Abete P, Ferrara N, Leosco D, Caccese P, Landino P, Sederino S, Balbi R, Rengo F
Institute of Internal Medicine, Cardiology and Cardiovascular Surgery, University of Napoli, Italy.
Aging (Milano). 1992 Jun;4(2):157-64. doi: 10.1007/BF03324085.
The effect of age on ventricular automaticity in the isolated perfused rat heart was determined under different conditions. When the ventricle is electrically stimulated at a faster rate, drive cessation is followed by a temporary suppression of ventricular automaticity (overdrive suppression). The effects of ischemia, lidocaine and verapamil on overdrive suppression were studied in isolated perfused adult and senescent rat hearts with complete atrio-ventricular block, by monitoring ventricular escape rate and escape rhythm recovery time after 1 minute of overdrive at a constant multiple (x3) of the spontaneous rate. The results demonstrated that: 1) lidocaine decreases ventricular automaticity especially in senescent hearts; 2) verapamil does not modify ventricular automaticity in basal conditions in either adult or senescent hearts; 3) myocardial ischemia causes a reduction in ventricular automaticity and more markedly in senescent hearts; and 4) lidocaine exaggerates the effect of ischemia, while verapamil seems to antagonize its depressant effect more in adult than in senescent hearts.
在不同条件下测定了年龄对离体灌流大鼠心脏心室自律性的影响。当以较快频率对心室进行电刺激时，驱动停止后会出现心室自律性的暂时抑制（超速抑制）。通过监测在自发率恒定倍数（x3）下超速驱动1分钟后的心室逸搏率和逸搏节律恢复时间，研究了缺血、利多卡因和维拉帕米对完全性房室传导阻滞的离体灌流成年和老年大鼠心脏超速抑制的影响。结果表明：1）利多卡因降低心室自律性，在老年心脏中尤为明显；2）维拉帕米在成年和老年心脏的基础条件下均不改变心室自律性；3）心肌缺血导致心室自律性降低，在老年心脏中更为明显；4）利多卡因夸大了缺血的影响，而维拉帕米在成年心脏中似乎比在老年心脏中更能拮抗其抑制作用。
