Cardiac diagnostic test results and outcomes in 44 dogs naturally infected with Trypanosoma cruzi

Abstract

Background: The protozoal parasite Trypanosoma cruzi causes myocarditis in dogs.Objectives: To describe the cardiac diagnostic test results and outcomes of dogs naturally infected with T. cruzi.Animals: Forty-four client-owned dogs.Methods: Medical records were retrospectively reviewed to identify dogs with an indirect fluorescent antibody test result for T. cruzi ≥1 : 80. Data collected included signalment, cardiac diagnostic test results (ECG, echocardiography, cardiac troponin I) and outcome. Outcomes were categorized as alive, dead (cardiac or noncardiac) or lost to follow up.Results: ECG abnormalities were present in 41 dogs with ventricular arrhythmias (n = 28) and atrioventricular block (AVB) (n = 15) most commonly identified. Echocardiographic chamber enlargement was present in 28 dogs and most often included the right ventricle (RV) (n = 15) and left atrium (n = 12). Troponin was ≥2 times the reference range in 20/36 (56%) dogs. In univariate analysis using nonparametric Kaplan-Meier, ventricular arrhythmias with a modified Lown score ≥2 (P = .02

Antiparasitic treatment with itraconazole and amiodarone in 2 dogs with severe, symptomatic Chagas cardiomyopathy

“…The Rassi score incorporates 6 factors associated with increased risk of death in people including New York Heart Association class III or IV, presence of cardiomegaly on thoracic radiography, echocardiographic segmental or global wall motion abnormalities, nonsustained ventricular tachycardia on ambulatory ECG, low QRS voltage, and male sex 25 . In dogs with CCM, right ventricular enlargement as well as ventricular arrhythmias with a high, modified Lown score have been associated with worse outcomes 26,27 . Development of risk assessment scores might be useful in predicting survival including risk for sudden death in dogs with CCM.…”

Trypanosoma cruzi infection diagnosed in dogs in nonendemic areas and results from a survey suggest a need for increased Chagas disease awareness in North America

“…For dogs in this study, arrhythmias and cardiac remodeling were consistent with those reported with Chagas cardiomyopathy including the predominate finding of ventricular arrhythmias and combinations of arrhythmias. [26][27][28]30 In humans with Chagas cardiomyopathy, arrhythmias correlated to disease severity and outcome including risk of sudden death. 2 While cardiac arrhythmias can be the primary manifestation of Chagas disease in humans and dogs, Chagas cardiomyopathy is also characterized by myocardial dysfunction and congestive heart failure in the acute stage of the disease, in young dogs < 1 year of age, and in end-stage chronic infections.…”

“…5,6,29 In humans and dogs, remodeling of the right ventricle serves as a marker of overall severity of cardiac disease and has been associated with a worse prognosis. 26,30 While research efforts continue to work to identify effective prophylaxis and antiparasitic treatment for T cruzi infection in dogs, management is predominately symptomatic for cardiac disease.…”

Cardiac Magnetic Resonance Imaging Detects Myocardial Abnormalities in Naturally Infected Dogs with Chronic Asymptomatic Chagas Disease

“…with the following data recorded: duration of analysis, heart rate (average, maximum, minimum), presence and number of ventricular premature complexes, presence and number of supraventricular premature complexes, presence of supraventricular tachycardia, number of pauses over 3 s, longest pause > 4 s, and presence of second or third degree atrioventricular block. Ventricular arrhythmias were assigned a modified Lown score based on the highest grade observed as follows: 1 = single ventricular premature complexes, 2 = ventricular bigeminy or trigeminy, 3 = accelerated idioventricular rhythm, 4 = ventricular couplets or triplets, and 5 = ventricular tachycardia or R-on-T phenomenon [ 24 , 25 ].…”