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) Heart rate increases2) Blood pressure increases3) Cardiac output increases4) Total peripheral resistance decreases5) 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 systolic3) Patient physically unable to complete test4) Marked hypertension, >260/1155) Chest Pain and/or unusual shortness of

breath

Normal Response of ECG to Stress Testing

1) ECG Changes1) QRS complex decreases in size2) J point depresses, resulting in up sloping of ST

segment3) ST segment returns to baseline by 80

milliseconds4) PR segment may down slope – thus baseline is

defined as PQ junction5) R amplitude may decrease at rates that go above

1306) 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