11.2 Peripartum Cardiomyopathy (PPCM), Acute Heart Failure, Acute Coronary Syndromes & Maternal Arrhythmias

Peripartum Cardiomyopathy (PPCM), Acute Heart Failure & SCAD

Cardiovascular disease has emerged as the leading cause of maternal mortality in developed countries, accounting for over 26% of pregnancy-related deaths. The normal physiological hemodynamic adaptations of pregnancy—including a 40% to 50% expansion in blood volume, a 30% to 50% increase in cardiac output, and profound peripartum fluid shifts—can unmask or trigger catastrophic cardiac crises. Among these, Peripartum Cardiomyopathy (PPCM), Spontaneous Coronary Artery Dissection (SCAD), and Acute Aortic Dissection represent critical life-threatening conditions demanding rapid multidisciplinary management.

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1. Peripartum Cardiomyopathy (PPCM): Diagnostic Criteria & Pathophysiology

PPCM is an idiopathic form of heart failure with reduced ejection fraction that presents late in pregnancy or in the early months following delivery.

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|                         DIAGNOSTIC CRITERIA FOR PPCM (NHLBI / ESC)                                |
|                                                                                                   |
|  1. TIMING OF ONSET:                                                                              |
|     • Development of heart failure toward the end of pregnancy (last gestational month) or        |
|       within 5 months following delivery (peak onset is in the first postpartum month).            |
|                                                                                                   |
|  2. EXCLUSION OF ALTERNATIVE CAUSES:                                                              |
|     • Absence of another identifiable etiology for heart failure (e.g., severe ischemic heart     |
|       disease, viral myocarditis, severe uncorrected valvular stenosis, toxic cardiomyopathy).     |
|                                                                                                   |
|  3. NO PRIOR HEART DISEASE:                                                                       |
|     • Absence of recognizable cardiac disease prior to the last month of pregnancy.               |
|                                                                                                   |
|  4. ECHOCARDIOGRAPHIC LEFT VENTRICULAR SYSTOLIC DYSFUNCTION:                                      |
|     • Left Ventricular Ejection Fraction (LVEF) < 45% (and/or fractional shortening < 30%),       |
|       frequently accompanied by Left Ventricular End-Diastolic Dimension (LVEDD) > 2.7 cm/m2.     |
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Pathophysiological Mechanisms: The Prolactin-Vasculo-Toxic Hypothesis

1. The 16-kDa Prolactin Fragment: In late gestation and early puerperium, enhanced oxidative stress activates myocardial cathepsin D, which cleaves full-length, protective prolactin (23 kDa) into an angiostatic, pro-apoptotic 16-kDa prolactin fragment. This fragment damages cardiac microvasculature, impairs cardiomyocyte metabolism, and triggers extensive myocardial apoptosis.
2. Anti-Angiogenic Signaling (sFlt-1): Placental secretion of soluble Fms-like tyrosine kinase-1 (sFlt-1) neutralizes VEGF. In women with genetic vulnerability, excess sFlt-1 combined with 16-kDa prolactin leads to profound microvascular endothelial dysfunction.
3. Genetic Predisposition: Approximately 10% to 15% of patients with PPCM harbor truncating mutations in the Titin (TTN) gene or other dilated cardiomyopathy-associated genes (e.g., MYH7, FLNC).

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2. Clinical Presentation, Biomarkers & Echocardiography

Distinguishing Normal Pregnancy from Acute Heart Failure

Because normal pregnancy causes physiological dyspnea, dependent pedal edema, and fatigue, the diagnosis of PPCM is frequently delayed. Pathologic red flag symptoms include: orthopnea (requiring multiple pillows), paroxysmal nocturnal dyspnea (PND), persistent nocturnal cough with pink frothy sputum, jugular venous distension (>8 cm H2O), a new S3 gallop, and pulmonary crackles.

