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Activation of neurohumoral systems in postinfarction left ventricular dysfunction
J L Rouleau1, J de Champlain, M Klein
1Institut de Cardiologie, Montreal, Quebec, Canada.
Insights
Neurohumoral activation is common in patients after myocardial infarction (MI) upon hospital discharge. Factors influencing this activation vary by neurohormone, impacting patient prognosis and treatment strategies.
Area of Science:
- Cardiology
- Neuroendocrinology
- Internal Medicine
Background:
- Pharmacologic interventions targeting neurohumoral activation improve post-myocardial infarction (MI) prognosis.
- Persistent neurohumoral activation may exist in patients until hospital discharge.
- Determinants of neurohumoral activation can differ across various physiological systems.
Purpose of the Study:
- To evaluate the extent of neurohumoral activation in patients around the time of hospital discharge following myocardial infarction (MI).
- To investigate the relationship between neurohumoral activation and clinical/laboratory variables in post-MI patients.
- To understand the variability in neurohormone activation and its determinants.
Main Methods:
- Analysis of plasma neurohormones in 519 patients from the Survival and Ventricular Enlargement (SAVE) study.
- Measurements taken before randomization, an average of 12 days post-MI.
- Inclusion criteria: left ventricular ejection fraction <= 40%, no overt heart failure.
Main Results:
- Elevated levels of norepinephrine, renin activity, arginine vasopressin, and atrial natriuretic peptide were observed compared to controls.
- A wide spectrum of neurohumoral activation was evident, with no consistent correlation between different neurohormone activations.
- Killip class, left ventricular ejection fraction, age, and diuretic use were key associated clinical/laboratory variables.
Conclusions:
- Neurohumoral activation is present in a significant number of patients at hospital discharge after MI.
- The specific neurohormone activated and the clinical/laboratory factors driving this activation are variable.
- Understanding these variations is crucial for personalized post-MI management.
Objectives:
This study was conducted to evaluate the degree of neurohumoral activation around the time of hospital discharge after myocardial infarction.
Background:
Because pharmacologic interventions that block the effects of neurohumoral activation improve the prognosis after infarction, we hypothesized that widespread neurohumoral activation persists in some patients until at least the time of hospital discharge and that the determinants of activation vary from one system to another.
Methods:
Five hundred nineteen patients in the Survival and Ventricular Enlargement Study (SAVE) had plasma neurohormones measured before randomization at a mean of 12 days after infarction. All patients had left ventricular dysfunction (left ventricular ejection fraction < or = 40%) but no overt heart failure.
Results:
Although all neurohormones except epinephrine were increased compared with values in age-matched control subjects, plasma norepinephrine (301 +/- 193 vs. 222 +/- 87 pg/ml, p < 0.001), renin activity (3.0 +/- 3.7 vs. 1.2 +/- 1.2 ng/ml per h, p < 0.001), arginine vasopressin (1.9 +/- 6.9 vs. 0.7 +/- 0.3 pg/ml, p < 0.001) and atrial natriuretic peptide (75 +/- 75 vs. 21 +/- 9 pg/ml, p < 0.001) values ranged from normal to very high, indicating a wide spectrum of neurohumoral activation. Activation of one system did not correlate with activation of another. The clinical and laboratory variables most closely associated with neurohumoral activation were Killip class, left ventricular ejection fraction, age and use of diuretic drugs. The association between neurohumoral activation and clinical and laboratory variables varied from one neurohormone to another.
Conclusions:
Neurohumoral activation occurs in a significant proportion of patients at the time of hospital discharge after infarction. Which neurohormone is activated and which clinical and laboratory variables determine this activation vary from one neurohormone to another.