Introduction:-
heart failure is common. Nowadays, it is getting more common as the non-communicable disease (namely diabetes, hypertension and ishemic heart disease) prevalence is increasing day by day.
Heart failure is defined as progressive syndrome characterised by complex cardiac and systemic adaptations that vary over time.
Pathogenesis of heart failure:-
-myocardial ischaemia (regional/ global) with myocardium insult
-left ventricular remodeling/ inflammation (hypertrophy, fibrosis, and dilatation)
-reduced force of contraction
-reduced stroke volume
-local and systemic neurohumoral and cytokine activation,
-sympathetic over activity stimulates hypothalamus to secrete vasopressin (ADH, water
retention)
-impairment of renal hemodynamic function
-stimulates the release of renin, catalyses vasopressor angiotensin and it stimulate aldosterone, adrenal glands). neuroendocrine hormones promotes salt and fluid retention
-vascular dysfunction
-> systolic and (or) diastolic dysfunction
American College of Cardiology/American Heart Association degree of functional impairment classification:-
Framingham criteria is used to diagnose heart failure.Heart failure can be classified into few classifications:
1) systolic versus diastolic heart failure
2) right heart failure versus left heart failure
3) backward versus forward failure
4) low-output heart failure versus high-output heart failure
systolic versus diastolic heart failure:-
50% of the heart failure patient has normal ejection fraction (>50%)
therefore these patient are classified as diastolic heart failure (DHF)
studies shown that DHF associated with
-elderly patient
-female predominance
-chronic hypertensive patient rather than ischaemic heart disease patient
diastolic heart failure is also known as preserved ejection fraction heart failure
it is hypothesised that failure to relax in diastolic phase reduces the venous return hence reduces the stroke volume. However, the sysolic function may be preserved. Thats why, left ventricular ejection fraction (LVEF) is not impaired.
Management:-
Once we understand the pathogenesis, therefore doctors normally prescribe a cocktail of pharmacological drugs (BB + ACEi + aldosterone antagonist + diuretics + vasodilators).
Latest addition to the management are as follows:-
a) Recombinant neuroendocrine hormones (Nesiritide, a recombinant form of B-natriuretic peptide)
- promotes diuresis and natriuresis,
-thereby ameliorating volume overload.
b) Vasopressin receptor antagonists
-Tolvaptan and conivaptan antagonize the effects of antidiuretic hormone (vasopressin),
-thereby promoting the specific excretion of free water, directly ameliorating the volume overloaded state
cardiac resynchronization therapy:-
CRT indicated for patients with NYHA class III or IV and left ventricular ejection fraction (LVEF) of 35% or less and a QRS interval of 120 ms
Implantable cardioverter-defibrillator:-
ICD may be beneficial for patients with NYHA class II, III or IV, and LVEF of 35% (without a QRS requirement).
Left ventricular assist devices (LVADs):-
-commoner and often used by whom waiting for heart transplants
Prognostic hemodynamic categories are based on
-the relative derangement in cardiac output,
-filling pressures, and
-systemic vascular resistance.
No comments:
Post a Comment