WHAT IS ETT?

• AN EXERCISE TOLERANCE TEST OR STRESS TEST RECORDS THE HEART'S ELECTRICAL ACTIVITY (RATE AND

RHYTHM) DURING EXERCISE.

• IS ONE OF THE COMMONEST FORMS OF STRESS TESTS USED TO INDUCE PROVOKABLE MYOCARDIAL

ISCHEMIA FOR DIAGNOSTIC EVALUATION OF CORONARY ARTERY DISEASE.

EQUIPMENT REQUIRED

• TREADMILL MACHINE OR EXERCISE BIKE

• 12-LEADS ELECTROCARDIOGRAPH (ECG) MACHINE

• STOP WATCH

• LEADS

• CLIPS

• STICKING TAPE

PROCEDURE

• A PROGRESSIVE AND MAXIMUM EXERCISE TEST (STARTING FROM A WALKING PACE AND GRADUALLY

INCREASING PACE) IS PERFORMED WHILE THE ELECTRICAL IMPULSES FROM THE HEART TISSUE ARE

RECORDED BY SURFACE ELECTRODES PLACES ON THE CHEST WALL.

ETT POINTS

WHAT DOES ETT DO?

IN ETT, (ALSO KNOW AS STRESS TEST), IT MEASURES:

• HEART RATE

• BLOOD PRESSURE

• ECG

ETT

• PATIENT IS REQUESTED TO DO EXERCISE ON A TREADMILL MACHINE.

• DURATION 6 TO 10 MINUTES

Useful in diagnosis of…

• Cardiac Arrhythmias

• Myocardial ischemia and infarction

• Pericarditis

• Chamber hypertrophy

• Electrolyte disturbances

• Drug effects and toxicity

CALCULATING HEART RATE

Normal H.R. 60-90 bpm

What is an ECG?

An ECG is the recording (gram)

of the electrical activity(electro) generated by the cells of the heart(cardio) that reaches the body surface.

ECG Leads

Leads are electrodes which measure the difference in electrical potential between either:

1. Two different points on the body (bipolar

leads)

2. One point on the body and a virtual reference

point with zero electrical potential, located in

the center of the heart (unipolar leads)

ECG Leads

The standard ECG has 12 leads:

The axis of a particular lead represents the viewpoint from

which it looks at the heart.

3 Standard Limb Leads

3 Augmented Limb Leads

6 Precordial Leads

Basics

ECG graphs:

–1 mm squares

–5 mm squares

Paper Speed:

–25 mm/sec standard

Voltage Calibration:

–10 mm/mV standard

ECG Paper: Dimensions5 mm

1 mm

0.1 mV

0.04 sec

0.2 sec

Speed = rate

Voltage

~Mass

+-

RA

RA

LL+

+

--LA

LL

LA

LEAD II

LEAD I

LEAD III

Remember, the RL

is always the ground

• By changing the

arrangement of which

arms or legs are

positive or negative,

three unipolar leads (I,

II & III ) can be derived

giving three "pictures"

of the heart's electrical

activity from 3 angles.

Leads I, II, and III

I

II III