stress echocardiography
DESCRIPTION
TRANSCRIPT
STRESS ECHOCARDIOGRAPHY
Dr. Muhammad Mobarock HossainMBBS(CU), MD (card) phase BUniversity cardiac centre, BSMMUDHAKA, BANGLADESH.Contact: +8801914007246Email: [email protected]
History
History :
The Krannert Institute and Indiana University introduced the technique of dobutamine stress echocardiography in the United States over 17 years ago.
Link: http://medicine.iupui.edu/krannert/programs/echo/dobutamine/
Cont…
Cardiac ultrasound is used to image the function of the heart and Medicines (dobutamine or dopamine) are used to
stress the heart.
Cardiac ultrasound can detect the presence of blockages in the arteries to the heart if a region of the heart is seen to have reduced pumping function during stress.
Link: http://medicine.iupui.edu/krannert/programs/echo/dobutamine/
Stress echocardiography:
Definition
Definition of stress echocardiography :
SE is an effective method for the evaluation of
myocardial ischemia, based on the detection of
“ Stress induced regional wall motion abnormality”.
About SE
Accuracy of SE in the detection of significant
coronary artery disease is 80-90%.
SE is superior to ETT and can be comparable
to nuclear stress imaging. SE is safe and economical. Mortality 1 in 1000
Pathophysiology
Pathophysiology :
Exercise and inotropic stress normally provoke a generalised increase of regional wall motion andthickening, with an increment of ejection fraction mainly caused by a reduction of systolic dimensions.
Regional systolic dysfunction is usually caused by coronary artery disease, but cardiomyopathiesmay also show regional variation in function.
Cont…
The presence of residual viable tissue is more
common in hypo kinetic than akinetic
Segments & least common in dyskinetic segments.
Ischemic cascade Myocardial ischemia due to coronary luminal obstruction
Decreased myocardial perfusion ――> [NS,PET,CPE]
Metabolic changes ――> [ PET scan]
Diastolic dysfunction ――> [Stress Echo]
Systolic dysfunction ――> [Stress Echo]
ECG change ――> [ECG]
Chest pain ――> [History]
Importance of SE:
SE can differentiate viable myocardium from
the scarred myocardium which may help
whether there will be any benefit from the
revascularization or not.
Cont…
The severity of valvular disease Hypertrophic cardiomyopathy Exercise induced pulmonary
hypertension
Contraindications to SE:
1. Unstable angina2. Severe base line hypertension3. Uncontrolled arrhythmias4. Mobile LV thrombus5. Severe Aortic stenosis6. HOCM7. Decompensated HF.
Stressors
Stressors :
Exercise Pharmacological agents Atrial pacing
TREADMILL
Methodology
Methodology :
Patient’s preparation
Equipments
Performing the test
Patient’s preparation
Patient’s preparation
Written consent from the patient.Avoid heavy meal several hours
before the test.Rate limiting drugs like beta blockers
should be stopped 3-5 half lives.Standard connections for a 12 lead
ECG.
Equipments
Equipments:
Exercise echocardiographic machine with standard hemodynamic monitoring equipment is needed.
Resuscitation equipments and defibrillator should be available for emergency crisis.
Software for the echocardiographic machine is necessary to acquire digital images and to allow side by side comparison of pre test with post peak stress images
Performing the test
Exercise stress echocardiography :
Treadmill exercise echocardiography Upright bicycle echocardiography Supine bi cycle exercise
echocardiography
Treadmill exercise echocardiography
Supine bi cycle exercise echocardiography
Exercise stress test:
Exercise stress is preferred over non exercise stress because it is more closely reproduce daily activities .
Images are to be obtained at peak exercise with bicycle ergometry while the patient continues to exercise.
Sensitivity will be reduced if the images are not taken within 90 sec after exercise.
End points for exercise SE:
Target HR (85% of APMHR)Chest pain and dyspnoeaSevere hypertension( Sys>220 mm of Hg, Dia > 110
mm of Hg)Hypotension( Sys < 90 mm of Hg or fall of
> 20 mm of Hg from the base line).Ventricular tachycardia or sustained SVTDevelopments of WMA in at least two
contiguous segments
Advantages DisadvantagesTreadmill Widely available
High workloadPost stress imagesMild ischemia may revert
Upright bicycle Imaging during exercise Technically difficult
Supine bicycle Imaging during exerciseDopplers readily available
Low workload
Dobutamine Continuous imaging Side effects
Dipyridamole Continuous imaging Side effects
Pharmacological stress echocardiography
Dobutamine stress echocardiography Dipyridamole / adenosine stress echocardiography
American society of echocardiography (ASE) In 2007, American society of echocardiography (ASE) guidelines
recommended “ Dobutamine” as the 1st line agent for pharmacologic
stress echocardiography.
Dobutamine
Sympathomimetic drugs which causes increase ionotrophic, increase chronotrophic and increase Blood pressure.
Plasma half life is 2-3 minutesLow dose dobutamine causes (+)
ionotrophic effect through cardiac α₁ and β₁ receptors
thus causing increase contractality of heart. Higher dose causing (+) chronotrophic
effects through cardiac β₂ receptors.
Dopamine vs Dobutamine
Contraindication for dobutamine :
Unstable ventricular arrhythmias
Other factors
1. Unstable angina2. Severe base line hypertension3. Uncontrolled arrhythmias4. Mobile LV thrombus5. Severe Aortic stenosis6. HOCM7. Decompensated HF.
How to start with Dobutamine
Dobutamine:
Started with 10 microgram /kg/min and then increase every 3 minutes to 20,30,40 μgm/kg/min.
If 85% of APMHR is not achieved at 40 μgm/kg/min then a 3 min 50 microgram/kg/min may be used.
If dobutamine alone is not effective then we may use Inj Atropine (.25-.50 mg) I/V every minute starting at the 40 μgm/kg/min of dobutamine.
Max 2 mg Atropine can be used.
Side effects :
Most serious- arrhythmia provocation.
Rare but serious – Cardiac arrest,
Arrhythmia, MI.
Less serious – Tremor, nervousness, marked
hypotension( due to ischemia
and dynamic outflow tract obstruction).
Combat with the side effects of Dobutamine
Emergency management for S/E :The effect of dobutamine may be
reversed if angina or other severe side effects
develops by Giving…
Inj Esmolol (0.5 to 1 mg/kg body wt)
over 1 min
or Inj Metoprolol ( 2 to 5 mg/kg body wt)
over 2-5 min
WMA grading :
Normal Hypokinetic : marked reduction in endocardial
motion and thickening . Akinetic : virtual absence of
inward motion and
thickening Dyskinetic /paradoxical wall motion
during systole.
Interpretation:
Causes of false positive and false negative stress echo:
Myocarial zone : coronary vessels
Sample pictures of DSE
Apical 4 chamber view:
Apical 2 chamber view :
Short axis view :
Parasternal long axis view :