14.7 : Exercise Stress Test

Introduction

Exercise stress testing, commonly known as a treadmill test, is a noninvasive procedure used to evaluate cardiovascular function and diagnose heart conditions.

Definition

An exercise stress test measures the heart's response to exertion using a treadmill or stationary bicycle. Chest electrodes record the heart's electrical activity through an ECG, and blood pressure is monitored regularly.

Purposes

1. The central purpose of an exercise stress test is to discover coronary artery disease (CAD) symptoms and assess the severity of existing heart conditions.
2. It also helps determine safe exercise levels for patients and evaluates heart treatments.

Indications

1. Exercise stress tests are indicated for patients with chest pain, worsening angina, past heart attacks, or those who have undergone heart procedures like angioplasty or bypass surgery.
2. It also evaluates heart valve function and monitors patients with heart disease risk factors.

Pre-Procedure Care

The patient is informed about the procedure and its purpose, including monitoring equipment and reporting symptoms. The nurse instructs the patient to:

1. Wear comfortable clothing and shoes.
2. Fast for at least three hours before the test.
3. Avoid caffeine, alcohol, and tobacco for 24 hours.

Some medications, such as beta-blockers, calcium channel blockers, and digitalis, may need to be paused 48 hours before the test. Patients must consult their healthcare provider for specific medication adjustments.

The nurse prepares the skin by cleaning it and possibly shaving small areas for better electrode contact. A resting supine standard 12-lead ECG is obtained to compare with previous ECGs.

Care During the Procedure

Electrodes are put on the patient's chest to record heart activity. Baseline heart rate, blood pressure, and ECG readings are taken before starting exercise. The patient engages in physical activity on a treadmill or a stationary bicycle with gradually increasing intensity. Throughout the exercise phase, the following parameters are monitored:

1. Electrocardiogram (ECG): To detect ischemic changes, arrhythmias, and other abnormalities.
2. Heart Rate: It is monitored if it reaches the target level. 85% of the maximum heart rate (Subtract age from 220 ) should be observed, and changes should be observed with exercise.
3. Blood Pressure: To monitor the cardiovascular response to exercise.
4. Symptoms: To observe for chest pain, dizziness, shortness of breath, or leg cramps.
5. Physical Appearance: Observations of skin color, sweating, and overall condition.
6. Perceived Exertion: It is observed for the patient's subjective feeling of effort and fatigue.

The exercise continues until the patient reaches their target heart rate or exhibits symptoms like severe shortness of breath, chest pain, dizziness, leg cramps, or any other abnormalities that necessitate stopping the test.

Post-Procedure Care

1. After exercise, the patient is monitored for 10 to 15 minutes until the heart rate returns to normal. Monitoring stops when the patient is stable and exhibits no concerning symptoms.
2. If the patient experiences signs of myocardial ischemia, such as chest pain, or ECG changes, such as ST-segment depression, ST-segment elevation, and T-wave inversion, additional monitoring and interventions may be necessary.
3. Patients are informed about potential post-test symptoms and specific instructions for abnormal results.

Safety and Risk Management

Stress tests are generally safe, but minimal risks include chest pain, fainting, or, in rare cases, Myocardial Infarction. Medical personnel and emergency equipment are available to manage adverse events during the test.