Given below are few of the physiological abnormalities that may be associated with a diseased condition. Choose the appropriate condition that is associated with heart failure.
Heart failure is a condition where the force of contraction of heart is insufficient to meet the demands of blood supply required by systemic organs. When such situation arises our physiological system tries temporarily to restore the condition by few adaptive physiological changes. Two of them are activation of RAS and sympathetic system. Former mainly causes release of aldosterone which increases water reabsorption and thereby increases body volume.
Given below are few of the drug targets. Identify one which is NOT a good drug target for treatment of cardiac failure
(A) Q only
(D) S only
Calcium channel blockers decrease force of contraction and hence contraindicated in heart failure.
Given below are few of the drugs which act as vasodilators. Identify the drugs that act by release of nitric oxide.
All the above listed drugs are vasodilators but act by various mechanisms. Nicorandil is a potassium channel activator while sildenafil is a phosphodiesterase V inhibitor. On the other hand, sodium nitroprusside is a nitrovasodilator that releases nitric oxide producing vascular smooth muscle relaxation. Finally nebivolol is a beta blocker with additional vasodilatory action again due to release of nitric oxide.
All of the following are the actions of the sympathetic system on heart , except
(A) Increase in force of contraction
(B) Increased automaticity
(C) Decreased AV conduction
(D) Reduced cardiac efficiency
Sympathetic system increases rate and fore of contraction. It also increases automaticity leading to generation of own impulses by ventricles. Parasympathetic system acts quite opposite to sympathetic system leading a decrease in both rate and force of contraction. Decrease in AV conduction is another role of parasympathetic system resulting in conduction block.
The important effect of natriuretic peptides in heart failure is
(A) Increasing Na+ excretion in kidney
(B) Release of aldosterone
(C) Release of antidiuretic hormone
(D) Release of endothelin
Natriuretic peptide is released in heart failure to increase the natriuresis i.e. increase excretion of sodium thereby decreases body volume.