Etiology

Acute or Severe Pulmonary Hypertension (see Pulmonary Hypertension, [[Pulmonary Hypertension]])

• General Comments: typically causes right-sided failure
• Acute Pulmonary Embolism (PE) (see Acute Pulmonary Embolism, [[Acute Pulmonary Embolism]])
• Chronic Thromboembolic Pulmonary Hypertension (CTEPH)(see Chronic Thromboembolic Pulmonary Hypertension, [[Chronic Thromboembolic Pulmonary Hypertension]])
• Idiopathic Pulmonary Arterial Hypertension (IPAH) (see Idiopathic Pulmonary Arterial Hypertension, [[Idiopathic Pulmonary Arterial Hypertension]])
• Other Causes of Severe Pumonary Hypertension

Arrhythmia/Conduction Disturbance

• Tachyarrythmia
  • Atrial Fibrillation (see Atrial Fibrillation, [[Atrial Fibrillation]])
  • Atrial Flutter (see Atrial Flutter, [[Atrial Flutter]])
  • Supraventricular Tachycardia (SVT) (see Supraventricular Tachycardia, [[Supraventricular Tachycardia]])
  • Ventricular Fibrillation (see Ventricular Fibrillation, [[Ventricular Fibrillation]])
  • Ventricular Tachycardia (VT) (see Ventricular Tachycardia, [[Ventricular Tachycardia]])
• Bradyarrhythmia
  • Second Degree Atrioventricular Block-Mobitz Type II (Second Degree Heart Block-Mobitz Type II) (see Second Degree Atrioventricular Block-Mobitz Type II, [[Second Degree Atrioventricular Block-Mobitz Type II]])
  • Sinus Bradycardia (see Bradycardia, [[Bradycardia]])
  • Third Degree Atrioventricular Block (Third Degree Heart Block, Complete Heart Block) (see Third Degree Atrioventricular Block, [[Third Degree Atrioventricular Block]])

Cardiomyopathy (see Congestive Heart Failure, [[Congestive Heart Failure]])

• Infection
  • Myocarditis (see Myocarditis, [[Myocarditis]])
  • Sepsis-Induced Myocardial Depression (see Sepsis, [[Sepsis]])
  • Hantavirus Pulmonary Syndrome (see Hantavirus, [[Hantavirus]]): unusually produces sepsis with a high SVR and low CO state
• Endocrine/Metabolic Disturbance
  • Acidosis (see Metabolic Acidosis-General, [[Metabolic Acidosis-General]])
  • Hypoxia (see Hypoxemia, [[Hypoxemia]])
  • Hypophosphatemia (see Hypophosphatemia, [[Hypophosphatemia]])
  • Hypocalcemia (see Hypocalcemia, [[Hypocalcemia]])
  • Thyrotoxicosis (see Hyperthyroidism, [[Hyperthyroidism]])
• Myocardial Ischemia/Infarction
  • Acute Myocardial Infarction (MI) (see Coronary Artery Disease, [[Coronary Artery Disease]]): involving >40% of left ventricular myocardium
  • Myocardial Ischemia/Stunned Myocardium
• Post-Cardiopulmonary Bypass (see Cardiopulmonary Bypass, [[Cardiopulmonary Bypass]])
• Restrictive Cardiomyopathy (see Restrictive Cardiomyopathy, [[Restrictive Cardiomyopathy]])
• Trauma
  • Cardiac Contusion (see Cardiac Contusion, [[Cardiac Contusion]])
• Takotsubo Cardiomyopathy (Stress-Induced Cardiomyopathy) (see Takotsubo Cardiomyopathy, [[Takotsubo Cardiomyopathy]])
• Tamponade (see Tamponade, [[Tamponade]]): produces diastolic dysfunction
• Drugs/Toxins
  • Antiarrhythmics
  • Beta Blockers (see β-Adrenergic Receptor Antagonists): particularly in the setting of intoxication
  • Calcium Channel Blockers (see Calcium Channel Blockers, [[Calcium Channel Blockers]]): particularly in the setting of intoxication
  • Propofol Infusion Syndrome (see Propofol, [[Propofol]])

Increased Afterload

• Aortic Coarctation (see Aortic Coarctation, [[Aortic Coarctation]])
• Hypertrophic Obstructive Cardiomyopathy (HOCM) (see Hypertrophic Cardiomyopathy, [[Hypertrophic Cardiomyopathy]])
• Malignant Hypertension (see Hypertension, [[Hypertension]])
• Severe Aortic Stenosis (see Aortic Stenosis, [[Aortic Stenosis]])

