Definition of Peripartum Cardiomyopathy
Peripartum cardiomyopathy (PPCM) is an idiopathic cardiomyopathy presenting with heart failure secondary to left ventricular systolic dysfunction towards the end of pregnancy or in the months following delivery, where no other cause of heart failure is found, with ejection fraction nearly always reduced below 45%. 1
Core Diagnostic Criteria
The Heart Failure Association of the European Society of Cardiology Working Group (2010) provides the most clinically applicable definition, emphasizing that PPCM is fundamentally:
- A diagnosis of exclusion - all other causes of heart failure must be ruled out
- Timing-specific - occurs towards the end of pregnancy or in the months following delivery
- Characterized by LV systolic dysfunction - ejection fraction <45%
- Idiopathic in nature - no identifiable cause of heart failure
Important Nuance on Left Ventricular Dilation
The left ventricle may not be dilated - this is a critical distinction from older definitions. 1 The traditional requirement for LV dilation (end-diastolic dimension >2.7 cm/m² body surface area) is considered arbitrary and may lead to under-diagnosis. The reduced ejection fraction is the key echocardiographic finding, not chamber size.
Temporal Window
While the National Heart, Lung and Blood Institute definition specifies "the last month of pregnancy or within 5 months post-partum," the ESC Working Group considers this timeframe somewhat arbitrary. 1 The emphasis should be on:
- Late pregnancy presentation (typically last month)
- Postpartum presentation (in the months following delivery)
- Recognition that rigid cutoffs may miss cases
Essential Exclusion Criteria
To diagnose PPCM, you must confirm:
- No pre-existing heart disease prior to the last month of pregnancy
- No alternative explanation for heart failure (valvular disease, congenital heart disease, pre-existing cardiomyopathy, hypertensive heart disease)
- No identifiable secondary causes (viral myocarditis, toxins, etc.)
Common Pitfall
The most critical diagnostic challenge is distinguishing PPCM from familial dilated cardiomyopathy that becomes clinically apparent during the hemodynamic stress of pregnancy. 1 Some cases initially diagnosed as PPCM may actually represent unmasked familial DCM, which has important implications for family screening.
Clinical Significance
PPCM is distinct from other forms of heart failure because it:
- Can progress rapidly to end-stage heart failure within days 1
- Has potential for spontaneous complete recovery of ventricular function 1
- Both features are unusual in other cardiomyopathies
The cardiac phenotype resembles dilated cardiomyopathy, but the clinical course and potential for recovery distinguish it as a separate entity. 1