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Exercise stress ecg. dmo
 

Exercise stress ecg. dmo

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    Exercise stress ecg. dmo Exercise stress ecg. dmo Presentation Transcript

    • Exercise stress testing Dr Shivanand Patil
    • General Applications
      • Diagnosis : Who has coronary artery disease
      • Prognosis : Who is high risk? Who needs intervention
      • Functional assessment : Who is disabled? What activities can be done safely?
      • Treatment assessment : Is medication or intervention effective?
    • METABOLIC EQUIVALENT
      • Unit of sitting , resting O2 uptake
      • 1 MET = 3.5 ml O 2 / kg / min
      • Measured VO2 =NO.Of METS 3.5ml O2/Kg/min
      • Asses disability
      • Standardize different protocols
    •  
    • ELECTROCARDIOGRAPHIC MEASUREMENTS
    • Mason –Likar modification
      • Extremity electrodes moved to the torso to reduce motion artifact
      • Arm electrodes - lateral aspects of infraclavicular fossae
      • Leg electrodes -above the anterior iliac crest and below the rib cage
    • Mason –Likar modification
      • It results in
      • Right axis shift
      • Increased voltage in inferior leads
      • May produce loss of inferior Q waves and development of new Q waves in lead aVL
      • Thus, the body torso limb lead positions cannot be used to interpret a diagnostic rest 12-lead ECG
    • Mason –Likar modification
    • Baseline Abnormalities - Obscure ECG changes during exercise
      • Left bundle branch block
      • LVH with repolarization abnormality
      • Digitalis Therapy
      • Ventricular paced rhythm
      • WPW syndrome
      • ST abnormality associated with SVT (or) AF
      • ST abnormalities with MVPS and severe anemia
    • Types of ST Segment Displacement
      • In normal persons
      • The PR, QRS, and QT intervals shorten as heart rate increases
      • P amplitude increases
      • PR segment becomes progressively more downsloping in the inferior leads
      • J point or junctional depression will occur
    • Normal
    • Types of ST Segment Displacement
      • In patients with myocardial ischemia
      • ST segment usually becomes more horizontal (flattens) as the severity of the ischemic response worsens.
      • With progressive exercise, the depth of ST segment depression may increase, involving more ECG leads, and the patient may develop angina
    • Abnormal
    • False-positive
    • Types of ST Segment Displacement
      • In the immediate postrecovery phase
      • ST segment displacement may persist, with downsloping ST segments and T wave inversion, gradually returning to baseline after 5 to 10 minutes
      • Ischemic response ---only in the recovery phase
      • Occur in 10 percent of patients
      • Prevalence is higher in asymptomatic populations compared with those with symptomatic CAD
    • Different ECG patterns
    • MEASUREMENT OF ST SEGMENT DISPLACEMENT
      • True isoelectric point ----TP segment
      • For purposes of interpretation--- PQ junction is usually chosen as the isoelectric point
      • Abnormal response
      • The development of 1 mm or greater of J point depression
      • with a relatively flat ST segment slope (<1 mV/sec )
      • depressed greater than or equal to 0.10 mV 80 msec after the J point (ST 80) in three consecutive beats with a stable baseline
    • Ischemic exercise-induced ECG
    • MEASUREMENT OF ST SEGMENT DISPLACEMENT
      • When the ST 80 measurement is difficult to determine at rapid heart rates (e.g., >130 beats/min), the ST 60 measurement should be used.
      • The ST segment at rest may occasionally be depressed. When this occurs, the J point and ST 60 or ST 80 measurements should be depressed an additional 0.10 mV or greater to be considered
      • When the degree of resting ST segment depression is 0.1 mV or greater, the exercise ECG becomes less specific, and myocardial imaging modalities should be considered
    • MEASUREMENT OF ST SEGMENT DISPLACEMENT
      • In early repolarization
      • Normal response---Resting ST segment elevation returns to the PQ junction
      • Magnitude of exercise-induced ST segment depression should be determined from the PQ junction and not from the elevated position of the J point before exercise
    • MEASUREMENT OF ST SEGMENT DISPLACEMENT
      • Localization of site of myocardial ischemia
      • ST segment depression do not localize the site of myocardial ischemia and which coronary artery is involved
      • ST segment elevation is relatively specific for the territory of myocardial ischemia and the coronary artery involved.
    • UPSLOPING ST SEGMENTS
      • Normal response
      • J point depression
      • Rapid upsloping ST segment (>1 mV/sec)
      • depressed less than 1.5 mm after the J-point
      • Abnormal response
      • Depression of ST segment > 1.5 mm at ST80
      • Patients with a high CAD prevalence--- abnormal.
      • Asymptomatic or with a low CAD prevalence--- less certain.
