A. It is a beneficial effect of smoking

B. Better outcome following reperfusion strategies

C. Likely to undergo reperfusion strategies at a younger age

D. Lower co-morbidity

Answer: A. It is a beneficial effect of smoking

Braunwald’s heart diseases, 8th Edition, Chapter 39, Page 1004.

A. Type I

B. Type II

C. Type III

D. Type IV

Answer: C. Type III

Endothelial nitric oxide synthase (eNOS) is Type III. The other types are brain or neuronal NOS (b or nNOS, type I) and inducible NOS (iNOS, type II). All NOS isoforms contain domains for binding calmodulin, nicotinamide adenine dinucleotide phosphate (NADPH), flavin adenine dinucleotide (FAD), and flavin mononucleotide (FMN). NOS catalyzes the oxidation of L-arginine to produce L-citrulline and nitric oxide (NO).

A. Reperfusion injury salvage kinase (RISK) pathway

B. MEK1/2-ERK pathway

C. PI3K-Akt pathway

D. GMP Shunt pathway

Answer: D. GMP Shunt pathway

Ischemic postconditioning, was initially described as a 44% reduction in infarct size with three cycles of 30 second occlusion – re-occlusion during reperfusion after a 60 minute occlusion of left anterior descending coronary artery in a dog model. The mechanism proposed is the upregulation of prosurvival kinases termed the reperfusion injury salvage kinase (RISK) pathway.  PI3K-Akt and MEK 1/2-p42/44 kinases are important components of this cell survival pathway. These have anti-apoptotic effects.

Tsang A et al,Myocardial postconditioning: reperfusion injury revisited. Am J Physiol Heart Circ Physiol 289: H2-H7, 2005

A. Tricupsid valve disease

B. Mitral valve disease

C. Aortic valve disease

D. Pulmonary valve disease

Answer: A. Tricupsid valve disease

Maternal intake of lithium during pregnancy has been associated with Ebstein’s anomaly of tricuspid valve.

A. Activation of protein kinase C in vascular smooth muscle

B. Prostacyclin activation in vascular smooth muscle

C. Synthesis of EDHF in vascular endothelium

D. Acetyl choline mediated vasoconstriction

Answer: A. Activation of protein kinase C in vascular smooth muscle

Endothelins (ET-1, ET-2 and ET-3) are peptide endothelium dependent constricting factors. ET-1 is a potent vasoconstrictor and is formed from the precursor pre-pro-endothelin by endothelin converting enzyme. ET-A and ET-B receptors are present,of which ET-A receptor mediates vasoconstiction by activation of protein kinase C in vascular smooth muscle. ET-B mediated vasoconstriction is partially offset by ET-B mediated eNOS activity.

A. Heparan sulphate

B. Thrombomodulin

C. t-PA

D. Lipoprotein (a)

Answer: D. Lipoprotein (a)

Heparan sulfate proteoglycan molecules on the surface of the endothelial cell act as a co-factor for antithrombin III.
Thrombomodulin binds thrombin molecules and exerts antithrombotic properties by activating proteins S and C. Tissue type plasminogen activator produced by endothelial cells can lyse thrombi as soon as they start forming. Lipoprotein (a) on the other hand promotes ahterothrombosis.

A. Hyperpolarizes vascular smooth muscle

B. Acts via nitric oxide

C. Metabolite of arachidonic acid

D. Produced by cytochrome P-450 epoxygenase pathway

Answer: B. Acts via nitric oxide

Endothelium-dependent hyperpolarizing factor (EDHF) hyperpolarizes vascular smooth muscle and dilates arteries by opening calcium-activated potassium channels. The exact biochemical nature of EDHF is to be determined. The possible candidates are epoxyeicosatienoic acid and endothelium-derived hydrogen peroxide.

A. Systolic pressure

B. Diastolic pressure

C. Heart rate

D. Left ventricular contractility

Answer: B. Diastolic pressure

The major determinants of myocardial oxygen consumption are heart rate, systolic pressure and left ventricular contractility. The product of systolic pressure and heart rate is known as double product. The product of double product and left ventricular ejection time is sometimes called the triple product. The double product is a commonly measured indicator of myocardial oxygen consumption. The summary report of the treadmill exercise test displays the double product in each stage.

A. Downregulation of iNOS

B. Upregulation of COX-2

C. Opening of mitochondrial K+ATP channels

D. Involves protein synthesis

Answer: A. Downregulation of iNOS

Chronic or delayed preconditioning involves protein synthesis with upregulation of iNOS (inducible nitric oxide synthase), cyclooxygenase (COX-2) and opening of mitochondrial K+ATP channels. It can persist up to 4 days.

A. R1

B. R2

C. R3

D. R4

Answer: C. R3

R1 is the epicardial conduit resistance, which is negligible unless the obstruction is more than 50% of luminal diameter. R2 is the microcirculatory resistance in the small arteries and arterioles. R3 is compressive resistance and is related to the cardiac contraction and the systolic pressure developed in the left ventricle.