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: The Effect of Metoprolol in Patients With Hypertrophic Obstructive Cardiomyopathy.

Eligibility criteria:
Inclusion Criteria:

          -  Wall thickness ≥ 15 mm in one or more myocardial segments that is not explained by
             loading conditions.

          -  LVOT gradient > 30 mmHg at rest and/or > 50 mmHg at Valsalva's maneuver or exercise

          -  New York Heart Association Functional class (NYHA) ≥ II

        Exclusion Criteria:

          -  Age < 18 years

          -  Known allergy to trial medicine

          -  Contraindications to beta-blocker treatment

          -  Contraindications to Magnetic resonans scan, including contraindication to the
             contrast agent gadolinium.

          -  Female patients who are pregnant (positive plasma-HCG), breastfeeding or of
             child-bearing potential while not practicing effective chemical contraceptive
             hormones.

          -  In case of patients having a pacemaker, they may not be pace-dependent.

          -  Treatment with Amiodarone

          -  Atrial fibrillation/flutter at the time of examination

          -  Bradycardia < 49 beats/min

          -  Systolic blood pressure < 100 mmHg

          -  Trifascicular block

          -  Previous transcoronary ablation of septum hypertrophy (TASH) or myectomy

          -  Current abuse of alcohol and/or drugs

          -  Significant co-morbidity or issues that makes the patient unsuitable for
             participation, judged by the investigator

          -  Patients who cannot give valid consent (e.g. mental illness or dementia)

          -  Patients who do not understand danish
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): Entailment