Adjuvant antiarrhythmic therapy in patients with implantable cardioverter defibrillators

Chagas cardiomyopathy and heart failure: From epidemiology to treatment

Chagas disease is among the neglected tropical diseases recognized by the World Health Organization that have received insufficient attention from governments and health agencies. Chagas disease is endemic in 21 Latin America regions. Due to globalization and increased migration, it has crossed borders and reached other regions including North America and Europe. The clinical presentation of the disease is highly variable, from general symptoms to severe cardiac involvement that can culminate in heart failure. Chagas heart disease is multifactorial, and can include dilated cardiomyopathy, thromboembolic phenomena, and arrhythmias that may lead to sudden death. Diagnosis is by methods such as enzyme-linked immunosorbent assay (ELISA) and the degree of cardiac involvement should be investigated with complementary exams including ECG, chest radiography and electrophysiological study. There have been insufficient studies on which to base specific treatment for heart failure due to Chagas disease. Treatment should therefore be derived from guidelines for heart failure that are not specific for this disease. Heart transplantation is a viable option with satisfactory success rates that has improved survival.

Chagas Disease and Heart Failure: An Expanding Issue Worldwide

Chagas disease, originally a South American endemic health problem, is expanding worldwide because of people migration. Its main impact is on the cardiovascular system, producing myocardial damage that frequently results in heart failure. Pathogenic pathways are mainly related to inmunoinflamatory reactions in the myocardium and, less frequently, in the gastrointestinal tract. The heart usually shows fibrosis, producing dilatation and damage of the electrogenic cardiac system. These changes result in cardiomyopathy with heart failure and frequent cardiac arrhythmias and heart blocks. Diagnosis of the disease must include a lab test to detect the parasite or its immune reactions and the usual techniques to evaluate cardiac function. Therapeutic management of Chagas heart failure does not differ significantly from the most common treatment for dilated cardiomyopathy, with special focus on arrhythmias and several degrees of heart block. Heart transplantation is reserved for end-stage cases. Major international scientific organisations are delivering recommendations for prevention and early diagnosis. This article provides an analysis of epidemiology, prevention, treatment and the relationship between Chagas disease and heart failure.

Differences in amiodarone efficacy in relation to ejection fraction and basal rhythm in patients with implantable cardioverter defibrillators

BACKGROUND

Atrial fibrillation (AF) and ventricular arrhythmias (VAs) are associated with increased morbidity and mortality. However, data are lacking concerning the association of AF and VAs. This study aimed to clarify the association between AF and VAs and to investigate the effect of amiodarone on the incidence of VAs in patients with implantable cardioverter defibrillators (ICDs).

METHODS AND RESULTS

We enrolled 612 patients who had ICDs or who underwent cardiac resynchronization therapy with a defibrillator (CRT-D) and classified them into two groups (sinus rhythm [SR] group, n = 427; AF group, n = 185) according to their basal rhythm at enrollment. Patients with paroxysmal AF were grouped into the AF group. The incidence of VAs, i.e., ventricular tachycardia (VT) and ventricular fibrillation (VF), was significantly lower in the AF group than in the SR group (0.54 vs 0.95 episodes/person/year, P = 0.032). Furthermore, amiodarone use was significantly higher in the AF group than in the SR group (P = 0.003). Non-use of amiodarone was associated with a significant increase in the occurrence of VT/VF in the two groups. This beneficial suppressive effect of amiodarone on the incidence of VT/VF was present in the AF group regardless of left ventricular ejection fraction (LVEF). However, this effect of amiodarone was present only in patients with LVEF ≥ 40% in the SR group.

CONCLUSIONS

Amiodarone was negatively associated with VT/VF occurrence and was frequently used in ICD/CRT-D patients with AF. VT/VF was controlled by amiodarone in all cases in the AF group but only in patients with an LVEF ≥ 40% in the SR group.

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.

Intravenous Sotalol - Reintroducing a Forgotten Agent to the Electrophysiology Therapeutic Arsenal

Sotalol is a racemic mixture possessing beta-blocker and class III anti arrhythmic properties. Approved by US food and drug administration (FDA) since 2009 based on its bioequivalence with oral sotalol, clinicians are less familiar with the potential uses of the intravenous form despite its re-launch in United States in 2015. Available literature suggests that intravenous sotalol in recommended doses can be safely administered in adult and pediatric population achieving rapid reliable therapeutic plasma concentration and without additional proarrhythmic effects when compared to its oral form as well as other antiarrhythmic medications. Intravenous sotalol may have potential uses as an alternative agent for highly symptomatic atrial fibrillation post cardiac surgery as well as in life threatening ventricular arrhythmias. As with its oral form, judicious use with close attention to QTc and renal function is warranted. Further studies are needed to better understand the safety, efficacy and different dosing regimens of parenteral sotalol in adults and children.

Long-term pretreatment with desethylamiodarone (DEA) or amiodarone (AMIO) protects against coronary artery occlusion induced ventricular arrhythmias in conscious rats

The aim of this investigation was to compare the effectiveness of long-term pretreatment with amiodarone (AMIO) and its active metabolite desethylamiodarone (DEA) on arrhythmias induced by acute myocardial infarction in rats. Acute myocardial infarction was induced in conscious, male, Sprague–Dawley rats by pulling a previously inserted loose silk loop around the left main coronary artery. Long-term oral pretreatment with AMIO (30 or 100 mg·(kg body mass)−1·day−1, loading dose 100 or 300 mg·kg−1 for 3 days) or DEA (15 or 50 mg·kg−1·day−1, loading dose 100 or 300 mg·kg−1 for 3 days), was applied for 1 month before the coronary artery occlusion. Chronic oral treatment with DEA (50 mg·kg−1·day−1) resulted in a similar myocardial DEA concentration as chronic AMIO treatment (100 mg·kg−1·day−1) in rats (7.4 ± 0.7 μg·g−1 and 8.9 ± 2.2 μg·g−1). Both pretreatments in the larger doses significantly improved the survival rate during the acute phase of experimental myocardial infarction (82% and 64% by AMIO and DEA, respectively, vs. 31% in controls). Our results demonstrate that chronic oral treatment with DEA resulted in similar cardiac tissue levels to that of chronic AMIO treatment, and offered an equivalent degree of antiarrhythmic effect against acute coronary artery ligation induced ventricular arrhythmias in conscious rats.