Prophylactic Lignocaine and Early Post‐coronary Artery Occlusion Dysrhythmias in Anaesthetized Greyhounds

Abstract

Lignocaine (1 mg kg−1 min−1 infused intravenously for 30 min) greatly reduced the incidence of ventricular ectopic beats that resulted from acute coronary artery ligation in anaesthetized greyhound dogs. However, the incidence of ventricular fibrillation was only slightly reduced by this treatment which caused significant myocardial depression. There is no good evidence from this study that lignocaine is a particularly effective prophylactic in acute myocardial infarction.

ASPIRIN INHIBITS THE EARLY MYOCARDIAL RELEASE OF THROMBOXANE B2 AND VENTRICULAR ECTOPIC ACTIVITY FOLLOWING ACUTE CORONARY ARTERY OCCLUSION IN DOGS

“…None of the dogs treated with aspirin fibrillated after coronary artery occlusion whereas in a total of 12 control dogs, occlusion resulted in ventricular fibrillation in 3 of them. This is similar to the results of a previous control group (Marshall & Parratt, 1980) when the incidence was 5/14.…”

“…Results The haemodynamic, metabolic and electrocardiographic effects of coronary artery occlusion in the present experiments were similar to those previously described (Marshall et al, 1974;Marshall & Parratt, 1980). The main purpose of the present communication is to describe the effects of aspirin on the time course of TxB2 release from the ischaemic region of the left ventricular wall.…”

“…None of the dogs treated with aspirin fibrillated after coronary artery occlusion whereas in a total of 12 control dogs, occlusion resulted in ventricular fibrillation in 3 of them. This is similar to the results of a previous control group (Marshall & Parratt, 1980) when the incidence was 5/14. Discussion This study demonstrates that the thromboxane, which is released within a few minutes of coronary artery occlusion, comes only from the ischaemic region (Figure 1).…”

“…Results The haemodynamic, metabolic and electrocardiographic effects of coronary artery occlusion in the present experiments were similar to those previously described (Marshall et al, 1974;Marshall & Parratt, 1980 The only significant haemodynamic effect of intravenously administered aspirin was a reduction in coronary blood flow (from 49 + 7 to 40 + 6 ml/min; P < 0.05); there were no significant changes in coronary sinus Po2, Pco2 or pH. However, there was a reduction in both arterial and coronary sinus levels of TxB2 (from 293 + 63 and 230 + 49 pg/ml respectively before aspirin to 168 + 51 and 163 + 57 pg/ml respectively 30 min after aspirin).…”

“…Methods Greyhound dogs were prepared as previously described (Marshall & Parratt, 1980) and respired with oxygen. Catheters were placed, under fluoroscopic control, in the aorta, coronary sinus and pulmonary artery and were used for blood sampling, pressure measurement and for the determination of cardiac output.…”