session, the heart rhythm, breathing, and blood pressure of the patient are monitored to detect abnormalities. The test is normally done after detecting signs or symptoms of coronary heart disease. It can assist the physician in understanding the severity of heart disease. Generally, the treadmill test is safe and devoid of any risks. However, patients suffering from low blood pressure can feel dizzy or faint due to the impact of the exercise. Figure 2.4 shows a patient running on a treadmill under the supervision of a nurse; their blood pressure is being monitored as is their heart rate via ECG electrodes placed on their chest.
Figure 2.4 Treadmill assessment.
A treadmill test is required for individuals who have been experiencing angina or other heart disease symptoms. Specifically, the treadmill test is preferred for patients with symptoms of myocardial ischemia, acute chest pain, valvular heart disease, etc. Moreover, the treadmill test is preferred for patients with cardiac arrhythmias to evaluate the chronotropic competence.
Chronotropic competence is the capability of the heart to raise its rate when the body demands or during increased activity. The purpose of the test is to determine whether the patient’s heart is receiving enough oxygen as well as proper blood flow under stressed conditions, such as exercise or vigorous activities.
The target heart rate is calculated by the equation: target heart rate = 0.85 ×(220-Age). If the patients feel chest pain or severe arrhythmia the test result is considered positive. Furthermore, ECG recorded during the treadmill test is analyzed to evaluate the condition of the patient. If the ST-segment changes are greater or equal to 1 mm then the test is considered positive. In addition, changes in T-wave and a prolonged QT interval indicate abnormalities with the heart. These abnormalities are not usually found in resting ECG.
2.2.6 Cardiac Biomarker Examination
Cardiac biomarkers are the enzymes released into the blood when the heart experiences any discomfort or defects, such as stress or impairments. The quantity of cardio enzymes in the blood can be utilized to detect heart diseases, especially acute coronary syndrome (ACS) and cardiac ischemia. The test is done by taking a sample of the patient’s blood and analyzing it to measure the level of cardiac biomarkers in their blood. It can detect low oxygen intake conditions or injuries in the heart. Myoglobin, troponin, and creatine kinase are the three cardiac biomarkers or enzymes. Among these, the most commonly used cardiac biomarker is troponin due to its highest sensitivity [3]. Usually, the quantity of cardiac markers in the blood is measured in nanogram/milliliter (ng/ml) units. The normal measure of troponin in the blood ranges from 0 to 0.4 ng/ml. The high-sensitivity troponin test can detect a very small level of troponin. The normal range value is 14 ng/l for troponin during cardiac biomarker examination (high-sensitivy troponin test). Anything above 14 ng/l is considered abnormal.
2.2.7 Chest Roentgenography
Despite the increasing number of modern diagnostic imaging techniques accessible to clinicians, chest roentgenography remains a straightforward, low-cost, and highly insightful examination. A roentgenogram, also known as an x-ray image is a photograph of internal structures made by moving x-rays through the body and forming a shadow image on specially sensitized film. Roentgenography was named after Wilhelm Conrad Röntgen, a German physicist who invented it in 1895. The chest x-ray is a reliable method for predicting pulmonary hemodynamic events in patients without chronic obstructive pulmonary disease and offers a fair estimation of pulmonary venous and arterial pressures. Unfortunately, the pulmonary vascular distribution of patients with chronic obstructive pulmonary disease may be substantially altered. This complicates roentgenographic assessment.
2.3 Physiological Values and Characteristics Considered for Clinical Examination
Apart from analyzing the symptoms and manifestations in the face, the physician or cardiologist examines several physiological values as well as characteristics to detect the presence of heart disease. This section briefly describes the physiological attributes/characteristics and values that aid the physician or cardiologist in diagnosing heart disease.
2.3.1 Exercise Capacity
Exercise capacity, also known as cardiorespiratory endurance, is the total amount of physical effort that a person can bear without discomfort. A precise evaluation of workout capacity requires the patient to exert maximal physical effort for an adequate enough time to reflect the stable effect on the circulation. The exercise capacity evaluation is one of the key characteristics for assessing the condition of the patient. Lower exercise capacity is linked with various risks including hypertension, cardiovascular disease, heart failure, etc. Many studies have shown the correlation between lower exercise capacity and acute health conditions [4]. Furthermore, the response of the cardiovascular system during exercise can identify heart diseases as well as mortality [5, 6].
The exercise capacity of an individual can be assessed either by a face-to-face interview or by using laboratory methods based on the available facilities in the clinic. In the face-to-face interview with the patient, the cardiologist will ask about any unprecedented events experienced during various daily activities, such as walking, running, or exercise. On the other hand, the laboratory methods include multiple tests, such as an exercise stress test, a cardiopulmonary exercise test, a 6-minute walk test, a submaximal treadmill test, etc.
2.3.2 Chest Pain or Discomfort
Chest pain or discomfort is the most common symptom found in adults for several reasons either serious or trivial. It occurs due to many causes, such as muscle strain, peptic ulcers, gastroesophageal reflux disease (GERD), asthma, etc. The pain or discomfort generated in the chest can be an important indication of possibly genuine cardiac or cardiovascular disorders. Proper care and treatment should be done early to identify the underlying cause of the chest pain and prevent it worsening. Regular exercise and healthy eating habits can greatly avoid getting chest pain.
Self-diagnosing chest pain based merely on symptoms is quite difficult. However, the frequency of pain and accompanying symptoms may help to shed light on the possible cause to some extent. The pain that arises from mild health issues including muscle strain, GERD, and asthma can last only for a few seconds and affect a specific point on the chest. Moreover, the pain is often relieved when the chest area is massaged, or after taking medication or a deep breath. Specifically, chest pain related to muscle strain gets better with massage and gets worse with sharp and sudden inhalation. Gastroesophageal reflux can cause chest pain which may be experienced shortly after a meal or consumption of alcohol. Sudden and intense pain that lasts longer than a few minutes can be an indicator of heart disease.
2.3.3 Palpitations
Palpitation generally refers to irregular and rapid heartbeats and can arise for a multitude of reasons. It can be caused by certain harmless conditions, such as strenuous exercise, lack of sleep, stress, anxiety, fear, etc., or it can be an alarming indication of certain illnesses relating to the heart, such as cardiac arrhythmia, which involve changes in heart rate and the contraction pattern. It can give the sensation that the heart has skipped, stopped, or added an extra beat, making us more aware of our heartbeat. Heart palpitations can become a significantly diagnosable characteristic in persons already diagnosed with heart failure or defective heart valves.
2.3.4 Dyspnea, Orthopnea, and Paroxysmal Nocturnal Dyspnea
Dyspnea is a condition where the patient suffers from shortness of breath
