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Treadmill test (TMT)

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TMT

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Treadmill test (TMT)

  1. 1.  Exercise testing is a noninvasive tool to evaluate the cardiovascular system's response to exercise.  Exercise is the body's most common physiologic stress, and it places major demands on the cardiopulmonary system.  Thus, exercise can be considered the most practical test of cardiac perfusion and function.  Body increase its resting metabolic rate up to 20 times, cardiac output 6 times
  2. 2.  Total body or ventilatory oxygen uptake (volume oxygen consumption [VO2]) is the amount of oxygen that is extracted from inspired air as the body performs work.  The determinants of VO2 are cardiac output and the peripheral arteriovenous oxygen difference. Maximal arteriovenous difference is physiologically limited to roughly 15 to 17 mL/dL.  Thus maximal arteriovenous difference behaves more or less as a constant, making maximal oxygen uptake an indirect estimate of maximal cardiac output.
  3. 3.  Myocardial oxygen uptake is the amount of oxygen consumed by the heart muscle.  Myocardial oxygen demand is related to heart rate, blood pressure, left ventricular contractility (myocardial shortening per beat), and left ventricular wall stress(related to left ventricular pressure, wall thickness, and cavity size).  It has been shown that myocardial oxygen uptake can be reasonably estimated by the product of heart rate and systolic blood pressure (double product).  Higher the double product achieved the better is myocardial perfusion and prognosis
  4. 4.  Metabolic Equivalents  Exercise testing fundamentally involves the measurement of work.  The MET, or metabolic equivalent, is a term commonly used clinically to express the oxygen requirement of the work rate during an exercise test on a treadmill or cycle ergometer.  One MET is equated with the resting metabolic rate (approximately 3.5 mL of O2/kg/min),
  5. 5.  EXERCISE PROTOCOLS  The exercise protocol should be progressive with even increments in speed and grade whenever possible.  Smaller, even, and more frequent work increments are preferable to larger, uneven, and less frequent increases, because the former yield a more accurate estimation of exercise capacity  In general, 6 to 12 minutes of continuous progressive exercise during which the myocardial oxygen demand is elevated to the patient's maximal level is optimal for diagnostic and prognostic purposes.  The protocol should include a suitable recovery or cool-down period
  6. 6. ARM ERGOMETRY.  Arm crank ergometry protocols involve arm cranking at incremental workloads of 10 to 20W for 2- or 3-minute stages.  A bicycle ergometer with the axle placed at the level of the shoulders is used, and the subject sits or stands and cycles the peddles so that the arms are fully extended alternately.  The most common frequency is 50rpm. In normal individuals, maximal Vo2 for arm cycling approximates 50 to 70 percent of the same measures as leg cycling.  Peak Vo2 and peak heart rate are approximately 70 percent of the measures during leg testing
  7. 7.  BICYCLE ERGOMETRY.  Bicycle protocols involve incremental workloads calibrated in watts (W) or kilopond-meters per minute (kpm).  One watt is equivalent to approximately 6kpm.  Most protocols start with a power output of 10 or 25W/min (150kpm), usually followed by increases of 25W every 2 or 3 minutes until endpoints are reached.  Work rate is increased by a uniform amount each minute, ranging from 5- to 30-W increments  The bicycle ergometer is associated with a lower maximal Vo2 and anaerobic threshold than the treadmill; maximal heart rate, and maximal lactate values are often similar
  8. 8.  TREADMILL PROTOCOL  Bruce protocol is popular, and a large diagnostic and prognostic data base has been published  The Bruce multistage maximal treadmill protocol has 3-minute periods to allow achievement of a steady state before workload is increased .
  9. 9.  A limitation of the Bruce protocol is the relatively large increase in Vo2 between stages and the additional energy cost of running as compared with walking at stages in excess of Bruce's stage III
  10. 10.  Starts at a lower workload than the standard test.  Typically used for elderly or sedentary patients.  The fist two stages of the Modified Bruce Test are performed at a 1.7 mph and 0% grade and 1.7 mph and 5% grade.  The third stage corresponds to the first stage of the Standard Bruce Test protocol.
