At the post-dive examination, circulating bubbles were present in 10/16 subjects (62.5 % ). Divers with circulating bubbles showed a significant post-dive increase of pulmonary systolic arterial pressure (evaluated by the maximal velocity of the physiological tricuspid regurgitation; P?<?0.01)) and right ventricular internal dimension (P?<?0.05). Divers without circulating bubbles showed no significant change in cardiac anatomy and pulmonary arterial pressure. Both groups showed a significant post-dive decrease of transmitral E/A ratio (index of left ventricular diastolic function: subjects with bubbles P?<?0.01; subjects without bubbles P?<?0.05).
These results seem to indicate that circulating gas bubbles may lead to a hemodynamically relevant increase of pulmonary arterial pressure, able to induce an acute right ventricular dilation. Post-dive diastolic function changes, observed in both groups, may be explained by a preload reduction due to immersion natriuresis.
The results of the present study add some evidence that post-dive circulating bubbles, although symptomless, have an easily detectable pathogenetic potential, inducing unfavorable hemodynamic changes in the lesser circulation.