Cardiac dysfunction in pregnancy may be due to exacerbation of pre-existing cardiac disease or may be a new cardiac disease triggered by the physiological changes of pregnancy.
Physiological cardiovascular changes in pregnancy
| Parameter | Change |
|---|---|
| Cardiac output | ↑ 20–50% |
| Stroke volume | ↑ ~25% in 1st trimester |
| Heart rate | ↑ 15–30% |
| Systemic vascular resistance | ↓ ~30% |
| Blood pressure | Slight decrease initially (especially diastolic BP) |
| Left ventricular mass | ↑ up to 50% |
| Chamber size | Enlargement of all four chambers |
NYHA functional classification of heart failure (Symptoms = fatigue, palpitations, dyspnea)
| NYHA Class | Symptoms at rest | Symptoms during activity |
|---|---|---|
| I | No | No |
| II | No | Mild |
| III | No | Severe |
| IV | Yes | Severe |
Maternal mortality risk
| Risk for maternal mortality | Conditions |
|---|---|
| Low risk (<1%) | Atrial septal defect, Ventricular septal defect, Minimal Mitral stenosis, Porcine valve, Corrected tetralogy of fallot |
| Intermediate risk (5-15%) | Mitral stenosis + A-fib, Uncorrected tetralogy of fallot, Marfan’s with normal aortic root diameter, Artificial valve |
| High risk (25-50%) | Pulmonary hypertension, Eisenmenger’s syndrome, Peripartum cardiomyopathy, Marfan’s with dilated aortic root |
- Causes
- Cardiomyopathy
- Coronary artery disease
- Pregnancy-associated myocardial infarction
- Valvular heart disease
- Pathophysiology
- Physiological cardiovascular changes in pregnancy occur as early as 5 weeks gestation
- The relatively “high output” state can precipitate decompensation if there is cardiomyopathy, congenital heart disease or valvular heart disease
- Eisenmenger syndrome
- Reduced systemic vascular resistance → reduced afterload → reduced pressure in left ventricle → increased right to left shunting
- Signs and symptoms
- Clubbing
- Cyanosis
- Jugular venous distension
- Fatigue
- Dyspnoea
- Paroxysmal nocturnal dyspnoea
- Chest pain or angina
- Syncope
- Orthopnea
- Palpitations
- Diastolic murmur
- Systolic murmur with a thrill
- Increasing oedema
- Investigations
- Complete blood count for myocarditis
- Urea and creatinine to evaluate hypoperfusion
- Liver enzymes to evaluate congestive hepatopathy
- Urinalysis to evaluate proteinuria (preeclampsia)
- BNP
- Elevated in heart failure or peripartum cardiomyopathy
- Electrocardiogram
- Echocardiography
- Treatment
- Pre-conception evaluation by a cardiologist, including these tests:
- 12-lead EKG
- Echocardiography
- Assessment of functional class
- Perform all interventions before conception
- Patient Education
- Close follow up with cardiologist during pregnancy
- The frequency depends on the functional class
- For heart failure
- Beta-blockers (preferably metoprolol)
- Diuretics
- Hyralazine + nitrates
- Pre-conception evaluation by a cardiologist, including these tests: