01Approach to the Critical Patient/attcp45

Hemodynamic priorities

›Acute hemodynamic compromise in HOCM

›Dynamic LVOTO worsening with hypotension

›Avoid vasodilators (nitroglycerin, nitroprusside)

›Avoid positive inotropes (dobutamine, dopamine, milrinone)

›Avoid diuretics in acute setting

›IV fluid bolus as first-line intervention

›Normal saline 500 mL IV bolus

›Goal to restore preload and reduce LVOTO gradient

›Phenylephrine (pure alpha-agonist) for vasopressor support

›100–200 mcg IV bolus; infusion 0.5–6 mcg/kg/min

›Increases afterload without increasing inotropy

›IV beta-blocker if tachycardia contributing to instability

›Metoprolol 5 mg IV over 2 minutes; repeat every 5 minutes x3

›Slows heart rate and prolongs diastolic filling time

Arrhythmia management

›Rapid atrial fibrillation with hemodynamic compromise

›Rate control priority over rhythm control in acute setting

›IV metoprolol or IV diltiazem for rate control

›Avoid digoxin (positive inotrope)

›Cardioversion if hemodynamically unstable

›Anticoagulation recommended for all HCM patients with AF

›Regardless of CHA2DS2-VASc score

›DOAC preferred over warfarin (Class IIa)

›Ventricular tachycardia or fibrillation

›Standard ACLS defibrillation protocol

›Avoid isoproterenol

›Amiodarone for refractory VT

02History/hx59

Presenting symptoms

›Cardinal exertional symptoms

›Dyspnea on exertion — most common presenting complaint

›Assess NYHA functional class (I–IV)

›Exercise intolerance, fatigue with minimal activity

›Chest pain — anginal type, typically exertional

›Microvascular ischemia and elevated myocardial oxygen demand

›Pressure or tightness quality

›Syncope and presyncope

›Exertional syncope — major red flag for SCD risk

›Postural syncope with standing or Valsalva maneuver

›Recurrent unexplained syncope warrants urgent evaluation

›Palpitations

›Paroxysmal rapid irregular — atrial fibrillation

›Rapid regular — ventricular tachycardia

Symptom triggers

›Provocative factors worsening LVOTO

›Dehydration and volume depletion

›Heat exposure, vomiting, diarrhea

›Valsalva maneuver (straining, coughing)

›Standing quickly from seated or lying position

›Post-prandial states (splanchnic vasodilation)

›Intense physical exertion

›Vasodilating medications (nitrates, dihydropyridine CCBs, ACE inhibitors)

Alarm features

›High-risk features requiring urgent evaluation

›Exertional syncope or cardiac arrest

›Secondary prevention ICD indication

03Physical Exam/exam43

Vital signs

›Hemodynamic assessment

›Blood pressure — hypotension is a danger sign in HOCM

›Narrow pulse pressure may indicate severe LVOTO

›Heart rate — tachycardia worsens LVOTO

›Target heart rate 50–70 bpm for optimal diastolic filling

›Respiratory rate and oxygen saturation

›Elevated in decompensated heart failure

Cardiac examination

›Murmur characteristics — key diagnostic finding

›Harsh crescendo-decrescendo systolic murmur

›Best heard at left lower sternal border and apex

›Radiates to apex, not to carotids (unlike aortic stenosis)

›Dynamic nature — distinguishing feature of HOCM

›Increases with Valsalva (decreased preload)

›Increases with standing from squatting (decreased preload)

›Decreases with squatting (increased preload and afterload)

›Decreases with passive leg raise

›Concurrent mitral regurgitation murmur

›Apical, posteriorly directed

›Systolic anterior motion (SAM) of mitral valve leaflet

Precordial and peripheral findings

›Characteristic physical signs

›Prominent sustained apical impulse

›Laterally displaced, may be bifid (double impulse)

›S4 gallop — reduced ventricular compliance

›Best heard at apex with patient in left lateral decubitus

›Abnormal carotid pulse character

04Differential Diagnosis/ddx42

Structural cardiac causes

›Aortic stenosis — most critical mimic

›ICD-10: I35.0

›Fixed LVOTO; murmur does not increase with Valsalva

›Delayed carotid upstroke (pulsus parvus et tardus)

