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Electrocardiographic changes during antihypertensive therapy in the International Prospective Primary Prevention
Insights
Antihypertensive treatment, particularly with beta-blockers, reduced cardiac abnormalities in hypertensive patients. Optimal blood pressure control is crucial for preventing heart damage and reducing cardiac events.
Area of Science:
- Cardiology
- Hypertension Research
- Preventive Medicine
Background:
- Hypertension significantly impacts cardiac health, leading to various electrocardiographic (ECG) abnormalities.
- Understanding the effects of antihypertensive treatment on ECG changes is vital for cardiovascular risk assessment.
Purpose of the Study:
- To investigate electrocardiographic (ECG) changes in hypertensive patients undergoing antihypertensive treatment.
- To evaluate the impact of a slow-release beta-blocker, oxprenolol, on these ECG changes.
- To correlate blood pressure control with ECG abnormality progression.
Main Methods:
- Analysis of ECGs from 5819 hypertensive individuals (aged 40-64) in the International Prospective Primary Prevention Study in Hypertension.
- Random allocation to treatment groups with or without oxprenolol over 3-5 years.
- ECG assessment using the Minnesota Code, categorizing abnormalities into pressure-related, ischemic, intermediate, and other.
Main Results:
- Antihypertensive treatment decreased pressure-related and intermediate abnormalities, but increased ischemic abnormalities, especially in men.
- Oxprenolol inclusion led to greater reduction in intermediate abnormalities and less increase in ischemic ones.
- Better blood pressure control correlated with reduced ischemic and pressure-related abnormalities.
- ST depression and left bundle branch block on entry ECG predicted higher risk of sudden death and myocardial infarction.
Conclusions:
- Optimal blood pressure control effectively prevents cardiac target organ damage and heart failure.
- Antihypertensive therapy, especially with beta-blockers, can mitigate adverse ECG changes in hypertensive patients.
- Early ECG abnormalities are significant predictors of major adverse cardiac events.
Abstract:
In the International Prospective Primary Prevention Study in Hypertension, electrocardiographic changes before and during 3- to 5-year antihypertensive treatment were investigated in a cohort of 5819 men and women aged 40 to 64 years with entry diastolic blood pressures of 100 to 125 mm Hg. They were randomly allocated to treatment regimens that either included or excluded the slow-release beta-blocker oxprenolol. Electrocardiograms (ECGs) were assessed using the Minnesota Code and assigned to groups of normal ECGs or ECGs with pressure-related, ischemic, "intermediate," or "other" abnormalities. Antihypertensive treatment was associated with a decrease (mainly in men) of pressure-related and (mainly in women) of intermediate abnormalities. Ischemic abnormalities increased, particularly in men. Inclusion of the beta-blocker resulted in a greater reduction in intermediate abnormalities and in a lesser increase in ischemic abnormalities. Better blood pressure control was associated with a lesser increase in ischemic abnormalities and in a regression of pressure-related abnormalities. The presence of ST segment depression and of a complete left bundle branch block in the entry ECG was associated with a significant risk for sudden death and myocardial infarction. Optimal blood pressure control prevents pressure-induced cardiac target organ damage and, hence, heart failure, and may delay the progression of ischemic abnormalities. This tallies with the lower critical cardiac event rate associated with lower blood pressure that was observed in the same study.