Hoshino P K, Blaustein A S, Gaasch W H
Department of Medicine (Cardiology), Tufts University School of Medicine, Boston, Massachusetts.
Am J Cardiol. 1988 Feb 1;61(4):400-4. doi: 10.1016/0002-9149(88)90953-8.
Ten normal subjects performed the Valsalva maneuver before and after the administration of propranolol (1 mg/kg). Changes in left ventricular (LV) size and function were assessed with noninvasive techniques (echocardiography and sphygmomanometer). Data were obtained at baseline, at 20 seconds of the strain phase (phase II) and 10 seconds after the release of strain (phase IV). In the control state (before propranolol), blood pressure decreased during phase II and exceeded baseline after the release of strain ("overshoot") in phase IV; after the administration of propranolol, the pressure overshoot characteristic of phase IV was no longer present. End-diastolic dimension decreased during the strain phase, but returned to baseline values during recovery in both control and propranolol states. LV stress-dimension and stress-shortening relations before and after propranolol indicate that an increase in LV contractility beginning during phase II and extending into phase IV was attenuated after propranolol. Although the absence of phase IV blood pressure overshoot may be clinically useful in identifying patients with impaired left ventricular function, beta-adrenergic receptor blocking agents can also produce this hemodynamic response in the presence of normal ventricular function.
十名正常受试者在服用普萘洛尔（1毫克/千克）前后进行了瓦尔萨尔瓦动作。采用非侵入性技术（超声心动图和血压计）评估左心室（LV）大小和功能的变化。在基线、用力期20秒（II期）和用力解除后10秒（IV期）获取数据。在对照状态（服用普萘洛尔前），II期血压下降，IV期用力解除后血压超过基线（“过冲”）；服用普萘洛尔后，IV期的血压过冲特征不再出现。舒张末期内径在用力期减小，但在对照和普萘洛尔状态下恢复过程中均恢复到基线值。普萘洛尔前后的左心室应力-内径和应力-缩短关系表明，II期开始并延伸至IV期的左心室收缩力增加在服用普萘洛尔后减弱。尽管IV期血压过冲的缺失在临床上可能有助于识别左心室功能受损的患者，但β-肾上腺素能受体阻滞剂在心室功能正常的情况下也可产生这种血流动力学反应。