›Murmur radiates to carotids

›Calcified valve on echocardiography

›Hypertensive heart disease

›ICD-10: I11.9

›Concentric LVH; wall thickness rarely exceeds 20 mm

›History of poorly controlled hypertension

›Does not produce dynamic LVOTO

›Valvular mitral regurgitation (primary)

›ICD-10: I34.0

›Murmur does not change dynamically with preload maneuvers

Infiltrative and storage diseases

›Cardiac amyloidosis

›ICD-10: E85.4 / I43

›Biventricular thickening with low ECG voltage (voltage-mass discordance)

›Sparkling granular texture on echo

›Bone scintigraphy (99mTc-PYP) positive in ATTR amyloid

›Consider in older patients with HCM phenotype

›Fabry disease (alpha-galactosidase A deficiency)

›ICD-10: E75.21

›X-linked; concentric LVH with neuropathic pain, renal dysfunction, angiokeratomas

›Alpha-galactosidase A enzyme assay for screening

›Short PR interval on ECG may be clue

›Danon disease and other glycogen storage diseases

05Laboratory Tests/lt32

Cardiac biomarkers

›BNP or NT-proBNP

›Elevated in symptomatic HCM and heart failure

›Correlates with diastolic dysfunction severity

›Useful for monitoring disease progression and therapy response

›NT-proBNP rises with mavacamten therapy benefit

›Troponin (high-sensitivity)

›Chronically mildly elevated due to myocardial ischemia and fibrosis

›Acute elevation warrants evaluation for ACS or myocardial injury

›Serial troponin if acute coronary syndrome in differential

Metabolic and hematologic tests

›Basic metabolic panel

›Renal function — relevant for medication dosing and contrast use

›eGFR before CMR with gadolinium

›Potassium level for antiarrhythmic safety

›Electrolytes — hypokalemia and hypomagnesemia increase arrhythmia risk

›Complete blood count

›Anemia — worsens exertional symptoms and increases myocardial oxygen demand

›Polycythemia — thrombotic risk in AF

›Thyroid function tests

›Hyperthyroidism — exacerbates tachycardia and precipitates AF

›Hypothyroidism — affects heart rate control with beta-blockers

Targeted metabolic screening

›Alpha-galactosidase A enzyme activity

›Screen when Fabry disease suspected (concentric LVH, young male, neuropathic pain)

›Low enzyme activity in affected males; genetic testing for female carriers

›Lysosomal enzyme panel if glycogen storage disease suspected

›Acid alpha-glucosidase (Pompe disease)

06Diagnostic Tests/dt87

Scoring Systems

›HCM Risk-SCD Calculator (ESC model)

›Estimates 5-year SCD risk using clinical variables

›Maximum LV wall thickness (mm)

›Left atrial diameter (mm)

›Maximum LVOT gradient (mmHg)

›Family history of SCD

›Unexplained syncope

›NSVT on Holter

›Age at evaluation

›Risk thresholds for ICD decision-making

›Less than 4% at 5 years — ICD not recommended as routine

›4–6% at 5 years — ICD may be considered (Class IIb)

›Greater than 6% at 5 years — ICD should be considered (Class IIa)

›Limitation: should not be the sole criterion for ICD decisions

›AHA/ACC 2024 guidelines use major risk factor-based algorithm

›NYHA Functional Classification

›Guides pharmacologic therapy escalation

›Class I — no symptoms with ordinary activity

›Class II — slight limitation with ordinary activity

›Class III — marked limitation; comfortable only at rest

›Class IV — unable to perform any activity without symptoms

›Mavacamten indicated for symptomatic NYHA Class II–III obstructive HCM

MRI

›Cardiac MRI (CMR) — gold standard for HCM characterization

›Indications

›Inconclusive echocardiography (poor acoustic windows)

›Apical HCM suspected — echo may miss apical thickening

›LV apical aneurysm detection

›Pre-septal reduction therapy planning

›Recommended at initial evaluation; repeat every 3–5 years

›Late gadolinium enhancement (LGE)

