S. Chouairi et al., MYOCARDIAL PROTECTION WITH CALCIUM-CHANNEL BLOCKERS DURING ISCHEMIA AND REPERFUSION BY PTCA, European heart journal, 16, 1995, pp. 3-8
The effects of calcium channel blockers on acute myocardial ischaemia
have been evaluated over the past two decades. A number of experimenta
l studies have demonstrated that calcium antagonists protect the myoca
rdium when administered before or during PTCA. Intracoronary verapamil
prior to the second inflation attenuates the severity of ischaemic ST
-segment changes and anginal pain. Heart rate and blood pressure are n
ot influenced by verapamil or placebo. Similarly, there are multiple c
linical and biological data suggesting that intracoronary nifedipine,
diltiazem or bepridil, and intracoronary or intravenous nicardipine mi
ght result in a reduced incidence of myocardial ischaemia during PTCA.
The beneficial effect of these drugs can be explained by a direct car
dioprotective effect or by an enhanced collateral flow and haemodynami
c improvement. During early reperfusion in acute myocardial infarction
(AMI) administration of calcium channel blockers or agents that inhib
it calcium release from the sarcoplasmic reticulum can protect hearts
from stunning and can decrease the no-reflow phenomenon. The most rece
nt explanation relates this observation to decreased sensitivity of th
e myofibrils to calcium. Further clinical and experimental studies are
necessary to clarify the protective role in reperfusion injury. To su
mmarize, therefore, administration of calcium channel blockers can dec
rease ischaemia during elective PTCA and can reduce reperfusion injury
during early PTCA in AMI.