Angina Pectoris Flashcards
What are four key aspects of antidysrhythmic drug actions; aka why do they work?
- State-dependent (of ion channels) 2. Selectively affect abnormal/depolarized cells. 3. Dependent on membrane voltage and spike frequency. 4. Selectively affect different parts of the heart (e.g. Class IV target A-V and S-A nodes)
How is angina pectoris characterized (symptoms)?
Intermittent attacks of chest pains which radiates to the left arm/shoulder/jaw. Ass’d w/ excitation, exertion.
What is the general developmental sequence of angina pectoris (5 steps)?
Coronary atherosclerosis-coronary narrowing-coronary insufficiency-myocardial hypoxia-angina pectoris
What are the four types of angina and their O2 needs?
A: Typical: Inc O2 demand and fixed supply
B: Variant: Dec O2 supply, unchgd demand
C: Unstable: usually at rest, dec O2 supply, dec blood flow due to blood clot (acute emergency)
D: Microvascular: atherosclerosis in small coronary artery
What are the four other names for the types of angina?
Typical=Stable/effort, Variant= Prinzmetal, Unstable is itself, Microvascular=Syndrome X
Which angina has partially occlude lumen with just plaque? Muscles suddenly spasm? Platelets and thrombus on top of plaque?
- Stable and microvascular
- Variant angina
- Unstable angina
What are the two crucial ratios to remember for angina pectoris?
Coronary blood flow/cardiac work and
O2 supply/O2 requirement
What are the three primary determinants of myocardial O2 supply (note which is major determinant)?
Coronary blood flow (major determinant), O2 content of blood and O2 extraction by myocardium
What are the primary determinants of myocardial O2 consumption?
Ventricular systolic pressure, heart size, heart rate and myocardial contractility
What is the afterload and what is the preload factor for the heart?
Ventricular systolic pressure and heart size, respectively
What do clinicians hope to do to the myocardial O2 consumption with drugs?
Decrease it (and increase coronary blood flow)
What are eight risk factors for angina?
Obesity, high blood cholesterol, physical inactivity, smoking, age, gender, family history, and hypertension
What are the four classes of angina drugs?
Nitrates (“N”), beta blockers (“B”), and CCRB (“C”)
What are the four possible mechanisms for altering supply/demand ratio and which drugs generally go with each?
Relaxation of resistance vessels (N/C), relaxation of capacitance vessels (N), blockade of sympathetic influence on heart (B) or coronary dilation (N)
How do nitrates and nitrites work?
Interaction between thiols and NO to make nitrosothiols-activate guanylate cyclase-turns GTP to cGMP
What does an increased cGMP cause (4 steps)?
- Inc Ca2+ uptake by sarcoplasmic reticulum
- Less ca2+ to interact with calmodulin
- Decreased phosphorylation of MLC
- Dec smooth muscle tone
What causes NO tolerance?
Sulfhydral groups (SH) are oxidized and form disulfide groups, which are no longer reactive- this prevents the action of NO, so may need abstinence periods)
How are nitrates degraded? CI Meds?
Phosphodiesterase-5 increases NO release which prevents breakdown of cGMP so effects last longer (viagra)
How is nitroglycerin take for prompt relief of chest pain? What are other forms intended for?
Oral spray or sublingual (Nitrostat); anginal prophylaxis
What are two drugs that specifically help with angina prophylaxis?
Isosorbide dinatrate and isosorbide mononitrate; nitroglycerin-like effect with a long duration of action
What drug reports the reduction in frequency of anginal attacks?
Propranolol
What two beta blockers are selective vs. non-selective? Has partial agonist activity (ISA)? 3. Membrane stabilizing action (LA)? 4. Lipid solubility?
- Atenolol (beta-1) vs. propranolol
- Pindolol (yes) vs. propranolol (no)
- Metoprolol (yes) vs. atenolol (no)
- Propranolol (high) vs. atenolol (low)
What beta-blocker is most common for angina? 2nd most common?
Atenolol, metoprolol
How do beta blockers affect elderly?
Both good and bad effects enhanced
How does beta blockers affect the myocardial reserve?
Decrease (block cardiac beta-one)
What three types of people must you be careful giving beta-blockers to?
Asthma (blocks bronchial beta-two), diabetes (blocks hepatic beta-two) and can exacerbate Raynaud’s
What class of drugs may cause constipation, tachycardia, or hypotension?
CCBs
What class of drugs may cause Nightmares, mental depression, insomnia?
Beta-blockers
What are the two types of CCB’s and which are used more often with angina?
Dihydropyridines (DHPs): used more often
Non-DHP’s: Verapamil and diltiazem
What is the Mech of action for CCBs?
Block Ca2+ through channels, causing dec in muscle tone.
What type of angina does CCBs help the most?
Variant (or stable/effort)
How are CCB’s given for angina?
Orally
What drugs help stable/effort angina? 2. Variant? 3. Unstable?
- BCN and aspirin
2. N/C and 3. BCM and anti-coagulants
What are three aims in use of antianginal drugs and each of their goals/what used?
- Tx of acute attack: oral spray or sublingual nitroglycerin
- Short term prophylaxis: Nitroglycerin prior to anticipated physical/emotional stress
- Long-term prophylaxis: Reduce frequency of anginal attacks (BCN)
