Cardiovascular · PANCE / PANRE

Dilated Cardiomyopathy (DCM)

Written & clinically reviewed by Ryan Busch, PA-C · Updated October 2026 · Report an error

LV dilation with systolic dysfunction not explained by ischemia or pressure overload — many etiologies converge on the same phenotype.

Also known as: DCM, dilated cardiomyopathy, non-ischemic cardiomyopathy, NICM

Overview

Left ventricular (or biventricular) dilation and systolic dysfunction (LVEF <40%) not explained by coronary artery disease, valvular heart disease, hypertension, or congenital heart disease.

Epidemiology

Most common form of non-ischemic cardiomyopathy. Prevalence ~1 in 250. Familial in 30-50% of cases (autosomal dominant most common). Peak age 20-60. Leading non-ischemic indication for heart transplantation.

Try two board-style Dilated Cardiomyopathy questions

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Question 1CardiovascularMedium
A 48-year-old female develops exertional dyspnea and bilateral leg edema 6 weeks after delivering her second child. She is breastfeeding. Echocardiogram shows ejection fraction (EF) 28% with a dilated left ventricle (LV). She has no prior cardiac history. Which of the following is the most likely diagnosis?
  • ASpontaneous coronary artery dissection
  • BPostpartum preeclampsia with pulmonary edema
  • CViral myocarditis
  • DPeripartum cardiomyopathy
  • EPulmonary embolism
Reveal answer & full explanation
Correct answer: D — Peripartum cardiomyopathy
  • ASpontaneous coronary artery dissection
  • BPostpartum preeclampsia with pulmonary edema
  • CViral myocarditis
  • DPeripartum cardiomyopathy✓
  • EPulmonary embolism

Why Peripartum cardiomyopathy is correct

  • Peripartum cardiomyopathy (PPCM) is new-onset heart failure in the last month of pregnancy or within 5 months postpartum, with ejection fraction below 45% and no other identifiable cause
  • This patient presented 6 weeks postpartum with EF 28%, a dilated left ventricle, and no prior cardiac history

Why the others are wrong

  • Pulmonary embolism - causes acute dyspnea and hypoxia but not a dilated LV with reduced EF on echocardiogram (confused-with postpartum dyspnea)
  • Postpartum preeclampsia with pulmonary edema - produces pulmonary edema through severe hypertension, diastolic dysfunction, and capillary leak, usually with preserved systolic function, not a dilated left ventricle with EF 28% (anchoring on postpartum timing)
  • Viral myocarditis - can cause a dilated LV with reduced EF at any time, but no preceding viral illness is described, and new systolic heart failure within 5 months of delivery with no other cause is PPCM (right-concept-wrong-etiology)
  • Spontaneous coronary artery dissection - a leading cause of pregnancy-associated myocardial infarction, most often postpartum, but it presents as an acute coronary syndrome with chest pain, troponin elevation, and a regional wall motion abnormality in the dissected artery's territory; this patient has heart failure symptoms with no chest pain described and a dilated LV with EF 28%, the picture of a cardiomyopathy (confused-with postpartum MI)

Additional high-yield points

  • Treatment: standard heart failure therapy including beta-blocker, diuretics, and spironolactone
  • While she is breastfeeding, use an ACE inhibitor with lactation data (enalapril or captopril) rather than an ARB; hydralazine plus nitrate is the substitute during pregnancy or when an ACE inhibitor cannot be used
  • Bromocriptine suppresses prolactin and may aid EF recovery (it is the B of the BOARD treatment mnemonic: Bromocriptine, Oral heart failure therapy, Anticoagulation, vasoRelaxing agents, Diuretics), but it ends lactation, must be given with anticoagulation, and remains investigational in the US
  • Prognosis: about half or more recover a normal EF (46% at 6 months in the global ESC registry, 72% at 1 year in the US IPAC cohort); roughly 10-20% have persistent severe cardiomyopathy; recurrence risk with a subsequent pregnancy is high, especially if EF has not normalized
Question 2CardiovascularMedium
A 34-year-old female has new bilateral leg swelling and dyspnea on exertion 2 weeks postpartum. Echo shows ejection fraction (EF) 25% with global hypokinesis and no other cardiac abnormality. Which of the following is the strongest risk factor for this condition?
  • APre-pregnancy left ventricular dysfunction
  • BFamily history of dilated cardiomyopathy
  • CMultiple gestation pregnancy
  • DFirst-time pregnancy in a young primigravida
  • EDelivery of a macrosomic infant
Reveal answer & full explanation
Correct answer: C — Multiple gestation pregnancy
  • APre-pregnancy left ventricular dysfunction
  • BFamily history of dilated cardiomyopathy
  • CMultiple gestation pregnancy✓
  • DFirst-time pregnancy in a young primigravida
  • EDelivery of a macrosomic infant

Why Multiple gestation pregnancy is correct

  • Peripartum cardiomyopathy (PPCM) is a dilated cardiomyopathy presenting in the last month of pregnancy or up to 5 months postpartum with no other identified cause
  • Recognized risk factors: multiple gestation, multiparity, preeclampsia, hypertension, maternal age >30, and (epidemiologically) African ancestry
  • Treatment: standard heart failure regimen; avoid angiotensin-converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB) while pregnant, but use after delivery
  • Recovery occurs in 50–70% of cases; recurrence risk exists in subsequent pregnancies

