CAD Flashcards
What are some age related changes in cardiac anatomy?
Valves
Calcific and fatty degeneration of valve leaflets and annuli
Coronary Arteries
Dilation, tortuosity and medial calcification
Conduction system
Fibrosis and loss of special cells and fibers
Loss of 75% of pacemaker cells in SA node
Fibrosis of AV node and left anterior fascicleMyocardial relaxation decreases
Diastolic dysfunction develops
Valvular regurgitation develops
Peak exercise heart rate declines
PR, QRS, QT are prolonged
What are the effects of cigarette smoking on the body?
increase LDL decrease HDL heart rate Vasoconstriction impairs oxygen transport myocardial oxygen demand. Facilitates atherosclerosis endothelium more porous= activation of the clotting cascade = risk of thrombosis)
What are the hemodynamic effects of CAD?
Decreased lumen size (when~ 70%-angina)
reduction in the amount of blood able to pass through the narrowed area.
O2 demand >O2 supply: hemodynamically significant
(exercise& emotional stress =increased demands)
If blood flow and O2 are significantly reduced, the heart tissue has potential to become ischemic or necrotic.
Atherosclerosis=arterial stiffening=decreased compliance
Stiffening=decreased blood flow distal to plaque region.
WHAT IS CHEST PAIN?
One of the most common complaints of adult patients
Symptom- not a diagnosis
Somatic sensation of discomfort in the thoracic region
defined as that which is described by the patient
In elderly-complaint may be dyspnea or
“some type of feeling in the chest”
– not necessarily chest pain
Women-atypical symptoms
What is chronic stable angina?
Effort induced discomfort that has not changed in duration, intensity or frequency for at least two months
May be mild or debilitating
Occurs at rest or on exertion
Exertion may=increase in demand beyond supply
What is variant angina?
Angina that occurs without an increase in exercise or exertion and without warning
Believed that this pain is caused by coronary artery vasospasm
Seems to occur in cyclic fashion; same time of day
Hallmark sign on ECG
What is acute coronary syndrome (ACS)?
Occurs at rest, awakens pt at night, persists
Pt w/symptoms of ACS should not be evaluated over the telephone
Refer to a facility that allows evaluation by an NP or MD, 12-lead ECG, and biomarker determination
What does ischemia look like on EKG?
inverted T waves
What is ischemia?
T wave inversion and S-T segment depression can occur with anginal symptoms and return to baseline with relief of symptoms.
Acute decrease in blood flow and oxygen supply leads to severely ischemic tissue
may result in necrosis if interventions are not implemented within 6 hours of coronary occlusion.
Reversible if treated quickly.
what does injury look like on an EKG?
tombstones
ST elevation
What is injury?
Represented by ST segment elevation greater than .5 mm.
Represents damage to myocardium, not necessarily necrosis.
ST elevation can also be caused by pericarditis and/or ventricular aneurysm.
ST elevation is an ominous sign, it can go either way (want it to reverse!!!!!)
What are EKG representations of infarction?
Represented by pathological Q waves
Q wave width is greater than 0.04 seconds
Q wave depth is greater than 25% of the R wave
What are factors to consider when ordering stress testing?
Ability to exercise
Exercise protocol (Bruce, Modified Bruce, Naughton)
Ability to achieve target heart rate?
Asthma/Emphysema?
What should yo u prescribe to a patient in a low risk setting that is awaiting outpatient stress testing?
In low-risk patients who are referred for outpatient stress testing:
ASA, sublingual NTG, and/or beta blockers should be given while awaiting results of the stress test
What are indicators of a positive exercise stress test?
Exercise ECG or Exercise Stress Test Positive if:
new ST segment depression> 1 mm early after start of exercise
new ST segment depression> 2 mm in multiple leads
Pt unable to exercise for > 2 minutes
Pt has decreased SBP with exercise
Pt develops arrhythmias or HF w/exercise
Pt. has prolonged ECG abnormality after cessation of exercise (ST depression)
What are medications used in a medically induced stress test?
Dipyridamole
Adenosine
Dobutamine
What is a stress echo?
Ultrasound- at rest and during peak stress
Stress–exercise or pharmacologic
Ischemia defined by development of wall motion abnormalities
What is a stress MPI?
Myocardial accumulation of radioactivity in proportion to blood flow
Ischemia defined by diminished perfusion during stress vs rest imagesA wide range of noninvasive nuclear studies can be performed, and these studies vary according to the characteristics of the agent used, imaging techniques, and clinical questions to be answered.
Stress MPI is one of the most commonly used procedures for the evaluation of CAD.
MPI alone measures the presence of ischemia; with simultaneous gated single-photon emission computed tomography (SPECT), wall motion and chamber function can be evaluated.
The test is based on the myocardial accumulation of a radioactive agent that is distributed in proportion to blood flow to each area of the myocardium.
Studies are interpreted by comparing distribution of the radioactivity in rest and stress images. Areas of decreased perfusion at stress that do not appear at rest are characteristic of myocardial ischemia, while defects that appear on both sets of images are characteristic of myocardial infarction.
Exercise or pharmacologic stress can be used in conjunction with nuclear studies.
An important advantage of stress MPI is the ability to perform simultaneous ECG-gated SPECT to obtain functional data.
What are Benefits of Exercise Stress Testing over Pharmacologic?
Information about functional status Indication of threshold for ischemia Correlation with symptoms Evaluation of exercise induced arrhythmias Additional prognostic information
Discuss CT imaging role in CAD
CT angio-imaging coronary vessels
If images are NL, high sensitivity for excluding CAD
Risks: allergy to dye, radiation, patient with CKD
Discuss cardiac MRI
To evaluate the following and more: Aorta and large vessels Imaging coronary arteries Evaluation of myocardial perfusion No radiation exposure “Metal unfriendly environment” High level of technical expertise required
What are indications for cath?
Angina that is not easily controlled with medication, that disrupts daily routine, occurs at rest, or recurs after heart attack
Heart failure with suspected coronary artery disease
Markedly abnormal stress test results
Recurring chest pain of unidentified cause
Recurring angina despite medical therapy
Patients at high risk of severe ischemia or sudden cardiac death
Patients who have survived sudden cardiac death or have high-risk arrhythmia
Who is the ideal patient for cardiac cath?
Patients who have a high pretest probability of having stenoses
40% are negative
What is included in management for stable angina?
Reduction of Risk Factors
Lifestyle changes
Medications - nitrates, beta blockers, ASA, calcium channel blockers
Control of associated illnesses which can worsen angina: anemia, hyperthyroidism, tachycardia, CHF, infection, fever