Increased Intrathoracic Pressure (with Impaired Right-Sided Venous Return)

• Herniation of Abdominal Viscera Into Thorax
• Positive-Pressure Ventilation with High Airway Pressures (see Acute Lung Injury-ARDS, [[Acute Lung Injury-ARDS]])
• Tension Pneumothorax (see Pneumothorax, [[Pneumothorax]])

Intracardiac Shunt (see Intracardiac and Extracardiac Shunt, [[Intracardiac and Extracardiac Shunt]])

• Atrial Septal Defect (ASD) (see Atrial Septal Defect, [[Atrial Septal Defect]])
• Ruptured Sinus of Valsalva Aneurysm (see Sinus of Valsalva Aneurysm, [[Sinus of Valsalva Aneurysm]])
• Ventricular Septal Defect (VSD) (see Ventricular Septal Defect, [[Ventricular Septal Defect]])
• Ventricular Septal Rupture (see Ventricular Septal Rupture, [[Ventricular Septal Rupture]])

Valvular Disease/Mechanical Disturbance

• Aortic Insufficiency (AI) (see Aortic Insufficiency, [[Aortic Insufficiency]])
• Aortic Stenosis (AS) (see Aortic Stenosis, [[Aortic Stenosis]])
• Atrial Myxoma (see Atrial Myxoma, [[Atrial Myxoma]])
• Atrial Thrombus (see Intracardiac Thrombus, [[Intracardiac Thrombus]])
• Mitral Regurgitation (MR) (see Mitral Regurgitation, [[Mitral Regurgitation]])
• Mitral Stenosis (see Mitral Stenosis, [[Mitral Stenosis]])
• Papillary Muscle Dysfunction/Rupture
• Ruptured Left Ventricular Aneurysm (see Left Ventricular Aneurysm, [[Left Ventricular Aneurysm]])
• Tricuspid Regurgitation (TR) (see Tricuspid Regurgitation, [[Tricuspid Regurgitation]])
• Ventricular Septal Defect (VSD) (see Ventricular Septal Defect, [[Ventricular Septal Defect]])

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Diagnosis

• Echocardiogram: usually diagnostic
• Swan
  • Cardiac Output (CO): usually decreased
  • Increased Extraction Ratio (Decreased SvO2): in cases with decreased CO

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Clinical

• Hypotension (see Hypotension, [[Hypotension]])
• Pulseless Electrical Activity (PEA) (see Pulseless Electrical Activity, [[Pulseless Electrical Activity]]): may occur in cases of tension pneumothorax, tamponade

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Treatment

Inotropes

• Norepinephrine: improves myocardial oxygen metabolism (increases myocardial lactate extraction) in patients with cardiogenic shock by increasing perfusion pressure and myocardial oxygen supply
• Dopamine: worsens myocardial oxygen metabolism because of the associated tachycardia
  • In cardiogenic shock, the use of dopamine increases mortality, as compared to norepinephrine

Intra-Aortic Balloon Pump (IABP)

• Useful for cases unresponsive to medical therapy
• Inflates during early diastole (pushing blood toward head and neck arteries and coronary arteries) with rapid deflation prior to systole: decreased afterload (decreased SVR)/ decreased LV-EDP/ modestly decreased aortic systolic pressure -> increased CO
  • In cases of MR or VSD, aortic systolic pressure usually increases modestly
• Improves myocardial lactate production, arterial BP, and CO
• Proven to improve survival only in MI patients with complicating ruptured ventricular septum or ruptured papillary muscle

PRBC Transfusion

• No specific Hct has been documented to improve any clinical factor or outcome
• However, doubling the Hct (from 20 to 40%) will double plasma viscosity, increasing O2 delivery to coronary arteries but increasing myocardial work

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References

• Effect of isoproterenol, norepinephrine and intraaortic counterpulsation on hemodynamics and myocardial metabolism in shock following myocardial infarction. Circulation 1972; 37:335- 351
• Effect of dopamine on hemodynamics and myocardial metabolism in shock following acute myocardial infarction in man. Circulation 1978; 57:361-365
• Comparison of dopamine and norepinephrine in the treatment of shock. N Engl J Med 2010; 362:779-789