Unraveling Dual Cardiomyopathy: Ischemic Etiology Complicated by Cardiac Amyloidosis

Abstract

Background: Heart failure (HF) is a major global health concern, defined by a complex clinical condition arising from structural and functional cardiac abnormalities. Cardiac amyloidosis is an increasingly recognised, albeit historically underdiagnosed, cause of infiltrative cardiomyopathy, often leading to restrictive physiology and HF, particularly HF with preserved ejection fraction (HFpEF). Aims: Dual cardiomyopathy, characterised by the coexistence of two distinct cardiac dysfunctions, poses significant diagnostic and therapeutic challenges. This case report highlights a unique instance of a patient diagnosed with both ischemic cardiomyopathy and cardiac amyloidosis. Presentation of Case: A 56-year-old male with a history of heart failure underwent catheterization. previously, in the last two years had a stent was implanted in the right coronary artery (RCA) and left anterior descending artery (LAD). He presented with worsening dyspnea and signs of pulmonary congestion. The patient was admitted to the cardiac intensive care unit (CVCU) and treated for fluid decongestion, achieving a negative fluid balance of -5000 cc over 48 hours. While his dyspnea initially improved, it recurred upon transfer to a general ward. Echocardiography revealed an ejection fraction of 56%, an E/e' ratio of 12, and left ventricular concentric hypertrophy. Subsequent coronary angiography during this admission confirmed patent stents. Cardiac magnetic resonance imaging (CMR) was performed to assess myocardial viability, revealing infiltrative disease consistent with cardiac amyloidosis, characterised by hypertrophied myocardium (LVMI 101 g/m²; normal range 38-67 g/m²) and poor nulling of myocardium signal on T1 look locker and diffuse fibrosis late gadolinium enhancement (LGE) images. Analysis of free light chains indicated elevated kappa chains and normal lambda chains, maintaining a normal kappa/lambda ratio ruled out AL type cardiac amyloidosis. The patient was diagnosed with ischemic cardiomyopathy and non-ischemic cardiomyopathy due to transthyretin amyloidosis (ATTR). The recommended management for this dual cardiomyopathy includes heart failure therapy targeting ischemic cardiomyopathy with SGLT2 inhibitors and specific treatment for ATTR amyloidosis using tafamidis. Discussion and Conclusion: Worsening dyspnea in heart failure patients is often attributed to exacerbations of heart failure. In patients with coronary artery disease, it is frequently associated with ischemic cardiomyopathy. This highlights the importance of cardiac magnetic resonance imaging to assess myocardial viability and to investigate potential non-ischemic causes, thereby facilitating the development of appropriate treatment strategies. This report describes a case of dual cardiomyopathy involving both ischemic heart disease and transthyretin cardiac amyloidosis in a patient presenting with refractory heart failure despite patent coronary stents. It highlights the critical importance of maintaining a high index of suspicion for alternative or coexisting cardiac pathologies in patients with known CAD whose clinical course is atypical or refractory to standard therapy.