Diagnostic Biomarkers & Imaging

• Natriuretic Peptides (BNP / NT-proBNP): NT-proBNP is significantly elevated in PPCM (frequently >1,000–5,000 pg/mL). In healthy pregnancy, NT-proBNP rises only minimally (<2-fold).
• Transthoracic Echocardiogram (TTE): Definitive gold standard diagnostic modality. Quantifies LVEF, LV end-diastolic/end-systolic dimensions, detects functional mitral/tricuspid regurgitation, assesses RV strain, and screens for apical intracardiac mural thrombi.
• Cardiac MRI (CMR): Safe in pregnancy (without gadolinium) to evaluate myocardial edema, fibrosis, and differentiate myocarditis from PPCM.

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3. Medical Management: The "BOARD" Protocol & Trimester Specifics

Pharmacological management of heart failure with reduced ejection fraction must be strictly tailored depending on whether the fetus is in utero (antepartum) or delivered (postpartum).

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|                         ANTEPARTUM VS POSTPARTUM HF PHARMACOTHERAPY                               |
|                                                                                                   |
|  ANTEPARTUM REGIMEN (FETUS IN UTERO):                                                             |
|  • CONGESTION CONTROL: **Furosemide (Lasix) 20 to 40 mg IV/PO**. Relieves pulmonary edema.        |
|    - Caution: Avoid excessive diuresis to prevent uterine hypoperfusion and oligohydramnios.      |
|  • AFTERLOAD REDUCTION: **Hydralazine (10–25 mg PO TID) + Isosorbide Dinitrate (20–40 mg PO TID)**|
|    - Potent arterial and venous vasodilators safe in all trimesters.                              |
|  • BETA-BLOCKADE: **Metoprolol Succinate** (beta-1 selective) or **Carvedilol**.                  |
|    - Initiate once euvolemia is established; titrate slowly. Avoid atenolol (fetal growth restrict).|
|  • STRICTLY CONTRAINDICATED ANTEPARTUM:                                                           |
|    - **ACE Inhibitors, ARBs, ARNIs (Sacubitril/Valsartan), and Spironolactone/Eplerenone** are     |
|      fetotoxic, causing renal dysgenesis, oligohydramnios sequence, pulmonary hypoplasia, & death.|
|                                                                                                   |
|  POSTPARTUM REGIMEN (DELIVERED):                                                                  |
|  • Rapid transition to Guideline-Directed Medical Therapy (GDMT):                                 |
|    - **ACE Inhibitor (Enalapril or Captopril)**: Compatible with breastfeeding.                   |
|    - **Beta-Blocker (Metoprolol Succinate or Carvedilol)**: Continue and optimize dose.           |
|    - **Mineralocorticoid Receptor Antagonist (Spironolactone)**: Compatible with breastfeeding.   |
|    - **SGLT2 Inhibitors (Empagliflozin/Dapagliflozin)**: Add postpartum (avoid if breastfeeding).  |
|    - **ARNI (Sacubitril/Valsartan)**: First-line if patient chooses formula feeding.              |
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Bromocriptine Therapy in PPCM

• Mechanism: Bromocriptine is a dopamine D2 receptor agonist that inhibits anterior pituitary prolactin secretion, blocking the generation of the cardiotoxic 16-kDa prolactin fragment.
• Indications & Dosing Regimen (ESC Guidelines):
  • Uncomplicated PPCM (LVEF 30–45%): Bromocriptine 2.5 mg PO once daily for 1 week.
  • Severe PPCM (LVEF <30%, cardiogenic shock, or RV dysfunction): Bromocriptine 2.5 mg PO twice daily for 2 weeks, followed by 2.5 mg PO once daily for 2 weeks (total 4-week course).
• Mandatory Safety Rule: Bromocriptine suppresses lactation and increases the risk of venous and arterial thrombosis. It MUST ALWAYS be co-administered with prophylactic or therapeutic anticoagulation (e.g., LMWH).