Why the others are wrong

  • Family history of dilated cardiomyopathy — a risk factor for cardiomyopathy in general but not the strongest specific risk factor for PPCM
  • First-time pregnancy in a young primigravida — multiparity, not primigravida status, is the risk factor for PPCM, and younger age is less of a risk than age >30
  • Pre-pregnancy left ventricular dysfunction — by definition PPCM occurs without a prior identified cardiac cause, so pre-existing LV dysfunction would exclude the diagnosis
  • Delivery of a macrosomic infant — a large single fetus seems to add hemodynamic load much as twins do, but fetal macrosomia is not a recognized risk factor for PPCM; the recognized obstetric risks are multiple gestation, multiparity, and preeclampsia or hypertension

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Risk factors

  • Genetic mutations — TTN (titin) most common, also LMNA (lamin A/C — high risk of arrhythmia), MYH7, RBM20, DSP
  • Alcohol (chronic heavy use)
  • Cocaine, methamphetamine, anthracyclines (doxorubicin), trastuzumab, immune checkpoint inhibitors
  • Viral myocarditis (coxsackie B, parvovirus B19, HHV-6, HIV, SARS-CoV-2)
  • Peripartum cardiomyopathy (last month of pregnancy to 5 months postpartum, LVEF <45%, no other cause; risk factors: age >30, multiparity, multiple gestation, preeclampsia or hypertension, African ancestry)
  • Tachycardia-mediated (chronic uncontrolled AF, frequent PVCs)
  • Autoimmune disease, hemochromatosis, thyroid disease

Pathophysiology

Insult to the myocardium triggers maladaptive remodeling: chamber dilation, eccentric hypertrophy, increased wall stress, and neurohormonal activation (renin-angiotensin-aldosterone, sympathetic) that worsens fibrosis and dysfunction. Functional mitral regurgitation develops from annular dilation. The dilated, fibrosed LV is prone to ventricular arrhythmia.

Clinical presentation

Symptoms

  • Progressive dyspnea on exertion, orthopnea, PND
  • Fatigue, exercise intolerance
  • Peripheral edema, abdominal distension
  • Palpitations, syncope (atrial or ventricular arrhythmia)
  • Embolic events (LV thrombus → stroke)

Signs / physical exam

  • Displaced laterally apical impulse, S3 gallop
  • Functional MR or TR murmur
  • Elevated JVP, pulmonary rales, hepatomegaly, peripheral edema
  • Cool extremities and narrow pulse pressure in advanced disease
  • Pulsus alternans in severe LV dysfunction

Differential diagnosis

  • Ischemic cardiomyopathy — CAD distribution of wall motion abnormalities, prior MI, obstructive disease on cath; treat with revascularization plus GDMT
  • Hypertensive cardiomyopathy — History of poorly controlled HTN with concentric LVH that has progressed to dilation; treat BP
  • Valvular cardiomyopathy — Significant primary valvular disease driving LV dysfunction; correct valve
  • Takotsubo (stress) cardiomyopathy — Reversible apical ballooning after emotional/physical stress; normal coronaries; recovers in weeks
  • Peripartum cardiomyopathy — DCM presenting in late pregnancy or up to 5 months postpartum
  • Cardiac amyloidosis — Restrictive physiology with thick walls but reduced voltage on ECG; PYP scan, light chains, biopsy
  • Arrhythmogenic right ventricular cardiomyopathy — RV-predominant disease with epsilon waves, T-wave inversion V1-V3, family history of SCD
  • Wet beriberi (thiamine deficiency) — Heavy alcohol use or malnutrition with high-output failure — warm extremities, bounding pulses, wide pulse pressure; improves rapidly with IV thiamine

Diagnostic workup

Labs

  • BNP / NT-proBNP, troponin
  • CBC, BMP, LFTs, TSH, iron studies (hemochromatosis), HIV
  • HbA1c, lipid panel
  • Selected etiologic testing: ANA, SPEP/light chains (amyloid), genetic panel if familial, viral serologies
  • Alcohol and drug history (always elicit)

Imaging

  • Transthoracic echo — chamber size, EF, wall motion (typically global hypokinesis), functional MR, RV function
  • Cardiac MRI with late gadolinium enhancement — etiology (mid-wall fibrosis = non-ischemic, subendocardial = ischemic), risk stratification
  • Coronary angiography (or CTA in selected patients) — exclude obstructive CAD
  • ECG — sinus tachycardia, LBBB common; PVCs, atrial fibrillation
  • Endomyocardial biopsy reserved for unexplained acute heart failure, suspected giant cell myocarditis, or eosinophilic disease

Diagnostic algorithm

flowchart TD
  A[New DCM<br/>LVEF <40%, dilated LV] --> B[Etiology workup]
  B --> C[CAD: angiography]
  B --> D[Toxic: alcohol, cocaine,<br/>anthracyclines]
  B --> E[Infiltrative: amyloid, sarcoid,<br/>hemochromatosis]
  B --> F[Familial: cascade<br/>genetic testing]
  B --> G[Other: viral, peripartum,<br/>tachy-mediated]
  A --> H[Start GDMT 4 pillars<br/>ARNI/ACEi/ARB + β-blocker +<br/>MRA + SGLT2i]
  H --> I[Reassess EF at 3 months]
  I --> J{LVEF still ≤35%?}
  J -->|Yes, NYHA II-III| K[ICD ± CRT<br/>if QRS ≥150 LBBB]
  J -->|Improved| L[Continue GDMT]
Workup and longitudinal management of newly diagnosed dilated cardiomyopathy.