    • ST SEGMENT ELEVATION
      • ST segment elevation may occur in
      • an infarct territory where Q waves are present
      • in a noninfarct territory.
      • Abnormal response
      • 1 mm elevation at ST60 for 3 consecutive beats with a stable baseline.
    • ST SEGMENT ELEVATION
      • ST segment elevation in leads with abnormal Q waves
      • Occur in 30% of anterior MI & 15% of inferior MI
      • Have a lower ejection fraction
      • greater severity of resting wall motion abnormalities
      • worse prognosis.
      • not a marker of more extensive CAD
      • rarely indicates myocardial ischemia.
    • ST SEGMENT ELEVATION
      • ST segment elevation in leads without Q waves
      • Indicates transmural myocardial ischemia caused by coronary vasospasm or a high-grade coronary narrowing
      • Occurring in a 1 percent of patients with obstructive CAD.
      • Site of ST segment elevation is relatively specific for the coronary artery involved
    • ST SEGMENT ELEVATION
    • T WAVE CHANGES
      • Pseudonormalization of T waves
      • T-waves inverted at rest and becoming upright with exercise
      • Nondiagnostic finding --- in low CAD prevalence populations
      • In rare instance--- marker for myocardial ischemia
    • Pseudonormalization of T waves
    • OTHER ECG MARKERS
      • Changes in R wave amplitude
      • Relatively nonspecific and are related to the level of exercise performed
      • In LVH the ST segment response cannot be used reliably to diagnose CAD
      • U wave inversion
      • may occasionally be seen in the precordial leads at heart rates of 120 beats/min
      • Relatively specific and relatively insensitive for CAD
    • NONELECTROCARDIOGRAPHIC OBSERVATIONS
    • Blood Pressure
      • Normal Exercise response
      • SBP - Increase to 160 to 200 mm HG
      • DBP - Does not change significantly
      • In LV dysfunction (or) an excessive reduction in systemic vascular resistance
      • Failure to increase SBP> 120 mm HG
      • (or) Sustained decrease > 10 mm HG
      • (or) Fall in SBP below standing rest values
    • Exertional Hypotension
      • Ranges from 3 to 9 %
      • Higher in patients with TVD (or) Left main CAD
      • Cardiomyopathy
      • Cardiac arrhythmias
      • Vasovagal reactions
      • LVOT Obstruction
      • On Antihypertensive drugs
      • Hypovolemia
      • Prolonged Vigorous Exercise
    • Work Capacity
      • Limited work capacity
        • Associated with increased risk of cardiac events in known(or) suspected CAD
      • In estimating functional capacity, the amount of work performed (or exercise stage achieved ) should be the parameter measured and not the number of minutes of exercise
    • Sub-Maximal Exercise
      • APMHR (Age Predicted Maximum Heart Rate) = 220 - Age
      • Patient should achieve atleast 85 - 90 % of APMHR to test the cardiac reserve
      • Non - Diagnostic Test
        • PVD
        • Orthopedic Limitation
        • Neurological Impairment
        • Poor Motivation
    • Heart Rate Response
      • Inappropriate increase in heart rate at low exercise workloads
        • Atrial fibrillation
        • Physically Deconditioned
        • hypovolemic
        • Anaemic
        • Marginal LV function
    • Heart Rate Response
      • Chronotropic incompetence
        • Heart rate increment per stage of exercise that is less than normal (or) a peak rate below predicted at maximal work loads
      • Occurs in
        • sinus node disease
        • Beta Blocker
        • Compensated CCF
        • Myocardial ischemic response
    • Rate-Pressure Product
      • Heart rate x Systolic BP Product
      • Indirect measure of myocardial oxygen demand
      • increases progressively with exercise
      • used to characterize cardiovascular performance
      • Normal - 20 to 35 mm HG x beats/m x 10 -3
      • In CAD - < 25 mm HG x beats/m x 10 -3
    • Chest discomfort
      • It occurs usually after the onset of ischemic ST segment depression
      • In some patients , it may be the only signal of obstructive CAD
      • In CSA , Chest discomfort occurs less frequently than ischemic ST segment depression
    • Diagnostic use of Exercise testing
    • Sensitivity and Specificity
      • Both varies with the population being tested
      • Exercise ECG is best used in
      • The evaluation of a patient at intermediate risk with an atypical history (pre-test probability-30-70%)
      • Patient at low risk with a typical history
    • Sensitivity and Specificity 66% 53% 81% 86% Multivessel CAD Left main or TVD --- 25-71% LAD>RCA>LCx SVD 77% 68% In CAD (General) Specificity Sensitivity Patients
    • Limitations
      • Bayes theorem
      • The probability of a positive test result is affected by the likelihood (conditional probability) of positive test result among the population that has undergone the test (pretest probability)
