Stable Angina Flashcards
What is the most common cause of myocardial ischemia?
Atherosclerotic disease of an epicardial coronary artery (or arteries)
Powerful risk factors for IHD
Obesity
insulin resistance
type 2 diabetes mellitus
Major determinants of myocardial oxygen demand (MVO2)
Heart rate
Myocardial contractility
Myocardial wall tension (stress)
Blood flows through the coronary arteries in a phasic fashion, with the majority occurring during ____.
diastole
Coronary resistance occurs in three sets of arteries:
_____(R1)
Prearteriolar vessels (R2)
Arteriolar and intramyocardial capillary vessels (R3)
Large epicardial arteries
In the absence of significant flow-limiting atherosclerotic obstructions, R 1 is trivial; the major determinant of coronary resistance is found in __
R2 and R3
The normal coronary circulation is dominated and controlled by the heart’s requirements for _____
oxygen
The major site of atherosclerotic d ease.
Epicardial coronary arteries.
What are the major risk factors for atherosclerosis?
High levels of plasma low-density lipoprotein (LDL)
Cigarette smoking
Hypertension
Diabetes mellitus
nomal functions of the vascular endothelium
local control of vascular tone
maintenance of an antithrombotic surface
and control of inflammatory cell adhesion and diapedesis.
There is also a predilection for atherosclerotic plaques to develop at sites of increased turbulence in coronary flow, such as at branch points in the ___
epicardial arteries.
Critical obstructions in vessels, such as the ____ and the ____ coronary artery, are particularly hazardous.
left main coronary artery
proximal left anterior descending
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 more severe ____
transmural ischemia
The typical patient with angina
man >50 years or a woman >60 years of age who complains of episodes of chest discomfort, usually described as heaviness, pressure, squeezing, smothering, or choking and only rarely as frank pain
Hand over the sternum, s times with a clenched fist, to indicate a squeezing, central, substernal discomfort
(Levine’s sign)
Angina is usually ____ in nature (typically with the severity of the discomfort not at its most intense level at the outset of symptoms), typically lasts ____, and can radiate to either ___ (especially the ulnar aspects of the forearm and hand). It also can arise in or radiate to the back, interscapular region, root of the neck, jaw, teeth, and epigastrium.
crescendo-decrescendo
2–5 min
shoulder and to both arms
may be due to episodic tachycardia, diminished oxygenation as the respiratory pattern changes during sleep, or expansion of the intrathoracic blood volume that occurs with recumbency; the latter causes an increase in cardiac size (end-diastolic volume), wall tension, and myocardial oxygen demand that can lead to ischemia and transient LV failure.
Nocturnal angina
Exertional angina typically is relieved in ___ by slowing or ceasing activities and even more rapidly by rest and sublingual nitroglycerin
1–5 min
sublingual nitroglycerin
Anginal “equivalents” are symptoms of myocardial ischemia other than angina. They include _______ and are more common in the elderly and in diabetic patients.
dyspnea, nausea, fatigue, and faintness
A particularly challenging problem is the evaluation and management of patients with persistent ischemic-type chest discomfort but no flow-limiting obstructions in their epicardial coronary arteries. This situation arises more often in women than in men. Potential etiologies include ____(detectable on coronary reactivity testing in response to vasoactive agents such as intracoronary adenosine, acetylcholine, and nitroglycerin) and ____.
microvascular coronary disease
abnormal cardiac nociception.
Auscultation can uncover arterial bruits, a third and/or fourth heart sound, and, if acute ischemia or previous infarction has impaired papillary muscle function, an apical systolic murmur due to mitral regurgitation. These auscultatory signs are best appreciated with the patient in the ____position.
left lateral decubitus
Tenderness of the chest wall, localization of the discomfort with a single fingertip on the chest, or reproduction of the pain with palpation of the chest makes it unlikely that the pain is caused by myocardial ischemia.
True
Evidence exists that an elevated level of high-sensitivity ____ (specifically, between 1 and 3 mg/L) is an independent risk factor for IHD and may be useful in therapeutic decision-making about the initiation of hypolipidemic treatment.
C-reactive protein (CRP)
A positive result on exercise indicates that the likelihood of CAD is 98% in males who are >50 years with a history of typical angina pectoris and who develop chest discomfort during the test.
True
Obstructive disease limited to the circumflex coronary artery may result in a ___stress test since the posterolateral portion of the heart that this vessel supplies is not well represented on the surface 12-lead ECG.
false-negative
Modified (heart rate–limited rather than symptom-limited) exercise tests can be performed safely in patients as early as __ days after uncomplicated myocardial infarction
6
Contraindications to exercise stress testing include r___
rest angina within 48 h, unstable rhythm, severe aortic stenosis, acute myocarditis, uncontrolled heart failure, severe pulmonary hypertension, and active infective endocarditis.
Failure of the blood pressure to increase or an actual decrease with signs of ischemia during the exercise stress test is an important adverse prognostic sign, since it may reflect ___
ischemia-induced global LV dysfunction.
Exercise Stress Test Discontinued on symptoms or specific signs: __
chest discomfort, shortness of breath, dizziness, severe fatigue, ST-segment depression >0.2 mV, drop in systolic BP >10 mmHg, or ventricular tachyarrhythmia.
The principal prognostic indicators in patients known to have IHD are ____
age, the functional state of the left ventricle, the location(s) and severity of coronary artery narrowing, and the severity or activity of myocardial ischemia.
Angina Characteristics Indicating Higher Risk or coronary events
Recent-onset or unstable angina
Post-myocardial infarction angina
Angina unresponsive to medical therapy
Angina with congestive heart failure symptoms
Most important, any of the following signs during noninvasive testing indicates a high risk for coronary events:
Inability to complete 6 minutes (Stage II) on Bruce protocol exercise test
Strongly positive exercise test:
Onset of ischemia at low workloads
≥0.1 mV ST-segment depression before Stage II or ≥0.2 mV at any stage
Persistent ST-segment depression >5 minutes post-exercise
Systolic pressure drop >10 mmHg or ventricular tachyarrhythmias during exercise