Circulation, Vol 65, 1078-1085, Copyright © 1982 by American Heart Association
PR Vouhe, J Helias, P Robert and CM Grondin
Intermittent aortic root infusion of a cold solution containing either
potassium chloride (KCl) or diltiazem was performed in 32 dogs during a
2-hour aortic clamping. Half of the dogs in each group had a critical
stenosis created on the circumflex artery before cardiopulmonary bypass.
Global left ventricular (LV) function was determined 1 hour after bypass by
means of LV pressure, peak dP/dt, LV end-diastolic pressure, cardiac and
stroke work indexes. Regional function was assessed through microcrystals
in the areas of the circumflex and left anterior descending coronary
arteries. LV pressure decreased in all dogs, but more so with the KCl
solution (p = 0.02). The stenosis had no specific effect on LV pressure,
but affected peak positive dP/dt (p = 0.007) and LV end-diastolic pressure
(p less than 0.0001). Cardiac and stroke work indexes decreased more in the
KCl group than in the diltiazem group (p less than 0.002) with or without
stenosis. Both positive and negative dP/dt were affected by the type of
solution (a greater decrease with KCl), but the narrowing affected only the
positive dP/dt. Regional LV function remained unchanged in the absence of a
narrowing and was depressed equally in dogs with a narrowing whether they
received KCl or diltiazem. Overall LV function appeared to be better
preserved with diltiazem, with or without impairment of circumflex flow.
ARTICLES
Myocardial protection through cold cardioplegia with potassium or diltiazem. Experimental evidence that diltiazem provides better protection even when coronary flow is impaired by a critical stenosis