Indications for Anticoagulants in Cardiomyopathy

1. Dilated Cardiomyopathy (DCM)

• Intracavitary/mural thrombus — DCM causes ventricular dilation with wall motion abnormalities, predisposing to LV thrombus formation. Anticoagulation is standard therapy.
• Atrial fibrillation (AF) — Anticoagulate per standard AF guidelines (CHA₂DS₂-VASc score).
• Very low ejection fraction (EF <15%) — Secondary analysis of the WARCEF trial suggests this subgroup has sufficiently high stroke risk to consider anticoagulation; warfarin appeared to reduce ischemic stroke, though offset by increased major bleeding.
• Thromboembolic complications — Anticoagulants should be considered to decrease the risk of thrombus formation in general.

"Anticoagulants should be considered to decrease the risk of thrombus formation [in dilated cardiomyopathy]." — The Harriet Lane Handbook, 23rd ed.

Note: Prophylactic warfarin in DCM patients without AF or thrombus (targeting INR 2.0–3.5) did NOT show a significant reduction in the composite endpoint of ischemic stroke, ICH, or all-cause death vs. aspirin in the full WARCEF trial. Routine prophylactic anticoagulation for DCM alone (without the above indications) is therefore NOT currently recommended. — Bradley and Daroff's Neurology in Clinical Practice

2. Hypertrophic Cardiomyopathy (HCM)

• AF occurs in ~25% of HCM patients and carries a significant risk of systemic embolization.
• Anticoagulation principles are similar to other conditions using standard AF guidelines; however, the embolic risk in HCM with AF is considered higher than in the general AF population, and anticoagulation is strongly recommended regardless of CHA₂DS₂-VASc score.

"In general, the principles of managing atrial fibrillation in patients with hypertrophic cardiomyopathy are similar to those in other conditions, including the use of anticoagulation because of the significant risk of systemic embolization." — Goldman-Cecil Medicine

3. Peripartum Cardiomyopathy (PPCM)

• Thromboembolism prevention and treatment during pregnancy and postpartum — PPCM is associated with a particularly elevated thromboembolic risk due to the hypercoagulable state of pregnancy plus reduced EF.
• LMWH is preferred during pregnancy (does not cross the placenta); bridging to warfarin postpartum.
• Anticoagulation indicated if EF is significantly reduced or if thrombus is present.

"For prevention and treatment of thromboembolic complications during pregnancy and as bridge to warfarin postpartum." — Fuster and Hurst's The Heart, 15th ed.

4. Restrictive Cardiomyopathy

• Atrial enlargement from impaired ventricular filling → risk of AF and thrombus.
• Treatment is typically supportive: diuretics, anticoagulants, calcium channel blockers, pacemaker (if heart block), and eventual transplant.

"Treatment is supportive with diuretics, anticoagulants, calcium channel blockers, a pacemaker for heart block, and cardiac transplantation, if severe." — Harriet Lane Handbook, 23rd ed.

5. Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

• Atrial fibrillation
• Marked ventricular dilation
• Ventricular aneurysms

"Anticoagulation should be considered in the presence of atrial fibrillation, marked ventricular dilation, or ventricular aneurysms." — Goldman-Cecil Medicine

6. Takotsubo (Stress) Cardiomyopathy

• Associated with elevated stroke risk among the cardiomyopathy subgroups with reduced EF.
• Anticoagulation considered if LV thrombus is demonstrated or if AF is present.

7. Left Ventricular Non-Compaction (LVNC)

• In hypokinetic (dilated) LVNC: anticoagulation is prescribed based on the clinical indications dictated by the underlying cardiomyopathy (e.g., AF, thrombus).
• In hyperkinetic or restrictive LVNC: anticoagulation is driven more by complications such as left atrial dilation or arrhythmias.

Summary Table