  11. 11.  The Naughton and Weber protocols use 1- to 2- minute stages with 1-MET increments between stages; these protocols may be more suitable for patients with limited exercise tolerance, such as patients with compensated congestive heart failure.
  12. 12.  The Asymptomatic Cardiac Ischemia Pilot (ACIP) trial use 2-minute stages, with 1.5-MET increments between stages after two 1min warm-up stages with 1-MET increments.  Developed to test patients with established CAD .  Result in a linear increase in heart rate and, distributing the time to occurrence of ST-segment depression over a wider range of heart rate and exercise time than protocols with more abrupt increments in workload between stages.
  13. 13.  The mACIP protocol produces a similar aerobic demand as the standard ACIP protocol for each minute of exercise  Well suited for short or older individuals who cannot keep up with a walking speed of 3 mph.
  14. 14.  This protocol is good for a wider range of fitness levels depending on starting grade.  Allows for gradual increase in grade and speed and may be started at 0%, 5%, 10%, grade depending on fitness level.
  15. 15.  Computer driven protocol that continuously increase workload until max exertion is reached.  Steady state may not be reached at any given work load.
  16. 16.  Computer driven protocol that continuously increase workload until max exertion is reached.  Steady state may not be reached at any given work load.
  17. 17. PROTOCOL USES COMMENTS BRUCE Normally used large↑Vo2 bet stagesrunning≥st 4 NAUGHTON&WEBER Limited ex tolerance- CCF 1-2 min stages1 MET increment ACIP Established CAD 2 min stages> linear ↑ in HR & Vo2 MOD-ACIP elderly individuals
  18. 18.  Walk Test.  A 6-minute walk test or a long-distance corridor walk test can be used to provide an estimate of functional capacity in patients who cannot perform bicycle or treadmill exercise, such as elderly patients or those with heart failure, claudication, or orthopedic limitations.  During a 6-minute walk test, patients are instructed to walk down a 100-foot corridor at their own pace, attempting to cover as much ground as possible in 6 minutes.  At the end of the 6-minute interval, the total distance walked is determined and the symptoms experienced by the patient are recorded
  19. 19. ♥Class I (Definitely appropriate) – ♥ Adult males or females (including RBBB or < 1mm resting ST depression) with an intermediate pre-test probability of coronary artery disease based on gender, age and symptoms (specific exceptions are noted under Class II and III below). ♥Class IIa (Probably appropriate) – ♥ Patients with vasospastic angina.
  20. 20.  Class IIb (maybe appropriate) ◦ Patients with a high pretest probability of CAD by age, symptoms, and gender. ◦ Patients with a low pretest probability of CAD by age, symptoms, and gender. ◦ Patients with less than 1 mm of baseline ST depression and taking digoxin. ◦ Patients with electrocardiographic criteria for left ventricular hypertrophy (LVH) and less than 1 mm of baseline ST depression.
  21. 21. ♥Class III (Not appropriate) ♥ ♥1. To use the ST segment response in the diagnosis of coronary1. To use the ST segment response in the diagnosis of coronary artery disease in patients who demonstrate the following baselineartery disease in patients who demonstrate the following baseline ECG abnormalities:ECG abnormalities: ♥pre-excitation (WPW) syndrome;pre-excitation (WPW) syndrome; ♥electronically paced ventricular rhythm;electronically paced ventricular rhythm; ♥more than one millimeter of resting ST depression;more than one millimeter of resting ST depression; ♥LBBBLBBB ♥2. To use the ST segment response in the2. To use the ST segment response in the diagnosis of coronary artery disease indiagnosis of coronary artery disease in MIMI patientspatients
  22. 22.  Pretest Preparations  Patients should be instructed not to eat, drink caffeinated beverages, or smoke for 3 hours before testing and to wear comfortable shoes and loose-fitting clothes.  Unusual physical exertion should be avoided before testing.  A brief history and physical examination should be performed, and patients should be advised about the risks and benefits of the procedure.  A written informed consent form is usually required.  A standard 12-lead ECG is usually obtained.
