Transient dilated cardiomyopathy phenotype and positive Bartonella serology in a cat

A one-and-a-half-year-old spayed female domestic shorthaired cat, originally obtained as a stray, presented with a two-day history of lethargy, anorexia, and progressive dyspnea. Point-of-care ultrasound showed marked bilateral pleural effusion and a small volume of ascites. Thoracocentesis resulted in the removal of 220 mL of protein poor transudate. Subsequently, a gallop was auscultated and an echocardiogram was performed. Significant findings on echocardiography were a dilated cardiomyopathy phenotype characterized by biventricular eccentric hypertrophy with normal left ventricular diastolic wall thickness and reduced biventricular systolic function with biatrial enlargement. The cat was fed a standard diet and had adequate plasma and whole blood taurine concentration. Infectious disease testing detected Bartonella spp. immunoglobulin G antibodies (1:512) including Bartonella vinsonii of which the cat is not a natural reservoir host. The cat was treated for dilated cardiomyopathy and congestive heart failure with pimobendan, furosemide, and clopidogrel as well as with pradofloxacin and doxycycline for suspected bartonellosis. At 2.5-, 5-, and 9-month rechecks, echocardiogram findings were markedly improved with a reduction in atrial and ventricular chamber enlargement to normal and normal ventricular systolic function and without any further evidence of congestive heart failure. Repeat Bartonella spp. titers were unchanged at 2.5 months. This case describes reverse remodeling of a dilated cardiomyopathy phenotype and resolution of congestive heart failure with discontinuation of cardiac medications in a young cat with suspected Bartonella myocarditis.