Show notes
CardioNerds (Drs. Teodora Donisan, Jenna Skowronski, and Johnny Hourmozdi) discuss Cardiomyopathies with Dr. Steve Ommen. Through a case-based discussion, we review the diagnostic evaluation of suspected restrictive cardiomyopathy, and Dr. Ommen shares his expertise in the nuances of caring for patients with hypertrophic cardiomyopathy, from counseling to pharmacologic, device, and septal reduction therapies. We cover the foundations of diagnosis and management that will be helpful to CardioNerds preparing to encounter hypertrophic cardiomyopathy on the boards or on the wards.
Dr. Johnny Hourmozdi drafted notes. The audio was engineered by Dr. Atefeh Ghorbanzadeh.
The CardioNerds Beyond the Boards Series was inspired by the Mayo Clinic Cardiovascular Board Review Course and designed in collaboration with the course directors Dr. Amy Pollak, Dr. Jeffrey Geske, and Dr. Michael Cullen.
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Pearls and Quotes - Cardiomyopathies
The presence of an S4 and a rapid y-descent in the jugular venous pulsation on exam should clue you to the presence of a restrictive filling pattern. Restrictive filling doesn’t necessarily mean restrictive cardiomyopathy and is more commonly due to dilated or ischemic cardiomyopathy.
The five main topics of counseling that every hypertrophic cardiomyopathy (HCM) patient should understand: (1) Prognosis, (2) Family Screening, (3) Risk of Sudden Death, (4) Treatments, and (5) Physical Activity.
Remember 1/3: In clinical trials of cardiac myosin inhibitors for HCM (mavacamten), about a third of patients had a tremendous improvement in symptoms, another third had some improvement, and the final third had no improvement or had to discontinue the drug due to negative inotropy.
When counseling patients about septal reduction therapy, consider the patient’s age. For younger patients, surgical myectomy at an experienced center offers a higher success rate and greater durability with lower rates of pacemaker placement when compared to alcohol septal ablation.
Historically, the conclusion that it was higher risk to be an athlete with HCM was unfortunately generalized to mean that it was high risk to exercise for patients with HCM. “And we turned a generation of HCM patients into HCM cardiometabolic syndrome patients, which is actually a worse combination.”
Notes - Cardiomyopathies
What is the initial approach to evaluating a patient with new or suspected cardiomyopathy, including hypertrophic cardiomyopathy (HCM)?
A history and physical exam, including a thorough past medical and family history, is always the first step and helps determine the patient’s risk for potential underlying etiologies, including genetic cardiomyopathies, hypertrophic cardiomyopathy, or those related to treatments of previous cancer.
In terms of ECG findings, pay attention to QRS voltage (high or low) and the presence of any arrhythmias.
TTE should be obtained in all patients and is often sufficient to diagnose many underlying cardiomyopathies, including HCM.
Cardiac MRI (CMR) is helpful as an adjunct when TTE alone is inconclusive or imaging quality is poor. CMR can help provide a better idea of chamber sizes and wall thickness, and late gadolinium contrast enhancement (LGE) can also be helpful if present in a specific pattern, though often HCM patients may have non-specific patterns of LGE.
Invasive hemodynamics assessment is reserved for patients with discordance between non-invasive testing and the clinical impression. It can also be useful to guide the management of heart failure, especially in advanced disease.
How do you treat patients with hypertrophic obstructive cardiomyopathy (HOCM)?
In patients with HCM and LVOT obstruction (defined as a resting peak LVOT gradient 30 mmHg), we want to avoid medications that increase inotropy, reduce preload (diuretics), or reduce afterload (pure vasodilators).
First-line medical therapies for symptomatic HOCM include non-vasodilating beta-blockers (e.g., metoprolol) and/or non-dihydropyridine calcium channel blockers (e.g., diltiazem, verapamil).
For those with symptoms despite the above first-line medications, second-line therapies include the addition of disopyramide or the newer myosin inhibitors (e.g., mavacamten).
In patients who don’t respond to medical therapies, a referral should be made for septal reduction therapy at an experienced center. Surgical myectomy involves open heart surgery and has a success rate of 90-95% with a durable result. Alcohol septal ablation can be done percutaneously and offers a shorter recovery time, but it has a lower success rate of 75-85%. Septal ablation comes with a similar risk of stroke and mortality compared to surgery (