267 IHD Flashcards
Ischemic Heart Diease
ECG changes not characteristic of ischemia
Up sloping or Junctional ST segment changes
Signs (not symptoms) when stress testing has to be stopped
ST segment depression of more than 0.2 mV
Development of ventricular tachyarrhythmia
Fall in systolic blood pressure of more than 10 mmHg
Is a condition in which there is inadequate supply of blood and oxygen to a portion of the myocardium; typically when there is an imbalance between myocardial oxygen supply and demand
ischemic heart disease
most common cause of myocardial ischemia
atherosclerotic disease of an epicardial coronary artery
Major determinants of myocardial oxygen demand
heart rate, myocardial contractility and myocardial wall tension (stress)
when does majority of blood flow to the coronary arteries happen
diastole
75% of the total coronary resistance to flow occurs where
three sets of arteries 1. large epicardial arteries R1, 2. prearteriolar vessels R2, 3. arteriolar and intramyocardial capillary vessels R3
ischemic ST segment response in stress testing
Flat or downslopin depression of the ST segment more than 0.1 mv below the baseline and lasting for more than 0.08 s
non diagnostic ST segment response in stress testing
T wave abnormalities, conduction disturbances, ventricular arrhythmias
when is an exercise test negative
when heart rate 85% of maximal predicted for age and sex is not achieved
When should stress testing be discontinued
chest discomfort, severe shortness of breath, dizziness, severe fatigue, ST segment depression more than 0.2 mV, fall in SBP of more than 10 mmHg, ventricular tachyarrythmia
contraindication to stress testing
rest angina in the last 48 hrs, unstable rhythm, severe aortic stenosis, acute myocarditis, uncontrolled heart failure, severe pulmonary hypertension, active infective endocarditis
best treated with CABG
patients with stenosis of the left main coronary artery and those with three-vessel IHD
(especially with diabetes and/or impaired LV function)
changing oxygen needs of the heart with exercise and emotional stress affect coronary vascular resistance and in this manner regulate the supply of oxygen and substrate to the myocardium
metabolic regulation
coronary resistance vessels also
adapt to physiologicalterations in blood pressure to maintain coronary
blood flow at levels appropriate to myocardial needs
autoregulation
major site of atherosclerosis disease
Epicardial coronary arteries
major risk factors for atherosclerosis
(high levels of plasma low-density lipoprotein [LDL], low plasma high-density lipoprotein [HDL], cigarette smoking, hypertension, and diabetes mellitus
The combination of a “vulnerable vessel” in a patient with “vulnerable blood” promotes a state of ________ especially true in patients with diabetes mellitus
state of hypercoagulability and hypofibrinolysis
predilection for atherosclerotic plaques to develop at sites of
increased turbulence in coronary flow, such as at branch points in the epicardial arteries
Segmental atherosclerotic narrowing of epicardial coronary arteries is caused most commonly by
commonly by the formation of a plaque, which is subject to rupture or erosion of the cap separating the plaque from the bloodstream
Upon exposure of the plaque contents to blood, two important and interrelated processes are set in motion:
(1) platelets are activated and aggregate, and (2) the coagulation cascade is activated, leading to deposition of fibrin strands
critical obstructions in vessels, such as ______ are particularly hazardous
left main coronary artery and the proximal left anterior descending coronary artery
True or false. Chronic severe coronary
narrowing and myocardial ischemia frequently are accompanied by
the development of collateral vessels, especially when the narrowing develops gradually
True.
The relatively
poor perfusion of the _____ causes more intense ischemia
of this portion of the wall (compared with the ______)
The relatively poor perfusion of the subendocardium causes more intense ischemia of this portion of the wall (compared with the subepicardial region).
The severity and duration of the imbalance between myocardial oxygen supply and demand determine whether the damage is reversible ____
Less than 20 mins in the absence of collaterals
The severity and duration of the imbalance between myocardial oxygen supply and demand determine whether the damage is permanent
More than 20 mins
Transient T-wave inversion probably reflects
nontransmural, intramyocardial ischemia
transient ST-segment depression often reflects
patchy subendocardial ischemia
ST-segment elevation is thought to be caused by
caused by more severe transmural ischemia
True or false. Exercise stress tests in asymptomatic persons may show evidence of silent myocardial ischemia
True.
This episodic clinical syndrome is due to transient myocardial ischemia.