Anticoagulation Protocol in PPCM

• Indication: Mandatory in all patients with LVEF < 35% (due to the combined prothrombotic state of pregnancy/puerperium and ventricular blood stasis) or in the presence of intracardiac mural thrombus.
• Agents:
  • Antepartum: Full therapeutic Low-Molecular-Weight Heparin (Enoxaparin 1 mg/kg SC Q12H) or Unfractionated Heparin (does not cross placenta).
  • Postpartum: LMWH, Warfarin (target INR 2.0–3.0; safe in breastfeeding), or DOACs (if not breastfeeding).

Mechanical Circulatory Support & Transplant Evaluation

In patients with refractory cardiogenic shock despite inotropes (milrinone, dobutamine), emergency mechanical circulatory support (MCS) must be initiated: Impella CP / 5.5 (microaxial transvalvular pump) for LV unloading, Veno-Arterial ECMO (VA-ECMO) for combined cardiopulmonary collapse, or surgical LVAD / orthotopic heart transplantation.

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|                         COUNSELING FOR SUBSEQUENT PREGNANCIES IN PPCM                             |
|                                                                                                   |
|  • UNRECOVERED LVEF (<50% at 6 to 12 months postpartum):                                          |
|    - Subsequent pregnancy carries a **30% to 50% risk of clinical heart failure relapse**,         |
|      irreversible myocardial deterioration, and up to **15% to 20% maternal mortality**.          |
|    - **SUBSEQUENT PREGNANCY IS STRONGLY DISCOURAGED / CONTRAINDICATED.**                          |
|                                                                                                   |
|  • RECOVERED LVEF (>=50% to 55%):                                                                 |
|    - Recurrence risk remains **20% to 30%** (decline in LVEF or symptomatic failure).              |
|    - Requires extensive multidisciplinary pre-conception counseling, early baseline echo, and     |
|      intensive serial surveillance in a specialized Cardio-Obstetrics clinic.                     |
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4. Spontaneous Coronary Artery Dissection (SCAD) in Pregnancy

Spontaneous Coronary Artery Dissection (SCAD) is the single most common cause of acute myocardial infarction in pregnancy and the puerperium, accounting for up to 40% of pregnancy-associated MIs. Peak incidence occurs in the third trimester and the first 6 weeks postpartum.

Pathophysiology & Predisposing Factors

• High levels of progesterone disrupt normal collagen and elastin architecture in the coronary arterial media.
• Increased cardiac output and shearing forces lead to either an intimal tear or spontaneous rupture of the adventitial vasa vasorum, creating an intramural hematoma (IMH) that compresses the true coronary lumen, precipitating acute myocardial ischemia or infarction.
• Frequently associated with underlying Fibromuscular Dysplasia (FMD).

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|                         SCAD CLINICAL PRESENTATION & MANAGEMENT                                   |
|                                                                                                   |
|  • CLINICAL PRESENTATION:                                                                         |
|    - Acute STEMI (most common, >60%–70%) or NSTEMI with severe crushing chest pain, diaphoresis. |
|    - High prevalence of multivessel dissection and involvement of the Left Anterior Descending    |
|      (LAD) artery and Left Main Coronary Artery.                                                  |
|    - High risk of ventricular arrhythmias, cardiogenic shock, and maternal arrest.                |
|                                                                                                   |
|  • DIAGNOSIS: Urgent Coronary Angiography (Yip-Saw SCAD Classification: Types 1, 2, and 3).        |
|                                                                                                   |
|  • MANAGEMENT PARADIGM: CONSERVATIVE VS INTERVENTIONAL                                            |
|    1. CONSERVATIVE MEDICAL THERAPY (PREFERRED FIRST-LINE STRATEGY):                               |
|       - Indicated for: **Hemodynamically stable patients without ongoing refractory ischemia     |
|         and preserved distal coronary blood flow (TIMI 2–3 flow)**.                               |
|       - Medical Regimen: Aspirin, Beta-blockers (Metoprolol; reduces coronary shear stress),      |
|         short-term systemic anticoagulation during initial diagnostic workup, and nitroglycerin.  |
|       - Rationale: Coronary arteries in SCAD spontaneously heal in **>85% of cases within         |
|         1 to 3 months**.                                                                          |
|                                                                                                   |
|    2. INVASIVE REVASCULARIZATION (PCI OR CABG):                                                   |
|       - Strictly reserved for: **Ongoing active ischemia, hemodynamic instability/cardiogenic    |
|         shock, or Left Main / Proximal LAD dissection with TIMI 0–1 flow**.                       |
|       - CAUTION: Primary PCI in SCAD is technically challenging and hazardous; stent placement    |
|         frequently propagates the intramural hematoma proximally and distally, leading to complete|
|         vessel occlusion and iatrogenic extension of the dissection.                              |
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5. Acute Aortic Dissection in Pregnancy