  23. 23.  The ECG should be obtained and blood pressure recorded in both positions, and patients should be instructed on how to perform the test.  Adequate skin preparation is essential for high-quality recordings, and the superficial layer of skin needs to be removed to augment signal-to-noise ratio.  The areas of electrode application are rubbed with an alcohol- saturated pad to remove oil and rubbed with free sandpaper or a rough material to reduce skin resistance.  Silver chloride electrodes with a fluid column to avoid direct metal- to-skin contact produce high-quality tracings; these electrodes have the lowest offset voltage
  24. 24.  Room temperature should be between 64° and 72°F (18° and 22°C) and humidity less than 60 percent.  The heart rate, blood pressure, and ECG should be recorded at the end of each stage of exercise, immediately before and immediately after stopping exercise, at the onset of an ischemic response.  Hyperventilation should be avoided before testing. Subjects with and without disease can exhibit ST-segment changes with hyperventilation
  25. 25.  If maximal sensitivity is to be achieved with an exercise test, patients should be supine as soon as possible during the postexercise period (maximal wall stress)  A cool-down walk can be helpful in performing tests on patients with an established diagnosis undergoing testing for other than diagnostic reasons – in testing athletes or patients with congestive heart failure (CHF), valvular heart disease, or a recent (MI).  A cool-down walk after the test can delay or eliminate the appearance of ST-segment depression.  Monitoring should continue for at least 5 minutes after exercise or until changes stabilize.
  26. 26.  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
  27. 27.  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
  28. 28. Age Gender Typical/Definite Angina Pectoris Atypical/Probable Angina Pectoris Non- Anginal Chest Pain Asymptomatic 30-39 Males Intermediate Intermediate low (<10%) Very low (<5%) 30-39 Females Intermediate Very Low (<5%) Very low Very low 40-49 Males High (>90%) Intermediate Intermediate low 40-49 Females Intermediate Low Very low Very low 50-59 Males High (>90%) Intermediate Intermediate Low 50-59 Females Intermediate Intermediate Low Very low 60-69 Males High Intermediate Intermediate Low 60-69 Females High Intermediate Intermediate Low High = >90% Intermediate = 10-90% Low = <10% Very Low = <5%
  29. 29. ST-Segment Analysis
  30. 30.  ST Segment Displacement  In normal persons, the PR, QRS, and QT intervals shorten as heart rate increases. P amplitude increases, and the PR segment becomes progressively more downsloping in the inferior leads.  J point, or junctional, depression is a normal finding during exercise.  In patients with myocardial ischemia, however, the 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.
  31. 31.  In the immediate postrecovery phase, the ST segment displacement may persist, with downsloping ST segments and T wave inversion, gradually returning to baseline after 5 to 10 minutes.  In about 10 percent of patients, the ischemic response may appear only in the recovery phase.  Patients should not leave the exercise laboratory area until the postexercise ECG has returned to baseline
  32. 32.  Measurement of ST Segment Displacement  For purposes of interpretation, the PQ junction is usually chosen as the isoelectric point.  The development of 0.10 mV (1 mm) or more of J point depression measured from the PQ junction, with a relatively flat ST segment slope (e.g., less than 0.7 to 1 mV/sec), depressed 0.10 mV or more 80 milliseconds after the J point (ST 80) in three consecutive beats, with a stable baseline, is considered to be an abnormal response.  the ST 60 measurement should be used at heart rates higher than 130/min.  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 more to be considered abnormal
