The long-term outcome of visually directed subendocardial resection in patients without inducible or mappable ventricular tachycardia at the time of surgery

Surgery for ventricular tachycardia in patients undergoing surgical ventricular restoration: The Karolinska approach

This article presents a review on the efficacy of surgical ventricular restoration and direct surgery for ventricular tachycardia in patients with left ventricular aneurysm or dilated ischemic cardiomyopathy. The procedure includes a non-electrophysiologically guided subtotal endocardiectomy and cryoablation in addition to endoventricular patch plasty of the left ventricle. Coronary artery bypass surgery and mitral valve repair are performed concomitantly as needed. In our experience, this procedure yielded a 90% success rate in terms of freedom from spontaneous ventricular tachycardia, with an early mortality rate of 3.8%. A practical guide to the pre- and postoperative management of these patients is provided.

Endoaneurysmorrhaphy and cryoablation for postinfarction left ventricular aneurysm with ventricular tachycardia

BACKGROUND

Early reperfusion in the acute phase of myocardial infarction and better medical treatment of consequent heart failure and tachyarrhythmia have decreased the incidence of massive myocardial infarction, left ventricular (LV) aneurysm and also postinfarction-sustained ventricular tachycardia (VT). However, for a number of patients, surgical ablation combined with aneurysm resection and myocardial revascularization remains a possible curative procedure. In this study, the efficacy of endoaneurysmorrhaphy and cryoablation was evaluated in patients with postinfarction LV aneurysm with VT.

METHODS

The medical records of 9 patients who underwent LV endoaneurysmorrhaphy and cryoablation for VT at Taipei Veterans General Hospital between January 1995 and August 2005 were reviewed retrospectively.

RESULTS

There were 8 men and 1 woman, with a mean age of 69.7 years (range, 52-77 years). Preoperative VT and LV aneurysm were found in all patients, who underwent extensive cryoablation at the transitional zone of scar and viable tissue without intraoperative mapping and LV remodeling with prosthetic patch. Associated procedure included coronary artery bypass grafting in 8 patients. During follow-up, no surgical or in hospital mortality were noted. There was 1 late sudden death at home 1.7 months after the operation. No recurrent VT was detected, and all patients showed improvement in New York Heart Association functional class (mean, 2.33 vs.1.67; p=0.025) and LV ejection fraction (mean, 26.3% vs.34.1%; p=0.021).

CONCLUSION

In patients suffering from postinfarction LV aneurysm complicated with VT, combining cryoablation and endoaneurysmorrhaphy offers good arrhythmia control and clinical outcome.

Intraoperative computerized mapping of ventricular tachycardia: differences between anterior and inferior myocardial infarctions

INTRODUCTION

Although direct ventricular tachycardia (VT) surgery has been shown to be effective for treatment of inferior myocardial infarction (MI), the differences in the arrhythmia substrates compared to anterior MI have not been systematically delineated. We sought to compare operative procedures and VT substrates between anterior and inferior MI locations.

METHODS AND RESULTS

Computerized mapping was performed in 30 patients with a 128-electrode system using epicardial sock and transatrial left ventricular endocardial balloon arrays, followed by combined endocardial resection and cryoablation. At surgery, there were 51 and 34 different VTs in 18 patients with anterior MI and 12 patients with inferior MI, respectively. The proportion of aneurysms was lower in inferior MI (25% vs 78%, P = 0.008). Total activation times accounted for 65% +/- 23% and 50% +/- 22% of the VT cycle length in anterior and inferior infarcts, respectively (P = 0.005). Complete superficial reentry was identified in 12 VTs related to anterior infarcts and in only two VTs associated with inferior infarction (P = 0.038). Involvement of papillary muscles occurred in two patients with inferior MI. Patients with inferior infarcts received more cryolesions and required epicardial cryolesions or mitral valve replacement more frequently, and their operative mortality was greater (2/12 vs 0/18). Noninducibility rate (89.3%) and 2-year survival (76% +/- 8%) did not differ according to infarct location.

CONCLUSION

VT associated with inferior MI can be ablated successfully; however, the substrate is more complex, with frequent participation of intramural layers rendering the ablative procedure more difficult.

