Buda A J, Pinsky M R, Ingels N B, Daughters G T, Stinson E B, Alderman E L
N Engl J Med. 1979 Aug 30;301(9):453-9. doi: 10.1056/NEJM197908303010901.
Left ventricular dysfunction is common in respiratory-distress syndrome, asthma and obstructive lung disease. To understand the contribution of intrathoracic pressure to this problem, we studied the effects of Valsalva and Müller maneuvers on left ventricular function in eight patients. Implantation of intramyocardial markers permitted beat-by-beat measurement of the velocity of fiber shortening (VCF) and left ventricular volume. During the Müller maneuver, VCF and ejection fraction decreased despite an increase in left ventricular volume and a decline in arterial pressure. In addition, when arterial pressure was corrected for changes in intrapleural pressure during either maneuver it correlated better with left ventricular end-systolic volumes than did uncorrected arterial pressures. These findings suggest that negative intrathoracic pressure affects left ventricular function by increasing left ventricular transmural pressures and thus afterload. We conclude that large intrathoracic-pressure changes, such as those that occur in acute pulmonary disease, can influence cardiac performance.
左心室功能障碍在呼吸窘迫综合征、哮喘和阻塞性肺疾病中很常见。为了解胸内压对这一问题的影响，我们研究了瓦尔萨尔瓦动作和米勒动作对8例患者左心室功能的影响。植入心肌标记物可逐搏测量心肌纤维缩短速度（VCF）和左心室容积。在米勒动作期间，尽管左心室容积增加且动脉压下降，但VCF和射血分数仍降低。此外，在任何一种动作过程中，当根据胸膜腔内压的变化对动脉压进行校正时，它与左心室收缩末期容积的相关性比未校正的动脉压更好。这些发现表明，胸内负压通过增加左心室跨壁压从而增加后负荷来影响左心室功能。我们得出结论，诸如急性肺部疾病中出现的大幅度胸内压变化可影响心脏功能。