  33. 33.  In patients with early repolarization and resting ST segment elevation, return to the PQ junction is normal.  Therefore, the magnitude of exercise-induced ST segment depression in a patient with early repolarization should be determined from the PQ junction and not from the elevated position of the J point before exercise.  Exercise-induced ST segment depression does not localize the site of myocardial ischemia, nor does it indicate which coronary artery is involved.  Exercise-induced ST segment elevation is relatively specific for the territory of myocardial ischemia and the coronary artery involved
  34. 34.  LBBB,  LVH  WPW syndrome,  Pacemakers,  Digoxin and  In patients with more than one millimeter of resting ST- depression.  ST-segment changes isolated to the inferior leads are more likely to be false-positive responses unless profound (i.e., more than 1 mm )
  35. 35.  lead II has been shown to have a high false-positive rate.  Exercise-induced ST-segment depression in inferior limb leads is a poor marker for CAD.  In patients without prior myocardial infarction and normal resting ECG, ST-depression in precordial lead V5 along with V4 and V6 are reliable markers for CAD,
  36. 36.  UPSLOPING ST SEGMENTS.  J point depression is a normal finding during maximal exercise, and a rapid upsloping ST segment (more than 1 mV/sec) depressed less than 0.15 mV (1.5 mm) after the J point should be considered to be normal.  Slow upsloping ST segment may be the only finding in patients with obstructive CAD.  In patient subsets with a high CAD prevalence, a slow upsloping ST segment depressed 0.15 mV or more at 80 ms after the J point should be considered abnormal.  The importance of this finding in asymptomatic individuals or those with a low CAD prevalence is less certain.
  37. 37.  ST depression at rest becoming normal with exercise  Does not indicate CAD  Common in females
  38. 38. ST SEGMENT ELEVATION.  The development of 0.10 mV (1 mm) or more of J point elevation, persistently elevated higher than 0.10 mV at 60 milliseconds after the J point in three consecutive beats with a stable baseline, is considered an abnormal response.  Without pathologic Q waves, exercise-induced ST elevation usually indicates either significant proximal coronary stenosis or epicardial coronary spasm.  In contrast, when pathologic Q waves are present, ST-segment elevation is usually indicative of a left ventricular aneurysm or significant wall motion changes.
  39. 39.  T WAVE CHANGES.  In patient populations with a low CAD prevalence, pseudonormalization of T waves is a nondiagnostic finding  In rare cases, this finding may be a marker for myocardial ischemia in a patient with documented CAD
  40. 40.  When the R wave amplitude meets voltage criteria for left ventricular hypertrophy, the ST segment response cannot be used reliably to diagnose CAD, even in the absence of a strain pattern.  Loss of R wave amplitude, commonly seen after MI, reduces the sensitivity of the ST segment response in that lead to diagnose obstructive CAD  U wave inversion can occasionally be seen in the precordial leads at heart rates of 120 beats/min. Although this finding is relatively specific for CAD, it is relatively insensitive.
  41. 41.  ST/HEART RATE SLOPE MEASUREMENTS  Calculation of the maximal ST/heart rate slope in mV/beats/min is performed by linear regression analysis relating the measured amount of ST segment depression in individual leads to the heart rate at the end of each stage of exercise, starting at the end of exercise.  An ST/heart rate slope of 2.4 mV/beats/min is considered abnormal, and values that exceed 6 mV/beats/min are suggestive evidence of three-vessel CAD.  The use of this measurement requires modification of the exercise protocol so that increments in heart rate are gradual, as in the Cornell protocol, as opposed to more abrupt increases in heart rate between stages, as in the Bruce or Ellestad protocols.
  42. 42.  A modification of the ST segment/heart rate slope method is the ST segment/heart rate index calculation, which represents the average change of ST segment depression with heart rate throughout the course of the exercise test.  The ST/heart rate index measurements are less than the ST/heart rate slope measurements, and an ST/heart rate index of 1.6 is defined as abnormal.
