Stress Testing Source Elstead and experience STRESS

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Stress Testing

• Source Elstead and experience

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STRESS TESTING INDICATIONS

• Precordial chest pain
• Determine prognosis and severity of disease
• Evaluation of arrhythmia
• Evaluation of functional capacity and make
  exercise prescription.
• Evaluate congenital heart disease i.e. shunts
  right-sided pressures

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STRESS TESTING ABSOLUTE CONTRAINDICATION

• Patient with acute MI
• Patient with acute myocarditis or pericarditis
• Patient with unstable progressive angina
• Patient with rapid ventricular and atrial
  arrhythmias
• Patient with 2nd and 3rd degree AV block
• Acutely ill patient ie with infection,
  hyperthyroidism or severe anemia

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STRESS TESTINGRELATIVE CONTRAINDICATION

• Aortic stenosis
• Hi-grade LVOT
• Suspected left main equivalent
• Severe hypertension 240/130 (Gracin max 180)
• Severe ST depression at rest and history of
  angina
• Congestive heart failure rales, edema
• AAA (adenosine most forgiving type of stress
  test)

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STRESS TESTING WHEN TO TERMINATE THE EXERCISE
TEST

• Blood pressure or heart rate drops
• Hypertension - 220 systolic or 110 diastolic
  especially if headache or visual changes
• Severe ST depression i.e. 2mm in 2 contiguous
  lead
• Patient has reached or exceeded the predicted
  maximum heart rate (need 85 nuclear 15-20 bpm
  over 85 for stress echo)
• VT or runs of three or more
• Atrial tachycardia, atrial fibrillation, or
  atrial flutter
• 2nd or 3rd degree heart block
• Angina pain
• Dyspnea, faint, fatigue
• Muscular pain of arthritis and claudication
• Patient looks vasoconstricted pale and clammy

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ST ABNORMALITIES
2mm upsloping ST depression at .08 sec after the
J point (the tail end of QRS complex) 1mm
horizontal ST depression 1mm downsloping ST
depression
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ST DEPRESSIONS

• ST depression distribution does not correlate to
  coronary territory at risk.
• ST depressions are particularly specific on
  Adenosine and dipyridamole stress but less
  specific on dobutamine protocols.
• ST depressions are often falsely positive for
  ischemia with hypertension, digoxin, hypokalemia,
  and women.

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ST ELEVATIONS

• ST elevations reflect transmural ischemia and are
  significant in exercise, adenosine stress and DO
  CORRELATE to coronary territory at risk.
• The exception is Dobutamine, which often has
  ischemic changes not strictly correlated to
  ischemia.

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T-WAVE INVERSIONS

• T-Wave inversions are not specific and you do not
  need to wait until they return to normal before
  phasing out of the study.

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BRUCE PROTOCOL

• Stage 1 0-3 min 1.7 mph 10 grade 5.0 Mets
• Stage 2 3-6 min 2.5 mph 12 grade 6.8 Mets
• Stage 3 6-9 min 3.4 mph 14 grade 9.4 Mets
• Stage 4 9-12 min 4.2 mph 16 grade 13.3 Mets
• Stage 5 12-15 min 5.0mph 18 grade 16.6 Mets
• Stage 6 15-18 min 5.5 mph 20 grade 19.5 Mets
• Stage 7 18-21 min 6.0 mph 22 grade 22.7 Mets

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• Mets are defined as
• Metabolic equivalents Multiples of 02
  consumption of 3.5 ml/kg/min by a person in the
  sitting position. Describes functional capacity.
• Rate pressure product Max HR x Max SBP
• (25,000 is a good effort) Useful if Hr is low and
  SBP is high.

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Modified Bruce 2 minute intervals ½ stages
Speed is constant grade increases. Naughton
Protocol 2 minute interval at 2 mph with grade
changes 0, 3.5, 7, 10.5, 14, 17.5, 20
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Bicycle Protocol

• Upright and Reclined
• Reclined is harder physically as legs are
  above the heart level. We do upright. Can watch
  RVSP rise with exercise.
• Start at 25 watts 60 rpm increase by 25 watts
  usually to 125 watts. Goal - still 85 max HR.
  Use a Dobutamine format on the echo machine.

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ADENOSINE/DIPYRIDAMOLE (PERSANTINE)

• Adenosine Protocol
• 140 mcg/kg/min for 6 minutes and inject MIBI at 3
  minutes
• Can do 4 minute and inject MIBI at 2 minutes and
  spare the patient the misery.
• Adenosine and Dyperidamole - vasodilatory drugs
• Normal vessels dilate while atherosclerotic
  vessels do not , leading to an imbalance of blood
  flow favoring the normal vessels causing a
  defect in atherosclerotic vessels distribution.

