Juan D. Ramírez

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.

Ventricular Tachycardia in the Setting of Chagasic Cardiomyopathy: Use of Voltage Mapping to Characterize Endoepicardial Nonischemic Scar Distribution

Background: Chagasic cardiomyopathy (CC) is the most frequent nonischemic substrate causing left ventricular (LV) tachycardia in Latin America. Systematic characterization of the LV epicardial/endocardial scar distribution and density in CC has not been performed. Additionally, the usefulness of unipolar endocardial electroanatomic mapping to identify epicardial scar has not been assessed in this setting. Methods and Results: Nineteen patients with CC undergoing detailed epicardial and endocardial LV tachycardia mapping and ablation were included. A total of 8494 epicardial and 6331 endocardial voltage signals and 314 epicardial/endocardial matched pairs of points were analyzed. Basal lateral LV scar involvement was observed in 18 of 19 patients. Bipolar voltage mapping demonstrated larger epicardial than endocardial scar and core-dense (⩽0.5 mV) scar areas (28 [20–36] versus 19 [15–26] and 21 [2–49] versus 4 [0–7] cm2; P=0.049 and P=0.004, respectively). Bipolar epicardial and endocardial voltages within scar were low (0.4 [0.2–0.55] and 0.54 [0.33–0.87] mV, respectively) and confluent, indicating a dense/transmural scarring process in CC. The endocardial unipolar voltage value (with a newly proposed ⩽4-mV cutoff) predicted the presence and extent of epicardial bipolar scar (P<0.001). Conclusions: CC causes a unique ventricular tachycardia substrate concentrated to the basal lateral LV, with marked epicardial predominance. The scar pattern is particularly dense and transmural as compared with the more erratic/patchy scar patterns seen in other nonischemic cardiomyopathies. Endocardial unipolar voltage mapping serves to characterize epicardial scar in this setting.

Young Male With Incessantly Wide Complex Tachycardia: What Is the Substrate of the Arrhythmia?

A 26-year-old male with no past medical issues presented with 24-hour sudden onset palpitations, chest discomfort, and dizziness. He was hemodynamically stable and his heart rate was 189 bpm, with no other remarkable findings on physical examination. A 12-lead ECG (Figure 1) showed regular wide complex tachycardia with right bundle-branch block and extreme superior axis. Stepwise management was provided with vagal maneuvers, escalating doses of adenosine, uptitrated intravenous verapamil, and cardioversion with serial discharges ≤270 J of biphasic energy. However, all interventions were ineffective, and the tachycardia remained incessant. What is the arrhythmia, and what cardiac structure is involved in its origin? Figure 1. Twelve-lead ECG recorded in the emergency department showing a regular wide complex tachycardia with right bundle-branch block morphology and right superior axis deviation. Please turn the page to read the diagnosis. The ECG shows a regular wide complex tachycardia with right bundle-branch block morphology and right superior axis, suggesting a fascicular ventricular tachycardia (VT), poor responsiveness to intravenous verapamil, and cardioversion is not characteristic of this …

Role of intracardiac echocardiography for guiding ablation of tricuspid valve arrhythmias

Introduction Ventricular tachycardia and premature ventricular contractions (PVCs) arising from around the tricuspid valve (TV) annulus represent 8%–9% of idiopathic ventricular arrhythmias (VAs). Additionally, in some patients with nonischemic cardiomyopathy, the perivalvular region is a common source of VAs. Tada and colleagues showed that the outcomes of catheter ablation for TV arrhythmias are relatively modest. In our experience, the 3 main obstacles for ablation of these VAs are a prominent Eustachian ridge that sometimes interferes with advancing the catheter into the right ventricle (RV), the exaggerated annular mobility during the cardiac cycle that limits catheter stability, and the presence of the valve leaflets and chordae, which are often interposed between the tip of the catheter and the myocardial tissue. The same considerations apply for ablation of right-sided accessory pathways (APs) and explain why primary failure and recurrence rates are higher compared to ablation of left free-wall APs. In this report, we describe 5 cases that illustrate the utility of intracardiac echocardiography (ICE) to guide mapping and ablation of tricuspid annular arrhythmias. In all these cases an initial attempt of ablation had failed using the standard femoral approach.

Response by Miranda-Arboleda et al to Letter Regarding Article, “Young Male With Incessantly Wide Complex Tachycardia: What Is the Substrate of the Arrhythmia?”

We thank Wang and Zhao for their interest in our recently published article.1 We agree that the emergency department ECG is very suggestive of ventricular tachycardia, specifically of fascicular ventricular tachycardia (verapamil sensitive); however, the initial management with vagal maneuvers and adenosine, although usually reserved for supraventricular atrioventricular reciprocating tachycardias, can also provide diagnostic information by demonstrating atrioventricular dissociation and suggesting a ventricular …

CARDIOLOGÍA DEL ADULTO - PRESENTACIÓN DE CASOSAspergillus fumigatus en cardiodesfibrilador implantado cinco años antesAspergillus fumigatus in cardioverter defibrillator implanted five years ago

Fungal infections of cardiac devices infections are exceptional and the have only been a few reported cases reported for the Aspergillus species. Its diagnosis requires a high index of suspicion including complete removal of the device in order to document it. We describe a rare case of Aspergillus fumigatus infection five years after being implanted, complemented with a review of the literature and reviewing the main features of the largest reported series.