Patient case (clinical description): A 23-year-old man comes to the emergency department following an episode of syncope.  He was working out when he felt dizzy and passed out without head injury.  He has had 3 other episodes of light-headedness over the last year, all happening during physical activity. He never had this experience while resting. He has no other medical conditions.  The patient does not use tobacco, alcohol, or illicit drugs.  His father died suddenly at age 35.  Vital signs are within normal limits.  On physical examination, the patient has a harsh systolic murmur.  The lungs are clear with no peripheral edema. Echocardiography shows asymmetric interventricular septal hypertrophy.

Patient's own account: I'm 23, and I got admitted to the ER because I fainted all of a sudden. I was in the gym, working out, when all of a sudden, I just got dizzy and passed out. Hopefully, I didn't hit my head. It's not my first time having that kind of dizziness at the gym, never when I'm chilling at home tho. I don't have any special medical conditions and I'm not even smoking, drinking or doing drugs! My dad died suddenly when he was 35, so I'm kind of scared. My vitals were normal while at the ER and they did a physical exam and they told me my heart sounds abnormal. My lungs are ok, but I had to do an echography of my heart, and they told me it is bigger than average.

Clinical trial: A Phase 2 Study of Mavacamten in Adults With Symptomatic Non-Obstructive Hypertrophic Cardiomyopathy (nHCM)

Eligibility criteria:
Key Inclusion Criteria:

          -  Diagnosed with nHCM (hypertrophied and non-dilated left ventricle in absence of
             systemic or other known cause), with LV wall thickness ≥ 15mm at Screening or ≥ 13mm
             with a positive family history of HCM.

          -  Age 18 and greater, Body weight ≥ 45kg

          -  Documented LVEF ≥ 55% at the Screening as determined by echo central lab

          -  LVOT gradient < 30 mmHg at rest AND during Valsalva AND post-exercise

          -  NYHA functional class II or III

          -  Elevated NT-proBNP at rest

        Key Exclusion Criteria:

          -  History of syncope, sustained ventricular tachyarrhythmia with exercise, obstructive
             coronary artery disease or myocardial infarction within the past 6 months

          -  History of resuscitated sudden cardiac arrest at any time or known appropriate
             implantable cardioverter defibrillator (ICD) discharge within 6 months prior to
             Screening

          -  Current treatment with disopyramide or ranolazine (within 14 days prior to Screening)

          -  Current or planned treatment during the study with a combination of beta-blockers and
             calcium channel blockers

          -  Has been treated with invasive septal reduction (surgical myectomy or percutaneous
             alcohol septal ablation [ASA]) within 6 months prior to Screening

          -  History of resting or post-exercise LVOT >30 mmHg unless subsequently treated by
             septal reduction

          -  Has QTc Fridericia (QTcF) >480 ms or any other ECG abnormality considered by the
             investigator to pose a risk to participant safety (eg, second-degree atrioventricular
             block type II)

          -  Has persistent or permanent atrial fibrillation not on anticoagulation for at least 4
             weeks prior to Screening and/or not adequately rate-controlled within 1 year of
             Screening

          -  History of clinically significant malignant disease within 10 years such as
             non-metastatic cutaneous squamous cell or basal cell carcinoma

          -  History or evidence of any other clinically significant disorder, condition, or
             disease that, in the opinion of the investigator or MyoKardia physician, would pose a
             risk to subject safety or interfere with the study evaluation, procedures, or
             completion.
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.
Subject must be at least 18 Years old.


Eligibility (NLI label): Contradiction