Stable angina pectoris
clenched fist, to indicate a squeezing, central, substernal
discomfort
Levine’s sign
Angina is rarely localized below the _____ or above the _____
Angina is rarely localized below
the umbilicus or above the mandible
True or false. myocardial ischemic discomfort does not radiate to the trapezius muscles; that radiation pattern is more typical of pericarditis.
True
True or false. Sharp, fleeting chest pain or a prolonged, dull ache localized to the left submammary area is rarely due to myocardial ischemia
True.
Anginal “equivalents” are symptoms of myocardial
ischemia other than angina. They include ______
dyspnea, nausea, fatigue, and
faintness and are more common in the elderly and in diabetic patients
Abnormal cardiac nociception is more difficult to manage and may be ameliorated in some cases by _____
imipramine
these disorders may cause angina in the absence of
coronary atherosclerosis
Aortic stenosis, aortic regurgitation, pulmonary hypertension, and hypertrophic cardiomyopathy
auscultatory signs
are best appreciated with the patient in _____
patient in the left lateral decubitus position
The presence of _____ is a significant indication of increased risk of adverse outcomes from IHD
presence of LVH
Stress testing is discontinued upon evidence of
chest discomfort, severe shortness of breath, dizziness, severe fatigue,
ST-segment depression >0.2 mV (2 mm), a fall in systolic blood pressure >10 mmHg, or the development of a ventricular tachyarrhythmia
The ischemic ST-segment response generally is defined as
flat or downsloping depression of the ST segment >0.1 mV below baseline (i.e., the PR segment) and lasting longer
than 0.08 s
True or false. Upsloping or junctional ST-segment changes
are not considered characteristic of ischemia and do not constitute a
positive test
True.
True or false. Although T-wave abnormalities, conduction disturbances, and ventricular arrhythmias that develop during exercise should be noted, they are also not diagnostic.
True.
True or false. Obstructive disease limited to the circumflex coronary artery may result in a false-negative stress test since the lateral portion of the heart that this vessel supplies is not well represented on the surface 12-lead ECG.
True.
this vessel supplies is not well represented on the surface 12-lead ECG.
Coronary Circumflex artery
Sensitivity of the exercise stress echocardiography
75% a negative result does not exclude CAD
What does a negative stress testing ECG mean?
Negative means CAD is less likely a three vessel or left main CAD
When can stress testing can be after uncomplicated MI
6 days after
Contraindications to stress testing
rest angina within 48 h, unstable rhythm,
severe aortic stenosis, acute myocarditis, uncontrolled heart failure,
severe pulmonary hypertension, and active infective endocarditis.
Most important, any of the following signs during noninvasive testing indicates a high risk for coronary events
inability to exercise for
6 min, i.e., stage II (Bruce protocol) of the exercise test;
a strongly positive
exercise test showing onset of myocardial ischemia at low workloads
(≥0.1 mV ST-segment depression before completion of stage II, ≥0.2 mV
ST-segment depression at any stage, ST-segment depression for >5 min
after the cessation of exercise, a decline in systolic pressure >10 mmHg
during exercise, or the development of ventricular tachyarrhythmias
during exercise);
the development of large or multiple perfusion
defects or increased lung uptake during stress radioisotope perfusion
imaging; and a decrease in LV ejection fraction during exercise on
radionuclide ventriculography or during stress echocardiography.
Obstructive lesions of the _____ are associated with a greater risk than are lesions of the ______ because of the greater quantity of myocardium at risk.
left main (>50% luminal diameter) or left anterior descending coronary artery proximal to the origin of the first septal artery Than right or left circumflex coronary artery
True or false. Cigarette smoking accelerates coronary atherosclerosis
True.
central in aiming for long-term relief from angina, reduced need for revascularization, and reducltion in myocardial infarction and death.
treatment of dyslipidemia
To minimize the effects of nitrate tolerance, the minimum effective dose should be used and a _____ kept free of the drug to restore any useful response(s)
minimum of 8 h each day
The most common clinical indication for PCI
symptom-limiting angina pectoris, despite medical therapy, accompanied by evidence of ischemia during a stress test.
Drug therapy in ischemic heart disease
Nitrates Beta blockers Calcium channel blockers Anti platelet Add ons ACEI Statins
Preferred procedure in CABG
Anastomosis of one or both of the internal mammary arteries or a radial artery to the coronary artery distal to the obstructive lesion is the preferred procedure.
It is usual clinical practice to administer after the implantation of a bare metal stent
aspirin indefinitely and a P2Y12 antagonist for 1–3 months
