Exercise Management Myocardial Infarction Chapter 06

Exercise Management - Myocardial Infarction PathophysiologyPathophysiology Coronary AtherosclerosisCoronary Atherosclerosis Significant Plaque OcclusionSignificant Plaque Occlusion Ischemic Events Thrombosis, and InfarctionIschemic Events Thrombosis, and Infarction Coronary ThrombosisCoronary Thrombosis

Exercise Management - Myocardial Infarction Myocardial Infarction (MI) Signs /SymptomsMyocardial Infarction (MI) Signs /Symptoms Severe chest pain / pressure radiating to arms, back, or neck. Frequently associated with sweating, nausea, and vomitingSevere chest pain / pressure radiating to arms, back, or neck. Frequently associated with sweating, nausea, and vomiting Dead (necrotic) myocardial muscle cells secret CPK (creatine phosphokinase) and elevate blood levels of CPK. Trace amounts of troponin may also be present.Dead (necrotic) myocardial muscle cells secret CPK (creatine phosphokinase) and elevate blood levels of CPK. Trace amounts of troponin may also be present. ECG changes (ST segment elevation, T wave inversion) in the leads that detect the region of the infarction.ECG changes (ST segment elevation, T wave inversion) in the leads that detect the region of the infarction. ST Segment Elevation

Exercise Management - Myocardial Infarction Basic types of MI’sBasic types of MI’s Transmural – extends the full thickness of the ventricular wallTransmural – extends the full thickness of the ventricular wall Subendocardial – limited to the inner layer of the ventricular myocardium Subendocardial – limited to the inner layer of the ventricular myocardium

Exercise Management - Myocardial Infarction MI’s are described according to the involvement of the coronary circulation:MI’s are described according to the involvement of the coronary circulation: Anterior (Wall)Anterior (Wall) Posterior (Wall)Posterior (Wall) SeptalSeptal LateralLateral Or larger area combinationsOr larger area combinations AnterolateralAnterolateral AnteroseptalAnteroseptal

Exercise Management - Myocardial Infarction Cardiovascular Morbidity and Mortality is largely determined by:Cardiovascular Morbidity and Mortality is largely determined by: The extent of Left Ventricular (LV) damage and dysfunction. Criterion measure is LV ejection fraction.The extent of Left Ventricular (LV) damage and dysfunction. Criterion measure is LV ejection fraction.ejection fractionejection fraction Degree of resultant myocardial ischemia, which suggests future problems with myocardial vitalityDegree of resultant myocardial ischemia, which suggests future problems with myocardial vitalitymyocardial ischemiamyocardial ischemia Level of Cardiorespiratory Fitness (METS) where increase risk of 5-year motality when capacity in < 4 METSLevel of Cardiorespiratory Fitness (METS) where increase risk of 5-year motality when capacity in < 4 METS

Exercise Management - Myocardial Infarction MI Effects on the Exercise ResponseMI Effects on the Exercise Response ↓ Contractility = ↓ Cardiac Output = ↓O 2 delivery↓ Contractility = ↓ Cardiac Output = ↓O 2 delivery ↓ SBP response to exercise load resulting in exertional hypotension↓ SBP response to exercise load resulting in exertional hypotension ↑ ischemia, ↑angina, ↑ventricular arrhythmias↑ ischemia, ↑angina, ↑ventricular arrhythmias Subnormal aerobic exercise capacity (50-70%)Subnormal aerobic exercise capacity (50-70%) Chronotropic impairment may occur with damage to the SA or AV node. This blunting or HR will reduce Cardiac Output.Chronotropic impairment may occur with damage to the SA or AV node. This blunting or HR will reduce Cardiac Output.

