Key result
Left atrial pressure waves arrive in the pulmonary artery by two distinct routes: rapidly and directly through the heart, and delayed and in-series through the pulmonary vasculature (P<0.05).
Absolute Event Rate: 90% vs 103%
p-value: p=< 0.05
Demonstrates that left atrial pressure waves transmit to the pulmonary artery both directly through the heart and in-series through the pulmonary vasculature.
Supports dual left atrial-pulmonary artery pressure transmission in animals; hypothesis-generating for human hemodynamics with no current clinical implications.
Pressure waves are thought to travel from the left atrium (LA) to the pulmonary artery (PA) only retrogradely, via the vasculature. In seven anesthetized open-chest dogs, a balloon was placed in the LA, which was rapidly inflated and deflated during diastole, early systole, and late systole. High-fidelity pressures were measured within and around the heart. Measurements were made at low volume [LoV; left ventricular end-diastolic pressure (LVEDP) = 5-9 mmHg], high volume (HiV; LVEDP = 16-19 mmHg), and HiV with the pericardium removed. Wave-intensity analysis demonstrated that, except during late systole, balloon inflation created forward-going PA compression waves that were transmitted directly through the heart without measurable delay; backward PA compression waves were transmitted in-series through the pulmonary vasculature and arrived after delays of 90 +/- 3 ms (HiV) and 103 +/- 5 ms (LoV; P < 0.05). Direct transmission was greater during diastole, and both direct and series transmission increased with volume loading. Pressure waves from the LA arrive in the PA by two distinct routes: rapidly and directly through the heart and delayed and in-series through the pulmonary vasculature.
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Hollander et al. (2004) studied this question. Left atrial balloon inflation and deflation vs. Different volume states (low volume vs high volume) was evaluated on Backward pulmonary artery compression wave delay (p=< 0.05). Left atrial pressure waves arrive in the pulmonary artery by two distinct routes: rapidly and directly through the heart, and delayed and in-series through the pulmonary vasculature (P<0.05).
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