  43. 43.  Exercise Induced Arrhythmias  NSVT is uncommon during routine clinical treadmill testing and is usually well-tolerated.  In patients with a history of syncope, sudden death, physical examination with a large heart, murmurs, ECG showing prolonged QT, preexcitation, Q waves, and heart failure (HF), then exercise- testing–induced ventricular arrhythmias are more worrisome.  When healthy individuals exhibit premature ventricular contractions (PVCs) during testing, there is no need for immediate concern.  Exercise-testing–induced supraventricular arrhythmias are relatively rare and appear to be benign except for their association with the development of AF in the future
  44. 44.  The normal exercise response is to increase systolic blood pressure progressively with increasing workloads to a peak response ranging from 160 to 200 mmHg, with the higher range of the scale in older patients with less compliant vascular systems.  In normal persons, the diastolic blood pressure does not usually change significantly.
  45. 45.  Failure to increase systolic blood pressure beyond 120 mmHg,  A sustained decrease greater than 10 mmHg repeatable within 15 seconds,  or a fall in systolic blood pressure below standing resting values during progressive exercise,  is abnormal and reflects inadequate elevation of cardiac output because of left ventricular systolic pump dysfunction or an excessive reduction in systemic vascular resistance
  46. 46.  Defined as >210 mmhg in men and >190 mmhg in women.  Indicative of future development of HTN or adverse cardiac events.
  47. 47.  This variable is one of the most important prognostic measurements obtained from an exercise test  In patients with known or suspected CAD, a limited exercise capacity is associated with an increased risk of cardiac events and, in general, the more severe the limitation, the worse the CAD extent and prognosis.  In estimating functional capacity, the amount of work performed (or exercise stage achieved) expressed in METs, not the number of minutes of exercise, should be the parameter measured
  48. 48.  The best methods for estimating predicted METs are the following simple regression equations:  Men: Predicted METs = 18 −(0.15 × Age)  Women: Predicted METs = 14.7 −(0.13 × Age)
  49. 49. SUBMAXIMAL EXERCISE.  A submaximal study is assigned when the peak heart rate achieved is below the age-predicted maximum heart rate.  An inadequate study is defined by failure to achieve a predefined goal, such as 85% of the age-predicted maximum heart rate.
  50. 50.  The most familiar equation, which was developed principally in middle- aged men, is  HRmax = 220 − Age  Although easy to apply and calculate, there is considerable variability with this equation, especially in patients with CAD who are taking beta blockers. Newer equations have been proposed to replace the 220 − age rule to generate the age-predicted maximum heart rate:  Men: HRmax = 208 −(0.7 × Age)  Women: HRmax = 206 −(0.88 × Age)  CAD with beta blockers: HRmax = 164 −(0.7 × Age)
  51. 51.  The sinus rate increases progressively with exercise.  In some patients who may be anxious about the exercise test, there may be an initial overreaction of heart rate and systolic blood pressure at the beginning of exercise, with stabilization after approximately 30 to 60 seconds.  An inappropriate increase in heart rate at low exercise workloads may occur in patients who are in atrial fibrillation, physically deconditioned, hypovolemic, or anemic, or who have marginal left ventricular function; this increase may persist for several minutes in the recovery phase
  52. 52.  When the heart rate fails to increase appropriately with exercise, it is associated with an adverse prognosis.  Chronotropic incompetence is determined by decreased heart rate sensitivity to the normal increase in sympathetic tone during exercise and is defined as inability to increase heart rate to at least 85 percent of age-predicted maximum or as an abnormal heart rate reserve.  It reflects an inability to use up all the heart rate reserve.
  53. 53.  This finding may indicate autonomic dysfunction, sinus node disease, drug therapy such as beta blockers, or a myocardial ischemic response.  When the chronotropic index is 80 percent or less, long-term mortality is increased.  Chronotropic incompetence should not be used to estimate prognosis in patients on beta blocker therapy.  % of HR reserve used = HR peak – HR rest / 220 – age – HRrest
  54. 54.  Abnormal heart rate recovery (HRR) refers to a relatively slow deceleration of heart rate following exercise cessation.  This type of response reflects decreased vagal tone and is associated with increased mortality.  HRR = HR peak – HR 1 min later.  When the postexercise phase includes an upright cool-down, a value 12 beats/min or less is abnormal.  For patients undergoing stress echocardiography or otherwise assuming a supine position immediately after exercise, a value 18 beats/min or less is abnormal.  When HRR is measured 2 minutes into recovery, a value 22 beats/min or less is abnormal
  55. 55.  The prognostic value of abnormal HRR is independent of the exercise level attained, beta blocker usage, severity of coronary disease, left ventricular function, chronotropic incompetence, Duke treadmill score, and presence of exercise-induced angina or ischemic electrocardiographic abnormalities.