›Marker of myocardial fibrosis and replacement scarring

›LGE greater than 15–20% of LV mass — extensive fibrosis, elevated SCD risk

›Patchy mid-wall pattern at RV insertion points is characteristic

›Morphologic assessment

›Superior wall thickness quantification vs echocardiography

›Identifies unusual hypertrophy patterns (apical, mid-ventricular)

›LV apical aneurysm — independent SCD risk factor

›Routine repeat CMR optional in patients over 65 years

CT

›CT cardiac imaging in HCM — secondary role

›CT coronary angiography (CCTA)

›Excludes significant coronary artery disease as alternative diagnosis

›Pre-operative evaluation before septal reduction therapy

›Alternative to invasive coronary angiography in lower-risk patients

›CT for procedural planning

›Alcohol septal ablation anatomy assessment

›Cardiac surgery (myectomy) pre-operative planning

›Limitations compared to CMR

›Does not provide LGE-based fibrosis quantification

›Radiation exposure and contrast requirement

Ultrasound

›Transthoracic echocardiography (TTE) — first-line diagnostic test

›Indications and initial evaluation

›Diagnoses HCM when LV wall thickness 15 mm or greater in any segment

›Lower threshold of 13 mm if family history or genetic diagnosis present

›Annual echocardiogram recommended as standard follow-up

›Key measurements and findings

›Maximum LV wall thickness (asymmetric septal hypertrophy most common)

›LVOT gradient — resting and provocable

›Resting gradient 50 mmHg or greater — hemodynamically significant obstruction

›Gradient 30–49 mmHg — obstructive; provocable gradient at 50 mmHg threshold

›Systolic anterior motion (SAM) of mitral valve

›Left atrial size — marker of chronic filling pressure elevation and AF risk

›LVEF — typically hyperdynamic; reduced LVEF indicates end-stage progression

›Exercise stress echocardiography

›Provokes latent LVOT obstruction when resting gradient below 50 mmHg

›Evaluates functional capacity and blood pressure response

›LVOT gradient 50 mmHg or greater with provocation = significant obstruction

›Transesophageal echocardiography (TEE)

›Superior visualization for septal reduction therapy guidance

›Intraoperative TEE during surgical myectomy

›Alcohol septal ablation guidance (contrast echo for target vessel identification)

›ECG — screening and risk stratification

›Abnormal in up to 95% of HCM patients — most sensitive routine screening test

›LVH voltage criteria (large R waves lateral leads, deep S waves V1–V2)

›Prominent septal Q waves — inferior and lateral leads; not from infarction

›ST-segment depression and T-wave inversions — repolarization abnormalities

›Giant T-wave inversions in precordial leads — apical HCM variant

›Left axis deviation

›P-wave abnormalities — left atrial enlargement

›Atrial fibrillation — present in greater than 50% over lifetime

›NSVT — SCD risk marker

›Normal ECG does not exclude HCM (5–10% have normal ECG)

›Ambulatory ECG monitoring

›24–48 hour Holter or 2-week wireless patch monitor

›Detects NSVT (SCD risk factor)

›Detects paroxysmal AF

›Part of SCD risk stratification at initial evaluation

›Repeat every 1–3 years or with arrhythmia symptoms

07Disposition/dispo38

Admission criteria

›Indications for hospital admission

›Exertional or recurrent unexplained syncope

›Telemetry monitoring for arrhythmia detection

›SCD risk stratification workup

›Acute hemodynamic compromise or hypotension

›ICU-level care for vasopressor requirement

›New-onset rapid atrial fibrillation with hemodynamic instability

›Rate control and anticoagulation initiation

›Sustained ventricular tachycardia or VF

›Post-arrest monitoring and ICD evaluation

›Acute decompensated heart failure

›New orthopnea, PND, peripheral edema, hypoxia

›New diagnosis with high-risk features

›Massive LVH (wall thickness 30 mm or greater)