Acute aortic dissection during pregnancy is a catastrophic surgical crisis with maternal and fetal mortality rates exceeding 20% to 30%. Over 50% of aortic dissections in women under age 40 occur in the setting of pregnancy, predominantly during the third trimester or early postpartum period.

High-Risk Conditions & Aortic Root Thresholds

• Heritable Thoracic Aortic Diseases: Marfan Syndrome (aortic root >4.0 cm carries high risk; >4.5 cm represents extreme risk and elective preconception repair is advised), Loeys-Dietz Syndrome, Vascular Ehlers-Danlos (VEDS, extreme fragility with fatal rupture risk), Bicuspid Aortic Valve with aortopathy, Turner Syndrome.
• Hypertensive Disorders: Severe preeclampsia and chronic hypertension superimpose extreme hemodynamic stress on hormonal aortic wall remodeling.

Stanford Classification & Emergency Management

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6. Acute Coronary Syndrome & Myocardial Infarction in Pregnancy

Spontaneous coronary artery dissection (Section 4) is the single most common mechanism of pregnancy-associated myocardial infarction, but it is not the only one: atherosclerotic disease, coronary thrombus or embolism, vasospasm, and myocardial infarction with non-obstructive coronary arteries (MINOCA) account for the remainder. The clinical presentation of acute coronary syndrome in pregnancy is the same as in the non-pregnant population. Suspect it in any pregnant or recently delivered woman with cardiac arrest, acute chest pain, dyspnea, ischemic electrocardiographic changes, or elevated cardiac biomarkers.

Interpreting the ECG and Biomarkers — Where Pregnancy Misleads

• Normal pregnancy ECG findings: increased heart rate, a minor leftward QRS axis shift, prominent Q waves in II, III, and aVF, and flat or inverted T waves in III, aVF, V1 and V2. Transient ST-segment depression and T-wave inversion can also be normal, and ST-segment changes are commonly seen during cesarean delivery under neuraxial anesthesia.
• What is never normal: ST-segment elevation is not a finding of pregnancy and warrants urgent attention. Major ischemic ECG changes are not expected from pregnancy itself.
• Troponin: standardized cardiac troponin I and troponin T values for pregnancy and the postpartum period have not been established, so current European Society of Cardiology guidance advises that troponin should not be used alone during pregnancy. A troponin rise nevertheless indicates myocardial injury exactly as it does outside pregnancy and must be interpreted together with the ECG and echocardiogram. Preeclampsia can itself produce mild elevations.
• Anatomy of maternal STEMI: the anterior wall is involved in 70% to 80% of cases, and more than half of patients develop an LVEF below 40%, which drives the high complication rate.

