Development of Denovo Hypertrophic Cardiomyopathy after 7 years of orthotopic heart transplant (QF_SA_123)

A 55-year-old female with a past medical history of hypertension, type 2 diabetes mellitus, atrial tachycardia, and familial non-ischemic dilated cardiomyopathy—diagnosed in 2010—complicated by congestive heart failure with a left ventricular (LV) ejection fraction (EF) of 15%. She underwent a LV assist device (LVAD) placement, followed by mitral, tricuspid, and aortic valve repair due to severely regurgitant valves. Three years later, she underwent orthotopic heart transplantation (Sept, 2014). The patient had been followed up yearly until September 2021, when TTE showed severely increased LV wall hypertrophy, at that time, she started to develop symptoms of exertional shortness of breath, orthopnea, and paroxysmal nocturnal dyspnea. She was extensively worked up for graft rejection with adjustments to her anti-rejection medications. There was also a concern for new-onset hypertrophic obstructive cardiomyopathy, for which mavacamten was suggested. However, the patient’s family eventually chose hospice care for palliative treatment.

Diagnostic Techniques and Their Most Important Findings:

During the course of the disease, there was progressive worsening of LV septal dimensions on TTE. However, the patient consistently refused to undergo cardiac magnetic resonance imaging (CMRI). In 2024, she finally underwent a CMRI, which showed concentric severe LV hypertrophy (LVH) with a maximum basal septal and basal lateral wall thickness of 23.9 mm and 22.9 mm respectively. There was normal left ventricular systolic function and wall motion, with a LVEF of 66% and evidence of global LV interstitial fibrosis (native T1 MOLLI sequence of 1103 msec - normal on a 1.5T scanner 975 ± 25 msec and ECV of 38%). There was no evidence of myocardial edema on T2 images. Delayed enhancement imaging revealed diffuse patchy late gadolinium enhancement (LGE) in the myocardium. The total % LGE was 21% (FWHM). Hypertrophic cardiomyopathy was suspected but cardiac amyloidosis was not completely ruled out. Patient refused Tc99 PYP scan as well as endomyocardial biopsy.

Learning Points from this Case:

This is the fourth reported case of de novo hypertrophic cardiomyopathy developing in a transplanted heart, underscoring its rarity and clinical significance. This case suggests that hypertrophic cardiomyopathy could be a potential cause of transplant failure, beyond the common assumption of graft rejection. Early recognition of this condition is crucial, as timely initiation of medications targeting the cardiac myosin ATPase system, alongside adjustments in anti-rejection therapy, could be beneficial. Also, during literature review, There are no reported cases of amyloid development in transplanted hearts. This case also highlights the critical role of multimodality imaging, including echocardiography and cardiac MRI, in early diagnosis and guiding management, thereby optimizing patient outcomes.