Approach to the Critical Patient

Acute hemodynamic collapse

Immediate recognition triggers

Immediate stabilization steps

Conditions absolutely contraindicated in acute HOCM crisis

Arrhythmia emergencies

Atrial fibrillation with rapid ventricular response

Ventricular tachycardia or fibrillation

Monitoring and escalation

Hemodynamic monitoring targets

Escalation triggers to ICU

Consult triggers

History

Presenting symptoms

Cardinal exertional symptoms

Postprandial symptom worsening

Orthopnea and paroxysmal nocturnal dyspnea

Alarm features requiring urgent evaluation

Syncope without prodrome or exertional syncope

Cardiac arrest or ICD shock

Progressive dyspnea at rest or NYHA class III-IV

New sustained palpitations or irregular rhythm

Family history and genetics

Three-generation family history recommended at initial evaluation

Autosomal dominant inheritance pattern

Risk factor history

Personal risk factors for SCD in HCM

Comorbidity risk factors

Medication history

Activity and lifestyle history

Competitive athletic participation

Exercise patterns and limitations

Physical Exam

Dynamic murmur assessment

Characteristic murmur of HOCM

Mitral regurgitation murmur

Cardiovascular examination

Pulse characteristics

Apical impulse

Heart sounds

Hemodynamic assessment

Vital signs in context of HOCM

Volume status assessment

Neurological and peripheral examination

Neurological signs

Peripheral stigmata suggesting HCM phenocopies

Differential Diagnosis

Life-threatening diagnoses

Aortic stenosis (ICD-10: I35.0)

Acute coronary syndrome (ICD-10: I24.9)

Hypertensive emergency with acute LVH (ICD-10: I16.1)

Structural and genetic cardiomyopathies

Hypertensive heart disease (ICD-10: I11.9)

Athlete's heart (ICD-10: Z87.39)

Cardiac amyloidosis (ICD-10: E85.4)

Fabry disease (ICD-10: E75.21)

Glycogen storage diseases (ICD-10: E74.00)

Mitochondrial cardiomyopathy (ICD-10: I42.8)

Laboratory Tests

Cardiac biomarkers

BNP or NT-proBNP

Troponin I or T (high-sensitivity)

Metabolic and renal panel

Basic metabolic panel

Thyroid-stimulating hormone

Complete blood count

Genetic and specialized testing

Sarcomere gene panel

Phenocopy exclusion labs when indicated

Coagulation profile

Lipid panel and HbA1c

Diagnostic Tests

Scoring Systems

HCM Risk-SCD calculator (ESC model)

2024 AHA/ACC individual risk marker strategy

NYHA Functional Classification

MRI

Cardiac MRI (CMR) with gadolinium

CMR contraindications and alternatives

CT

Cardiac CT angiography

CT limitations in HOCM

Ultrasound

Transthoracic echocardiography (TTE)

Transesophageal echocardiography (TEE)

Point-of-care ultrasound in the emergency setting

Ambulatory monitoring and functional testing

12-lead ECG

Disposition

Admission indications

Criteria for hospital admission

ICU-level care criteria

Indications for ICU admission

Observation and monitoring

Observation unit criteria (12-24 hours)

Discharge criteria

Safe discharge requirements

Referral and transfer

Referral to comprehensive HCM center

Transfer criteria

Treatment

Acute medical management (ED setting)

Volume resuscitation for preload-dependent hypotension

Vasopressor therapy: phenylephrine first-line

IV beta-blockade for acute rate/contractility control

Chronic pharmacologic management (per 2024 AHA/ACC Guidelines)

First-line: nonvasodilating beta-blockers

Second-line: nondihydropyridine calcium channel blockers

Cardiac myosin inhibitors

Mavacamten (Camzyos) - FDA approved 2022

Aficamten (Myqorzo) - FDA approved 2025

Disopyramide

Mechanism: class Ia antiarrhythmic with strong negative inotropic effect

Dosing

Monitoring

Septal reduction therapy

Surgical septal myectomy

Alcohol septal ablation (ASA)

SCD prevention

ICD implantation: secondary prevention

ICD implantation: primary prevention

Subcutaneous ICD (S-ICD) considerations

Atrial fibrillation management

Anticoagulation: mandatory for all HCM patients with AF

Rate control

Rhythm control preferred for symptomatic AF in HCM

Special Populations

Pregnancy

Hemodynamic changes in pregnancy affecting HOCM

Risk stratification in pregnancy

Medication safety in pregnancy

Delivery planning

Genetic counseling in pregnancy

Geriatric

Age-related phenotype differences

Medication considerations in older adults

SCD risk in elderly HCM

Functional assessment

Pediatrics

Presentation in children and adolescents

Diagnosis in pediatric patients

SCD risk stratification in pediatrics

Athletic participation and restriction

Medication dosing in children

Genetic testing in pediatric HCM

Background

Epidemiology

Prevalence and incidence

LVOTO prevalence

Mortality and complications

Prognosis by phenotype

Pathophysiology

Genetic basis

Dynamic left ventricular outflow tract obstruction

Diastolic dysfunction

Myocardial ischemia mechanisms

Myocyte disarray and fibrosis

Therapeutic Considerations

Pharmacologic goals in obstructive HCM

Drug classes that worsen HOCM: absolute avoidance

Anticoagulation principles in HCM

Physical activity and lifestyle

Emerging therapies and research

Patient Discharge Instructions

copy discharge instructions

Condition overview

Medications to take as prescribed

Medications and substances to AVOID

Lifestyle instructions

Family screening

Return to emergency department immediately for

Follow-up plan

References

Guidelines and key sources

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy

Braunwald E. Hypertrophic Cardiomyopathy. New England Journal of Medicine. 2025

Maron BJ, Desai MY, Nishimura RA, et al. Management of Hypertrophic Cardiomyopathy: JACC State-of-the-Art Review. JACC. 2022

Maron BJ, Desai MY, Nishimura RA, et al. Diagnosis and Evaluation of Hypertrophic Cardiomyopathy: JACC State-of-the-Art Review. JACC. 2022

Landmark trials

EXPLORER-HCM Trial: mavacamten for symptomatic obstructive HCM

SEQUOIA-HCM Trial: aficamten for symptomatic obstructive HCM

ACAMARA Trial: Garcia-Pavia P, Maron MS, Masri A, et al. NEJM. 2025

Dybro AM, Rasmussen TB, Nielsen RR, et al. Randomized Trial of Metoprolol in Obstructive HCM. JACC. 2021

Additional references

Sikand N, Stendahl J, Sen S, Lampert R, Day S. Current Management of Hypertrophic Cardiomyopathy. BMJ. 2025

Veselka J, Anavekar NS, Charron P. Hypertrophic Obstructive Cardiomyopathy. Lancet. 2017

Coppiano J, Carrasco M, Asif I. Cardiomyopathy: A Guide for Primary Care. American Family Physician. 2026

Martens P, Olivotto I, Garcia-Pavia P, et al. Comprehensive Evaluation of Hypertrophic Cardiomyopathy: European Journal of Heart Failure Expert Consensus. 2026

Leggit JC, Whitaker D. Diagnosis and Management of HCM: Updated ACC/AHA Guidelines. American Family Physician. 2022