Incidence and significance of pleomorphism in patients with postmyocardial infarction ventricular tachycardia. Acute and long-term outcome of radiofrequency catheter ablation

Irrigated Radiofrequency Catheter Ablation Guided by Electroanatomic Mapping for Recurrent Ventricular Tachycardia After Myocardial Infarction

Background— Recurrent ventricular tachycardia (VT) is an important cause of mortality and morbidity late after myocardial infarction. With frequent use of implantable cardioverter-defibrillators, these VTs are often poorly defined and not tolerated for mapping, factors previously viewed as relative contraindications to ablation. This observational multicenter study assessed the outcome of VT ablation with a saline-irrigated catheter combined with an electroanatomic mapping system.

Methods and Results— Two hundred thirty-one patients (median LV ejection fraction, 0.25; heart failure in 62%) with recurrent episodes of monomorphic VT (median, 11 in the preceding 6 months) caused by prior myocardial infarction were enrolled. All inducible monomorphic VTs with a rate approximating or slower than any spontaneous VTs were targeted for ablation guided by electroanatomic mapping during sinus rhythm and/or VT. Patients were not excluded for multiple VTs (median, 3 per patient) or unmappable VT (present in 69% of patients). Ablation abolished all inducible VTs in 49% of patients. The primary end point of freedom from recurrent incessant VT or intermittent VT after 6 months of follow-up was achieved for 123 patients (53%). In 142 patients with implantable cardioverter-defibrillators before and after ablation for intermittent VT who survived 6 months, VT episodes were reduced from a median of 11.5 to 0 ( P <0.0001). The 1-year mortality rate was 18%, with 72.5% of deaths attributed to ventricular arrhythmias or heart failure. The procedure mortality rate was 3%, with no strokes.

Conclusions— Catheter ablation is a reasonable option to reduce episodes of recurrent VT in patients with prior myocardial infarction, even when multiple and/or unmappable VTs are present. This population remains at high risk for death, warranting surveillance and further study.

[Successful epicardial ablation of a postinfarction ventricular tachycardia]

Endocardial radiofrequency catheter ablation was performed because of frequent, 150/min monomorphic ventricular tachycardia (VT). In February 2005 it was many times terminated only by ICD shock in a 55-year-old postinfarction patient who received an implantable cardioverter defibrillator (ICD) 5 years ago because of rapid, monomorphic VT. After being asymptomatic for two months, a slower, 120/min, however, incessant ventricular tachycardia was present which was untreatable by a repeated endocardial ablation. Combined antiarrhythmic treatment was not effective either. In June 2005, after another unsuccessful endocardial ablation, epicardial ablation was decided as an "ultimum refugium". After subxyphoidal percutaneous pericardial punction we positioned the ablation catheter in the pericardial space, and ablation at the earliest activation point terminated the permanently ongoing arrhythmia for one and a half month within 5 seconds. After another three ablations we were unable to induce ventricular arrhythmia even with programmed ventricular extrastimulation. During a three-year follow-up, ventricular tachycardia was noticed in only two cases, ICD terminated both arrhythmias with the first antitachycardia pacing. The patient is in NYHA stage II at present. According to our knowledge, our case is the first successful epicardial ablation of incessant ventricular tachycardia in a postinfarction patient in Hungary.

Catheter Ablation for the Treatment of Electrical Storm in Patients With Implantable Cardioverter-Defibrillators

Background— Electrical storm (ES) caused by recurrent episodes of ventricular tachycardia (VT) can cause sudden death in patients with implantable cardioverter-defibrillators and adversely affects prognosis in survivors. Catheter ablation has been proposed for treating ES, but its long-term effect in a large population has never been verified.

Methods and Results— Ninety-five consecutive patients with coronary artery disease (72 patients), idiopathic dilated cardiomyopathy (10 patients), and arrhythmogenic right ventricular dysplasia/cardiomyopathy (13 patients) undergoing catheter ablation for drug-refractory ES were prospectively evaluated. Short-term efficacy was defined by a complete protocol of programmed electric stimulation and by in-hospital outcome; long-term analysis addressed ES recurrence, cardiac mortality, and VT recurrence. Pleomorphic/nontolerated VTs required electroanatomic and noncontact mapping in 48 and 22 patients, respectively, and percutaneous cardiopulmonary support in 10 patients. An epicardial approach was used in 10 patients. After 1 to 3 procedures, induction of any clinical VT(s) by programmed electrical stimulation was prevented in 85 patients (89%). ES was acutely suppressed in all patients; a minimum period of 7 days with stable rhythm was required before hospital discharge. At a median follow-up of 22 months (range, 1 to 43 months), 87 patients (92%) were free of ES and 63 patients (66%) were free of VT recurrence. Eight of 10 patients with persistent inducibility of clinical VT(s) had ES recurrence; 4 of them died suddenly despite appropriate implantable cardioverter-defibrillator intervention. All together, 11 of 95 patients (12%) died of cardiac-related reasons. In the group of patients presenting with all clinical VTs acutely abolished, no ES recurrence was documented, and cardiac mortality was significantly lower compared with the group of patients showing ≥1 clinical VT still inducible after catheter ablation.

Conclusions— Advanced strategies of catheter ablation applied to a large population of patients are effective in the short-term treatment of ES. By preventing ES recurrence, catheter ablation may play a protective role over the long term and, together with long-term pharmacological therapy, may favorably affect cardiac mortality.

Two Adults Requiring Implantable Defibrillators Because of Ventricular Tachycardia and Left Ventricular Dysfunction Caused by Presumed Kawasaki Disease

There is an adult patient population in Japan with undiagnosed coronary artery lesions caused by Kawasaki disease (KD) occurring before 1967, the time at which KD was first described. Two adult patients presented with a low left ventricular (LV) ejection fraction and ventricular tachycardia (VT) caused by presumed KD. A 43-year-old man with rapid VT had a history of an acute febrile illness with desquamation of the fingertips at the age of 10 months. Coronary angiography (CAG) showed segmental stenosis of the right coronary artery (RCA) and occlusion of the left anterior descending artery with a giant aneurysm. The other patient was a 48-year-old man with a history of ischemic cardiomyopathy diagnosed after a previous myocardial infarction when he was 32 years old. He had segmental stenosis of the RCA on CAG. Non-sustained VT with transient unconsciousness was observed during 24-h Holter electrocardiography. Rapid VT with syncope was induced in both patients in the electrophysiologic studies and an implantable defibrillator was required to prevent sudden death. Physicians must be aware that VT can occur in older patients with LV dysfunction many years after KD.