Catheter ablation of electrical storm in patients with structural heart disease.

AIMS: Electrical storm (ES) adversely affects prognosis of patients and may become a life-threatening event. Catheter ablation (CA) has been proposed for the treatment of ES. Our goal was to evaluate the efficacy of CA ablation both in acute and long-term suppression of ES. METHODS AND RESULTS: Fifty consecutive patients with coronary artery disease (38), idiopathic dilated cardiomyopathy (5), arrhythmogenic right ventricular cardiomyopathy (6), and/or with combined aetiology (1) underwent CA for ES. Mean left ventricular ejection fraction (LVEF) was 29 ± 11%. All patients underwent electroanatomical mapping, and CA was performed to abolish all inducible ventricular arrhythmias. The ES was suppressed by CA in 84% of patients. During the follow-up of 18 ± 16 months, 24 patients had no recurrences of any ventricular tachycardia (VT; 48%). Repeated procedure was necessary to suppress the recurrent ES in 13 cases (26%). Statistical analysis revealed that low LVEF (22 ± 3 vs. 31 ± 12%; P < 0.001), increased LVend-diastolic diameter (72 ± 9.1 vs. 64 ± 8.9 mm; P = 0.0135), and renal insufficiency (P < 0.001) were the univariate predictors of early mortality or necessity for heart transplantation. Recurrence of ES despite previous CA procedure was associated with a higher risk of death or heart transplant during follow-up (P < 0.05). CONCLUSION: Catheter ablation is effective in acute suppression of ES and often represents a life-saving therapy. In the long term, it prevents recurrences of any VT in about half of the treated patients.

Catheter ablation of arrhythmic storm triggered by monomorphic ectopic beats in patients with coronary artery disease.

BACKGROUND: Frequent episodes of polymorphic ventricular tachycardias/ventricular fibrillation (VT/VF) in patients with coronary artery disease can be triggered by monomorphic ventricular premature beats (VPBs) and thus, amenable to catheter ablation. The goal of this study was to review single-center experience in catheter ablation of electrical storm caused by focally triggered polymorphic VT/VF. METHODS: Catheter ablation of electrical storm due to focally triggered polymorphic VT/VF was performed in nine patients (mean age, 62+/-7 years; two females). All patients had previous myocardial infarction (interval of 3 days to 171 months). Mean left ventricular ejection fraction was 27+/-6 percent. All patients presented with repeated runs of polymorphic VT/VF triggered by monomorphic VPBs. RESULTS: Based on mapping data, the ectopic beats originated from scar border zone on interventricular septum (n=5), inferior wall (n=3), and lateral wall (n=1). Catheter ablation was performed to abolish the triggering ectopy and to modify the arrhythmogenic substrate by linear lesions within the infarct border zone. The ablation procedure was acutely successful in eight out of nine patients. During the follow-up of 13+/-7 months, two patients died due to progressive heart failure. One patient had late recurrence of electrical storm due to ectopic beats of different morphology and was successfully reablated. CONCLUSION: Electrical storm due to focally triggered polymorphic VT/VF may occur either in subacute phase of myocardial infarction or substantially later after index event. Catheter ablation of ectopic beats triggering these arrhythmias can successfully abolish electrical storm and become a life-saving procedure.

Omega-3 polyunsaturated Fatty Acid supplementation reduced atrial fibrillation recurrence after pulmonary vein antrum isolation.

OBJECTIVE: To assess if patients treated with omega-3(n-3) polyunsaturated fatty acids (PUFAS) had lower procedural failure rates compared to an untreated population. METHODS AND RESULTS: From January 2004 to 2007, 1500 PVAI patients underwent catheter ablation. Two hundred and eighty five (19%) patients were treated with PUFAs. These patients were matched in a nested case controlled analysis. After matching, there were 129 patients in the PUFA group and 129 in the control group. Thirty-five (27.1%) patients in the study group had early recurrence vs. 57 (44.1%) in the control group p-value< 0.0001. Twenty-nine (23.2%) patients in the PUFA group vs. 41 (31.7%) in the non-PUFA group had procedural failure (p-value < 0.003). There were no significant differences in complications in the PUFA and non-PUFA groups. CONCLUSION: Patients treated with PUFAs had lower incidences of early recurrence and procedural failure compared to an untreated population.

Pulmonary vein antrum isolation, atrioventricular junction ablation, and antiarrhythmic drugs combined with direct current cardioversion: survival rates at 7 years follow-up.

PURPOSE: To report survival rates in patients treated with pulmonary vein antrum isolation (PVAI), atrioventricular junctional ablation (AVJA), and antiarrhythmic and direct current cardioversion (A+DCCV) at 7 years follow-up. METHODS: From February 2002-December 2004, 1,000 consecutive patients underwent PVAI or A+DCCV or AVJA. These patients were matched in a nested casecontrolled methodology. Survival rates were compared at the end of 7 years. RESULTS: Three hundred and forty-five consecutive patients had undergone PVAI (34.5%), 157 (15.7%) consecutive patients AVJA, and 498(49.8%) A+DCCV. After matching the patients in a nested case-controlled methodology, 146 (32.3%) patients were in the PVAI group, 205 (59.4%) in the A+DCCV, and 101 (22.3%) in the AVJA. At 69+/-27 months, 63 (13.9%) patients had died in the matched population. Three (2.1%) patients died in the PVAI group, 34 (16.5%) in the A+DCCV group, and 26 (25.7%) in the AVJA group. In multivariable analysis, treatment strategy was a significant predictor of mortality. Compared to patients with PVAI (reference group), those with A+ DCCV (HR 4.9, p=0.011) and AVJA (HR 10.6, p=0.001) procedures had higher mortality risk. CONCLUSION: Compared to the other two procedures, patients with PVAI had the best survival rates at the end of 7 years. However, the observational case-control design of this study incurs the potential for confounding due to nonrandomized treatment selection, and creates a major limitation in making valid generalization of the findings.

Phrenic nerve injury after catheter ablation: should we worry about this complication?

INTRODUCTION: Phrenic nerve injury (PNI) is a complication that can occur with catheter ablation. METHODS: Data from 17 patients with PNI following different catheter ablation techniques were reviewed. PNI was defined as decreased motility (transient) or paralysis (persistent) of the hemi-diaphragm on fluoroscopy or chest X-ray. Patient's recovery was monitored. Normalization of chest images and sniff test would be considered as complete clinical recovery. RESULTS: Out of the 17 PNI patients (16 right, 1 left), 13 (11 persistent, 2 transient) occurred after pulmonary veins isolation with or without superior vena cava ablation. Three patients had persistent PNI after sinus node modification and one other patient experienced PNI after epicardial ventricular tachycardia ablation. Ablation was performed with different energy source including radiofrequency (n = 13), cryothermal (n = 1), ultrasound (n = 2) and laser (n = 1). Patient's symptoms varied broadly from asymptomatic to dyspnea, and even to respiratory insufficiency that required temporary mechanical ventilation support. Two patients with transient PNI resolved immediately after the procedure and the other 15 persistent PNI patients resolved within a mean time of 8.3 +/- 6.6 months. CONCLUSIONS: PNI caused by catheter ablation appears to functionally recover over time regardless of the energy sources used for the procedure.