Stress Testing TMT – Treadmill stress test

 

Stress Testing (TMT – Treadmill stress test)

  • It is the best test for angina.
  • 12 – lead ECG is recorded before, during, and after exercise on a bicycle or treadmill ergom­eter.
  • Patient’s ECG, arm blood pressure, heart rate, symptoms are monitored and the work load is gradually increased.
  • Exercise ECG testing is a preferred component of stress testing in most patients.
  • Stress testing is an important modality for the evaluation of patients with known or suspected coronary heart disease (CHD),
  • The emphasis will be on stable patients with known CHD
  • The test is stopped if patients gets chest dis­comfort, dyspnoea, fatigue, dizziness and ST-T changes (ST depression >2 mm), systolic blood pressure falls more than 10 mmHg, patient gets ventricular tachyarrhythmias.
  • The percentage of irreversibly scarred myocardium
  • Compare symptoms, especially chest discomfort or pain with ECG changes.
  • The amount and distribution of viable but jeopardized left ventricular myocardium

Stress Testing TMT 1

Stress Testing (TMT – Treadmill stress test)

 

Stress test / Treadmill stress test positive

   

  • The degree of ischemia can be graded semiquantitatively by each of these methods.
  • If ST depression >0.1 mv below baseline for more fhan 0.08 seconds or 2 small squares.
  • Exercise or pharmacologic stress (mostly using dobutamine) echocardiography;
  • ownsloping ST is significant

Stress Testing TMT ecg 1

Stress Testing (TMT – Treadmill stress test) ecg

 

The measure of induced ischemia —

 

  • Abnormally low peak systolic blood pressure (<130 mmHg) or a fall in systolic blood pressure below baseline during exercise
  • Poor exercise capacity (<5 METs) (show figure 1)
  • Exercise-induced angina, particularly at a low workload
  • Chronotropic incompetence
  • Evidence of ischemia may be assessed in several ways,
  • T wave changes, conduction abnormalities, veD­tricular and atrial arrhythmias ma not sig.o.jfy CAD.
  • Target heart rate -i.e. 85% maximum heart rcrre fo r ag e a nd sex, if Qot achi eve_d, testLs non-di~gnostic.
  • ensitivity of TMT is only 75% ( Treadmill stress test)
  • Complications and risks ofTMT (Treadmill stress test) One death can occur per 10,000 cases so equipments for resuscitation must be present.

 

Contraindications :

   

  • Acute MI (within 4-5 days)
  • Rest angina <48 hrs Unstable rhythm
  • Severe aortic stenosis Myocarditis
  • Heart failure
  • Acute infective endocarditis
  • Severe IHD is signified by .’
  • >0.2 mv ST segment depression at low ~orkload (before stage II).
  • ST segment depression> 5 minutes after termination of exercise.
  • adionuclide studies
  • This shows the m ocardium and hence infarcted ar­eas of the myocardium i.e. its viability can be seen.

 

Stress Myocardial Perfusion Imaging:

   

  • IV Thal­lium 201 or Technetium 99 m is given and then imag­ing is done immediately and after 4 hours to detect regions of infarction.
  • With thallium, infarcted areas do not take up the dye (cold spots). With technetium, infarcted areas take up the dye (hot spots).

 

The Duke treadmill score uses three exercise parameters:

 

  • Duke prognostic treadmill score = Exercise time (minutes based on the Bruce protocol) – (5  x  maximum ST segment deviation in mm)  –  (4  x  exercise angina [0=none, 1=nonlimiting, and 2=exercise limiting])
  • Patients are classified as low, moderate, or high risk according to the score:
  • Low-risk — score ≥ +5
  • Moderate-risk — score from -10 to +4
  • High-risk — score ≤ -11
  • 16 percent had single vessel disease, and 9 percent had three vessel or left main disease; five-year survival was above 97 percent.
  • Among the 9 percent of patients categorized as high-risk, 74 percent had three vessel or left main disease and five-year survival was 65 percent.
  • Among the 36 percent of patients categorized as low-risk, 60 percent had no coronary stenosis ≥ 75 percent,