Exercise Management - Myocardial Infarction Effects of Exercise TrainingEffects of Exercise Training ↑ Max Vo 2 (mean 20%) which generally rises inversely with pre-training value↑ Max Vo 2 (mean 20%) which generally rises inversely with pre-training value ↑ in the ventilatory response to exercise↑ in the ventilatory response to exercise ↑ HR variability ( adjusting to workloads)↑ HR variability ( adjusting to workloads) ↑ HDL-C↑ HDL-C ↑ Psychosocial well being and self-efficacy↑ Psychosocial well being and self-efficacy Relief of angina symptoms due to ↓ in myocardial oxygen demand at any given submax. work rateRelief of angina symptoms due to ↓ in myocardial oxygen demand at any given submax. work rate

Exercise Management - Myocardial Infarction Effects of Exercise TrainingEffects of Exercise Training Typical reductions in body mass, fat, cholesterol, and blood pressure.Typical reductions in body mass, fat, cholesterol, and blood pressure. ↓ coronary inflammatory markers. (C-reactive protein, and Lp-PLA 2 )↓ coronary inflammatory markers. (C-reactive protein, and Lp-PLA 2 )C-reactive proteinLp-PLA 2C-reactive proteinLp-PLA 2 ↓ blood platelet adhesiveness, fibrinogen, and blood viscosity and increased fibrinolysis.↓ blood platelet adhesiveness, fibrinogen, and blood viscosity and increased fibrinolysis. ↑ numbers of endothelial progenitor cells and circulating angiogenic cells – promotion of endothelial repair and growth.↑ numbers of endothelial progenitor cells and circulating angiogenic cells – promotion of endothelial repair and growth. ↑ vagal tone and ↓ adrenergic activity↑ vagal tone and ↓ adrenergic activity

Exercise Management - Myocardial Infarction Note - Patients who have BOTH left ventricular dysfunction and exercise induced myocardial ischemia show little or no increase in VO 2 max after early outpatient rehabilitation.Note - Patients who have BOTH left ventricular dysfunction and exercise induced myocardial ischemia show little or no increase in VO 2 max after early outpatient rehabilitation. Thus, success of exercise training does depend on the degree of ventricular damage and oxygen delivery capacity to the myocardiumThus, success of exercise training does depend on the degree of ventricular damage and oxygen delivery capacity to the myocardium Types of patients include those with MI to a large portion of the anterior wall and those with silent ischemia ( ↓ O 2 delivery).Types of patients include those with MI to a large portion of the anterior wall and those with silent ischemia ( ↓ O 2 delivery).

Exercise Management - Myocardial Infarction Management and MedicationsManagement and Medications Minimize the severity of the clinical symptoms resulting from the MIMinimize the severity of the clinical symptoms resulting from the MI Attempt to slow, halt, or reverse the progression of atherosclerosis through medication and health behavior management (diet, exercise, stress management)Attempt to slow, halt, or reverse the progression of atherosclerosis through medication and health behavior management (diet, exercise, stress management) Additional surgical intervention may be required to increase blood flow to high risk areas of the myocardium (bypass, angioplasty)Additional surgical intervention may be required to increase blood flow to high risk areas of the myocardium (bypass, angioplasty)

Exercise Management - Myocardial Infarction MedicationsMedications Effects of various medications used to control the risk factors associated with MI should be considered.Effects of various medications used to control the risk factors associated with MI should be considered. What effect does the medication have on exercise performance?What effect does the medication have on exercise performance? HR ? (chronotropic vs. ionotropic effects)HR ? (chronotropic vs. ionotropic effects)chronotropicionotropicchronotropicionotropic Contractility?Contractility? SBP ?SBP ? Circulating Ions used on muscle contractions (K)Circulating Ions used on muscle contractions (K) Overall “feeling” of the patientOverall “feeling” of the patient You do not need to memorize the effects of drugs. You should always review medications (See Appendix, p. 397)You do not need to memorize the effects of drugs. You should always review medications (See Appendix, p. 397)