      • The higher the probability that a disease is present in a given individual before a test is ordered, the higher is the probability that a test result is true-positive
    • Noncoronary causes of ST segment depression
      • Severe aortic stenosis
      • Severe hypertension
      • Cardiomyopathy
      • Anemia
      • Hypokalemia
      • Severe hypoxia
      • Digitalis use
      • Sudden excessive exercise
    • Noncoronary causes of ST segment depression
      • Glucose load
      • Left ventricular hypertrophy
      • Hyperventilation
      • Mitral valve prolapse
      • Interventricular conduction disturbance
      • Preexitation syndrome
      • Severe volume overload (aortic,mitral regurgitation)
      • Supraventricular tacyarrhythmias
    • Adverse prognosis and multivessel CAD
      • Duration of symptom-limiting < 6 METS
      • Failure to increase SBP >120 mm hg , or a sustained decrease >10 mm hg , or below rest levels, during progressive exercise
      • ST segment depression > 2mm , downsloping ST segment, starting at < 6 METS , involving > 5 leads, persisting > 5 min into recovery
    • Adverse prognosis and multivessel CAD
      • Exercise–induced ST segment elevation (avr excluded)
      • Angina pectoris at low exercise workloads
      • Reproducible sustained (>30 sec) or symptomatic ventricular tacycardia
    • Exercise testing in determining prognosis
    • Symptomatic Patients
      • TMT should be performed, before coronary Angiography -in patients with chronic CAD
      • Excellent exercise tolerance ( > 10 Mets) usually have an excellent prognosis regardless of the anatomical extent of CAD
    • After Myocardial infarction
      • TMT is useful to determine
        • Risk stratification and assessment of prognosis
        • functional capacity activity prescription after hospital discharge
        • Assessment of adequacy of medical therapy
    • Cardiac Arrhythmias and conduction disturbances
    • Ventricular Premature Contraction
      • Occurs frequently during exercise testing and increase with age
      • not a useful marker of CAD in the absence of ischemic ST segment depression
    •  
    •  
        • In LBBB - Exercised induced ST segment depression is found in most patients - cannot be used as diagnostic of prognostic indicator
        • In RBBB - Exercise induced ST depression in leads V1 - V4 is common finding and is non diagnostic of CAD
    • Supraventricular Arrhythmias
      • Presence of SVT is not diagnostic for CAD
    • Pre-Excitation Syndrome
      • Disappearance of delta waves occurs while exercise in 20 - 50 % of cases
        • Abrupt disappearance – Good prognosis
      • Presence of WPW syndrome, invalidates the use of ST segment analysis as a diagnostic method for detecting CAD
    • Special Clinical Applications
      • Digitalis - Produce exertional ST depression
      • Hypokalemia - associated with ST depression
      • Antischemic therapy
        • prolongs the time of onset of ST depression
        • Increase exercise tolerance
        • normalize exercise ECG response.(10 to 15 %)
      • Heparin therapy
        • increase total exercise duration
    • Special Clinical Applications
      • In women
        • Sensitivity and specificity are less in women than men
        • False positive tests - due to greater release of catacholamines during exercise produce vasoconstriction
          • more common during menses (or) preovulation
    • Special Clinical Applications
      • Hypertension
        • In normotensive asymptomatic individuals- increased long term risk is found in
          • increased SBP > 214 mm HG
          • increased SBP (or) DBP at 3rd minute of recovery
        • Severe systemic hypertension cause exercise induced ST depression in the absence of atherosclerosis
        • Exercise tolerance is decreased in patients with poor blood pressure control
    • Special Clinical Applications
      • In elderly patients
        • cardiac arrhythmias , chronotropic incompetence and hypertension responses are more common
      • Diabetes Mellitus
        • in patients with autonomic dysfunction and sensory neuropathy , anginal threshold may be increased
    • Special Clinical Applications
      • After CABG
        • indicate graft occlusion , stenosis or progression of CAD
      • After PTCA
        • In asymptomatic patients , 6 months post procedural test allows to diagnose restenosis
    • Indications for terminating exercise testing
    • Indications for terminating exercise testing
    • CONTRAINDICATIONS
      • ABSOLUTE
      • RELATIVE
    • CONTRAINDICATIONS TO EXERCISE TESTING (ACC/AHA)
      • ABSOLUTE
      • Acute MI (within 2 d)
      • USAP high risk
      • Uncontrolled cardiac arrhythmias causing symptoms or hemodynamic compromise
      • Symptomatic severe AS
