II. Causes
-
Pulmonary Arterial Hypertension (e.g. Pulmonary Embolism, ARDS, Pulmonary Hypertension)
- Worsened with Hypoxia, hypercarbia and acidosis
- Decreased contractility (e.g. right ventricular Myocardial Infarction or Myocarditis)
- Volume overload (e.g. Excessive volume Resuscitation as in multisystem Trauma, Sepsis)
III. Pathophysiology: Right Ventricle
- Right Ventricle is a "perfusion princess" (Sara Crager)
- Right ventricle is normally perfused in systole and diastole
- Contrast with the left ventricle which is only perfused in diastole
- Right ventricle poorly tolerates hypoperfusion and contractility decreases significantly
- Right ventricle systolic perfusion is decreased in progressive Right Heart Failure
- High pulmonary artery pressure especially with low systemic pressure (decreased pressure gradient)
- Hyperexpansion of the right ventricle results in a precipitous drop in right-sided contractility
- Contrast with left ventricle contractility with hyperexpansion which compensates (Starling Curve)
- Right Ventricle hyperexpansion also shifts septum left, decreases EF, decreases MAP and perfusion
- Left ventricle has an interdependence with the right ventricle
- Right ventricular dilates with decreased contractility and tricuspid regurgitation
- LV diastolic filling decreases with falling RV ejection fraction
- RV dilation also encroaches on the LV via their shared septum
- LV can temporarily compensate for reduced Stroke Volume with an increase in Heart Rate (Tachycardia)
- Reduced LV Cardiac Output increases pulmonary vascular resistance and right sided Afterload
- Other factors increasing pulmonary vascular resistance include hypercapnia, Atelectasis and Hypoxemia
- Positive Pressure Ventilation may also increase right sided Afterload
IV. Pathophysiology: Right Ventricular Spiral of Death
- Uncompensated Right Ventricular Failure results in hemodynamic collapse
- Right Ventricular Afterload (pulmonary artery pressures) increases
- Decreases right ventricular coronary pressure (esp. in systole) and results in RV ischemia
- Decreases right ventricular ejection fraction
- Increases right ventricular volume
- Interventricular Septum shifts left (interventricular interpedence), reducing left ventricular volume and cardiac ouput
- Decreases mean arterial pressure and further decreases right ventricular pefusion
V. Management
VI. Resources
- Scott Weingart. EMCrit 272 – Right Heart Failure with Sara Crager. EMCrit Blog. Published 4/29/20. Accessed 8/22/20.