What are ventricular interdependence considerations in the perioperative management of pulmonary hypertension (PH)?

Updated: Sep 11, 2019
  • Author: Swapnil Khoche, MBBS, DNB, FCARCSI; Chief Editor: Sheela Pai Cole, MD  more...
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Answer

Answer

Ventricular interdependence

Superficial myocardial fibers encircle both the LV and the RV, and the two chambers share a pericardium along with a septal wall. Consequently, changes that affect one ventricle eventually affect the other as well. In view of the importance of this ventricular interdependence to RV function, every effort should be made to avoid drops in SVR and LV afterload.

In a normal heart, the RV contracts circumferentially onto the septal wall, leading to efficient contraction and good systolic function. However, when PAP is elevated and the RV is overloaded, the septal wall shifts out into the LV, impairing both RV systolic efficiency and LV diastolic function. [4]  This is one of the reasons why maintenance of sinus rhythm is essential for LV filling. Fortunately, if LV afterload is increased, LV end-diastolic pressure (LVEDP) increases, and this pressure pushes the septal wall back to midline, allowing efficient RV contraction. Phenylephrine or other predominantly alpha-agonist agents (eg, norepinephrine) can be given to help accomplish this.


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