Pre-assessment

Q1. Which of the following should be considered in the differential diagnosis of a patient with left ventricular septal thickness of 12 to 15 mm without dynamic outflow tract obstruction? (select all that apply)

Q2. When do the 2020 AHA/ACC guidelines suggest using cardiac magnetic resonance imaging? (select all that apply)

Q3. According to the 2020 AHA/ACC guidelines, which of the following are recommended as the first-line treatment for patients with obstructive HCM and symptoms (such as effort-related dyspnea or chest pain) attributable to left ventricular outflow tract obstruction?

Q4. What percentage of HCM patients have a left ventricular outflow tract (LVOT) pressure gradient at rest?

Q5. Patients with mild resting gradients (30 to 49 mmHg) are at about the same risk of developing heart failure symptoms as people with higher rest gradients (at least 70 mm Hg).

Q6. Which of these symptoms are commonly occurring in HCM? (Select all that apply)

Q7. An alternative diagnosis to HCM should be considered if: (Select all that apply)

Q8. Diastolic dysfunction can evolve into a restrictive filling pattern, secondary left atrial dilation or AF.

Q9.What is the definition of a resting or provoked gradient for diagnosis of obstructive HCM?

Clinical case using data from Kantor et al., 2021

• A 15-year-old male presented with intermittent chest pain during exercise.
• The patient’s paternal grandfather died suddenly aged 49 years, but cause was unconfirmed. The patient’s father received a diagnosis of HCM 10 years prior to the patient’s admission and underwent placement of an ICD. The patient and his sibling were not tested for HCM at the time.
• At age 11 years, the patient had undergone a 12-lead ECG and physical examination prior to treatment for ADHD with stimulant medication. The findings demonstrated borderline left‑axis deviation with nonspecific repolarization abnormalities; no voltage criteria for left ventricular (LV) hypertrophy.
• At age 15 years, an ECG demonstrated mid-precordial voltage hypertrophy, inferior Q waves, and lateral precordial repolarization abnormalities.
• An echocardiogram demonstrated asymmetrical septal hypertrophy with a diastolic septal thickness of 16 mm (z-score: 7.5). There was no evidence of LVOT obstruction or any systolic anterior motion of the mitral valve.
• The patient underwent ambulatory ECG monitoring, which revealed minimal ectopy and no exercise associated ST-segment changes. No chest pain was evident, and no evidence of any ventricular ectopy occurred. His maximum LVOT systolic gradient was <10 mmHg immediately after exercise.
• His stimulant medical therapy was continued, and he was started on a β-blocker to address his symptoms of intermittent chest pain.
• In discussion with the patient using a shared decision-making model, some restrictions were placed on exercise. It was agreed that the patient could walk or jog but should not participate in competitive high-intensity sports.

Q10. What deviations from the current American College of Cardiology/American Heart Association guidelines were noted in this case?

• A male patient in his 60s presented with progressive dyspnea on exertion and lightheadedness.
• His past medical history included atrial fibrillation and coronary artery disease.
• He had no known family history of cardiomyopathy.
• Transthoracic echocardiography (TTE) revealed septal hypertrophy of 17 mm, with LVOT gradients by spectral Doppler of 52 mmHg at rest and 144 mmHg with Valsalva.
• Moderate systolic anterior motion (SAM) of the anterior mitral valve leaflet was observed

Q11. The patient has obstructive HCM. What are the first- and second-line treatment options for this patient? (Select all that apply)

Clinical data from Al Ali et al., 2020

• A male patient in his 70s presented with angina pectoris.
• Physical examination showed a crescendo-decrescendo mid-peaking systolic murmur, grade 4, with punctum maximum at Erb’s point.
• The patient had a known history of hypertension, hyperlipoproteinemia and coronary artery disease.
• He was in New York Heart Association functional class II, without collapse episodes or chest pain
• The transthoracic echocardiography (TTE) found septal hypertrophy of 23 mm, significant chordal systolic anterior motion,
• Continuous-wave doppler echocardiography found a dagger-shaped late-peaking pressure gradient. The left ventricular outflow tract (LVOT) gradient was 132 mmHg, stroke volume index of 35 mL/m2 with normal ejection fraction (EF) of 58%.

Q12. Does the patient have obstructive or nonobstructive HCM?

Clinical data from D’Souza et al., 2017

• An 8-year-old boy presented with persistent palpitations.
• Past medical history included asthma, myopia, hypothyroidism, and speech delay. The family history was unremarkable for any cardiac issues
• On physical examination, he was hemodynamically stable. A grade 3/6 pansystolic murmur along the left lower sternal border was appreciated.
• Electrocardiogram (ECG) showed a Wolf-Parkinson-White (WPW) with a left bundle branch block pattern, and peaked QRS complexes.
• Echocardiogram revealed initial septal thickness of 26 mm.
• Continuous wave doppler echocardiogram revealed no LVOT obstruction at rest or provoked

Q13. Is the diagnosis of HCM definitive?

Clinical data from Feldman et al., 2020

• A male patient in his 30s presented with typical atrial flutter and underwent a cavotricuspid isthmus ablation
• Echocardiogram and cardiac MRI demonstrated wall thickness of 16 mm in the septum.
• Diagnosis of nonobstructive HCM was given
• Two months later, the patient had a cardiac arrest and received cardiopulmonary resuscitation for ventricular fibrillation
• The initial electrocardiogram was significant for 2-mm ST-segment elevations in V2 to V4 and mild ST-segment depressions in the inferior leads.
• The emergent coronary angiogram revealed absence of coronary artery disease
• Results of the CMRI were reviewed again. In addition to the increased wall thickness that prompted the initial diagnosis, there was also subepicardial late gadolinium enhancement (LGE) in the basal and mid-anteroseptum extending into the right ventricular free wall, and focal transmural enhancement in the inferior wall

Q14. Is the diagnosis of nonobstructive HCM the most likely explanation for the patient’s symptoms and test findings?