    • CONTRAINDICATIONS TO EXERCISE TESTING (ACC/AHA )…
      • ABSOLUTE …
      • Uncontrolled symptomatic HF
      • Acute pulmonary embolus or pulmonary infarction
      • Acute myocarditis or pericarditis
      • Acute aortic dissection
    • CONTRAINDICATIONS TO EXERCISE TESTING (ACC/AHA )
      • RELATIVE
      • Left main coronary stenosis
      • Moderate stenotic valvular heart disease
      • Electrolyte abnormalities
      • Severe arterial hypertension  200/110
    • CONTRAINDICATIONS TO EXERCISE TESTING (ACC/AHA )…
      • RELATIVE …
      • Tachyarrhythmias or bradyarrhythmias
      • Hypertrophic cardiomyopathy and other forms of outflow tract obstruction
      • Mental or physical impairment leading to an inability to exercise adequately
      • High-degree AV block
    • TMT Report
      • Exercise protocol used
      • Duration of exercise
      • Peak treadmill speed and grade
      • Peak workload in MET or VO2 max
      • Functional Capacity
      • Maximum heart rate percentage of APMHR
      • Resting and Peak Blood Pressure
      • Symptoms
      • Arrhythmias
      • ECG Changes
    • Thank You
    • Work Capacity in METS-Women
    • Work Capacity in METS-Men
    • Terms-Evalution of test results
      • True positive(TP) = abnormal test results in individual with disease
      • False positive(FP) = abnormal test results in individual without disease
      • True negative(TN) = normal test result in individual without disease
      • Likelihood ratio: odds of a test result being true
      • of an abnormal test: sensitivity/(1-specifity)
      • Of a normal test: specificity/(1-Sensitivity)
    • Terms-Evalution of test results
      • Sensitivity: % of patients with CAD who have an abnormal result= TP/(TP+FN)
      • Specificity: % of patients without CAD who have a normal results =TN/(TN+FP)
      • Predictive value: % of patients with abnormal result who have CAD= TN/(TN+FN)
      • Test accuracy: % of true test=(TP+TN)/total no. of tests performed
      • Relative risk: Disease rate in persons with a positive test result/ Negative test result
    • Pretest probability of CAD Low Very low Intermediate Very low Intermediate Low High Intermediate 40-49 Men Women Very low Very low Low Very low Intermediate Very low Intermediate Intermediate 30-39 Men Women Asymptomatic Nonanginal Chest pain Atypical or Probable angina Typical or Definite angina Age/ Sex
    • Pretest probability of CAD Low Low Intermediate Intermediate Intermediate Intermediate High High 60-69 Men Women Low Very low Intermediate Low Intermediate Intermediate High Intermediate 50-59 Men Women Asymptomatic Nonanginal Chest pain Atypical or Probable angina Typical or Definite angina Age/ Sex
    • Duke treadmill score
    • Duke Treadmill Score
      • Exercise time - ( 5 x ST deviation ) - (4 x Treadmill angina index)
      • used to identify prognostic , intermediate - high risk patients in whom coronary angiography would be indicated to define coronary anatomy
      • Low-risk patients - scores of five or higher
      • Intermediate risk -scores between five and –10
      • High risk -scores lower than -10
    • PROGNOSTIC SCORES
      • DUKE treadmill score - by mark etal in Exercise time - (5 x max. ST depression) - 4 x 1987, based on 2842 patients.
      • angina index.
      • 5 YEARS SURVIVAL :
      • > 5 - 97%
      • - 10 to 4 - 91%
      • < - 10 - 72%
      • Score contains prognostic information even after clinical and cath data.
      • Prognostic stratifing power greatest in 3 VD and lowest in SVD.
    • VETERENS AFFAIRS (VA) SCORE
              • H/O CHF / digoxin
      • Change in systolic BP.
      • METS achieved.
      • VA score = 5 x (CHF / digoxin) + ST depression + change in SBP - METS.
      • < -2 low risk (annual mortality 1%)
      • -2 to 2 moderate risk (annual mortality 7%)
      • > 2 high risk (annual mortality 15%)
    • METABOLIC EQUIVALENT… 1 IV 2-3 III 4-6 II 6-10 I METS NYHA
    • Special applications
      • After myocardial infarction/ unstable angina
      • Cardiac rehabilitation
      • Screening
      • Exercise prescription
      • Preoperation evaluation
      • Dysrhythmias
      • Intermittent claudication/Pulmonary disease
    • Asymptomatic Population
      • Abnormal ECG
        • Prevalance in Men - 5 to 12 %
        • Prevalance in Women - 20 to 30 %
        • Risk of development of cardiac events - 9 times more than normal
        • Cardiac events over 5 years - 25 %
        • Most common Cardiac event - Angina
        • Prognostic value of an ST segment shift in women is less than in men
    • Ventricular Premature Contraction
      • In CAD occurs in 20 % of patients
      • In SCD survivors - 50 to 75 %
      • More frequent during recovery phase
      • Suppressed by B - Blocker therapy
      • Exercise testing provokes repetitive VPC’s in patients with H/O sustained VT