Trypanosoma cruzi Cardiomyopathy Diagnosed via Explant Tissue 28S Ribosomal Gene Sequencing Following Orthotopic Heart Transplantation.

Trypanosoma cruzi, the protozoal agent responsible for Chagas disease, is a well-established cause of infectious cardiomyopathy. Diagnosing chronic Chagas cardiomyopathy can be exceptionally challenging due to the sparse presence of amastigotes in explanted cardiac tissue. We present a case of a 53-year-old male originally from Veracruz, Mexico, residing in the United States, who presented with rapidly progressive biventricular heart failure refractory to goal-directed medical therapy. The patient developed cardiogenic shock necessitating mechanical circulatory support and subsequent orthotopic heart transplantation. Histopathological evaluation of the explanted heart revealed end-stage dilated cardiomyopathy with mixed inflammatory infiltrates and poorly formed granulomas, but no visible amastigotes. Given the granulomatous pathology, a lab-developed 28S ribosomal gene sequencing assay was performed on the myocardial tissue, successfully identifying Trypanosoma cruzi. Subsequent recipient serological testing confirmed the diagnosis. Post-transplant molecular surveillance remained negative for parasitic reactivation under immunosuppression. This case highlights the critical utility of advanced molecular diagnostic techniques, such as tissue-based ribosomal gene sequencing, alongside traditional dual-methodology serology, to establish a definitive diagnosis of Chagas disease in atypical presentations and ensure appropriate post-transplant monitoring.