›NSVT on initial monitoring

Observation indications

›Step-down or observation unit

›New-onset AF, hemodynamically stable

›Rate control optimization on telemetry

›Anticoagulation initiation and monitoring

›Presyncope with unclear etiology pending workup

›Telemetry and further risk stratification

Discharge criteria

›Criteria for safe discharge

›Hemodynamically stable with no new symptoms

›Heart rate controlled, blood pressure acceptable

›Known HCM at baseline functional status

08Treatment/t105

Acute stabilization

›Acute HOCM hemodynamic crisis management

›IV fluid resuscitation — first intervention

›Normal saline 500 mL IV bolus; repeat as needed to restore preload

›Goal MAP 65 mmHg or greater

›Phenylephrine for vasopressor support

›IV bolus 100–200 mcg; titrate infusion 0.5–6 mcg/kg/min

›Pure alpha-1 agonist — increases afterload without inotropy

›Preferred vasopressor in HOCM (avoids reflex tachycardia of norepinephrine)

›IV beta-blocker for heart rate control

›Metoprolol 5 mg IV over 2 minutes; may repeat x2 every 5 minutes

›Esmolol if rapid titration needed: 500 mcg/kg IV load then 50–200 mcg/kg/min

›Target heart rate 50–70 bpm

›Contraindicated agents in acute HOCM

›Nitroglycerin — worsens LVOTO by reducing preload

›Dobutamine — increases inotropy and worsens LVOTO

›Dopamine — vasodilatory and inotropic effects are harmful

›Milrinone — phosphodiesterase inhibitor, worsens LVOTO

Chronic pharmacologic management

›Step 1 — Beta-blocker (first-line)

›Metoprolol succinate (extended release)

›Starting dose 25–50 mg orally once daily

›Titrate to symptom relief and heart rate suppression

›Maximum dose 200 mg daily

›Nadolol or propranolol as alternatives

›Propranolol 20–40 mg orally 3–4 times daily; titrate to 120–320 mg/day

›Goals of therapy

›Symptom relief (dyspnea, chest pain, presyncope)

›Heart rate 50–70 bpm at rest

›Blunted heart rate response to exertion

›Step 2 — Non-dihydropyridine calcium channel blocker (beta-blocker intolerant)

›Verapamil

›Starting dose 40–80 mg orally 3 times daily

›Titrate to 360–480 mg/day total

›Do not combine with beta-blocker — risk of AV block and bradycardia

›Diltiazem — alternative if verapamil not tolerated

›Extended release 120–360 mg orally once daily

›Caution: verapamil may worsen heart failure if baseline elevated filling pressures

›Step 3 — Disopyramide (refractory symptoms)

›Potent negative inotrope — reduces LVOTO gradient

›Starting dose 100 mg orally 3–4 times daily

›Target dose 400–600 mg/day in divided doses

›Must combine with AV nodal blocker (beta-blocker or CCB)

›Prevents 1:1 AF conduction due to vagolytic effect

›Contraindications

›QTc prolongation greater than 480 ms

›Closed-angle glaucoma

›Urinary retention

›Step 4 — Cardiac myosin inhibitors

›Mavacamten (Camzyos) — FDA-approved for symptomatic NYHA II–III obstructive HCM

›Starting dose 5 mg orally once daily

›Titration based on LVEF and LVOT gradient at 4 and 8 weeks

›Dose adjustment to 2.5, 5, 10, or 15 mg based on response

›Maximum dose 15 mg daily

›Mandatory REMS program — serial echocardiography LVEF monitoring

›Do not initiate if LVEF below 55%

›Interrupt therapy if LVEF falls below 50%

›Drug interactions — contraindicated with strong CYP2C19 inhibitors

›Avoid omeprazole, fluconazole, fluvoxamine

›Avoid strong CYP2C19/CYP3A4 inducers (rifampin, carbamazepine)

›Aficamten (Myqoryo) — FDA-approved for symptomatic obstructive HCM

›Next-in-class cardiac myosin inhibitor

›Starting dose 5 mg orally once daily; titrate based on LVOT gradient and LVEF

›Serial echocardiography monitoring required

Septal reduction therapy

›Surgical septal myectomy — gold standard intervention

›Indication: refractory symptoms despite optimal medical therapy

›Resting or provocable LVOT gradient 50 mmHg or greater

›NYHA Class III–IV symptoms on maximally tolerated medications

›Preferred approach when concomitant cardiac surgery is needed

›Concomitant mitral valve repair, coronary bypass

›Must be performed at experienced high-volume HCM center

›Operative mortality less than 1% at experienced centers

›Long-term symptom relief in greater than 90% of patients

›Alcohol septal ablation — alternative for non-surgical candidates

›Percutaneous catheter-based procedure

›Injection of absolute ethanol into first septal perforator coronary artery

›Creates controlled septal infarction to reduce LVOTO

›Indications: refractory symptoms, unsuitable surgical anatomy or risk

›Gradient reduction comparable to myectomy in selected patients

›Risks: complete heart block requiring pacemaker (3–5%), ventricular arrhythmia

SCD prevention

›Implantable cardioverter-defibrillator (ICD)

