Exercise Management

Exercise Management Angina and Silent Ischemia Chapter 08

Pathophysiology Ischemia may be symptomatic or silent Symptomatic ischemia may be present in several ways. The most common is angina. Symptomatic angina is divided into three forms: stable, unstable, and variant (also called vasospastic or Prinzmetal's angina). Coronary Ischemia Exercise Management – Angina and Silent Ischemia

Exercise Management – Angina and Silent Ischemia • Stable Angina • is reproducibly associated with a specific amount of physical exertion, emotional stress, or exposure to cold • is predictably relieved promptly with rest or sublingual nitroglycerin. • is associated with an ischemic event due to a coronary artery stenosis

Exercise Management – Angina and Silent Ischemia • Unstable angina (UA) • occurs unpredictably. It indicates intermittent complete blockage of an artery which may soon become permanent. • The three principal presentations of UA are: • angina that occurs at rest or upon awakening from sleep, lasting more than 20 min; • new onset, or first experience, of anginal chest pain; and • increasing severity, frequency, duration, or threshold pattern (level of activity that reproduces the pain) of previously diagnosed angina.

Exercise Management – Angina and Silent Ischemia • The pathogenesis of UA is multi-factorial and includes one or more of the following: • platelet aggregation or thrombosis (clot) at a site of coronary artery narrowing; • rupture and hemorrhage into an atherosclerotic plaque; and • transient periods of vasospasm at the atherosclerotic plaque. ** Often, UA is a precursor to MI . People with this form of angina must be admitted to a coronary care unit and treated immediately with anti-clotting (anticoagulant) drugs or emergency balloon angioplasty.

Exercise Management – Angina and Silent Ischemia • Variant, vasospastic, or Prinzmetal's angina • Occurs when the coronary arteries spasm, or contract suddenly. • Angiograms in this type of angina show no obstruction or stenoses, and very little evidence of atheroma. • Intense vasospasm (i.e., a form of cramp of the vessel wall muscles) alone reduces coronary oxygen supply and results in angina. This leads to transient narrowing. • Treatments with medications that decrease spasm, such as calcium-channel antagonists, are often effective.

Exercise Management – Angina and Silent Ischemia • Effects on the Exercise Response • People with exercise-related myocardial ischemia may need to stop a single session of physical activity prematurely. • This may result from abnormal hemodynamic responses. • a reduction occurs in the production of nitric oxide (inhibiting dilation), of the coronary artery and promoting vasoconstriction. • Also, with diseased arteries, increased platelet aggregation causes release of thromboxane A2, a chemical that strongly constricts blood vessels.

Exercise Management – Angina and Silent Ischemia • Effects on the Exercise Response • Since the myocardial cells are not well perfused with oxygen, they can not contract well. • This reduces stroke volume and left ventricular ejection fraction. • The reduction in stroke volume limits cardiac output and promotes fatigue. • The decreased stroke volume may lead to compensatory increases in heart rate, known as increased chronotropic response, thus, a longer warm-up is needed during exercise.

Exercise Management – Angina and Silent Ischemia • Effects of Exercise Training • The overall goal for people with angina is to raise the ischemic threshold, or the point during physical stress at which angina symptoms occur • With exercise training, a decrease in the severity and extent of exercise-related myocardial ischemia occurs via a reduction in myocardial oxygen demand. (RPP used to indirectly measure MVO2 ) • Myocardial oxygen demand is reduced by • 1) increasing vagal tone, which • 2) decreases heart rate, which • 3) increases ventricular filling time. • 4) the increased filling time produces increased end diastolic volume, and an increased stroke volume • Exercise training improves nitric oxide production

Exercise Management – Angina and Silent Ischemia • Effects of Exercise Training • There is a reduction the exercise systolic blood pressure because of an improved myocardial supply (vasodilatation) • This allows for a reduced double product at a given exercise workload, thus the symptomatic ischemic threshold is raised • Therefore the patient will be able to perform a more intense physical activity before exceeding the double product that elicits angina.

Exercise Management – Angina and Silent Ischemia • Effects of Exercise Training • Exercise training increases the supply of blood and oxygen to the heart at rest and during exercise. • With long-term exercise training (e.g., 4-7 times/wk for >12 wk), there is repeated laminar shear stress on the surface of the coronary endothelial cells of the arterioles. This stress changes the shape of the endothelial cells in the direction of the blood flow, and stimulates the production of nitric oxide, promoting vasodilation.

Exercise Management – Angina and Silent Ischemia • Effects of Exercise Training • With repeated exercise training, there is an improvement in calcium handling of the smooth muscle cells. This leads to a decrease in coronary tone (vasoconstriction) and an increase in the vasodilatation (relaxation) of the coronary arteries.

