In the Weeds: Identifying the Underlying Etiology in a Patient with Suspected Hypertrophic Obstructive Cardiomyopathy

Abstract

BACKGROUND Many cases of Hypertrophic Obstructive Cardiomyopathy (HOCM) go undetected or are underdiagnosed. Patients are typically young athletes who experience decreased cardiac output, syncope with exercise, or sudden death. The disease is diagnosed with echo but cannot be certain unless a gene mutation is identified. This creates challenges for those who do not fit the classic profile nor have an identified gene mutation.

METHODS A 57 y.o. black female presented with a heart murmur. A referral was made to cardiology where imaging results pointed to HOCM, but due to a history of hypertension (HTN) and missing medical records, an underlying etiology of hypertrophy secondary to HTN could not be ruled out. Genetic testing for HOCM was negative despite the patient’s extensive family history of cardiac disease. Due to these conflicting findings, a cardiac MRI was performed. While HTN could not be ruled out as a contributing factor, HOCM was placed as the leading differential.

RESULTS The fragmentation of the patient’s medical records meant that the duration of the murmur and HTN is unknown. In addition, each cardiology provider had different interpretations of the radiologic imaging. The led to difficulties obtaining a diagnosis of HOCM vs HCM due to HTN.

Given that the patient did not fit the classic demographic presentation of HOCM, it is possible that the diagnosis was not initially considered. By the time a full work-up had been conducted, her HTN had been poorly controlled for years and therefore delineating the root cause of HOCM was difficult.

Lastly, the patient tested negative for the 24 gene mutations linked to HOCM, despite an extensive family history of cardiac disease. This highlights that there are likely more unknown mutations and there is a need for improved diagnostic criteria independent of genetic tests.

CONCLUSION This case demonstrates the importance of keeping an expanded differential diagnosis, maintaining coherent and comprehensive medical records, and pursuing prompt diagnoses.