Calcium antagonists and acute myocardial ischemia: Comparative effects of gallopamil and nifedipine on ischemia-induced and reperfusion-induced ventricular arrhythmias, epicardial conduction times, and ventricular fibrillation thresholds

1987 ◽  
Vol 1 (4) ◽  
pp. 367-376 ◽  
Author(s):  
Hartmut Gülker ◽  
Wilhelm Haverkamp ◽  
Gerhard Hindricks ◽  
Franz Bender
1984 ◽  
Vol 53 (2) ◽  
pp. 307-312 ◽  
Author(s):  
Douglas C. Russell ◽  
Jan S. Lawrie ◽  
Rudolph A. Riemersma ◽  
Michael F. Oliver

1991 ◽  
Vol 261 (1) ◽  
pp. H63-H69 ◽  
Author(s):  
G. M. De Ferrari ◽  
E. Vanoli ◽  
M. Stramba-Badiale ◽  
S. S. Hull ◽  
R. D. Foreman ◽  
...  

The role of vagal tone and reflexes in the genesis of life-threatening arrhythmias was investigated in a clinically relevant animal model for sudden cardiac death. Forty-five dogs with a healed anterior myocardial infarction in which transient myocardial ischemia during exercise did not induce malignant arrhythmias were utilized for the study. They underwent a further exercise and ischemia test in which atropine (75 micrograms/kg) was injected before coronary artery occlusion. Novel occurrence of ventricular arrhythmia, or worsening of the type of arrhythmia present in the control test, occurred in 23 of 45 dogs (51%) and ventricular fibrillation occurred in 11 of 45 (24%, P = 0.001). Analysis of heart rate response to acute ischemia in the control test indicates that these 11 animals had powerful vagal reflexes during coronary artery occlusion, compared with the 34 survivors (-32 +/- 35 vs. +2 +/- 27 beats/min, P = 0.003). This study indicates that approximately 75% of animals resistant to ventricular fibrillation are characterized by weak sympathetic reflexes in response to acute myocardial ischemia. In the remaining 25% powerful vagal reflexes counteract concomitant reflex sympathetic hyperactivity, decrease heart rate, and are essential for survival.


1982 ◽  
Vol 50 (4) ◽  
pp. 844-848 ◽  
Author(s):  
Daniel David ◽  
Eric L. Michelson ◽  
Masahito Naito ◽  
Mark Schaffenburg ◽  
Leonard S. Dreifus

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