[6118] Unit 3.3.1: Vasodilator to Nitrates

vasodilators promote _____

vascular smooth muscle relaxation

vasodilators are commonly used for the treatment of ____

angina pectoris

vasodilators can be used for what other CV conditions?

HTN, ischemia, MI

cGMP

what factor?

Increased levels promote dephosphorylation of the myosin light chain of the smooth muscle

Calcium

what factor?

Decreased intracellular levels lead to non-activation of myosin light chain kinase

Potassium

what factor?

Increased levels leads to HYPERPOLARIZATION leading to cell membrane stabilization

dephosphorylation

Increased cGMP levels promote _________ of the myosin light chain of the smooth muscle leading to VASODILATION

non-activation

Decreased intracellular Ca levels lead to ________ of myosin light chain kinase leading to VASODILATION

Hyperpolarization

Increased K efflux leads to ________ leading to cell membrane stabilization and VASODILATION

Angina Pectoris

Chest pain caused by reduced blood flow which means lack of oxygen in the heart muscle

T

T OR F:

All types of angina pectoris has a REVERSIBLE injury to cardiomyocytes.

F (depression not elevation)

T OR F:

Vasopastic/Prinzmetal has ST segment depression seen on ECG diagram.

F (During stress or exertion (relieved by rest) not anytime)

T OR F:

Stable/Atherosclerotic has an onset of anytime even at rest

F (needs vasodilator; only vasospastic need CCBs also)

T OR F:

All types of angina pectoris needs CCBs for its management.

Cardiac Preload

what determinant?

• Diastolic filling pressure (stretch) • Volume of blood received by the heart

Cardiac Afterload

what determinant?

Arterial blood pressure or resistance to eject blood (squeeze)

Heart Rate

what determinant?

• Contributes to total fiber tension • Higher HR = higher tension = higher O2 requirement

Double Product

what determinant?

• Index of myocardial oxygen consumption (SBP x HR)

• Directly proportional to O2 demand

Contractility

what determinant?

• Force required go pump blood

• Increased contractility = increased O2 demand

Ejection Time

what determinant?

• Time between aortic valve opening and closure

• Increased time = increased O2 demand

Nitrates, CCBs and 𝛽-blockers

what drugs reduce cardiac O2 requirement in atherosclerotic angina?

Nitrates and CCBs

what drugs reduce vasospasm leading to increase O2 delivery?

Ranolazine and Trimetazidine

what drug increases efficiency in O2 utilization?

Ivabradine

what drug selectively reduces heart rate and O2 requirement with no detectable hemodynamic effects

Nitroglycerin (NTG)

most important nitrates

Nitroglycerin (NTG)

what drug?

- SL (DOA 10 to 20 minutes)

- TD (DOA 8-10 hours)

Isosorbide dinitrate (ISDN)

what drug?

SL and oral forms; rapidly denitrated; slightly longer DOA than NTG

Isosorbide mononitrate (ISMN)

what drug?

used orally as prophylaxis

Amyl nitrate

what drug?

volatile; inhalational route

aldehyde dehydrogenase (ALDH2)

isoform 3 (ALDH3)

Nitrates releases nitric oxide within the smooth muscle cells through the action of the mitochondrial enzyme ________ and ___________-

nitrite ion

aldehyde dehydrogenase (ALDH2) and isoform 3 (ALDH3) frees __________ which then converts to nitric oxide (NO)

nitric oxide

stimulates the increase in cGMP

decreased ventricular volume, arterial pressure, ejection time

vasodilation

increased coronary flow

decreased left ventricular diastolic pressure

reflex tachycardia

decreased diastolic perfusion time

What are the cardiovascular effects of nitrates?

F (Prinzmetal angina)

T or F:

Nitrates cause vasodilation of the epicardial coronary arteries resulting to relief of coronary artery system in Crescendo angina

relaxation of smooth muscles of bronchi, GIT, GUT

enhanced erection

reduced platelet aggregation

What other effects do nitrates have on the body?

tachycardia

headache

orthostatic hypotension

syncope

fluid retention

increased intracranial pressure

excessive hypotension

Monday disease

What are the adverse effects of nitrates?

Monday disease

What condition is characterized by the alternating tolerance and loss of tolerance for vasodilating action?

Syncope

What condition is characterized by the loss of consciousness and muscle strength in a person?