Cardiovascular Risk Factors
• Non-modifiable
– Age
– Gender
– Family History
• Modifiable
–
–
–
–
–
Hypertension
Smoking
Diabetes
Hyperlipedemia
Other:
•
•
•
•
Homocystine levels
CRP levels
Sedentary life style
obesity
Cardiovascular Evaluation
•
•
•
•
•
•
•
•
•
•
History
Blood Pressure
Pulse
Auscultation
CXR
EKG
Stress EKG
Scintigraphy – Thallium
Echocardiograms
Angiography
Exercise Stress Testing
• Pathophysiology:
– At rest, there may be adequate coronary blood
flow, with exercise, supply may not keep up with
demand leading to characteristic ST segment
changes and other end points due to obstruction.
– At least a 70-80%occlucions is needed before
coronary stenosis (obstruction) is reliably detected
by this test.
– Significant coronary artery disease can exist with a
negative Exercise Stress Test.
Indications for Stress Testing
• Evaluation of patients with suspected
coronary artery disease (CAD).
– Typical Angina Pectoris
– Atypical Angina Pectoris
• Evaluation of patients with known coronary
artery disease (CAD).
– After myocardial infarction
– After intervention
• Evaluation of exercise capacity
• Evaluation of cardiac rhythm disorders
Preparation for Stress Testing
• History
– Type, character, durations, radiation, position of
chest pain
– Factors that increase or decrease chest pain
– Associated symptoms i.e. SOB, Diaphoresis, leg
pain, etc
– Other illnesses:
- HTN, DM, COPD, >lipids, CNS disease, Physical
Limitations
– Medications
– General Activity level
Preparation for Stress Testing
• Physical Examination
– General appearance, gait and mobility
– Cardiac auscultation and palpation
– Pulmonary Exam
– Vascular- bruits, pulses
– Musculoskeletal – limb strength and mobility
• Laboratory Studies
– Screening chemistry and hematologic profiles
– Resting ECG
Contraindications to Stress Testing
• Acute myocardial infarction or unstable angina
• Acute cardiac inflammation, pericarditis,
endocarditis, or myocarditis
• Severe congestive heart failure
• Uncontrolled sustained ventricular
arrhythmias, symptomatic supraventricular
arrhythmias or high-grade block
• Hemodynamically significant aortic stenosis
Contraindications to Stress Testing
• Severe hypertension (>200/>100)
• Active thromboembolic processes within past
3 months
– Pulmonary embolism
– Deep vein thrombosis
• Poor candidate for exercise
• Extreme obesity, i.e. Exceeds equipment
capacity, usually can’t do over 350 lb.
• Severe mental or physical disabilities
Possible Contraindications to Stress Testing
based on Resting ECG
• ST-segment changes 1 mm or greater, either
depression or elevation
• Ventricular strain patterns or hypertrophy
• T-wave inversions
• Left bundle branch block
• Right bundle branch block, if significant
• Prolonged QT interval
Equipment for Stress Testing
• Treadmill or bicycle or
steps
• ECG machine
• Blood Pressure Cuff
• Computer is a ‘nice to
have’
• ACLS Certification
• Exit Strategy
• Good Help* (it takes two
to test)
Normal ECG
Normal Response to Stress Testing
1)
2)
3)
4)
5)
Heart rate increases
Blood pressure increases
Cardiac output increases
Total peripheral resistance decreases
Dysrhythmias – isolated unifocal PVC’s and
PAC’s not of concern, usually suppressed at
increased heart rate
6) Oxygen consumption increases
(1MET = 3.5 ml O2/Kg./min =
1 metabolic equivalent)
Abnormal Response
to Stress Testing
1) Heart rate fails to rise above 120 or unable
to attain target heart rate of 85% of max
2) Blood pressure shows a drop in systolic
3) Patient physically unable to complete test
4) Marked hypertension, >260/115
5) Chest Pain and/or unusual shortness of
breath
Normal Response of ECG
to Stress Testing
1) ECG Changes
1) QRS complex decreases in size
2) J point depresses, resulting in up sloping of ST
segment
3) ST segment returns to baseline by 80
milliseconds
4) PR segment may down slope – thus baseline is
defined as PQ junction
5) R amplitude may decrease at rates that go above
130
6) T wave decreases
Abnormal Response of ECG
to Stress Testing
 ECG Changes
 Horizontal or down sloping ST segments
 ST segment depressed or elevated
 ST segment does not return to baseline by 80
milliseconds
 U or T wave inversion
 Dysrhythmias – rate dependent blocks above
first degree, WPW appears, Atrial fib/flutter,
multiform and/or increasing PVC’s, V-tach occurs
Protocols
• EST’s utilize standard protocols to progressively
increase cardiovascular work load in a uniform and
reproducible manner.
• Work load is expressed in METS (1 MET = 3.5ml O2
/Kg/min).
– 1 MET (3.5 ml) = basal O2 requirement
– 5 METS (17.5 ml) = activities of daily life
– 13 METS (45.5 ml) = good work out and excellent
prognosis
• Myocardial O2 consumption is estimated by
multiplying HR by BP to obtain the ‘double product’.
– Double product < 20,000 is low heart work load
– Double product > 29,000 indicates high heart work load
Reasons to Terminate Test
• Absolute
– Patient requests to stop
– Technical/mechanical
difficulties
– Suspected MI
– CNS symptoms
– Serious dysrhythmias
– Drop in systolic BP
– Severe Angina
– ST elevation > 1mm
– Poor perfusion
• Relative
–
–
–
–
–
–
–
–
–
–
–
> 2mm of ST depression
Increasing chest pain
Tired or SOB
Wheezing
Claudication
SVT
SBP>260, DBP>115
Exercise induced BBB
85% of max predicted HR
> 15 METS
> 30,000 double product