🫀 Mirza's Cardiology Notes

Right Heart Failure

3 min read

  • Related:

  • Right heart failure can be broken down into “buckets”:

    • Volume overload
    • Pressure overload (or excessive afterload)
      • causes include pulmonary arterial hypertension, pulmonary embolism and chronic thromboembolic pulmonary hypertension, pulmonic stenosis, chronic hypoxemia, and longstanding elevated LAP causing group 2 PH (MR/MS, HFrEF, HFpEF)
    • primary cardiomyopathic processes (i.e., ischemia, infiltration, ARVC)
      • causes include cardiac amyloidosis, right ventricular myocardial infarction, post-transplant right ventricular dysfunction, and ARVC

  • 💡 In cases of severe right ventricular enlargement and dysfunction without apparent cause, look for a left to right shunt lesion (i.e., VSD, ASD, PAPVR). Sometimes further imaging (TEE, cardiac CT, cardiac MRI) is necessary to detect these lesions if not visualized on TTE.

  • Sinus venosus defect

  • RHC for characterizing shunt defects (Source: https://www.cardionerds.com/106-case-report-a-hole-in-the-hfpef-diagnosis-boston-university-massachusetts-general-hospital-and-brigham-and-womens-hospital/) o A left-to-right shunt is when oxygenated blood from the systemic circulation (left) inappropriately mixes with the pulmonary circulation (right), increasing the oxygen concentration. This can occur via anomalous pulmonary veins, defects at the atrial or ventricular level, or sometimes systemic arterio-venous fistulas. o As the SGC is passed through the great vessels and cardiac chambers, samples are collected at various levels. o A left to right shunt is detected by an oximetry “step up” where oxygenated blood from the systemic circulation blood mixes with deoxygenated blood from the venous circulation.  An oxygen saturation step up of >7% is considered significant at the level of the great veins and RA while a step up of >5% is considered significant at levels distal to the RA. o Qp/Qs  Calculated to examine the degree of left to right shunting  Small shunts are defined by Qp/Qs <1.5. • These are often asymptomatic and generally do not need to be treated.  Large shunts are defined by Qp/Qs >2 and often require closure.  Interpretation: for a Qp/Qs is 3.1, it means that for every 1 L of cardiac output through the systemic circulation, 3.1 L are going through the pulmonary circulation o Because intra-cardiac shunts will affect the mixed venous (pulmonary artery oxygen saturation), a systemic mixed venous saturation needs to be calculated to estimate “pre-shunt” mixed venous O2. This is defined by Flamm’s formula: (3*SVC +IVC)/4

Echo

  • RV systolic function can be assessed by:
    • tricuspid annular plane systolic excursion (TAPSE)
    • RV fractional area change
    • free-wall strain
    • tricuspid annular systolic mitral annular tissue velocity (s′)
    • RV index of myocardial performance

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