What are the presentation and pathogenesis of Takotsubo (stress) cardiomyopathy?

Presentation and Pathogenesis of Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy (TTS) is a transient, stress-induced dysfunction of the left ventricle that mimics acute coronary syndrome but occurs in the absence of obstructive coronary artery disease, predominantly affecting postmenopausal women (90%) following emotional or physical stressors. 1, 2

Clinical Presentation

Demographics and Triggers

• Predominantly affects females (90%), particularly postmenopausal women 2
• Typically precipitated by:
  • Emotional stressors (grief, fear, anxiety)
  • Physical stressors (acute illness, surgery, critical conditions) 1

Symptoms

• Chest pain (mimicking acute myocardial infarction)
• Dyspnea
• Occasionally presents with cardiogenic shock or hemodynamic instability 2, 1

Diagnostic Findings

• ECG abnormalities:

  • ST-segment elevation (typically in precordial leads V2-V5 and limb leads II and aVR)
  • Progressive T-wave inversion
  • QT interval prolongation 2, 1
  • Unlike anterior STEMI, ST elevation in TTS is less pronounced in lead V1 2

• Cardiac biomarkers:

  • Elevated troponin levels, but disproportionately low compared to the extent of wall motion abnormalities 1

• Imaging:

  • Echocardiography: Regional wall motion abnormalities extending beyond a single coronary territory, typically with LV apical akinesia (classic "apical ballooning") 2, 1
  • Coronary angiography: Absence of obstructive coronary artery disease that would explain the wall motion abnormalities 1
  • CMR: Myocardial edema in affected regions without late gadolinium enhancement (distinguishing it from myocardial infarction) 2

Variants

• Classic/apical form: Apical and mid-ventricular akinesia with basal hyperkinesis
• Mid-ventricular form: Mid-ventricular akinesia with apical and basal hyperkinesis
• Basal form: Basal akinesia with apical hyperkinesis
• Biventricular involvement in approximately 25% of cases 2

Pathogenesis

The exact pathophysiological mechanisms remain incompletely understood, but several key factors have been identified:

1. Catecholamine surge:

   • Excessive catecholamine release following emotional or physical stress is the primary trigger 1
   • Catecholamines may cause direct myocardial toxicity and microvascular dysfunction 1

2. Microvascular dysfunction:

   • Coronary microvascular spasm leading to myocardial ischemia despite patent epicardial coronary arteries 1
   • Metabolic imaging shows reduced metabolic activity in affected regions despite relatively normal perfusion 2

3. Neurohormonal brain-heart interactions:

   • Complex interplay between the central nervous system and cardiovascular system 1
   • Sympathetic nervous system hyperactivation affecting myocardial function

4. Myocardial stunning:

   • Transient myocardial dysfunction that recovers completely within weeks
   • Myocardial edema present in affected regions, suggesting inflammation or increased wall stress 2

5. Left ventricular outflow tract obstruction:

   • Occurs in approximately 20% of cases
   • May contribute to apical ballooning through increased wall stress 1

Clinical Course and Outcomes

• Complete recovery of LV function typically occurs within 3-4 weeks 1
• Overall good prognosis with 95% of patients making full recovery 1
• Potential complications include:
  • Left ventricular thrombus formation
  • Cardiogenic shock (in severe cases)
  • QT prolongation with risk of arrhythmias
  • Recurrence in approximately 5% of cases 1

Diagnostic Approach

The InterTAK Diagnostic Score can guide management:

• Score ≥70 indicates high probability of TTS
• Score <70 suggests proceeding with coronary angiography 2, 1

Cardiac magnetic resonance imaging in the subacute phase is valuable for:

• Confirming typical wall motion abnormalities
• Detecting myocardial edema
• Confirming absence of late gadolinium enhancement (ruling out myocardial infarction) 2

Takotsubo cardiomyopathy represents a unique stress-induced cardiomyopathy that highlights the important connection between emotional/physical stress and cardiovascular function.