The contraction of stunned myocardium: isovolumetric bulging and wasted ejection shortening in dog heart.

OBJECTIVE: The aim of the study was to assess the contraction of myocardium stunned by repetitive brief coronary occlusions by examining the response to alterations in loading and inotropy of systolic contraction on isovolumetric and ejection phase shortening. METHODS: Fourteen open chest anaesthetised dogs were used for the studies. After destruction of the sinus node, the heart was atrially paced and atrial extrasystoles were introduced followed by a short (400 ms) or long (700 ms) postextrasystole. The left anterior descending coronary artery was occluded for 5 min and reperfused for 10 min a total of eight times to produce stunned myocardium, followed by a final 60 min of reflow. Regional function was assessed with segment length sonomicrometers. RESULTS: With successive periods of occlusion there was an increase in the end diastolic segment length and a progressive decrease in total percent systolic shortening (baseline 22.3%, 1st reflow 14.5%, 8th reflow 7.9%) with some recovery after 60 min of reflow (12.0%). This was predominantly due to the development of bulging during isovolumetric systole (4.5%, -4.9%, and -8.3%, respectively) which diminished during 60 min recovery to -3.1%. Ejection shortening was relatively constant (17.8%, 19.4%, 16.3%, and 15.1%, respectively). Postextrasystolic potentiation resulted in an increased in total percent systolic shortening, but not to the baseline value, as slight isovolumetric bulging persisted. Similar changes were seen with the short and long postextrasystoles although the latter had a greater increase in ejection shortening. CONCLUSIONS: The decrease in function after repetitive occlusion and reflow is predominantly due to bulging during isovolumetric systole which persists after postextrasystolic potentiation in our model of stunned myocardium.     

Preventable Major Cardiovascular Events Associated With Uncontrolled Glucose,Blood Pressure,and Lipids and Active Smoking in Adults With Diabetes With and Without Cardiovascular Disease: A Contemporary Analysis

OBJECTIVEThe objective of this study was to assess the incidence of major cardiovascular (CV) hospitalization events and all-cause deaths among adults with diabetes with or without CV disease (CVD) associated with inadequately controlled glycated hemoglobin (A1C), high LDL cholesterol (LDL-C), high blood pressure (BP), and current smoking.RESULTSMean (SD) age at baseline was 59 (14) years; 48% of subjects were female, 45% were white, and 31% had CVD. Mean follow-up was 59 months. Event rates per 100 person-years for adults with diabetes and CVD versus those without CVD were 6.0 vs. 1.7 for MI/ACS, 5.3 vs. 1.5 for stroke, 8.4 vs. 1.2 for HF, 18.1 vs. 40 for all CV events, and 23.5 vs. 5.0 for all-cause mortality. The percentages of CV events and deaths associated with inadequate risk factor control were 11% and 3%, respectively, for those with CVD and 34% and 7%, respectively, for those without CVD.CONCLUSIONSAdditional attention to traditional CV risk factors could yield further substantive reductions in CV events and mortality in adults with diabetes.