patients were selected randomly from patients undergoing PSVT ablation with no inducible second arrhythmias during electrophysiological study (EPS). Patients with hypertrophic cardiomyopathy were excluded. Age, sex, coronary artery disease, valvular heart disease, systemic hypertension, left ventricular ejection fraction (LVEF), and patient symptoms before EPS were noted. Among 1743 patients who had undergone successful PSVT ablation, 105 patients with induced tachyarrhythmias during EPS (mean age = 41.5 ± 15.27, 52 [49.5%] males) were enrolled. The overall induction of tachyarrhythmia was 6%. The patient's symptoms before EPS were in 70.5% paroxysmal palpitation (P = 0.46) and in less than 1% syncope (P 0.08) in comparison with the controls; 75% palpitation and 5% syncope, respectively. Induced tachyarrhythmias in 55 (52.4%) patients were atrial tachyarrhythmia, in 23 (21.9%) atrial flutter, and in 3 (2.9%) atrioventricular nodal re-entrant tachycardia (AVNRT). The mean age in the patients with AVNRT and those with arrhythmias was 24.66 ± 5.77 and 47.57±9, respectively (P=0.008). Isuprel induction method was associated with more frequent atrial tachycardia (67.6% vs. 44.4% of total induced tachyarrhythmias [P=0.03]) (P>0.05). Atrial tachycardia was more frequent in the females (66% vs. 38.5% of total induced tachyarrhythmias, P=0.005), and atrial fibrillation was induced more frequently in the males (11.5% vs. 1.9%, P=0.04). LV dysfunction was accompanied with more frequent premature ventricular contraction induction (P=0.04). Also, 5.2% of the total induced tachyarrhythmias were in the patients with LVEF ≥ 50%, most of whom (33.3%) had EF<35%. Totally, 3 (69.1%) cases of all the induced atrial tachycardia were ablated and 17 (30.9%) were followed up, but the method of induction did not affect the asymptomatic patients on twomonth follow-up (P=0.97) in the ablated tachyarrhythmias and in the followed up tachyarrhythmias (P=0.46). The prevalence of AF in our population was only 5%, which is almost similar to that in previous studies. Atrial tachyarrhythmias are frequently induced in patients undergoing PSVT ablation. As routine ablation is time-consuming and costly, results carry risks to the patients and without effect on the patient’s symptoms during follow-up. It would be more beneficial to follow up tachyarrhythmias than perform early ablation.