›Secondary prevention — Class I indication

›Survivors of cardiac arrest or sustained VT

›All age groups; lifelong benefit

›Primary prevention — risk-factor based approach (AHA/ACC 2024)

›ICD recommended with any major risk factor

›Massive LVH (wall thickness 30 mm or greater)

›Family history of SCD in first-degree relative

›Unexplained syncope (likely arrhythmic)

›NSVT on ambulatory monitoring

›LV apical aneurysm

›Extensive LGE (greater than 15% of LV mass)

›LVEF below 50%

›SCD risk low in patients over 60 — ICD generally not recommended without high-risk features

›Subcutaneous ICD (S-ICD) preferred if pacing not required

›Avoids transvenous leads

AF management

›Anticoagulation for all HCM patients with AF

›Recommended regardless of CHA2DS2-VASc score — Class I

›DOAC preferred over warfarin (Class IIa) unless contraindicated

›Apixaban, rivaroxaban, or dabigatran

›Rate control strategy

›Metoprolol or verapamil/diltiazem for rate control

›Avoid digoxin (positive inotropy, worsens LVOTO)

›Rhythm control consideration

›Cardioversion for hemodynamically significant AF

›Amiodarone for rhythm maintenance if preferred

›Ablation for refractory symptomatic AF at experienced centers

09Special Populations/sp67

Pregnancy

›HCM in pregnancy — generally well-tolerated but requires specialized management

›Hemodynamic changes that affect HOCM

›Increased blood volume and cardiac output may actually reduce LVOTO

›Late pregnancy and postpartum — risk of acute volume shifts and hypotension

›Tachycardia of pregnancy may worsen symptoms

›Pre-conception counseling

›Risk assessment with cardiologist and maternal-fetal medicine

›Genetic counseling — 50% risk of autosomal dominant transmission

›Medication management during pregnancy

›Beta-blockers — generally safe (metoprolol preferred)

›Monitor fetal growth; associated with small-for-gestational-age risk

›Verapamil — use with caution; crosses placenta

›Mavacamten and aficamten — contraindicated in pregnancy

›Discontinue before conception

›Disopyramide — use cautiously; uterotonic effects reported

›Delivery planning

›Vaginal delivery generally preferred

›Epidural analgesia with caution — risk of preload reduction

›Avoid spinal block — may cause acute hypotension

›Experienced center delivery with cardiology support

›Postpartum monitoring

›Highest risk period — acute blood loss and volume shifts

›Breastfeeding generally compatible with beta-blockers

Geriatric

›HCM in older adults (age 60 and above)

›Epidemiology and phenotype

›HCM prevalence increases with age — previously underdiagnosed

›Wall thickness may be less extreme; diastolic dysfunction predominates

›Higher prevalence of AF in older patients

›Comorbidities complicate management (hypertension, coronary disease, CKD)

›SCD risk considerations

›Annual SCD risk lower in older patients with HCM

›ICD generally not recommended in patients over 60 without high-risk features

›Competing mortality from other comorbidities affects ICD decision

›Pharmacologic considerations

›Beta-blockers — effective but monitor for bradycardia and hypotension

›Renal impairment — adjust dosing; avoid nephrotoxic contrast when possible

›Polypharmacy — drug interactions with mavacamten (CYP2C19 pathway)

›Increased risk of disopyramide side effects (urinary retention, constipation)

›CMR

›Routine repeat CMR optional in patients over 65 years

›Septal reduction therapy

›Surgical myectomy remains an option at experienced centers

›Alcohol septal ablation may be preferred over surgery in older patients

Pediatrics

›HCM in children and adolescents

›Epidemiology and etiology

›Most common inherited cardiac disease presenting in youth

›Leading cause of SCD in young athletes in North America

›Sarcomeric mutations account for majority; RASopathies (Noonan) common in infants

