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Influence of heart rate on mortality after acute myocardial infarction
A Hjalmarson1, E A Gilpin, J Kjekshus
1Division of Cardiology, University of California, San Diego 92093.
Insights
Elevated heart rate after acute myocardial infarction (AMI) predicts death, especially in patients without severe heart failure. Monitoring heart rate is crucial for assessing mortality risk in AMI survivors.
Area of Science:
- Cardiology
- Clinical Medicine
- Morbidity and Mortality Studies
Background:
- Elevated heart rate (HR) post-acute myocardial infarction (AMI) is linked to increased mortality.
- The specific contribution of heart failure to this association remains unclear.
Purpose of the Study:
- To investigate the relationship between heart rate and mortality in patients with AMI.
- To differentiate the impact of HR on mortality in patients with and without heart failure.
Main Methods:
- A multicenter study involving 1,807 patients with AMI.
- Heart rate was measured on admission, at maximum in the coronary care unit, and at discharge.
- Mortality was assessed in-hospital, post-discharge, and up to 1 year, stratified by heart failure severity.
Main Results:
- In-hospital and post-discharge mortality increased with higher admission HR.
- Total mortality (day 2 to 1 year) significantly rose with admission HR levels (e.g., 48% for HR ≥ 110 bpm).
- In patients with less severe heart failure, higher HR (≥ 90 bpm) more than doubled mortality risk compared to lower HR (< 90 bpm).
Conclusions:
- Admission heart rate is a significant predictor of mortality in AMI patients, independent of severe heart failure.
- Heart rate monitoring is vital for risk stratification in AMI patients, particularly those with mild to moderate heart failure.
Abstract:
Elevated heart rate (HR) during hospitalization and after discharge has been predictive of death in patients with acute myocardial infarction (AMI), but whether this association is primarily due to associated cardiac failure is unknown. The major purpose of this study was to characterize in 1,807 patients with AMI admitted into a multicenter study the relation of HR to in-hospital, after discharge and total mortality from day 2 to 1 year in patients with and without heart failure. HR was examined on admission at maximum level in the coronary care unit, and at hospital discharge. Both in-hospital and postdischarge mortality increased with increasing admission HR, and total mortality (day 2 to 1 year) was 15% for patients with an admission HR between 50 and 60 beats/min, 41% for HR greater than 90 beats/min and 48% for HR greater than or equal to 110 beats/min. Mortality from hospital discharge to 1 year was similarly related to maximal HR in the coronary care unit and to HR at discharge. In patients with severe heart failure (grade 3 or 4 pulmonary congestion on chest x-ray, or shock), cumulative mortality was high regardless of the level of admission HR (range 61 to 68%). However, in patients with pulmonary venous congestion of grade 2, cumulative mortality for patients with admission HR greater than or equal to 90 beats/min was over twice as high as that in patients with admission HR less than 90 beats/min (39 vs 18%, respectively); the same trend was evident in patients with absent to mild heart failure (mortality 18 vs 10%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)