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Heart rate variability and left ventricular dilatation early after myocardial infarction
1Cardiovascular Center, Kansai Medical University, Moriguchi-city, Osaka, Japan.
Insights
Autonomic tone alterations, specifically higher low-frequency (LF) and total power (TP) of heart rate variability, were found to precede early left ventricular dilatation in patients post-myocardial infarction.
Area of Science:
- Cardiology
- Autonomic Nervous System Research
- Clinical Medicine
Background:
- Left ventricular dilatation post-myocardial infarction (MI) is a significant predictor of adverse outcomes.
- Understanding early predictors of left ventricular remodeling is crucial for timely intervention.
- Autonomic dysfunction is increasingly recognized as a factor in cardiovascular disease progression.
Purpose of the Study:
- To investigate whether changes in autonomic tone precede the development of early left ventricular dilatation after a first myocardial infarction.
- To identify specific heart rate variability (HRV) parameters associated with subsequent left ventricular remodeling.
Main Methods:
- Prospective observational study involving 53 patients after their first acute myocardial infarction.
- Ambulatory electrocardiogram was used on day 1 to assess heart rate variability (HRV) parameters: low-frequency power (LF), high-frequency power (HF), and total power (TP).
- Left ventricular end-diastolic volume was measured by echocardiography on day 1 and day 14. Stepwise linear regression analysis was employed for statistical assessment.
Main Results:
- Higher levels of low-frequency power (LF) and total power (TP) were significantly associated with early left ventricular dilatation.
- These associations remained significant after adjusting for multiple clinical variables including age, sex, MI location, revascularization, peak creatine kinase, hypertension history, and medications (ACE inhibitors, beta-blockers).
- The findings indicate that specific HRV parameters indicative of autonomic tone precede left ventricular dilatation.
Conclusions:
- Alterations in autonomic tone, particularly increased sympathetic modulation reflected by higher LF and TP, precede early left ventricular dilatation after myocardial infarction.
- HRV analysis, specifically LF and TP, may serve as an early clinical marker for identifying patients at risk of adverse left ventricular remodeling post-MI.
- These findings highlight the clinical relevance of assessing autonomic function in the early management of myocardial infarction patients.
Abstract:
To assess clinically whether alterations of autonomic tone precede left ventricular dilatation, heart rate variability and early left ventricular dilatation after a first myocardial infarction were assessed. Low-frequency power (LF), high-frequency power (HF), and total power (TP) were obtained by ambulatory electrocardiogram on day 1 in 53 patients with a first acute myocardial infarction. Left ventricular end-diastolic volume determined by echocardiography was obtained on day 1 and day 14. Stepwise linear regression analysis was used to assess the associations of early left ventricular dilatation with heart rate variability adjusted for clinical variables. Higher LF and TP were significantly associated with early left ventricular dilatation after adjustment for age, sex, site of myocardial infarction, acute revasucularization, peak creatine kinase level, history of hypertension, and use of angiotensin-converting enzyme inhibitors and beta-blockers. Higher LF and TP preceded early left ventricular dilatation after myocardial infarction.