›Massive concentric hypertrophy in infants may indicate metabolic syndrome

›SCD risk in pediatric HCM

›Higher SCD risk relative to adults with same risk features

›Wall thickness 30 mm or greater, NSVT, family history of SCD

›ICD use in children requires careful weighing of benefit vs device complications

›Pediatric electrophysiology consultation for ICD decision-making

›Sports participation and activity restriction

›Historically blanket restriction from competitive sports

›2024 AHA/ACC guideline — shared decision-making with cardiologist

›Avoid high-intensity competitive sports if major risk features present

›Screening of relatives

›Children of HCM patients — screen every 1–2 years until adulthood

›ECG and echocardiogram for all first-degree relatives

›Pharmacologic differences

›Beta-blockers — weight-based dosing (propranolol 1–4 mg/kg/day)

›Mavacamten — not approved for pediatric use under 18 years

›Genetic testing and counseling

›Beneficial for guiding family cascade screening

›Genetic counselor involvement recommended before testing

10Background/b77

Epidemiology

›Prevalence and incidence

›Most common inherited cardiac disease

›Prevalence approximately 1 in 200–500 in general population

›Affects approximately 600,000–1.5 million people in the United States

›Age and sex distribution

›Diagnosis at any age; bimodal peak in young adulthood and sixth decade

›Slightly more common and more severe in males

›Etiology

›Autosomal dominant inheritance in most cases

›Sarcomeric gene mutations in 30–60% of genotype-positive cases

›Sporadic mutations account for additional cases

›Morbidity and mortality

›Annual SCD risk approximately 0.5–1% overall in modern management era

›Substantially lower in patients without identifiable risk markers

›Leading cause of SCD in young competitive athletes in North America

›Atrial fibrillation develops in greater than 50% of patients over lifetime

›Annual AF incidence 2–3% in HCM

›Stroke risk elevated — anticoagulation for all HCM patients with AF

›End-stage (burned-out) HCM

›LVEF below 50% with LV dilation — affects 2–5% over 15 years

›Carries worse prognosis; may require cardiac transplantation

›Modern outcomes

›Most patients have favorable prognosis compatible with normal longevity

›Mortality rate with contemporary management approaches general population rate

Pathophysiology

›Core mechanism — dynamic LVOT obstruction

›Asymmetric septal hypertrophy narrows LVOT

›Hypertrophy caused by sarcomeric protein gene mutations

›MYH7 (beta-myosin heavy chain) and MYBPC3 (myosin-binding protein C) most common

›Gain-of-function mutations in contractile proteins

›Systolic anterior motion (SAM) of mitral valve

›Anterior mitral leaflet dragged into LVOT by Venturi effect and abnormal flow

›SAM contacts interventricular septum during systole — dynamic obstruction

›Degree of obstruction varies with loading conditions (preload, afterload, heart rate)

›LVOTO classification

›Obstructive HCM — resting or provocable gradient 30 mmHg or greater

›Hemodynamically significant: gradient 50 mmHg or greater

›Present in approximately 50–75% of patients

›Nonobstructive HCM — resting and provocable gradient below 30 mmHg

›Provocable obstruction — resting gradient below 50 mmHg; provocation unmasks gradient 50 mmHg or greater

