Ischemic Heart Disease (Lecture 6) Flashcards
(41 cards)
Concomitant antianginal therapy (notably the use of β-blockers) reduces the sensitivity of exercise testing as a screening tool. If the purpose of the exercise test is to diagnose ischemia, it should be performed, whenever possible, before β-blockers are initiated or ___ days after their discontinuation.
2 to 3
An ____ is the preferred test in patients who have suspected angina pectoris and are considered to have a moderate probability of coronary artery disease if the resting ECG is interpretable
exercise ECG
Interpretation of the exercise ECG should include the exercise capacity achieved (duration and metabolic equivalents of the external workload; see Table 45-5), the magnitude and extent of ____, the clinical and hemodynamic responses to exercise, and the rapidity with which the heart rate returns to normal after exercise (recovery phase)
ST segment deviation
Avoid exercise EKG in whom?
patients with ACS, severe aortic stenosis, severe hypertension, or uncontrolled heart failure. Other contraindications are acute MI, symptomatic arrhythmias, acute pulmonary embolism, and suspected acute aortic dissection.
Treadmill testing is preferred for patients who are capable of performing such physical activity because of the additional diagnostic and prognostic information achieved with graded exercise. In the 40 to 50% of patients who are unable to exercise
adequately, however, myocardial perfusion imaging with pharmacologic vaso- dilator stress with ___, ___, or ___ may be the pre- ferred approach to noninvasive testing.
dipyridamole, adenosine, or regadenoson
Exercise echocardiography can detect the presence of coronary artery disease with an accuracy similar to that achieved with stress myocardial perfusion imaging and is useful for localizing and quantifying ischemic myocardial seg- ments. Pharmacologic stress is usually performed with ___ in patients who are unable to exercise and in those unable to achieve adequate heart rates with exercise.
dobutamine
Anginal equivalents (i.e., symptoms of myocardial ischemia other than angina), such as dyspnea, fatigue, lightheadedness or dizziness, and ___, also may be manifestations of ischemic heart disease.
gastric eructations
Stress two-dimensional ____ with exercise or pharmacologic stress can detect regional ischemia by identifying new wall motion abnormalities
echocardiography
β-Blockers raise the ischemic threshold and delay or prevent the onset of angina with exercise
β-Blockers, which prevent the binding of catecholamines to the β-adrenergic receptor, lower heart rate and myocardial contractility, thereby reducing myocardial workload, myocardial oxygen demand, and ischemia and anginal symptoms.
When calcium-channel blockers are used alone, ___ is often preferred because dihydropyridine calcium-channel blockers can increase the heart rate.
diltiazem
Recommended on the basis of evidence or general consensus….
Aspirin in the absence of contraindications
β-Blockers as initial therapy in the absence of contraindications in patients with prior MI or without prior MI
Angiotensin-converting enzyme inhibitor in all patients with CAD who also have diabetes or left ventricular systolic dysfunction
Low-density lipoprotein–lowering therapy in patients with documented or suspected CAD, with a target <55 mg/dL using high-potency statins, ezetimibe, and PCSK9 inhibitors
Sublingual nitroglycerin or nitroglycerin spray for the immediate relief of angina
What about CCBs?
Calcium-channel antagonists or long-acting nitrates as initial therapy for reduction of symptoms when β-blockers are contraindicated
Calcium-channel antagonists or long-acting nitrates in combination with β-blockers when initial treatment with β-blockers is not successful
Calcium-channel antagonists and long-acting nitrates as a substitute for β-blockers if initial treatment with β-blockers leads to unacceptable side effects
In patients with severe three-vessel disease or left main disease randomized to either CABG surgery or PCI with a paclitaxel drug-eluting stent, ____ significantly reduced the end point of cardiac death, recurrent MI, and repeated revascularization in the ___-treated patients with multivessel disease, especially in patients with diabetes.
CABG
Associated Raynaud phenomenon and migraine headache have been described in some patients, suggesting that the syndrome may be part of a more generalized vasospastic disorder. The chest discomfort occurs predominantly at rest, although approximately one third of patients may also experience pain during exercise. There is a predilection for the pain to wake the patient in the early morning hours when sympathetic activity is increasing.
Prinzmetal (variant) angina
Dihydropyridine calcium-channel blockers (e.g., amlodipine, 5 to 10 mg orally per day) are preferred in patients with
Prinzmetal angina.
Coronary angiography, with a provocative test for spasm such as injection of acetylcholine into the affected coronary artery, usually precipitates the syndrome. Such testing is useful to establish the diagnosis and to assess the response to therapy,
3 non-modifiable risk factors for atherosclerosis?
Male sex
Age (men>45, women>55)
Fam Hx
Sympathetic nervous system innervation located where?
Parasympathetic controlled by?
SNS In the spine, T1-T5
PNS in the medulla, through the vagus
Stable angina implies what percentage (or less) is occluded?
70% or less
At 70%, flow decreases with exercise
Transient shifts in the ST segment (usually ST elevation)
Discomfort is most common in the night (midnight - 0400)
Variant/Prinzmetal angina
WITH ST ELEVATION, YOU’RE GOING TO ADMIT AND PCI… (of course you also admit unstable angina too)
Silent ischemia AND injury… what’s on the EKG?
ST ELEVATION
Factors that affect coronary vascular resistance:
- Accumulation of local metabolites
- Endothelium derived substances (usually vasodilate but when damaged can do more vasoconstriction)
- Neural innervation through sympathetic stimulation via ____
Both Alpha-adrenergic and ß2-adrenergic receptors
Factors that affect the demand of the heart…
1. Wall stress
- Heart rate
- Contractility
What works on contractility? What’s the caveat?
CCB affects contractility… they affect the “pump”
For ischemia, We wanna use meds that DON’T affect contracility/the pump… So we try to avoid CCBs if we can
Similarly, Digoxin is a positive inotrope and is also a last resort
____ inotropic drugs increase the force of contraction which therefore increases oxygen utilization and vice versa
Positive (digoxin()
What are the three groups that get silent MIs?
Women
Diabetics
Elderly
Regarding “stunned myocardium,” If you do an echo, it will show minimal movement, so you’d see an immediate wall motion abnormality. The heart will regenerate over several days. If you get an EF right away is it likely to be accurate?
no
“Stunned” myocardium = Short-term, total or near total reduction of coronary blood flow
• Reestablishment of coronary blood flow through PCI
• Subsequent LV dysfunction of limited duration
