PREDICTORS OF IN-HOSPITAL MORTALITY AFTER DC CATHETER ABLATION OF ATRIOVENTRICULAR JUNCTION - RESULTS OF A PROSPECTIVE, INTERNATIONAL, MULTICENTER STUDY

Background. The Catheter Ablation Registry was the first international, multicenter, prospective study of the safety and efficacy of catheter ablation. Methods and Results. From August 1987 through March 1990, the study comprised 136 patients in whom only DC energy was used in attempted production of third-degree atrioventicular block to treat uncontrollable supraventricular tachycardias. Eight patients died during hospitalization for ablation. In seven (5.1%), the ablation may have contributed to their deaths. Causes of death included ventricular fibrillation (five patients, three with polymorphic ventricular tachycardia), progressive heart failure (one patient), and respiratory failure (two patients, one dying after resuscitation from ventricular fibrillation). Compared with survivors, patients who died were more likely to have had prior aborted sudden death (38% versus 2%, p < 0.05), congestive heart failure (88% versus 22%, p < 0.001), cardiomyopathy (50% versus 16%, p < 0.05), lower baseline systolic blood pressure (106 versus 138 mm Hg, p < 0.001), prolonged baseline and postablation corrected QT interval (p < 0.01), and markedly reduced ejection fraction (27% versus 52%, p < 0.001). Ablation successfully produced third-degree atrioventricular block in 88% of the patients who died and in 83% of survivors. Conclusions. Catheter ablation of the atrioventricular junction with DC energy carries a significant, previously unrecognized risk of death (5.1%), particularly from lethal arrhythmias, when applied to patients with severe left ventricular dysfunction. Great care should be taken in these seriously ill patients to guard against postablation ventricular arrhythmias.