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Myocardial dysfunction in treated adult hypopituitarism: a possible explanation for increased cardiovascular
M Shahi1, S A Beshyah, D Hackett
1Clinical Department of Cardiology, St Mary's Hospital, London.
Insights
Cardiac structure and function in hypopituitarism patients are linked to growth hormone deficiency. Left ventricular diastolic dysfunction and exercise-induced ST changes are common, potentially explaining increased cardiovascular mortality and informing growth hormone replacement therapy.
Area of Science:
- Cardiology
- Endocrinology
- Metabolic Medicine
Background:
- Hypopituitarism is a complex endocrine disorder affecting multiple pituitary hormone axes.
- Cardiovascular complications are a significant concern in patients with hypopituitarism, contributing to increased mortality.
- The relationship between the degree of growth hormone deficiency, body composition, and cardiac function requires further elucidation.
Purpose of the Study:
- To evaluate cardiac structure and function in individuals with treated hypopituitarism.
- To investigate the association between the severity of growth hormone deficiency and cardiac parameters.
- To determine the influence of body composition on cardiac function in this patient cohort.
Main Methods:
- Cross-sectional study involving 26 patients with treated hypopituitarism.
- Utilized Doppler echocardiography to assess left ventricular mass and diastolic function.
- Performed exercise testing to evaluate exercise capacity and identify ischemic changes.
Main Results:
- No significant abnormalities in left ventricular mass index or ejection fraction were observed.
- Left ventricular diastolic dysfunction was present in 8 patients.
- Significant correlations were found between insulin-like growth factor 1 (IGF-1) and left ventricular mass, and between lean body mass and left ventricular mass and diastolic function.
- Exercise testing revealed significant correlations between IGF-1 and rate-pressure product, and ST segment changes in some patients.
Conclusions:
- Left ventricular mass and exercise rate-pressure product are associated with the degree of growth hormone deficiency.
- Left ventricular diastolic dysfunction is a frequent finding in hypopituitarism.
- Ischemic-like ST segment changes during exercise testing may occur in these patients, potentially contributing to increased cardiovascular mortality and informing growth hormone replacement therapy decisions.
Objective:
To assess cardiac structure and function in patients with treated hypopituitarism and to determine their relation to the degree of growth hormone deficiency and body composition pattern.
Design:
26 patients with treated hypopituitarism were studied by cross sectional and Doppler echocardiography and by exercise testing. The results were analysed and their relation to the degree of growth hormone deficiency and body composition determined.
Setting:
All tests were performed in the department of cardiology and the unit of metabolic medicine at a tertiary referral centre.
Patients:
Patients with hypopituitarism referred for endocrine assessment.
Main Outcome Measures:
Left ventricular mass, left ventricular diastolic function, and exercise capacity in patients with hypopituitarism and their relation to growth hormone deficiency.
Results:
Mean (SD) serum concentration of insulin-like growth factor 1 (IGE-1), a measure of growth hormone deficiency, was 82.4 (45) micrograms/l. Lean body mass calculated by measuring total body potassium was 50 (9) kg. All patients had a normal left ventricular mass index and a normal left ventricular ejection fraction. Eight patients had abnormal left ventricular diastolic function. There was a significant correlation between IGF-1 and left ventricular mass (r = 0.45, p less than 0.02). Lean body mass was also significantly correlated with left ventricular mass (r = 0.78, p less than 0.0001) and left ventricular diastolic function (r = -0.63, p less than 0.01). The mean exercise duration was 8.6 (3.6) minutes. There was a significant correlation between serum IGF-1 and the rate-pressure product on exercise (r = 0.47, p less than 0.01). Seven patients had planar ST segment depression greater than 0.1 mV during exercise testing. In five of these patients there was rapid resolution of ST segment depression immediately after exercise. Two patients developed considerable ST segment depression, and subsequent coronary angiography showed normal coronary arteries. Exercise-induced ST segment depression was not related to the severity or duration of growth hormone deficiency or serum cholesterol concentration.
Conclusions:
This study suggests that left ventricular mass and the rate-pressure product are related to the degree of growth hormone deficiency, that left ventricular diastolic dysfunction is frequently seen in hypopituitarism, and that these patients may have ischaemic-like ST segment changes during exercise testing. These findings may explain the increased cardiovascular mortality in patients with hypopituitarism and may also have implications for growth hormone replacement therapy in adults.