Electrophysiologic-structural correlations in chagasic aneurysms causing malignant arrhythmias

Epicardial and Endocardial Ablation Based on Channel Mapping in Patients With Ventricular Tachycardia and Chronic Chagasic Cardiomyopathy: Importance of Late Potential Mapping During Sinus Rhythm to Recognize the Critical Substrate

Background

Ventricular tachycardia (VT) in patients with chronic chagasic cardiomyopathy (CCC) is associated with considerable morbidity and mortality. Catheter ablation of VT in patients with CCC is very complex and challenging. The main goal of this work was to assess the efficacy of VT catheter ablation guided by late potentials (LPs) in patients with CCC.

Methods and Results

Seventeen consecutive patients with refractory VT and CCC were prospectively included in the study. Combined endo‐epicardial voltage and late activation mapping were obtained during baseline rhythm to define scarred and LP areas, respectively. The end point of the ablation procedure was the elimination of all identified LPs. Epicardial and endocardial dense scars (<0.5 mV) were detected in 17/17 and 15/17 patients, respectively. LPs were detected in the epicardial scars of 16/17 patients and in the endocardial scars of 14/15 patients. A total of 63 VTs were induced in 17 patients; 22/63 (33%) were stable and entrained, presenting LPs recorded in the isthmus sites. The end point of ablation was achieved in 15 of 17 patients. Ablation was not completed in 2 patients because of cardiac tamponade or vicinity of the phrenic nerve and circumflex artery. Three patients (2 with unsuccessful ablation) had VT recurrence during follow‐up (39 months).

Conclusions

Endo‐epicardial LP mapping allows us to identify the putative isthmuses of different VTs and effectively perform catheter ablation in patients with CCC and drug‐refractory VTs.

Advanced management of ventricular arrhythmias in chronic Chagas cardiomyopathy

Chagas cardiomyopathy is a parasitic infection caused by Trypanosoma cruzi. Structural and functional abnormalities are the result of direct myocardial damage by the parasite, immunological reactions, dysautonomia, and microvascular alterations. Chronic Chagas cardiomyopathy (CCC) is the most serious and important manifestation of the disease, affecting up to 30% of patients in the chronic phase. It results in heart failure, arrhythmias, thromboembolism, and sudden cardiac death. As in other cardiomyopathies, scar-related reentry frequently results in ventricular tachycardia (VT). The scars typically are located in the inferior and lateral aspects of the left ventricle close to the mitral annulus extending from endocardium to epicardium. The scars may be more prominent in the epicardium than in the endocardium, so epicardial mapping and ablation frequently are required. Identification of late potentials during sinus rhythm and mid-diastolic potentials during hemodynamically tolerated VT are the main targets for ablation. High-density mapping during sinus rhythm can identify late isochronal regions that are then targeted for ablation. Preablation cardiac magnetic resonance imaging with late enhancement can identify potentials areas of arrhythmogenesis. Therapeutic alternatives for VT management include antiarrhythmic drugs and modulation of the cardiac autonomic nervous system.

Advanced Therapies for Ventricular Arrhythmias in Patients With Chagasic Cardiomyopathy: JACC State-of-the-Art Review

Chagas disease is caused by infection from the protozoan parasite Trypanosoma cruzi. Although it is endemic to Latin America, global migration has led to an increased incidence of Chagas in Europe, Asia, Australia, and North America. Following acute infection, up to 30% of patients will develop chronic Chagas disease, with most patients developing Chagasic cardiomyopathy. Chronic Chagas cardiomyopathy is highly arrhythmogenic, with estimated annual rates of appropriate implantable cardioverter-defibrillator therapies and electrical storm of 25% and 9.1%, respectively. Managing arrhythmias in patients with Chagasic cardiomyopathy is a major challenge for the clinical electrophysiologist, requiring intimate knowledge of cardiac anatomy, advanced training, and expertise. Endocardial-epicardial mapping and ablation strategy is needed to treat arrhythmias in this patient population, owing to the suboptimal long-term success rate of endocardial mapping and ablation alone. We also describe innovative approaches to improve acute and long-term clinical outcomes in patients with refractory ventricular arrhythmias following catheter ablation, such as bilateral cervicothoracic sympathectomy and bilateral renal denervation, among others.

