Background-High catecholamine concentrations are cytotoxic to cardiac myocytes. We hypothesized that myocardial interstitial catecholamine levels are greatly elevated immediately after long-duration ventricular fibrillation (VF), defibrillation, and reperfusion and that the short-acting β-antagonist esmolol administered at reperfusion would protect against this catecholamine surge and improve survival. Methods and Results-In part 1 of this study, catecholamines from myocardial interstitial fluid (ISF) and aortic and coronary sinus plasma were quantified by use of 3H-labeled radioenzymatic assay in 8 open-chest, anesthetized pigs. Eight minutes of electrically induced VF was followed by internal defibrillation and reperfusion. By 4 minutes of VF, ISF norepinephrine increased significantly, from 1.3±0.3 to 7.4±2.4 ng/mL. Epinephrine increased significantly, from 0.4±0.2 to 1.5±0.7 ng/mL. ISF norepinephrine and epinephrine peaked at 219.2±92.1 and 63.7±25.1 ng/mL after defibrillation and reperfusion and decreased significantly to 12.2±3.5 and 6.7±3.1 ng/mL 23 minutes after defibrillation. Transcardiac catecholamine changes were similar. In part 2, 8 minutes of VF was followed by external defibrillation in anesthetized, closed-chest pigs. Animals received 1.0 mg/kg esmolol (n=8) or saline (n=8) intravenously at the start of cardiopulmonary resuscitation (CPR). Advanced cardiac life support, including CPR and epinephrine, was delivered to both groups. Esmolol before reperfusion improved return of spontaneous circulation and 4-hour survival (7/8 versus 3/8 survivors, χ2 P<0.05). Conclusions-Transcardiac and ISF norepinephrine and epinephrine levels are briefly massively elevated after 8 minutes of VF, defibrillation, and reperfusion. A short-acting β-antagonist administered immediately after defibrillation improves return of spontaneous circulation and 4-hour survival after this prolonged VF.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:etsu-works-19956 |
| Date | 25 May 2004 |
| Creators | Killingsworth, Cheryl R., Wei, Chih Chang, Dell'Italia, Louis J., Ardell, Jeffrey L., Kingsley, Melody A., Smith, William M., Ideker, Raymond E., Walcott, Gregory P. |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Source | ETSU Faculty Works |
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