The role of collateral blood supply in ventricular tachycardia after myocardial infarcation

The hypothesis that collateral or anterograde blood supply toan infarcted area maintains blood supply to cells responsiblefor ventricular tachycardia after myocardial infarction wasstudied in six patients. All patients had suffered a myocardialinfarction and developed spontaneous episodes of sustained monomorphicventricular tachycardia. The arrhythmia was paroxysmal in threepatients and incessant in the other three. During ventriculartachycardia iced isotonic saline (10 ml in approximately 4 s)was injected first in the coronary artery ostia and thereaftersuperselectively in the coronary artery providing collateralor anterograde blood supply to the infarcted area. A 2.5-F catheterwas used superselectively to catheterize coronary arteries ofapproximately 2–3 mm lumen for that purpose. Three patientshad anterograde blood supply to the infarcted area through areperfused infarct-related vessel. Two patients had only collateralretrograde blood supply to the infarcted region. One patienthad both anterograde and retrograde collateral blood supplyto the area of infarction. Ventricular tachycardia was not terminatedin any patient during non-selective injection of iced salinein the coronary ostia. In five of the six patients ventriculartachycardia was terminated by the super-selective administrationof iced saline. The morphology of ventricular tachycardia waschanged many times, but did not terminate, in the remainingpatient. Termination or change in morphology was achieved duringadministration of iced saline through collateral vessels intwo patients through the coronary artery supplying anterogradeflow in three patients and both through collaterals and anterogradeflow in the remaining patient. It is concluded that collaterolvessels or anterograde flow through the infarct-related vesselmaintain the viability of electrically normal, but electricallybadly coupled, cells responsible for ventricular tachycardiaafter myocardial infarction.