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ADENOSINE STRESS

• Contraindicated in bronchospasmic patients
• Most COPD are not bronchospasmic. Ask if
  patient was ever intubated, prednisone dependent
  or nebulizer dependent.
• 1. Rx stop infusion
• 2. Rx Theophylline
• Contraindicated in high gradient AV block
• If block down Rx, stop infusion, Rx atropine.
• If patient is on Theophylline or Dyperidamole
  chronically, hold drug for 24 hours.
• Caffeine extinquishes the effects of Adenosine
  and you do not really have a stress test.

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ADENOSINE THALLIUM IS ESPECIALLY GOOD IN PATIENTS

• 1. LBBB native or PACEMAKER induced
• Stress and Dobutamine both from the
  inability to interpret septal wall defects due to
  LBBB. There is not as much variation in motion
  of septum in adenosine stress.
• 2. Pre-op AAA

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NUCLEAR IMAGING

• Thallium Thallium
• Thallium Sestamibi exercise
• Sestamibi Sestamibi for very obese patients 2
  days, more Sestamibi on stress day
• Adenosine walk test save one hour of wait
  time to image stress and avoid bradycardia and
  symptoms

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(Short) Apex (Vertical) Sept (Horizontal)
Inf
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Berman, DS 1st Virtual Congress of Cardiology
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DOBUTAMINE protocol for echo or nuclear imaging

• Catecholamine Increases HR and BP, but also
  vasodilates so BP drop.
• Start at 5 mcg/kg/min if looking for viability
  but usually 10, 20, 30, 40, 50 mcg/kg/min for 3
  minutes infusions (begin imaging at 2 minutes)
• Use Atropine in .25 mg increments start at 30
  mcg/kg/min if HR is less than 100 there.

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Cautions in Dobutamine

• Caution in
• Rapid Afib, VT use metoprolol 5 mg IV I mg/min
  push
• Hypertension dobutamine can raise or lower
  blood pressure - may need to stop if you are
  starting out high. Can use atropine to get to
  goal if note BP is going to be limiting.
• Migrainers can get severe vasodilatory headaches
• Schizophrenic or other mentally unstable patients
  may not tolerate the catecholamine effects of
  dobutamine test may need to be aborted.

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DOBUTAMINE STRESS ECHO

• Dobutamine stress echo is especially good for
• Asthmatics
• Obese patients can dodge the anterior wall
  attenuation artifact of nuclear imaging

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16 SEGMENT MODEL
Diagram of the modified 16-segment model with
areas of coronary artery distribution shown as
areas of stippling or cross hatching. The
overlap areas are represented as a combination of
the graphics in the overlap territory. ANT
anterior 4C four chamber INF inferior LAT
lateral LAX long axis POST posterior SAX
PM short axis at the papillary muscle level
SEPT septal 2C 2 chamber.
Segar DS et al. JACC 1992 191199
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WALL MOTION SCORE

• Give each segment a score.
• Normal 1
• Hypokinetic 2
• Akinetic 3
• Dyskinetic 4
• Aneurysmal 5
• Add up all segment scores and divide by number of
  segment seen. 1 is normal.
• WMS 2.5 or greater is a poor prognosis.

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A 16-segment model can be used, without the
apical cap, as described in an ASE 1989
document. A 17-segment model, including the
apical cap, has been suggested by the American
Heart Association Writing Group on Myocardial
Segmentation and Registration for Cardiac
Imaging. Will be most useful if and when echo
perfusion imaging is available.
Lang et al. J Am Soc Echocardiogr
2005181440-1463
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Typical distributions of the right coronary
artery (RCA), the left anterior descending (LAD),
and the circumflex (CX) coronary arteries. The
arterial distribution varies between patients.
Some segments have variable coronary perfusion.
Lang et al. J Am Soc Echocardiogr
2005181440-1463
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Caveats in Stress echo

• False positives are seen in patients with
  hypertensive responses to exercise
• and in patients with cardiomyopathies.
• The LBBB does not disqualify a patient from a
  stress echo as you CAN read the anterior wall
  looking for an LAD lesion. The septal and
  anteroseptal walls are influenced by the LBBB so
  can not be used.

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Sensitivity Specificity

• ECG alone 53 vs 83
• Spect 90 vs 80
• Echo 85 (80 single vx) vs 85