Chest
Volume 143, Issue 5, May 2013, Pages 1294-1301
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Original Research
Sleep Disorders
Cardiac Workload in Patients With Sleep-Disordered Breathing Early After Acute Myocardial Infarction

https://doi.org/10.1378/chest.12-1930Get rights and content

Background

Sleep-disordered breathing (SDB) may promote an increase in cardiac workload early after acute myocardial infarction (AMI). We tested the hypothesis that in the early phase after AMI, SDB is associated with increased 24-h arterial BP, heart rate (HR), and, thus, cardiac workload.

Methods

In this prospective study, 55 consecutive patients with AMI and subsequent percutaneous coronary intervention (78% men; mean age, 54 ± 10 y; mean BMI, 28.3 ± 3.6 kg/m2; mean left ventricular ejection fraction [LVEF], 47% ± 8%) underwent polysomnography and 24-h ambulatory BP and heart rate monitoring within 5 days after MI. Cardiac workload was calculated as systolic BP multiplied by HR. The presence of SDB was defined as ≥ 10 apneas and hypopneas per hour of sleep.

Results

Fifty-five percent of the patients had SDB, of which 40% was predominantly central in nature. Patients with SDB had higher 24-h HR and systolic and diastolic BP compared with those without SDB (115 vs 108 mm Hg, P = .029; 71 vs 67 mm Hg, P = .034; 69 vs 64 beats/min, P = .050, respectively). Use of antihypertensive medication and β-receptor blockers was similar in both groups. In a multivariate linear regression analysis, SDB was significantly associated with an increased 24-h cardiac workload (β-coefficient, 0.364; 95% CI, 0.071-0.657; P = .016), independently of age, sex, BMI, LVEF, and antihypertensive medication.

Conclusion

Patients with AMI and SDB have significantly increased 24-h BP, HR, and cardiac workload. Treatment of SDB may be a valuable nonpharmacologic approach to lower cardiac workload in these patients.

Section snippets

Patients

In this prospective, observational clinical study, consecutive patients with AMI who were referred to the University Hospital Regensburg, Regensburg, Germany, between March 2009 and June 2011 were evaluated for eligibility. Inclusion criteria were: age 18-80 years; first acute AMI with ST elevation on ECG or non-ST elevation with complete occlusion of coronary artery; and percutaneous coronary intervention (PCI) within 24 h after AMI. Patients were excluded if they had any of the following:

Patients

Of 220 consecutive patients with AMI, 55 were eligible for the study and were included in the analysis (Fig 1). Patient demographic characteristics, stratified by the presence or absence of SDB, are shown in Table 2. Patients with SDB were older (P = .013), more likely to be male (P = .020), more likely to have diabetes mellitus (P = .024), and had a higher BMI (P = .029) than those without SDB.

N-terminal pro-brain natriuretic peptide at admission and maximum creatine kinase levels were

Discussion

This study makes several novel observations. First, that patients in the early phase after AMI with CSA and OSA had higher 24-h systolic and diastolic BP, HR, and cardiac workload than similar patients without SDB. Second, although the association between SDB and systolic or diastolic BP was not significant after accounting for demographic variables, there was a significant relationship between SDB and both HR and cardiac workload after accounting for multiple potential confounders, including

Acknowledgments

Author contributions: Dr Arzt is the guarantor of the manuscript and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Dr Hetzenecker: contributed to the conception, hypotheses delineation, and design of the study; acquisition, analysis, and interpretation of the data; and writing and revising the article prior to submission.

Dr Buchner: contributed to the conception, hypotheses delineation, and design of the study; acquisition, analysis, and interpretation

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  • Cited by (0)

    Funding/Support: This study was funded by Resmed; Philips Home Healthcare Solutions; and the Faculty of Medicine, University of Regensburg.

    Drs Hetzenecker and Buchner contributed equally to this study.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.

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