Cardiac magnetic resonance imaging in Chagas' disease: a parallel with electrophysiologic studies

Chagas' disease (CD), caused by the parasite Trypanosoma cruzi, is the leading cause of cardiac disability from infectious diseases in Central and South America. The disease progresses through an extended, asymptomatic form characterized by latency without clinical manifestations into a symptomatic form with cardiac and gastro-intestinal manifestations. In the terminal phase, chronic Chagas' myocarditis results in extensive myocardial fibrosis, chamber enlargement with aneurysms and ventricular tachycardia (VT). Cardiac magnetic resonance imaging (CMR) has proven useful in characterizing myocardial fibrosis (MF). Sub-epicardial and mid-wall fibrosis are less common patterns of MF in CHD than transmural scar, which resembles myocardial infarction. Commonly involved areas of MF include the left ventricular apex and basal infero-lateral wall, suggesting a role for watershed ischemia in the pathophysiology of MF. Electrophysiology studies have helped refine the relationship between MF and VT in this setting. This article reviews the patterns of MF in CHD and correlate these patterns with electrogram patterns to predict risk of ventricular arrhythmias and sudden death.

Chagas Cardiomyopathy: An Update of Current Clinical Knowledge and Management: A Scientific Statement From the American Heart Association

Background:

Chagas disease, resulting from the protozoan Trypanosoma cruzi , is an important cause of heart failure, stroke, arrhythmia, and sudden death. Traditionally regarded as a tropical disease found only in Central America and South America, Chagas disease now affects at least 300 000 residents of the United States and is growing in prevalence in other traditionally nonendemic areas. Healthcare providers and health systems outside of Latin America need to be equipped to recognize, diagnose, and treat Chagas disease and to prevent further disease transmission.

Methods and Results:

The American Heart Association and the Inter-American Society of Cardiology commissioned this statement to increase global awareness among providers who may encounter patients with Chagas disease outside of traditionally endemic environments. In this document, we summarize the most updated information on diagnosis, screening, and treatment of T cruzi infection, focusing primarily on its cardiovascular aspects. This document also provides quick reference tables, highlighting salient considerations for a patient with suspected or confirmed Chagas disease.

Conclusions:

This statement provides a broad summary of current knowledge and practice in the diagnosis and management of Chagas cardiomyopathy. It is our intent that this document will serve to increase the recognition of Chagas cardiomyopathy in low-prevalence areas and to improve care for patients with Chagas heart disease around the world.

Prevalence and Impact of Chagas Disease Among Latin American Immigrants With Nonischemic Cardiomyopathy in Los Angeles, California

Background—

Chagas disease is a well-known cause of cardiomyopathy in Latin America; however, 300 000 individuals are estimated to have Chagas disease in the United States. This study examined the prevalence and impact of Chagas cardiomyopathy (CCM) in a US population. We hypothesized that patients with CCM would have increased morbidity and mortality when compared with patients with non-CCM.

Methods and Results—

This is a single-center, prospective cohort study. Enrollment criteria were new diagnosis of nonischemic cardiomyopathy (left ventricular ejection fraction ≤40%) and previous residence in Latin America for at least 12 months. Serological testing for Trypanosoma cruzi was performed at enrollment. The primary end point was all-cause mortality or heart transplantation. The secondary end point was heart failure–related hospitalization. A total of 135 patients were enrolled, with a median of 43 months of follow-up. Chagas disease was diagnosed in 25 (19%) patients. The primary end point occurred in 9 patients (36%) in the CCM group and in 11 patients (10%) in the non-CCM group (hazard ratio [HR], 4.46; 95% confidence interval, 1.8–10.8; P =0.001). The secondary end point occurred in 13 patients (52%) in the CCM group and in 35 patients (32%) in the non-CCM group (HR, 2.22; 95% confidence interval, 1.2–4.2; P =0.01).

Conclusions—

There is a high prevalence of Chagas disease among Latin American immigrants diagnosed with nonischemic cardiomyopathy in Los Angeles. Advanced CCM portends a poor prognosis and is associated with increased all-cause mortality/heart transplantation and heart failure–related hospitalization.

