Catheter ablation for hemodynamically unstable monomorphic ventricular tachycardia

Introduction: Hemodynamic collapse precludes extensive catheter mapping to identify focal target regions in many patients with ventricular tachycardia (VT) associated with heart disease. This study tested the feasibility of c atheter ablation of poorly tolerated VTs by targeting a region identified d uring sinus rhythm. Methods and Results: Ablation was attempted in five patients, ages 44 to 59 years, with left ventricular ejection fractions of 0.15 to 0.20 and poorly tolerated VT causing multiple implantable defibrillator therapies (6 to 30 episodes/month). VT was due to prior infarction in three patients and noni schemic cardiomyopathy in two. Target regions were sought that met the foll owing criteria: (1) evidence of slow conduction from fractionated sinus rhy thm electrograms and stimulus-QRS delays during pace mapping, and (2) evide nce that the region contains the reentrant circuit exit from pace mapping. In 4 of 5 patients, a target region was identified and radiofrequency lesio ns applied. Ablation abolished all recurrences of VT in 3 of 4 patients dur ing follow-up of 14 to 22 months. There were no complications. Conclusion: Ablation of poorly tolerated VT is feasible in some patients by mapping during sinus rhythm and performing ablation over a region of ident ifiable scar that contains abnormal conduction and a presumptive VT exit.