Abstract 16396: A Tale of Two Maladies: An Interplay of Mendelian Principles

Abstract

A 22-year-old male with no medical history presented in acute decompensated heart failure and cardiogenic shock. Physical exam showed a thin body habitus, reduced muscle bulk, bilateral ptosis, limited extraocular motion, and upper extremity weakness. An echocardiogram revealed severe biventricular dilation and systolic dysfunction. Invasive hemodynamics revealed elevated cardiac filling pressures and low cardiac output. Coronary angiography excluded coronary artery disease and anatomical variants. He was initiated on dobutamine and eventually milrinone given persistently low index and elevated lactate. An evaluation for the etiology of his cardiomyopathy focused on nutritional deficiencies (e.g., Wet Beriberi), myocarditis, genetic mutations, infiltrative cardiomyopathy (e.g., Friedrich’s ataxia), and mitochondrial and myopathy-related cardiomyopathy. CMR had globally elevated T1 and normal T2 values ruling out acute myocarditis or infiltrative processes. Serum thiamine, TSH and B12 were within normal range. Muscle biopsy and mitochondrial genetic testing revealed a pathogenic deletion (m.7416_14556) and 70% heteroplasmy. Physical exam, biopsy and mitochondrial genetics were diagnostic of Kearns-Sayre Syndrome (KSS). Notably KSS does not typically cause severe cardiomyopathy suggesting an alternative cause. A genetic cardiomyopathy panel was sent revealing a pathologic mutation in the plakophilin 2 gene which was the suspected cause of his cardiomyopathy. A heart transplant evaluation was initiated as he developed refractory shock requiring mechanical support via an Impella 5.5, placed via the right innominate artery due to his small body and vessel size. He underwent an uncomplicated heart transplantation and is doing well. This case underscores the significance of a broad differential diagnosis, multidisciplinary collaboration, and a detailed physical examination in diagnosing and managing complex cardiac conditions.