›Diastolic dysfunction

›Impaired LV relaxation due to myocardial hypertrophy and fibrosis

›Elevated LV filling pressures

›Pulmonary venous hypertension and dyspnea

›Atrial contribution critical for ventricular filling

›Loss of atrial kick (AF) causes acute hemodynamic deterioration

›Microvascular ischemia

›Reduced capillary density relative to hypertrophied myocardium

›Mismatch between oxygen supply and demand

›Exertional chest pain without epicardial coronary disease

›Myocardial fibrosis — replacement and interstitial

›Substrate for ventricular arrhythmia

›Quantified by LGE on CMR

Therapeutic Considerations

›Rationale for treatment approach

›Beta-blockers and verapamil reduce heart rate

›Prolonged diastolic filling time — reduces LVOTO

›Reduced myocardial oxygen demand — improves angina

›Mavacamten and aficamten mechanism

›Cardiac myosin inhibitors — reduce actin-myosin crossbridge formation

›Directly reduces hyperdynamic contraction and LVOTO gradient

›First disease-modifying therapy class for HCM

›Disopyramide negative inotropic effect

›Reduces contractile force — reduces dynamic obstruction

›Vagolytic effect mandates concurrent AV nodal blockade

›Preload and afterload principle in HOCM

›Conditions increasing preload and afterload reduce LVOTO

›Conditions reducing preload or afterload worsen LVOTO

›Guides avoidance of vasodilators, diuretics, and inotropes

›ICD therapy evidence

›Secondary prevention ICD — proven mortality benefit

›Appropriate shock rates 10–11% per year in secondary prevention

›Primary prevention ICD — observational data support benefit with major risk factors

›Annual appropriate shock rate approximately 3–5% in high-risk primary prevention

›Exercise and lifestyle evidence

›2024 AHA/ACC guideline shift away from blanket restriction

›Individualized shared decision-making approach

›Moderate-intensity aerobic exercise generally safe

›High-intensity competitive sports — avoid if major risk features present

11Patient Discharge Instructions/pdi33

copy discharge instructions

›Discharge instructions for Hypertrophic Cardiomyopathy (HOCM)

›Understanding your diagnosis

›HCM is an inherited heart muscle disease causing thickening of the heart wall

›The thickened muscle can block blood flow out of the heart (HOCM)

›Most patients live normal lives with proper management

›Medications — take exactly as prescribed

›Do not stop beta-blockers or calcium channel blockers without consulting your doctor

›If prescribed mavacamten (Camzyos) or aficamten — take daily, attend all echo appointments

›Never take nitroglycerin — it can cause dangerous drop in blood pressure

›Never take medications that dilate blood vessels (ask doctor before any new medication)

›Avoid stimulant medications including ADHD medications and decongestants

›Lifestyle instructions

›Stay well hydrated — dehydration worsens your heart condition

›Avoid excessive alcohol — increases dehydration and irregular heart rhythm risk

›Avoid caffeine in large quantities

›Exercise — discuss with your cardiologist before changing your activity level

›Avoid high-intensity competitive sports unless cleared by your cardiologist

›Tell all healthcare providers (dentists, surgeons, anesthesiologists) about your HCM

›Family screening

›First-degree relatives (parents, siblings, children) should be screened

›Screening includes ECG and echocardiogram

›Genetic counseling available for you and your family

›Follow-up appointments

›Cardiology follow-up within 1–2 weeks of discharge

›Bring a list of all your current medications to each visit

›Annual echocardiogram and ECG as recommended by your cardiologist

›Return to the emergency department immediately if you experience

12References/r38

Guidelines and key sources

›AHA/ACC/AMSSM/HRS/PACES/SCMR 2024 Guideline for Management of HCM

›Ommen SR, Ho CY, Asif IM, et al.

›Journal of the American College of Cardiology. 2024

›https://doi.org/10.1016/j.jacc.2024.02.014

›2020 AHA/ACC Guideline for Diagnosis and Treatment of HCM

›Ommen SR, Mital S, Burke MA, et al.

›Journal of the American College of Cardiology. 2020

›PMID: 33229116

›Braunwald E. Hypertrophic Cardiomyopathy

›New England Journal of Medicine. 2025

›https://www.nejm.org/doi/full/10.1056/NEJMra2413445

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

›Journal of the American College of Cardiology. 2022

›PMID: 35086660

›Maron BJ, Desai MY, Nishimura RA, et al. Management of HCM: JACC State-of-the-Art Review

›Journal of the American College of Cardiology. 2022

›PMID: 35086661

Landmark trials and additional references

›Sikand N, Stendahl J, Sen S, Lampert R, Day S. Current Management of HCM

›BMJ. 2025

›PMID: 40425241

›Leggit JC, Whitaker D. Diagnosis and Management of HCM: Updated ACC/AHA Guidelines

›American Family Physician. 2022

›PMID: 35166485

›Fahim M, et al. Mavacamten and Aficamten in HCM: Systematic Review and Meta-Analysis

›American Journal of Cardiology. 2026

›PMID: 41672217

Evidence & Review

Evidence & Review