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Neuroendocrine changes in chronic cardiac failure
D P Nicholls1, G N Onuoha, G McDowell
1Department of Medicine, Royal Victoria Hospital, Northern Ireland.
Insights
Chronic cardiac failure involves hormonal imbalances, increasing vasoconstrictors like catecholamines and activating the renin-angiotensin-aldosterone system (RAAS). Vasodilators such as natriuretic peptides counterbalance these effects, offering therapeutic potential.
Area of Science:
- Cardiology
- Endocrinology
- Neuroendocrinology
Background:
- Patients with chronic cardiac failure exhibit significant hormonal and neuroendocrine alterations.
- These changes disrupt the balance between vasodilator and vasoconstrictor factors, negatively impacting circulation.
Purpose of the Study:
- To investigate the hormonal and neuroendocrine changes in chronic cardiac failure.
- To understand the role of vasoconstrictor and vasodilator factors in heart failure pathophysiology.
Main Methods:
- Review of existing literature on hormonal and neuroendocrine changes in heart failure.
- Analysis of the roles of catecholamines, renin-angiotensin-aldosterone system (RAAS), neuropeptide Y, endothelin, atrial natriuretic peptide (ANP), and B-type natriuretic peptide (BNP).
Main Results:
- Elevated catecholamine levels contribute to vasoconstriction and ventricular arrhythmias, particularly in severe heart failure.
- Activated RAAS leads to fluid retention and vasoconstriction; independent activation is evident in severe heart failure.
- Counterbalancing vasodilator peptides like ANP and BNP play a crucial role.
Conclusions:
- Hormonal and neuroendocrine changes are integral to chronic cardiac failure, favoring vasoconstriction.
- Therapeutic strategies targeting natriuretic hormone levels show promise for managing heart failure.
Abstract:
Numerous hormonal and neuroendocrine changes have been described in patients with chronic cardiac failure. These affect the balance of vasodilator and vasoconstrictor factors in favour of the latter, to the detriment of the circulation. Whether this is a reaction to central cardiac (haemodynamic) abnormalities, or is an integral part of the syndrome of heart failure, remains to be determined. Catecholamine levels are increased, especially in severe heart failure, and contribute to the vasoconstriction and probably also to lethal ventricular arrhythmias. The renin-angiotensin-aldosterone system (RAAS) is also activated, causing fluid retention and further vasoconstriction. In the earlier stages, some of this increase may be iatrogenic due to the use of loop diuretics or inhibitors of angiotensin converting enzyme, but there is evidence for independent RAAS activation in more severe grades of heart failure. The role of vasoconstrictor peptides such as neuropeptide Y and endothelin is briefly considered. Counterbalancing these are vasodilator peptides, in particular atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP). The possibility of therapeutic interventions to increase circulating natriuretic hormone levels is discussed.