Reperfusion and Antithrombotic Strategy

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|                         REPERFUSION IN PREGNANCY-ASSOCIATED ACS                                   |
|                                                                                                   |
|  • PRIMARY PCI IS THE PREFERRED REPERFUSION STRATEGY.                                             |
|    - Radial access by an experienced operator is preferable; apply the ALARA principle and        |
|      every available measure to reduce radiation.                                                 |
|    - Fetal risk from coronary procedures is low: no fetal anomalies or losses have been reported  |
|      with exposure under 50 mGy, and most coronary procedures stay well within that limit.        |
|                                                                                                   |
|  • SYSTEMIC THROMBOLYSIS IS A FALLBACK, NOT A FIRST CHOICE.                                       |
|    - Reserved for when timely PCI is unavailable. Recombinant tissue plasminogen activator does   |
|      not cross the placenta, but it causes maternal and subplacental bleeding.                    |
|                                                                                                   |
|  • IN SCAD, CONSERVATIVE MANAGEMENT IS PREFERRED (see Section 4).                                 |
|    - PCI carries a high rate of iatrogenic dissection and hematoma extension. Left main or        |
|      proximal involvement may warrant CABG after multidisciplinary discussion.                    |
|                                                                                                   |
|  • ANTIPLATELET THERAPY WHEN A STENT IS PLACED:                                                   |
|    - Aspirin plus clopidogrel, as in non-pregnant women; stent choice is likewise unchanged.      |
|    - DELIVERY-PLANNING RULE: clopidogrel must be withheld a MINIMUM OF 5 DAYS before neuraxial    |
|      anesthesia to avoid epidural hematoma. Stents approved for short dual antiplatelet therapy   |
|      may be preferred when delivery is near.                                                      |
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Manage every pregnant patient with acute coronary syndrome in an intensive cardiac care unit with a Pregnancy Heart Team, with continuous fetal monitoring once viable. Mode of delivery is decided by obstetric indications — vaginal delivery is appropriate for most women with obstructive coronary disease — and in stable women a minimum interval of 2 weeks between the acute coronary event and delivery is advised.

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7. Maternal Arrhythmias: Rhythm-Specific Emergency Therapy

Arrhythmia frequency rises in pregnancy because heart rate and automaticity increase, atrial stretch follows the 40% to 50% volume expansion, plasma catecholamines rise, estrogen alters repolarization, and electrolytes shift. Sinus tachycardia is the most common rhythm abnormality and is almost always a symptom — of hemorrhage, sepsis, pulmonary embolism, pain, or thyrotoxicosis. Treat the cause, never the number.

Narrow-QRS Supraventricular Tachycardia

Atrial Fibrillation and Atrial Flutter

• Unstable, or pre-excited atrial fibrillation with rapid ventricular rates: immediate electrical cardioversion.
• Absolute trap: in pre-excited atrial fibrillation (Wolff-Parkinson-White), atrioventricular nodal blocking drugs — beta-blockers, verapamil, digoxin, and adenosine — are contraindicated. Blocking the node accelerates conduction down the accessory pathway and can precipitate ventricular fibrillation. Cardiovert instead.
• Stable with severe structural heart disease: rate control with IV metoprolol, with verapamil or digoxin as alternatives.
• Stable without structural heart disease: pharmacologic cardioversion with IV flecainide or ibutilide.
• Amiodarone is not recommended in pregnancy — it causes fetal hypothyroidism, goiter, and neurodevelopmental impairment — and should be restricted to refractory or life-threatening arrhythmia.
• Anticoagulation uses low-molecular-weight heparin. Direct oral anticoagulants are contraindicated in pregnancy.

Ventricular Arrhythmias

Unstable ventricular tachycardia is cardioverted or defibrillated using standard energies. Beyond that, therapy is etiology-specific: torsades de pointes and long QT syndrome are treated by removing precipitants and giving IV magnesium and potassium, a beta-blocker such as propranolol, and overdrive pacing — amiodarone prolongs the QT further and must be avoided here. Fascicular ventricular tachycardia responds to verapamil, and idiopathic right ventricular outflow tract tachycardia responds to beta-blockers, with adenosine as a diagnostic and therapeutic adjunct.

If the Rhythm Becomes Cardiac Arrest

Cross-reference Chapter 6. Current guidance is explicit that antiarrhythmic and resuscitation drugs must not be withheld or dose-reduced over teratogenicity concerns; drug choices, doses, chest compressions, and defibrillation energies are identical to the non-pregnant protocol. Pregnancy-specific additions are continuous manual left uterine displacement, intravenous access above the diaphragm, and — in a patient receiving magnesium sulfate for preeclampsia — stopping the magnesium infusion and administering calcium gluconate.