Caroline Foote

Arrhythmogenic right ventricular dysplasia: clinical results with implantable cardioverter defibrillators.

Arrhythmogenic right ventricular dysplasia is a clinical entitycharacterized by fatty infiltration of the right ventricle and left bundlemorphology ventricular tachycardia occurring in young patients. The mostcommon cause of death is tachyarrhythmic. Pharmacological andnonpharmacological therapies, including implantable cardioverterdefibrillators, have been used to treat the arrhythmias. However, rightventricular endocardial leads in this population may be associated with anincreased risk of perforation and suboptimal sensing and defibrillationefficacy due to the diseased right ventricle. We report on 12 patients witharrhythmogenic right ventricular dysplasia who were treated with implantablecardioverter defibrillators. The mean age was 31± 9 years (range15-48). Patients presented with presyncope (5), syncope (4), or cardiacarrest (3). All patients had electrocardiographic abnormalitiescharacteristic of the condition.Follow-up averaged 22 ± 13months (range 1-45). There was one sudden death at 1 month of follow-up. Ofthe 12 patients, 8 have had appropriate therapy delivered by the implantabledefibrillator. Six patients are currently on sotalol to reduce the frequencyof implantable defibrillator discharges. In conclusion, implantablecardioverter defibrillators with nonthoracotomy leads are feasible and safein patients with arrhythmogenic right ventricular dysplasia. The frequencyof appropriate therapy is high, supporting the use of implantablecardioverter defibrillators in this population.During programmedelectrical stimulation nine patients had sustained ventricular tachycardia,while three patients had no inducible arrhythmia. Transvenous leads wereplaced in nine patients. In these patients pacing thresholds weresignificantly higher, R-wave amplitudes were significantly lower, anddefibrillation thresholds were not significantly different than in a cohortof patients without right ventricular dysplasia. There were no acute orchronic complications of right ventricular lead placement.

Comparison of frequency of complications of implantable cardioverter-defibrillators in children versus adults

Compared with adults patients (n = 309) receiving implantable cardioverter-defibrillators at the same institution, pediatric patients (n = 11) exhibited a trend toward lower defibrillation thresholds. At follow-up of 29 +/- 17 months, the incidence of recurrent arrhythmias was similar, but lead revisions and device infections were more common in the pediatric patients.

Perioperative and Long-term Results With Mapping-Guided Subendocardial Resection and Left Ventricular Endoaneurysmorrhaphy

BACKGROUND Surgical ablation of the arrhythmogenic focus in patients with life-threatening ventricular tachyarrhythmias can be curative. However, the surgical techniques have been plagued by a high perioperative mortality rate (averaging approximately 12%). Reconstruction of the left ventricle may reduce mortality. METHODS AND RESULTS Reconstruction of the left ventricle with a pericardial patch, or endoaneurysmorrhaphy, was performed with mapping-guided subendocardial resection for recurrent ventricular tachycardia in 25 patients over a 5-year period. Postoperatively, electrophysiological studies were conducted to assess the results of surgery, which were further evaluated during long-term follow-up with survival analyses. The study included 25 patients, 60 +/- 9 years of age, with coronary artery disease, discrete left ventricle aneurysms, and malignant ventricular tacharrhythmias. Left ventricular ejection fraction was 24 +/- 6% preoperatively. Left ventricular endocardial mapping, endocardial resection, and endoaneurysmorrhaphy were performed in all patients. There was no operative or postoperative (30-day) mortality. Postoperative ventricular tachycardia was induced in 2 of the 25 patients (8%); left ventricular function increased to 32 +/- 9% (range, 19% to 52%). At a mean follow-up of 37 +/- 16 months (range, 6 to 65 months), there had been 6 deaths, including 1 sudden cardiac death, 2 congestive heart failure deaths, and 3 noncardiac deaths. Analysis of multiple variables failed to identify predictors of postoperative inducibility, sudden cardiac death, cardiac death, or total mortality. CONCLUSIONS Endoaneurysmorrhaphy with a pericardial patch combined with mapping-guided subendocardial resection frequently cures recurrent ventricular tachycardia with low operative mortality and improvement of ventricular function. Long-term follow-up demonstrates low sudden cardiac death rates.

Primary Lymphoma of the Heart

Apreviously healthy 65-year-old woman presented with palpitations and positional chest discomfort 3 weeks after she sustained chest wall trauma in a motor vehicle accident. Physical examination revealed occasional premature ventricular beats and low-grade fever. Her erythrocyte sedimentation rate was elevated (66 mm/h). Transthoracic and transesophageal echocardiography revealed a 3×3-cm, well-demarcated, homogeneous, round mass moving with the heart adjacent to the right atrium (Figures 1A, B). There was invagination of nearby cardiac chambers but no obstruction to right heart filling. MRI showed a circumscribed mass with dense tissue characterization (isointense to myocardium) not consistent with blood or fat (Figure 2A). There was minimal enhancement of the mass after gadolinium injection. Coronary angiography was normal. Two weeks later, …