Exercise Management - Myocardial Infarction Recommendations for Exercise TestingRecommendations for Exercise Testing See pg. 54 text (Table 6.1, next slide) for summary chartSee pg. 54 text (Table 6.1, next slide) for summary chart Should begin with low-level testing < 5 METSShould begin with low-level testing < 5 METS Test will serve to assess:Test will serve to assess: Functional capacityFunctional capacity Diagnosis of hemodynamic compromiseDiagnosis of hemodynamic compromise Prognosis ( predictor of disease progression)Prognosis ( predictor of disease progression)Prognosis Future exercise therapy ( exercise capacity and progression)Future exercise therapy ( exercise capacity and progression) Test can improve patient confidenceTest can improve patient confidence

Exercise Management - Myocardial Infarction

Abnormal Exercise Test Findings:Abnormal Exercise Test Findings: Angina / Low functional capacity ( < 4 METS)Angina / Low functional capacity ( < 4 METS) Ischemic changes on ECG (ST segment depression) at < 4 METS.Ischemic changes on ECG (ST segment depression) at < 4 METS. Low Double ProductLow Double ProductDouble ProductDouble Product Exertional HypotensionExertional Hypotension These findings indicate additional areas of the myocardium that may be in jeopardyThese findings indicate additional areas of the myocardium that may be in jeopardy Thus, the exercise test will be symptom limited until peak performance is attained.Thus, the exercise test will be symptom limited until peak performance is attained. LVH, LBBB, pacemaker rhythms and digitalis can alter ST-segment changes so perfusion testing is indicated to detect ischemia in these conditions.LVH, LBBB, pacemaker rhythms and digitalis can alter ST-segment changes so perfusion testing is indicated to detect ischemia in these conditions.

Exercise Management - Myocardial Infarction Primary Objectives for Exercise TestingPrimary Objectives for Exercise Testing Determine the chronotropic capacity and HR recoveryDetermine the chronotropic capacity and HR recovery Determine aerobic (functional) capacityDetermine aerobic (functional) capacity Myocardial aerobic capacity ( measured by Peak Double Product [ a.k.a. rate-pressure product] (HR X SBP)Myocardial aerobic capacity ( measured by Peak Double Product [ a.k.a. rate-pressure product] (HR X SBP) Exertional symptoms (angina, pre-syncope, syncope, ataxia)Exertional symptoms (angina, pre-syncope, syncope, ataxia)pre-syncope syncopeataxiapre-syncope syncopeataxia Associated changes in the electrical conductivity function of the heart (arrhythmias, ST-T wave changes)Associated changes in the electrical conductivity function of the heart (arrhythmias, ST-T wave changes)

Exercise Management - Myocardial Infarction Indicators of Poor Prognosis from Exercise TestingIndicators of Poor Prognosis from Exercise Testing Ischemic ST-segment depression at a low level of exercise stressIschemic ST-segment depression at a low level of exercise stress Low functional capacity (< 4 METS)Low functional capacity (< 4 METS) Low double productLow double product Hypotensive (low SBP) response to an increasing exercise load.Hypotensive (low SBP) response to an increasing exercise load.

Exercise Management - Myocardial Infarction Recommendations for Outpatient Exercise Programming (see charts p. 55, next slide) Intensity between 40-80% VO 2 max, RPE / 20 (Borg Scale) especially for those patients on meds that effect HR.Intensity between 40-80% VO 2 max, RPE / 20 (Borg Scale) especially for those patients on meds that effect HR. Frequency 4-7 days/weekFrequency 4-7 days/week Duration minutes/session continuous or accumulatedDuration minutes/session continuous or accumulated Mode – useful in ADL’s, use large muscle groups, and rhythmical.Mode – useful in ADL’s, use large muscle groups, and rhythmical min warm-up and cool down (monitor medicated individuals for post-ex. hypotension)5-10 min warm-up and cool down (monitor medicated individuals for post-ex. hypotension)

Exercise Management - Myocardial Infarction

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