From the Research
Squatting increases right ventricular output by enhancing venous return to the heart, but patients with right ventricular dysfunction should use caution due to potential worsening of symptoms. When a person squats, the compression of veins in the lower extremities forces blood back toward the heart, increasing preload (the volume of blood entering the right ventricle) 1. Additionally, squatting raises peripheral vascular resistance, which increases afterload and blood pressure, causing blood to be redistributed from the peripheral circulation to the central circulation, further augmenting right ventricular filling. The increased preload stretches the myocardial fibers of the right ventricle, which according to the Frank-Starling mechanism, leads to stronger contractions and greater stroke volume. This physiological response makes squatting a useful maneuver for patients with certain cardiac conditions like hypertrophic cardiomyopathy, as it can temporarily improve cardiac output. However, patients with right ventricular dysfunction, such as those with pulmonary hypertension or heart failure with preserved ejection fraction, should use caution with squatting, as the sudden increase in preload could potentially worsen symptoms in those with limited right ventricular reserve 2, 1. Key factors to consider include the patient's underlying cardiac condition, their ability to tolerate increased preload and afterload, and the potential for RV-arterial uncoupling, which can lead to increased diastolic elastance and decreased RV function 1. In general, the decision to recommend squatting as a therapeutic maneuver should be made on a case-by-case basis, taking into account the individual patient's unique physiology and disease state. The most recent and highest quality study on the topic, published in 2023, highlights the importance of considering RV function and adaptation to loading in both health and disease 1. Overall, while squatting can increase right ventricular output, it is crucial to approach this maneuver with caution in patients with right ventricular dysfunction, and to carefully consider the potential risks and benefits in each individual case. Some key points to consider when evaluating the effect of squatting on right ventricular output include:
- The patient's underlying cardiac condition and ability to tolerate increased preload and afterload
- The potential for RV-arterial uncoupling and decreased RV function
- The importance of considering RV function and adaptation to loading in both health and disease
- The need for individualized decision-making and careful consideration of the potential risks and benefits of squatting in each patient.