Antiarrhythmic Drug Therapy for Ventricular Arrhythmias: Current Perspectives

Antiarrhythmic Drug Therapy. Pharmacologic therapy for ventricular arrhythmias has undergone a remarkable change recently. Recognition of the importance of underlying structural heart disease on prognostic implications of ventricular arrhythmias has resulted in the refinement of the clinical classification of these arrhythmias. With refinement of techniques of risk stratification, it is now possible to identify patients with ventricular arrhythmias at high risk for sudden death. Retrospective analyses of prior antiarrhythmic drug trials and new data from prospective randomized trials are now available and can more directly define the risks and benefits of antiarrhythmic therapy. Prevention of sudden death, reduction in total mortality, or improvement in symptoms remain the only benefits of antiarrhythmic drugs. With inclusion of total mortality as the major endpoint for assessment of pharmacologic interventions in high‐risk patients, the potential for excess mortality due to antiarrhythmic agents is now recognized. The pharmacologic diversity of newly released antiarrhythmic agents and others under development has resulted in a re‐evaluation of the traditional classification of these drugs. Multiple ongoing clinical trials will define the risks and benefits of antiarrhythmic therapy and other nonpharmacologic interventions in patients with ventricular arrhythmias.

ATRIOVENTRICULAR JUNCTIONAL ABLATION AND MODIFICATION FOR ATRIAL FIBRILLATION

RF catheter ablation is a safe and extremely effective method of achieving complete A-V block in patients with difficult-to-control ventricular rates in atrial fibrillation. In selected patients, A-V junction ablation may improve exercise capacity and functional status while reducing the need for emergency care and hospitalization. Prospective, randomized studies are needed, however, to compare A-V junction ablation as a management strategy to pharmacologic therapy to control ventricular rate or to maintain sinus rhythm. Similarly, additional data are needed to assess methods of achieving A-V junction modification with the lowest risk for A-V block.

Transcoronary Ethanol Ablation of the Atrioventricular Node in a Young Patient with Tricuspid Atresia

Catheter ablation of AV conduction with radiofrequency energy can be challenging in the presence of structural abnormalities of the AV junction, either congenitally or after reconstructive surgery. We used transcoronary ethanol to ablate the AV node in a patient with classic tricuspid atresia and refractory intraatrial reentry tachycardia. This approach provides an alternative means of creating complete heart block with catheter‐based techniques, when radiofrequency catheter ablation is technically impossible or ineffective.

Interdisciplinary strategies for arrhythmia program development: measuring quality, performance, and outcomes

Evidence-based medicine has provided the foundation for refinement of the guideline development process and the emergence of the disciplines of measuring quality, performance, and outcomes. With implementation of electronic medical records as part of healthcare reform, multiple aspects of these disciplines will be incorporated into clinical cardiac electrophysiology. Performance measures and quality metrics will assume an influential role in the management of patients with heart rhythm disturbances in the near future.

The Open Artery: Electrophysiologic Considerations

Prompt opening of the infarct-related artery reduces mortality and subsequent morbid events. Not all benefit of timely thrombolysis or angioplasty appears to be accounted for by myocardial preservation. A favorable modification of the electrophysiologic postinfarction milieu by a patent infarct-related artery has been proposed to help explain this improved outcome. This review investigates the support for such a hypothesis. Long-term follow-up data from controlled trials is scarce but suggests that episodes of life-threatening ventricular arrhythmias and sudden cardiac death are less frequent after thrombolysis with a patent infarct-related artery. The preponderance of data investigate the modification of postinfarction risk stratification parameters, including the signal-averaged electrocardiogram, assessment of heart-rate variability, response to programmed extrastimuli, and dispersion of refractoriness. Reduction of the incidence of late potentials after thrombolysis has been reported by many, but not all, investigators. Differences in signal-averaging technique and timing may help explain the disparity of findings. A patent infarct-related artery is associated with a reduction in late potential incidence. Heart-rate variability, a measure of autonomic balance, appears to be improved in those high-risk patients who receive thrombolysis. Likewise, most investigators reported an association of improved heart-rate variability with a patent infarct-related artery. QT interval dispersion, a measure of ventricular arrhythmic risk, declines as antegrade infarct-related artery flow improves. High-risk patients undergoing programmed extrastimuli have a lower incidence of inducibility and an improved response to pharmacologic therapy after thrombolysis or with a patent infarct-related artery. The mechanisms of arterial flows modulation of electrophysiologic substrate remains to be elucidated. Long-term follow-up of large post-infarction populations will be necessary to demonstrate benefit conclusivel y.

Combined radiofrequency ablation-cooling catheter for reversible cryothermal mapping and ablation.

Reversible cryothermal mapping of cardiac arrhythmias has beenperformed intraoperatively. However, a steerable cooling catheter forreversible mapping has not yet been developed. We therefore developed andtested a cooling system consisting of a +15°C hypertonic salinereservoir and a 7F steerable catheter also capable of radiofrequency (RF)ablation. Using excised ovine hearts placed in a 37°C circulating salinebath, we measured the temperatures at depths of 0 mm, 1 mm, and 2 mm. Thetemperature after 90 seconds of cooling was 16.5 ± 2.1°C at 0 mmcompared to 23.9 ± 4.1°C at 1 mm and 31.1 ± 3.9°C at 2mm depth (p < 0.01). These data suggest that a 7F steerable combined RFablation–cooling catheter may achieve temperatures suitable formapping arrhythmias such as atrial tachycardias and right ventricularoutflow tract tachycardias. Further enhancements to achieve lowertemperatures at depth may be needed to reversibly map other arrhythmiassuch as left ventricular tachycardias.