  56. 56.  The heart rate–systolic blood pressure product, an indirect measure of myocardial oxygen demand, increases progressively with exercise, and the peak rate-pressure product can be used to characterize cardiovascular performance.  Most normal individuals develop a peak rate pressure product of 20 to 35 mmHg×beats/min×10-3.  In many patients with significant ischemic heart disease, rate- pressure products exceeding 25 mmHg× beats/min×10-3 are unusual.  However, the cut point of 25 mmHg× beats/min×10-3 is not a useful diagnostic parameter;
  57. 57.  Exercise-induced chest discomfort usually occurs after the onset of ischemic ST segment abnormalities and may be associated with diastolic hypertension.  In some patients, however, chest discomfort may be the only signal that obstructive CAD is present.  In patients with chronic stable angina, exercise-induced chest discomfort occurs less frequently than ischemic ST segment depression.  The new development of an S3, holosystolic apical murmur, or basilar rates in the early recovery phase of exercise enhances the diagnostic accuracy of the test.
  58. 58. TM score  Mark and colleagues  Exercise time – ( 5 x ST deviation ) – ( 4 TM angina index )  Score of -11 or less, 5-year survival rate of 72 percent, as compared with a 97 percent survival rate among patients at low risk, with a TM score of +5 or higher.
  59. 59.  The strongest predictor of prognosis derived from the exercise test is exercise capacity.  The weakest predictor is ST-segment depression.  All other variables, such as the heart rate achieved, HRR, blood pressure response, ventricular arrhythmias, and exercise-induced angina, fall between these two extremes.
  60. 60.  1.Sex-Specific Scores- Separate scores for men and women incorporate three standard exercise test variables (ST- segment depression, peak heart rate, exercise angina score) and several other clinical variables
  61. 61.  Cleveland Clinic Score.  This score was initially reported in 2007.  It incorporates most of the important prognostic exercise test variables, as well as other important clinical variables.  It is more difficult to apply in routine clinical settings.
  62. 62.  MYOCARDIAL INFARCTION.  useful to determine (1) risk stratification and assessment of prognosis, (2) functional capacity for activity prescription after hospital discharge, and (3) assessment of adequacy of medical therapy and need to use supplemental diagnostic or treatment options.  A low-level exercise test (achievement of 5 to 6 METs, or 70 to 80 percent of age-predicted maximum) can be performed before hospital discharge.  The ability to complete 5 to 6 METs or 70 to 80 percent of age- predicted maximum in the absence of an abnormal ECG or blood pressure is associated with a 1-year mortality rate of 1 to 2 percent
  63. 63.  exercise testing carried class I indications before hospital discharge (submaximal 4 to 7 days), 14 to 21 days after discharge (symptom limited if not performed before discharge), and 3 to 6 weeks after discharge.  class IIa indication as part of an exercise prescription before cardiac rehabilitation for patients who underwent coronary revascularization.
  64. 64.  RISK STRATIFICATION IN THE EMERGENCY DEPARTMENT  Exercise testing in the emergency department should not be performed when (1) new or evolving ECG abnormalities are noted on the rest tracing, (2) the levels of cardiac enzymes are abnormal, (3) the patient cannot adequately perform exercise, (4) the patient reports worsening or persistent chest pain symptoms, (5) clinical risk profiling indicates that imminent coronary angiography is likely.  Several series of clinically low-risk subjects reported 6- month cardiac event rates lower than 1 percent with a normal exercise test result
  65. 65. PREOPERATIVE RISK STRATIFICATION BEFORE NONCARDIAC SURGERY  Exercise ECG before elective noncardiac surgery provides an objective measurement of functional capacity and the potential to identify the likelihood of perioperative myocardial ischemia in patients with a low ischemic threshold .  The risks of perioperative cardiac events and adverse long-term outcome are significantly increased in patients with abnormal exercise ECG results at low workloads
  66. 66.  EVALUATION OF VENTRICULAR ARRHYTHMIAS  Exercise testing provokes repetitive VPC in most patients with a history of sustained ventricular tachyarrhythmia, and in approximately 10 to 15 percent of such patients, spontaneously occurring arrhythmias are observed only during exercise testing.  Frequent VPC that occurs in the early postexercise phase is associated with a worse long-term prognosis than VPC that occur only during exercise.
