Radiofrequency catheter ablation of ventricular arrhythmia storm guided by high-density mapping in structural heart disease

Objective To investigate the efficacy of high density mapping using multielectrode catheters and EnSite-Velocity system(St.Jude Medical, US.)for guiding radiofrequency ablation of ventricular arrhythmia storm(VAS)in structural heart disease. Methods Fourteen VAS patients [12 men, mean age(49.1±16.1)years] with structural heart disease were retrospectively analyzed.Endocardial and/or epicardial high density mapping was performed with a steerable duodecapolar or decapolar catheter during the ventricular tachycardia(VT)and/or the baseline rhythm, either sinus or paced, with EnSite-Velocity system. Results A total of 15 mapping and ablation procedures were performed in 14 patients.Seven of them were performed only through endocardial approach.Combined endocardial and epicardial approach were carried out in other 8 procedures.The abnormal substrate areas in epicardium were significantly larger than that in endocardium.Twenty-eight types of VT(including 18% hemodynamically unstable VT or degenerated to ventricular fibrillation)were induced or spontaneous during the procedures [mean cycle length(358±107) ms]. The average X-ray fluoroscopy time and procedural time were(37.6±7.6) min and(227±34) min, respectively.Complete success, partial success, and failure rates immediately post ablation were 53.3%, 26.7% and 20.0%, respectively.During a mean follow-up of (8.2±3.6)months after the last ablation procedure, one patient died from severe heart failure after discharge in 2 weeks.The long-term complete success, partial success, and failure rates were 84.6%, 7.7% and 7.7%, respectively. Conclusion The VT substrates and/or channels could be effectively detected and ablated by high density mapping via using multielectrode catheters and EnSite-Velocity system. Key words: High density mapping; Catheter ablation; Ventricular tachycardia; Ventricular arrhythmia storm