PubMed · 38017
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L B Hinshaw. 1979. Myocardial function in endotoxin shock.. https://pubmed.ncbi.nlm.nih.gov/38017/
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Changes in calcium (Ca2+) regulation contribute to loss of contractile function in dilated cardiomyopathy. Clinical treatment using beta-adrenergic receptor antagonists (beta-blockers) slows deterioration of cardiac function in end-stage heart failure patients; however, the effects of beta-blocker treatment on Ca2+ dynamics in the failing heart are unknown. To address this issue, tropomodulin-overexpressing transgenic (TOT) mice, which suffer from dilated cardiomyopathy, were treated with a nonselective beta-receptor blocker (5 mg. kg-1. day-1 propranolol) for 2 wk. Ca2+ dynamics in isolated cardiomyocytes of TOT mice significantly improved after treatment compared with untreated TOT mice. Frequency-dependent diastolic and Ca2+ transient amplitudes were returned to normal in propranolol-treated TOT mice and but not in untreated TOT mice. Ca2+ kinetic measurements of time to peak and time decay of the caffeine-induced Ca2+ transient to 50% relaxation were also normalized. Immunoblot analysis of untreated TOT heart samples showed a 3.6-fold reduction of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA), whereas Na+/Ca2+ exchanger (NCX) concentrations were increased 2.6-fold relative to nontransgenic samples. Propranolol treatment of TOT mice reversed the alterations in SERCA and NCX protein levels but not potassium channels. Although restoration of Ca2+ dynamics occurred within 2 wk of beta-blockade treatment, evidence of functional improvement in cardiac contractility assessed by echocardiography took 10 wk to materialize. These results demonstrate that beta-adrenergic blockade restores Ca2+ dynamics and normalizes expression of Ca2+-handling proteins, eventually leading to improved hemodynamic function in cardiomyopathic hearts.
We hypothesized that pretreatment with beta blockers may improve clinical outcomes after primary angioplasty for acute myocardial infarction. We pooled clinical, angiographic, and outcomes data on 2,537 patients enrolled in the Primary Angioplasty in Myocardial Infarction (PAMI), PAMI-2, and Stent PAMI trials. We classified patients into a beta group (n = 1,132) if they received beta-blocker therapy before primary angioplasty or a no-beta group (n = 1,405) if they did not. We evaluated procedural complications and in-hospital and 1-year outcomes (death and major adverse cardiac events [death, reinfarction, target vessel revascularization, or stroke]) between groups. Beta patients were younger, had higher systolic blood pressure and heart rate, and were more likely to be in Killip class I at admission. They had lower left ventricular ejection fraction, greater door-to-balloon time, greater likelihood of having a left anterior descending artery culprit lesion, but a similar incidence of Thrombolysis In Myocardial Infarction 3 flow after angioplasty (92.6% vs 92.7%, p = 0.91). The beta group had less procedural complications (23% vs 34%, p <0.0001) and a lower incidence of death (1.8% vs 3.7%, p = 0.0035) and major adverse cardiac events (5.5% vs 7.8%, p = 0.027) during hospitalization. At 1 year, mortality remained lower in beta patients (4.9% vs 6.7%, log-rank p = 0.055). After adjustment for baseline differences, beta patients had significantly lower in-hospital mortality (odds ratio 0.41; 95% confidence interval 0.20 to 0.84; p <0.0148) and nonsignificantly lower 1-year mortality (odds ratio 0.72; 95% confidence interval 0.47 to 1.08; p = 0.11). Thus, pretreatment with beta blockers has an independent beneficial effect on short-term clinical outcomes in patients undergoing primary angioplasty for acute myocardial infarction.
CONTEXT: Variceal bleeding is the most frequent severe complication of portal hypertension and a leading cause of death and liver transplantation in patients with cirrhosis. Patients surviving a variceal bleed are at high risk of rebleeding (over 60% at 1 year). Portacaval shunts and transjugular intrahepatic portasystemic shunts (TIPS) are effective for prevention of rebleeding but carry a high risk of hepatic encephalopathy. Endoscopic techniques include band ligation (EBL) and injection sclerotherapy (EIS). Drug approaches are based on non-selective beta blocker with or without isosorbide-5-mononitrate (ISMN). STARTING POINT: David Patch and colleagues (Gastroenterology 2002; 123: 1013-19) randomised 102 patients surviving a variceal bleeding to EBL or drug therapy with propranolol with the addition of ISMN if target reductions in portal pressure (evaluated by the hepatic venous pressure-gradient [HVPG]) were not achieved at 3 months. Overall, results of drug therapy were similar to those of EBL (44% vs 54% rebleeding at 1 year). There were no differences in survival or non-bleeding complications. Christophe Bureau and colleagues (Hepatology 2002; 36: 1361-66) treated 34 patients with cirrhosis and portal hypertension with propranolol and measured HVPG after a median of 4 days. Target HVPG reductions were achieved in 13 "responders". ISMN was added in the 21 "non-responders" and HVPG measured again: seven more patients achieved target HPVG reduction. Re-bleeding rates were lower in responders than in non-responders (10% vs 64%). Both studies suggest that drug therapy can be improved by adding ISMN to b blockers in those patients with an insufficient decrease in HVPG. WHERE NEXT? Long-term drug therapy is emerging as effective treatment for the prevention of variceal rebleeding. The role of HVPG monitoring as a guide to identifying patients requiring further treatment needs to be further evaluated. Trials to determine the best treatment for patients who do not respond to drug therapies are also required.