Treatment

First-line

  • Guideline-directed medical therapy (GDMT) — four pillars of HFrEF therapy started simultaneously and titrated:
  • • ARNI (sacubitril-valsartan 24/26-97/103 mg PO BID) — preferred over ACEi (lisinopril, enalapril) or ARB (losartan, valsartan)
  • • Beta-blocker — carvedilol 3.125-25 mg PO BID, metoprolol succinate 12.5-200 mg daily, or bisoprolol 1.25-10 mg daily
  • • Mineralocorticoid receptor antagonist — spironolactone 12.5-50 mg daily or eplerenone 25-50 mg daily
  • • SGLT2 inhibitor — dapagliflozin 10 mg daily or empagliflozin 10 mg daily (with or without diabetes)
  • Loop diuretic (furosemide, torsemide, bumetanide) for congestion — titrate to euvolemia
  • Remove offending agents: alcohol abstinence, cessation of cardiotoxic drugs
  • Pregnancy (peripartum cardiomyopathy): avoid ACEi, ARB, ARNI, MRA, and SGLT2 inhibitors (fetotoxic or unstudied) — use a beta-1-selective beta-blocker (metoprolol), hydralazine plus nitrate, and a loop diuretic for congestion; after delivery start full GDMT, but while breastfeeding use enalapril or captopril instead of an ARNI or ARB and avoid SGLT2 inhibitors

Second-line / adjunct

  • Hydralazine + isosorbide dinitrate — added on top of GDMT in self-identified Black patients with persistent NYHA III-IV (A-HeFT) or as ACEi/ARB alternative when not tolerated
  • Ivabradine for sinus rhythm with HR ≥70 on maximal beta-blocker (SHIFT)
  • ICD for primary prevention if LVEF ≤35% after ≥3 months of GDMT and NYHA II-III with reasonable life expectancy
  • Cardiac resynchronization therapy (CRT) for LVEF ≤35%, LBBB with QRS ≥150 ms, NYHA II-IV
  • Anticoagulation if LV thrombus, atrial fibrillation, or prior embolism
  • Heart transplantation or LVAD for end-stage refractory disease

Complications

  • Heart failure decompensation requiring hospitalization
  • Sudden cardiac death from ventricular arrhythmia
  • Atrial fibrillation
  • LV thrombus and systemic embolization (especially stroke)
  • Hepatic and renal dysfunction (cardiorenal, congestive hepatopathy)
  • Progressive functional MR

PANCE pearls

  • Bromocriptine has been studied for peripartum cardiomyopathy (suppresses prolactin) — variable evidence; AVOID further pregnancy in patients with persistent LV dysfunction.
  • LMNA mutations carry a particularly high risk of sudden cardiac death and warrant lower ICD thresholds.
  • Tachycardia-mediated cardiomyopathy (chronic AF, frequent PVCs) is potentially reversible with rate/rhythm control or PVC ablation.
  • Alcoholic cardiomyopathy may improve substantially with sustained abstinence.
  • All four pillars of GDMT should be initiated rapidly (often before discharge) — outcome benefit is additive and shows up within weeks.

References

  • ACC/AHA/HFSA 2022 HF — 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure (Heidenreich et al., JACC 2022)
  • PARADIGM-HF — Angiotensin-Neprilysin Inhibition versus Enalapril in Heart Failure (McMurray et al., NEJM 2014)
  • DAPA-HF — Dapagliflozin in Patients with Heart Failure and Reduced Ejection Fraction (McMurray et al., NEJM 2019)
  • EMPEROR-Reduced — Cardiovascular and Renal Outcomes with Empagliflozin in Heart Failure (Packer et al., NEJM 2020)
  • ESC 2023 Cardiomyopathies — 2023 ESC Guidelines for the Management of Cardiomyopathies (Arbelo et al., Eur Heart J 2023)

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Related Cardiovascular diagnoses

Acute Coronary Syndrome (ACS)Stable AnginaHeart Failure with Reduced Ejection Fraction (HFrEF)Heart Failure with Preserved Ejection Fraction (HFpEF)Atrial FibrillationAtrial FlutterHypertensionHyperlipidemiaAortic StenosisMitral RegurgitationAortic Regurgitation (AR)Mitral Stenosis (MS)Mitral Valve Prolapse (MVP)Infective Endocarditis (IE)

Differentials & related conditions

Restrictive Cardiomyopathy

Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.