Exercise Management – Angina and Silent Ischemia • Management and Medications • The primary goals for treatment of myocardial ischemia are to increase myocardial supply and decrease myocardial demand. Primary management used to decrease myocardial oxygen demand includes medications and exercise.

Exercise Management – Angina and Silent Ischemia • Recommendations for Exercise Testing • See pg. 69 text for summary chart • Evaluation of people suspected of having CAD that may cause ischemia is primarily done with graded exercise testing and may not be safe for all people with ischemia. • Exercise testing is contraindicated in people with acute ischemia and UA. May be performed in persons with non-diagnostic ECGs, negative cardiac biomarkers, and no resting angina within the past six hours. Angina must be evaluated and rated during testing.

Exercise Management – Angina and Silent Ischemia • Recommendations for Exercise Testing • 12 lead ECG warranted • During the test, documentation of anginal symptoms, the rating of angina, and the exact onset and duration of angina should be carefully documented. • Indications to terminate exercise testing : • See Absolute Indications and Relative Indications for Terminating the Exercise Test (p 69), and Table 8.1.

Exercise Management – Angina and Silent Ischemia • Recommendations for Exercise Testing • Specificity in diagnosing CAD can be further obtained by combining cardiac imaging with the test. • Myocardial perfusion imaging • Echocardiography to detect wall motion • In persons unable to exercise adequately enough to perform the exercise test, pharmacological stress testing can be used in conjunction with nuclear perfusion imaging of the heart.

Exercise Management – Angina and Silent Ischemia • Recommendations for Exercise Testing • Pharmacological Stress Testing • Intravenous Coronary Vasodilators - ( ex. Persantine) These agents dilate normal coronary arteries more than diseased ones. Blood flow to the heart is assessed at rest and during infusion, along with simultaneous nuclear imaging with thallium or technetium. • Positive Chronotropic (heart rate) and Inotropic (contractility) Agents, also known as sympatho-mimetics .

Exercise Management – Angina and Silent Ischemia • Exercise Programming (see p.70-71, text) • Prior to exercise training, people with angina must be able to: • define angina; • define possible anginal symptoms; • identify their own anginal symptoms; • describe the immediate treatment (this includes • understanding the necessity and protocol for taking nitroglycerin in the event of an anginal attack); and • understand the appropriate upper limits of exercise (including heart rate, ratings of perceived exertion, and angina scales).

Exercise Management – Angina and Silent Ischemia • Exercise Programming (see p.70-71, text) • A prolonged warm-up and cool-down (>10 min), has been shown to have an anti-anginal effect. • Any changes in the angina frequency, type, or severity should be reported to the patient’s physician. • The upper exercise intensity limit should be set at least 10 to 15 contractions/min below the RPP (double product) at the original ischemic threshold measured during the exercise test.

Exercise Management – Angina and Silent Ischemia • Exercise Programming (see p.70-71, text) • In addition to the ischemic threshold, the upper limit may be based on ventricular dysrhythmia threshold or inadequate blood pressure response threshold. • The duration of the exercise session should use ischemic preconditioning (intervals), exercise periods of short duration (e.g., 5-10 min/session) separated by short rest periods, 2 to 3 sessions/day. • Frequency of exercise sessions may start out high and decrease as longer duration sessions begin

Exercise Management – Angina and Silent Ischemia • Exercise Programming (see p.70-71, text) • Avoid exercising in the cold because of the increased chance of Prinzmetal's angina. • Persons presenting with anginal symptoms should subjectively verbalize them using the following angina scale: • 1 = Perceptible but mild • 2 = Moderate • 3 = Moderately severe • 4 = Severe **If a person verbalizes a 2 or greater, decrease exercise (if possible); until resolved or stop exercise completely.

Exercise Management – Angina and Silent Ischemia • Exercise Programming (see p.70-71, text) • Nitroglycerin should be used if angina develops during the exercise session • Standard nitroglycerin protocol includes the following: • discontinue exercise if chest pain develops; • check pulse, blood pressure, and cardiac rhythm using telemetry monitor; • if no relief with 1 to 3 min of rest, take one sublingual nitroglycerin tablet; • obtain a 12 lead ECG (if possible); • if pain is still not relieved, repeat nitroglycerin under the tongue after 5 min: • give a third nitroglycerin after another 5 min; • place person on oxygen at 2 to 4 L/nasal prongs • notify EMS or a physician to determine further course of action.

Exercise Management – Angina and Silent Ischemia End of Presentation

Exercise Management