Treadmill Stress Testing - Indications, Process, and Contraindications

Introduction

A treadmill stress test is known by several different names - cardiac stress test, cardiac diagnostic test, cardiopulmonary exercise test, treadmill test, CPX test, and TMT. The treadmill test is a cardiovascular diagnostic test that can measure the ability of the heart to react to stress from an external source within a controlled environment. The stress in a patient is induced via exercise. The stress can be additionally introduced through intravenous stimulation.

A treadmill stress test aims to compare the functionality of the heart at rest against the functions during stress. The patient is put under maximum cardiac exertion. The result aids in finding the presence of any kind of cardiac abnormality of an underlying disease of the cardiovascular system. Conditions such as coronary artery disease, damage to heart tissues, and ischemic heart disease can be diagnosed through the treadmill test. Once the test is completed, the patient is suggested to avoid any vigorous activity and must rest for a couple of minutes before resuming normal day-to-day tasks, beginning with walking.

What Is Treadmill Stress Test Echography?

A treadmill stress test or TMT is generally accompanied by an echo-ultrasound study of the heart, which is done both before the treadmill stress test as well as after the treadmill exercise. This is done because there must be an apt comparison of the structural differences that have occurred in the cardiovascular system. A transthoracic echocardiogram is the chosen way to study the heart before the treadmill test called a resting echocardiogram. After the patient is done with the test, where the stress was induced either by exercise or chemically due to Dobutamine, post-echocardiography, called the stress echocardiogram, is compared with the images before the treadmill stress test. This is especially useful in the assessment of the walls of the heart.

What Are the Indications of Treadmill Stress Test?

A treadmill test is a form of cardiac stress testing that utilizes blood pressure monitoring and exercise and thus, it cannot be indicated in every cardiac disease. Treadmill stress testing is performed under strict protocols. Patients who are not able to exercise may undergo the test by the venous administration of chemicals that include stress in the heart. Mentioned below are a few of the indications of the treadmill stress test.

• Myocardial ischemia.

• Acute chest pain.

• Acute coronary syndrome or ACS.

• Prior coronary revascularization.

• Percutaneous coronary intervention or PCI.

• Valvular heart disease.

• To assess the prognosis of a surgery.

• Cardiac arrhythmias.

• Assess chronotropic competence.

• Heart failure.

• Cardiomyopathy.

What Are the Contraindications of Treadmill Stress Test?

A treadmill stress test is never recommended for patients who are asymptomatic or have a low risk of developing cardiovascular diseases. Until and unless there are underlying diseases that are known to pose cardiac risks to the patients, such as diabetes mellitus, peripheral artery diseases, or other immunocompromised conditions, a treadmill stress test may be indicated. Mentioned below are the contraindications of the treadmill stress test.

• Acute myocardial infarction within the recent 48 hours.

• Unstable angina pectoris.

• Uncontrolled arrhythmia of the heart.

• Ventricular tachycardia.

• Hemodynamic changes in the body.

• Aortic stenosis.

• Aortic dissections.

• Pericarditis.

• Pulmonary embolism.

• Multivessel coronary artery disorder.

• Congestive heart failure.

• Uncontrolled hypertension.

• Pulmonary hypertension.

• Acute illness.

When Must the Treadmill Stress Test Be Terminated?

A treadmill stress test occurs when there is intentional stress given to the cardiovascular system, especially the heart, and at times, this may turn into a painful and serious condition for the patient that runs out of control. Several monitoring devices keep track of the vital signs throughout the treadmill stress test but keeping in mind the sensitivity and vitality of the cardiac system, certain situations require the treadmill stress test to be immediately stopped. Mentioned below are a few of the reasons to terminate a treadmill stress test.

• Drop in systolic blood pressure to 10 mmHg.

• Ischemia.

• Dizziness.

• Ataxia.

• Syncope.

• A point 4 angina pain.

• Cyanosis.

• Pallor.

• Confusion.

• Elevation in the ST segment.

• Downsloping of QRS segment.

• Depression is a non-Q wave.

• The axial shift in the echocardiogram.

• Premature ventricular contraction.

• Heart block.

• Supraventricular tachycardia.

• Bradyarrhythmia.

• Bundle branch block.

• Intraventricular conduction delay.

• Fatigue.

• Shortness of breath.

• Wheezing.

• Claudications.

• Leg cramps.

• Difficulty in speech.

• Increased sweating.

• Loss of balance.

When Are the Adverse Effects of Treadmill Stress Test?

A treadmill stress test is a physical test and does not have a lot of side effects or adverse reactions in the body. Nevertheless, there have been reports of physical discrepancies and alterations in the patient's health after a treadmill stress test, no matter if it was done through exercise or chemical inducement. Mentioned below are a few of the adverse effects of the treadmill stress test.

• Palpitations.

• Chest pain.

• Heart attack.

• Headache.

• Nausea.

• Lethargy.

• Hypotension.

• A small risk of cancer due to the chemicals administered intravenously in the cardiac system.

When Are the Chemical Agents Used During a Treadmill Stress Test?

A treadmill stress test that requires a chemical agent to induce stress is done because the patient may not be able to perform physical exercises or movements that are necessary to conduct the test. The patient is then checked for hypersensitivity and then administered with certain chemical agents that induce stress. Mentioned below are a few of the pharmacological agents that are known to induce stress and are used during the treadmill stress test.

• Adenosine.

• Adenosine A2A receptor.

• Dobutamine.

• Dipyridamole.

• Aminophylline.

Conclusion

The treadmill stress test, or TMT, is known by multiple other names and is used to determine the changes in the walls of the heart as well as to compare the heart’s function during rest and stress. There are several reasons to suggest a treadmill stress test along with contraindications as well. The two limitations of this test are not being able to detect atheroma and vulnerable plaques. After the test is complete, the patient is asked to continue regular activities after a rest of a few minutes.