[Effects of L-carnitine on the regional function of the stunned myocardium caused by ischemia of short duration].
OBJECTIVE
Myocardial ATP is produced mainly by fatty acid oxidation, a process in which the fatty acid metabolite carrier carnitine is needed to carry the metabolites into the mitochondria. Cardiac ischemia is associated with carnitine depletion. Our objective was to study the functional effect of L-carnitine on myocardium stunned by very brief, repeated ischemias, and to examine its actions in the recovery period.


METHODS
The two series studied were the control series (7 dogs) and the carnitine series (7 dogs). L-carnitine was administered to the carnitine series at doses of 250 mg/kg/day starting 7 days before the ischemic protocol and continuing during the follow-up period (10 and 15 days). The ischemic protocol consisted of 20 anterior descending coronary artery occlusions lasting 2 min and with 3 min of reperfusion between occlusions. Global and regional cardiac function parameters were recorded daily.


RESULTS
No differences in the global functional (haemodynamic) or ECG of the two series were found, but there were differences in regional myocardial function. The control series segment shortening fraction fell to dyskinesis values during the occlusion periods, then recovered during reperfusions. The segment shortening fraction worsened during the stunning period, reaching its maximal impairment on the 5th day, after which it returned to basal values on the 15th day. The carnitine series showed the same performance in the occlusion/reperfusion period. However, during the stunning period the segment shortening fraction recovered and reached values close to the basal ones maintained them during the follow-up period.


CONCLUSIONS
L-carnitine induces an almost immediate recovery of myocardial contractility, when it has been affected by very brief, repeated coronary occlusions. It limits the myocardial stunning apparition.
Hernándiz Martínez
A
A
Unidad Cardiocirculatoria, Hospital Universitario La Fe, Valencia.
Pallarés Carratalá
V
V
Cosín Aguilar
J
J
Andrés Conejos
F
F
Capdevila Carbonell
C
C
Portolés Sanz
M
M
D000818:Animals; D002331:Carnitine / Q000097:blood / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects*; D004285:Dogs; D005260:Female; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D017202:Myocardial Ischemia / Q000503:physiopathology; D017682:Myocardial Stunning / Q000097:blood / Q000503:physiopathology*
D002331:Carnitine