Angina/Anti-Anginal Drugs Flashcards
What is angina?
Chest pain caused by an accumulation of metabolites as a result of myocardial ischemia
Angina is a _______, not a ______.
Symptom; disease
Most common cause of angina?
Atheromatous obstruction of large coronary vessels.
Primary cause of angina?
- Imbalance between the oxygen requirement of the heart and the oxygen supplied to it via the coronary vessels.
- Supply and Demand is disturbed.
Classic/Stable Angina
Inadequate blood flow in presence of CAD
Prinzmetal angina
vasospastic; spasm of coronary vessels; usually an underlying atheroma
Often nocturnal episodes - increase in venous return triggers neurogenic a-adrenergic coronary vasospasm
When does an imbalance in angina occur?
When the myocardial O2 requirement increases and coronary blood flow does not increase proportionally.
Why might coronary flow reserve be impaired?
endothelial dysfunction - impaired vasodilation
Ischemia occurs at low levels of demand
Unstable angina
Acute Coronary Syndrome
Angina at rest
Increased severity, frequency, duration of chest pain in patients with previous stable angina.
In unstable angina, imbalance occurs when there is reduced blood flow due to..
partially occlusive thrombi at the site of fissured or ulcerated plaque
Unstable angina and coronary resistance
increases
________ and _________. The main theory in treating angina.
Supply and demand
Ways to lessen demand (2)
Decrease cardiac work
Shift myocardial metabolism
Ways to increase supply
Reverse spasm
Treat atherosclerosis
What are the 4 determinants of Myocardial O2 demand?
Ventricular wall stress
Heart rate
Contractility
Basal Metabolism
What is ventricular Wall stress?
AKA Tension
Tangible force acting on the myocardial fibers, tending to pull them apart.
Energy expended opposing this force
Wall stress question?
LaPlace : T = (P x r)/2h
P: intraventricular pressure
r: radius of ventricle
h: ventricular wall thickness
Conditions that augment LV filling will do what to wall stress?
Increase it, therefore more O2 consumption.
Conditions that increase pressure in LV do what to wall stress?
increase it
HR and O2 requirement
Increased heart rate causes increased O2 requirement
more contractions per minute, more ATP consumed
In a healthy individual… an increased demand for O2 in heart is normally met by….
an increase in coronary blood flow
Coronary plow is related to ______ pressure and durations of ______
perfusion (aortic diastolic pressure); diastole
Coronary flow is inversely proportional to
coronary vascular resistance
How is resistance determined?
metabolic products; autonomic activity
