Understanding the Apical Variant of Hypertrophic Cardiomyopathy

Article Summary
  1. Apical hypertrophic cardiomyopathy (HCM) is a rare condition, but not as rare as previously thought.
  2. Around 10% of HCM cases are apical, and rates are higher in patients of Asian ancestry.
  3. Echocardiography is the primary approach to diagnosis, but the condition may require special attention when imaging.

A 60-year-old man with a history of hypertension was admitted to the hospital after three days of a drooping face and right arm weakness. He had no chest pain or shortness of breath, and no prior history of irregular heartbeat. However, his echocardiogram was abnormal, and his high sensitivity troponin level was mildly to moderately elevated.

Doctors ordered STAT echocardiogram with saline contrast, but the initial images were perplexing – normal left ventricle function, no evidence of systolic anterior motion, and nothing to suggest an LVOT obstruction.

Then the sonographer shifted to an apical 4 chamber view.

“Bingo,” says Karen Fossile, BS, RDCS, technical director of echocardiography laboratories for Temple Health. “This is where we see it.”

The images showed clear signs of apical obliteration and thickening of the apex, indicators of apical hypertrophic cardiomyopathy.

Thought to be Rare in HCM Cases, the Apical Variant is More Common Than Realized

“First described by cardiologists in Japan, apical HCM was thought to be a rare form of the condition,” says Martin G. Keane, MD, FASE, director of echocardiography laboratories at Temple University Hospital, and professor of medicine at the Lewis Katz School of Medicine at Temple University. “But we now know the variant is more common than previously thought.”

In fact, this apical variant represents around 10% of HCM cases overall, and as many as 25% of cases in Asian patients.”

Notably, recent studies have revised mortality risk upward, he says.

“When it was first discovered, [mortality] was thought to be significantly lower than other forms of hypertrophic cardiomyopathy, but once again we were wrong,” Keane says. “Mortality is between 0.5% to 4%, comparable to hypertrophic obstructive cardiomyopathy.”

Diagnosing Apical HCM Using Echocardiography and Ultrasound

“Echocardiography is the primary approach to diagnosing apical HCM, as well as assessing severity and pattern,” says Keane. “In addition to assessing diagnostic criteria of apical HCM, providers should also look for signs of distal apical aneurism, and measure the apical systolic cavity obliteration length, as a length greater than 20 mm is associated with poor prognosis. Ultrasound-enhancing agents should be used in every case,” he adds.

Fossile notes that apical HCM can present some unique challenges to sonographers, and that these cases may require more investigation than typical HCM.

She and Keane share more insights into apical HCM in the presentation above.


Published

June 11, 2024

Expires

June 11, 2024

Presenters

Karen Fossile, BS, RDCS

Karen Fossile, BS, RDCS

Technical Director, Echocardiography Laboratories, Temple Health

Martin G. Keane, MD

Martin G. Keane, MD

Professor, Medicine | Medical Director, Echocardiography Laboratory, Temple University Hospital | Director, Echocardiography Research/Quantitative Echo, Temple University Hospital | Interim Chief, Cardiology Section, Temple University Hospital