Mavacamten to Aficamten Transition in Patients With Obstructive Hypertrophic Cardiomyopathy

Inclusion Criteria:

* Documented history of oHCM with documented resting and/or Valsalva LVOT obstruction ≥ 50 mmHg who are currently receiving mavacamten commercially.
* Echo-derived LVEF ≥55% on mavacamten at the time of enrollment.
* Patient willing to consent for the study and undergo the study procedures.

Exclusion Criteria:

* Severe aortic stenosis or sub-aortic obstruction
* Known infiltrative or storage disorder causing cardiac hypertrophy that mimics HCM (eg, Noonan syndrome, Fabry disease, amyloidosis).
* History of LVEF \<30%.
* Paroxysmal atrial fibrillation (AF) with documented episode within 3 months.
* Atrial fibrillation (paroxysmal or permanent) not on systemic anticoagulation.
* Documented history of current obstructive coronary artery disease (\> 70% stenosis in one or more epicardial coronary arteries) or documented history of myocardial infarction.