  67. 67.  SUPRAVENTRICULAR ARRHYTHMIAS.  Supraventricular premature beats induced by exercise are observed in 4 to 10 percent of normal persons and in up to 40 percent of patients with underlying heart disease.  Sustained supraventricular tachyarrhythmias occur in only 1 to 2 percent of patients, although the frequency may approach as much as 10 to 15 percent in patients.  The presence of supraventricular arrhythmias is not diagnostic for ischemic heart disease, nor do they predict adverse long-term cardiovascular outcomes
  68. 68.  ATRIAL FIBRILLATION.  Patients with chronic atrial fibrillation tend to have a rapid ventricular response in the initial stages of exercise, and 60 to 70 percent of the total change in heart rate usually occurs within the first few minutes of exercise.  The effect of digitalis preparations and beta-adrenergic and selected calcium antagonists, such as diltiazem, on attenuating this rapid increase in heart rate for individual patients can be measured using exercise testing.
  69. 69.  SINUS NODE DYSFUNCTION.  In general, patients with sinus node dysfunction have a lower heart rate at submaximal and maximal workloads compared with control subjects.  However, as many as 40 to 50 percent of patients will have a normal exercise heart rate response.  ATRIOVENTRICULAR BLOCK.  Exercise testing may help determine the need for atrioventricular (AV) sequential pacing in selected patients.  In patients with congenital AV block, exercise-induced heart rates are low and some patients develop symptomatic rapid junctional rhythms that can be suppressed with DDD devices .  In patients with acquired conduction disease, exercise can occasionally elicit advanced AV block.
  70. 70.  LEFT BUNDLE BRANCH BLOCK.  Exercise-induced ST segment depression is found in most patients with left bundle branch block (LBBB) and cannot be used as a diagnostic or prognostic indicator, regardless of the degree of ST segment abnormality.  relative risk of death or other major cardiac events in patients with exercise-induced LBBB is increased approximately threefold over the risk in patients without this abnormality .  The development of ischemic ST segment depression before the LBBB pattern appears or in the recovery phase after the LBBB has resolved does not attenuate the diagnostic yield of the ST segment shift
  71. 71.  RIGHT BUNDLE BRANCH BLOCK.  The resting ECG in patients with RBBB is frequently associated with T wave and ST segment changes in the early anterior precordial leads (V1 to V3).  Exercise-induced ST depression in leads V1 to V4 is a common finding in patients with RBBB and is nondiagnostic.  The new development of exercise-induced ST segment depression in leads V5 and V6 or leads 2 and aVF, reduced exercise capacity, and inability to increase systolic blood pressure adequately.  The new development of exercise-induced RBBB is relatively uncommon, occurring in approximately 0.1 percent of test results.
  72. 72.  PREEXCITATION SYNDROME.  The presence of WPW syndrome invalidates the use of ST segment analysis as a diagnostic method for detecting CAD in preexcited as well as normally conducted beats; false-positive ischemic changes are frequently registered.  In patients with persistent preexcitation, exercise may normalize the QRS complex, with disappearance of the delta wave in 20 to 50 percent of cases .  Abrupt disappearance of the delta wave is presumptive evidence of a longer anterograde effective refractory period of the accessory pathway.
