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[Epidemiology and prognosis of myocardial infarct and chronic heart failure]
Insights
While myocardial infarction mortality declined, heart failure incidence rose. Impaired left ventricular function post-myocardial infarction significantly increases heart failure risk and poor prognosis.
Area of Science:
- Cardiology
- Internal Medicine
Context:
- Cardiovascular disease remains a leading cause of mortality in developed nations.
- While myocardial infarction (MI) mortality has decreased due to advancements like coronary care units, heart failure (HF) incidence is increasing.
- Coronary heart disease is the primary cause of current heart failure cases, particularly after large or recurrent MIs.
Purpose:
- To review the prognostic impact of left ventricular dysfunction and heart failure development following myocardial infarction.
- To outline the cascade from myocardial infarction to heart failure and death.
- To examine the evidence supporting the prognostic significance of each step in this cascade.
Summary:
- Reduced mortality from myocardial infarction (MI) has led to more survivors with impaired left ventricular function.
- This impaired function increases the risk of developing heart failure (HF) post-MI, with a significantly higher incidence than in the general population.
- Patients surviving MI but developing HF face a poor long-term prognosis, highlighting the need for better risk stratification.
Impact:
- Improved in-hospital survival post-MI due to advanced treatments means patients with larger infarcts now survive.
- These survivors often have severely impaired left ventricular function, leading to a high probability of developing heart failure and a poor long-term outlook.
- Understanding the prognostic impact of left ventricular dysfunction and heart failure post-MI is crucial for developing effective management strategies and improving patient outcomes.
Abstract:
The incidence of coronary heart disease and myocardial infarction fell gradually during the seventies. Reasons for this decline are not well understood. Speculations include changes of life style and health care. However, cardiovascular disease is still the leader of mortality in Western developed countries. Mortality of myocardial infarction has also declined. The major benefit was associated with broad establishment of coronary care units, smaller steps were achieved by various progresses in medical treatment. In contrast, the incidence of heart failure has increased. The major etiology of heart failure nowadays is coronary heart disease, especially large or recurrent myocardial infarction. The incidence of heart failure in patients having recovered from myocardial infarction is dramatically higher than in normal population. The Framingham Study showed an incidence of 14% in five years following a myocardial infarction. Prognosis of patients with manifestation of symptoms of heart failure is very poor. Patients with heart failure had an overall six years mortality of 55%. These observations suggest that coronary care units, thrombolysis and modern treatment as developed so far, suppressed in-hospital mortality and improved survival for the first year after a myocardial infarction. Thus, patients with larger infarcts who had succumbed early under previous regimens, survived. They carry, however, the burden of severely impaired left ventricular function, high probability to develop heart failure, and of a dubious long-term prognosis. Large efforts have put upon development of scores to estimate long-term prognosis after a myocardial infarction. With the development of techniques, composition of scores changed. However, residual ischemia, major left ventricular dysfunction, and ventricular arrhythmias are the basis of most scores indicating an adverse prognosis after an infarction. This review will be limited to the prognostic impact of left ventricular dysfunction and development of heart failure post myocardial infarction. A hypothetic cascade of events which may lead from myocardial infarction to heart failure and death is schematically outlined in Figure 1. Loss of contractile myocardium results in left ventricular dysfunction which may induce dilatation of the left ventricle, heart failure and ultimately death. This paper focuses on the evidence for the prognostic impact of the single steps and the whole cascade. Figure 1 shows in parenthesis the variables which were frequently measured to assess loss of contractile tissue, left ventricular dysfunction, and dilatation. Since heart failure is understood as a clinical syndrome of symptoms, it may only be semi-quantitated according to the classification of the New York Heart Association (NYHA).(ABSTRACT TRUNCATED AT 400 WORDS)