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Beta-blockade in acute myocardial infarction: is Swan-Ganz catheterization required before treatment?
Insights
Clinical assessment for congestive heart failure (CHF) signs can predict hemodynamic intolerance to beta-blockade in acute myocardial infarction (AMI) patients, potentially avoiding unnecessary Swan-Ganz catheterization.
Area of Science:
- Cardiology
- Critical Care Medicine
Background:
- Beta-blockade is increasingly used in early acute myocardial infarction (AMI).
- Beta-blockade may precipitate congestive heart failure (CHF).
- The necessity of Swan-Ganz catheterization before initiating beta-blockade in AMI is unclear.
Purpose of the Study:
- To evaluate if clinical signs of CHF can predict hemodynamic intolerance to beta-blockade in AMI patients.
- To determine if Swan-Ganz catheterization is essential prior to beta-blockade in AMI.
Main Methods:
- Retrospective analysis of 213 patients undergoing Swan-Ganz catheterization within 24 hours of AMI.
- Comparison of precatheter clinical CHF signs (dyspnea, lung crepitations, chest X-ray) with pulmonary artery wedge pressure (PAWP).
Main Results:
- Absence of clinical CHF signs accurately predicted normal PAWP (≤18 mmHg) in 86% of patients, indicating safety for beta-blockade.
- Beta-blockade was stopped due to increased PAWP more frequently in patients with CHF signs (25/74) than without (3/35; p<0.005).
- Only 7% of patients intolerant to beta-blockade had high PAWP without clinical CHF signs.
Conclusions:
- Clinical assessment of CHF signs can predict hemodynamic intolerance to beta-blockade in most AMI patients.
- Swan-Ganz catheterization may not be necessary before beta-blockade if clinical CHF signs are absent.
- Patients presenting with CHF signs may benefit from catheterization to guide beta-blockade therapy.
Abstract:
Beta-blockade is used increasingly in early acute myocardial infarction (AMI) but may cause congestive heart failure (CHF). It is not known whether Swan-Ganz catheterization is necessary before beta-blockade in AMI. We made a retrospective analysis of 213 patients who underwent Swan-Ganz catheterization within 24 hours of AMI and compared precatheter CHF signs (dyspnoea, lung crepitations and x-ray appearance) with initial pulmonary artery wedge pressure (PAWP). One hundred nine of these patients received beta-blockade after catheterization, 31 did not tolerate beta-blockade. Absence of clinical CHF signs predicted a normal PAWP (less than or equal to 18 mmHg) in 86% of patients (42 of 49) and considerable safety in giving beta-blockade. Beta-blockade had to be stopped because of PAWP increase (greater than 5 mmHg) in 25 of 74 patients with CHF signs vs. 3 of 35 patients without CHF signs (p less than 0.005), and in 9 of 15 patients with high PAWP vs. 19 of 91 patients with normal PAWP (p less than 0.01). Only 2/28 patients (7%) intolerant to beta-blockade had a high PAWP but no clinical CHF. In conclusion hemodynamic intolerance to beta-blockade could have been predicted clinically without prior Swan-Ganz catheterization in 25/28 patients. Patients with CHF signs require catheterization if beta-blockade therapy is to be considered.