Arrhythmias in chagasic cardiomyopathy

Chagas disease, a chronic parasitosis caused by the protozoa Trypanosoma cruzi, is an increasing worldwide problem because of the number of cases in endemic areas and the migration of infected individuals to more developed regions. Chagas disease affects the heart through cardiac parasympathetic neuronal depopulation, immune-mediated myocardial injury, parasite persistence in cardiac tissue with secondary antigenic stimulation, and coronary microvascular abnormalities causing myocardial ischemia. A lack of knowledge exists for risk stratification, management, and prevention of ventricular arrhythmias in patients with chagasic cardiomyopathy. Catheter ablation can be effective for the management of recurrent ventricular tachycardia.

Chagas' heart disease

Chagas' disease is caused by a protozoan parasite, Trypanosoma cruzi, that is transmitted to humans through the feces of infected bloodsucking insects in endemic areas of Latin America, or occasionally by nonvectorial mechanisms, such as blood transfusion. Cardiac involvement, which typically appears decades after the initial infection, may result in cardiac arrhythmias, ventricular aneurysm, congestive heart failure, thromboembolism, and sudden cardiac death. Between 16 and 18 million persons are infected in Latin America. The migration of infected Latin Americans to the United States or other countries where the disease is uncommon poses two problems: the misdiagnosis or undiagnosis of Chagas' heart disease in these immigrants and the possibility of transmission of Chagas' disease through blood transfusions. Diagnosis is based on positive serologic tests and the clinical features. The antiparasitic drug, benznidazole, is effective when given for the initial infection and may also be beneficial for the chronic phase. The use of amiodarone, angiotensin-converting enzyme inhibitors, and pacemaker implantation may contribute to a better survival in selected patients with cardiac involvement of chronic Chagas' disease.

Prognostic impact of Chagas disease in the United States

A prior publication from our group reported the fact that Chagas disease is underdiagnosed. This review will summarize several aspects of Chagas disease in the United States including modes of transmission, which will demonstrate that clinicians should be more aware of the disease and its consequences. Trypanosoma cruzi is present in many animal species spread throughout most of the United States. Chagas disease also reaches the North American continent through immigration, making it more frequent than expected. Apart from immigration, non-endemic countries should be aware of transmissions through blood transfusions, organ transplantations, or mother-to-child infections. In conclusion, it is possible that many chagasic cardiomyopathies are being misdiagnosed as "primary dilated idiopathic cardiomyopathies." Recognizing that there is an evident threat of Chagas disease present in the United States will allow an increase of clinician's awareness and hence will permit to correctly diagnose and treat this cardiomyopathy. Health authorities should guarantee a generalized screening of T cruzi of blood donors, before organ donations, and of pregnant women who were born or have lived in endemic areas.

[Heart pathology of extracardiac origin (V). Recent advances in chagasic cardiomyopathy]

INTRODUCTION AND OBJECTIVES

Chronic Chagas' heart disease is an important public health problem in Latin America. Rural migration from endemic to nonendemic countries has aroused widespread interest (United States, Spain) because of the possibility of observing affected patients.

METHODS

Review of recent literature.

RESULTS

The diagnosis of Chagas' cardiomyopathy is based on the triad of epidemiological history, positive serology and the clinical Chagas' syndrome. About 75% of asymptomatic seropositive subjects had no or almost no heart damage but the disease could be transmitted by blood donation. The other 25% may develop arrhythmias, heart failure and/or embolisms. Specific parasiticidal drugs are mainly used in the acute phase.

CONCLUSIONS

In countries where Chagas' disease is infrequent, patients may be inadvertently diagnosed as having primary dilated or ischemic cardiomyopathy. Disease reactivation in immunodepressed patients due to AIDS, chemotherapy for cancer or for organ transplantation constitutes a formidable clinical challenge. Sanitary prophylactic measures are the strategies of choice.

The apical ventricular lesion in Chagas' heart disease

Apical lesions of the left ventricle, ranging from endocardial thickening to aneurysms, are commonly found in Chagas' heart disease. These abnormalities can be identified by ventriculography, two-dimensional echocardiography and radioisotopic studies. Generally, clinical manifestations are limited to arrhythmias and thromboembolic. The lesions are usually small and apparently do not play a role in ventricular dysfunction.