  73. 73.  Progressive disappearance of the delta wave is less reassuring and occurs when the improvement in AV node conduction is greater than in the accessory pathway;  This finding does not preclude a possible significant or even critical shortening of the anterograde effective refractory period in the accessory pathway under the influence of sympathetic stimulation.  The presence of Wolff-Parkinson-White syndrome does not cause a limitation of physical work capacity.
  74. 74. WOMEN.  The diagnostic accuracy of exercise-induced ST segment depression for obstructive CAD is less in women than in men.  Women tend to have a greater release of catecholamines during exercise, which could potentiate coronary vasoconstriction and augment the incidence of abnormal exercise ECG results.  False-positive results have been reported to be more common during menses or preovulation, and in postmenopausal women on HRT
  75. 75.  In asymptomatic women, a low exercise capacity, low heart rate recovery, and failure to reach target heart rate are more important predictors of outcome than exercise-induced ECG changes.  The exercise ECG remains the recommended test of first choice for the assessment of symptomatic, intermediate-risk women who can exercise and have normal findings on a resting ECG.
  76. 76.  HYPERTENSION.  Exercise testing has been used in an attempt to identify patients who have an abnormal blood pressure response and are destined subsequently to develop hypertension.  In asymptomatic normotensive individuals, Exaggerated exercise systolic and diastolic blood pressure response during exercise or Exaggerated peak systolic blood pressure response to 214 mmHg or higher or an elevated systolic or Diastolic blood pressure at the third minute of recovery is associated with significant increased long-term risk of hypertension .
  77. 77.  Severe systemic hypertension may interfere with subendocardial perfusion and cause exercise-induced ST segment depression in the absence of atherosclerosis, even when the resting ECG does not show significant ST or T wave changes.
  78. 78.  Coronary Bypass Grafting  The degree of improvement in exercise-induced myocardial ischemia and aerobic capacity after CABG depends in part on the degree of revascularization achieved and on left ventricular function.  Exercise-induced ischemic ST segment depression may persist when incomplete revascularization is achieved, albeit at higher exercise workloads.  It also may persist in approximately 5 percent of patients in whom complete revascularization has been achieved.
  79. 79.  Percutaneous Coronary Intervention  In the early post-PCI phase (less than 1 month), an abnormal exercise ECG result may be secondary to a suboptimal result, impaired coronary vascular reserve in a successfully dilated vessel, or incomplete revascularization.  Thus, exercise electrocardiography has a low diagnostic accuracy to detect restenosis or an incomplete dilation in the periprocedural phase.
  80. 80.  A 6- to 12-month postprocedure test allows sufficient time to document restenosis should it occur and allows the dilated vessel an opportunity to heal.  Serial conversion of an initially normal exercise test result after PCI to an abnormal result in the initial 6 months after the procedure, particularly when it occurs at a lower exercise workload, is usually associated with restenosis.
  81. 81.  In patients with chronic severe mitral or aortic regurgitation, the diagnostic role of exercise testing is limited to the evaluation of exercise capacity in patients with equivocal symptoms.
  82. 82.  The exercise test carries a class IIa indication for assessing response to therapy and for risk stratification.  To define the presence of exercise-induced outflow tract obstruction via Doppler echocardiography in patients with no gradient at rest.  The second is identifying patients with coexistent CAD, and  The third is detecting patients with the high-risk indicator of an abnormal blood pressure response.
  83. 83.  Catecholaminergic Polymorphic Ventricular Tachycardia-  always inducible by a maximal exercise test and is frequently not inducible with programmed electrical stimulation.  determine the patient’s response to treatment,namely, beta blockade.
  84. 84.  changes in the QT interval with exercise can be useful in identifying and stratifying patients with this syndrome.  prolongation of an already prolonged QT interval with exercise is typical of long-QT1 syndrome.  Long-QT2 syndrome has normal shortening,  long-QT3 syndrome has supranormal shortening of the QT interval with exercise.
  85. 85.  augmentation of early precordial ST-segment elevation early in recovery from exercise is both specific to Brugada syndrome and a predictor of a poor prognosis.

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