Large encircling cryoablation without mapping for ventricular tachycardia after anterior myocardial infarction: long-term outcome

OBJECTIVE

Map-guided procedures have been the accepted standard for ventricular tachycardia surgery. However, promising results of visually guided resections without mapping have been reported. The goal of this study was to evaluate the efficacy of large encircling cryoablation without mapping for ventricular tachycardia after anterior myocardial infarction.

METHODS

Between 1985 and 1996, this procedure, along with aneurysmectomy, was performed on 38 patients for malignant ventricular tachycardia. The mean interval between the operation and myocardial infarction was 59.2 months; 7 patients (18.4%) were operated on within 1 month of myocardial infarction. The mean patient age was 62.1 +/-7.3 years and the mean left ventricular ejection fraction was 29.0% +/-7.2%.

RESULTS

Hospital mortality was 2.6% (1 patient). The electrical success rate based on postoperative electrophysiologic studies was 94.5%. Overall electrical success rate was 89.1%. Freedom from ventricular tachycardia was 77% (95% CI 61%-94%) at both 5 and 7 years. Freedom from sudden cardiac death was 91% (95% CI 80%-100%) at both 5 and 7 years, with overall actuarial survivals at 5 and 7 years of 63% (95% CI 47%-80%) and 42% (95% CI 22%-63%), respectively. The main cause of late death was congestive heart failure in 62.6% of these patients.

CONCLUSIONS

One can achieve good results without intraoperative mapping in the treatment of patients with ventricular tachycardia after anterior myocardial infarction by using large encircling cryoablation.

Ablation therapy for cardiac arrhythmias

Ablation has become an important and, in some cases, the first-line therapy for a number of tachyarrhythmias. The feasibility of treating arrhythmias with ablation was initially demonstrated with surgical ablation techniques. Recently, catheter ablation techniques have replaced the surgical approach in nearly all cases. Catheter ablation is highly effective for the Wolff-Parkinson-White syndrome, atrioventricular nodal reentry, and atrial ectopic tachycardia. It is effective for atrial flutter, although approximately one quarter of patients treated with catheter ablation continue to require therapy for concomitant atrial fibrillation. The surgical maze procedure has proved to be feasible for preventing atrial fibrillation. The risks and long-term efficacy of catheter ablation maze procedures for atrial fibrillation need to be defined. The efficacy of ablation for ventricular tachycardia varies with the type of tachycardia. Catheter ablation is very effective for the rare idiopathic ventricular tachycardias that occur in structurally normal hearts and for bundle-branch reentry ventricular tachycardia, which occurs most frequently in patients with dilated cardiomyopathy. When performed at an experienced center, surgical ablation is an excellent option for selected patients with ventricular tachycardia due to prior myocardial infarction who have a discrete aneurysm but otherwise well-preserved ventricular function. Catheter ablation shows promise for this arrhythmia, but it can be offered only to those patients who have relatively slow tachycardias that allow catheter mapping. Substantial advances in mapping and ablation technology will continue to occur, allowing nonpharmacologic control of cardiac arrhythmias to be achieved in an ever greater number of patients.

Ventricular tachycardia after myocardial infarction: from arrhythmia surgery to catheter ablation

Ventricular tachycardia due to prior myocardial infarction is caused by reentry. Intraoperative mapping at the time of arrhythmia surgery has shown that the reentry circuits are diverse in size and location. Many circuits are large, extending over several square centimeters. Endocardial excision guided by activation sequence mapping, fractionated sinus rhythm electrograms, or visual identification of scarred subendocardium renders 69% to 95% of patients free from inducible ventricular tachycardia, but with an operative mortality that exceeds 8% at most centers. Catheter ablation is difficult due to limitations of catheter mapping, relatively small size of lesions produced with current techniques, and limited access to intramural and epicardial portions of the reentry circuits. Many problems need to be overcome for catheter ablation to achieve success comparable to that of surgery. At present, only hemodynamically tolerated ventricular tachycardias can be mapped. Progress is being made, and it is likely that catheter ablation will become a viable therapy for subgroups of patients with postmyocardial infarction ventricular tachycardia.