Predicting Heart Failure. Группа авторов

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      42 42 Takci, H. (2018). Improvement of heart attack prediction by the feature selection methods. Turkish Journal of Electrical Engineering & Computer Sciences 26: 1–10. https://doi.org/10.3906/elk-1611-235.

2 Conventional Clinical Methods for Predicting Heart Disease

       Aisha A-Mohannadi, Jayakanth Kunhoth, Al Anood Najeeb, Somaya Al-Maadeed and Kishor Kumar Sadasivuni

      2.1 Introduction

      The heart is the most essential organ of the human body located at the center of the chest in between the lungs and is mainly responsible for pumping blood across the blood vessels of the cardiovascular system. The blood is pumped through a network of arteries, delivering oxygenated blood and other nutrients to different cells of the body. The two large veins (superior vena cava and inferior vena cava) carry carbon dioxide as well as other metabolic waste products to the lungs for purification via pulmonary arteries. Unhealthy life habits may lead to high blood pressure and cholesterol which may affect the proper functioning of the heart thus causing serious heart diseases. The unhealthy life habits which can affect the heart’s health are a sedentary lifestyle, smoking, overweight or obesity, poor eating habits, and excessive alcohol consumption. Smoking can raise the heart rate, tighten arteries, and cause irregular heart rhythm. Moreover, smoking can lead to atherosclerosis, where fat and cholesterol are deposited in the arteries. The deposit of fat and cholesterol is called plaque. This plaque narrows the arteries and blocks the blood flow. A sedentary lifestyle and poor eating habits can lead to overweight or obesity and high levels of bad cholesterol and triglycerides, leading to hypertension as well as the formation of plaque in arteries. Excessive drinking of alcohol can elevate blood pressure and weaken the heart’s muscles. Elevated blood pressure and weakened muscles can cause stroke or heart failure. Apart from unhealthy habits, congenital disorders can also affect the proper working of the heart and even cause mortality. Heart diseases such as coronary artery disease, arrhythmia, angina pectoris, and cardiomyopathy can often result in cardiac arrest leading finally to death. Having a well-balanced diet, proper medication, and early diagnosis of symptoms at an early stage can greatly reduce the chances of getting heart disease.

The common symptoms of heart diseases include chest pain, tightness in the chest, dyspnea, palpitations, fainting, as well as collapse. Dyspnea is a condition where the patient suffers from shortness of breath and feels suffocation as well tightness in the chest; palpitation is the condition that refers to irregular and rapid heartbeats, which can also lead to shortness of breath. Individuals who are frequently experiencing these symptoms are advised to contact the physician as early as possible. Other physical symptoms that can be seen in patients suffering from heart disease are unexpected color changes in the face and nails, and unexpected movements of the eyeballs. Moreover, patients suffering from coronary heart diseases experience chest pain called angina when involved in heavy exercise or heavy labor. Heart valve disease, cardiomyopathy, and heart failure conditions can cause swellings in the legs, ankles, or feet. In acute cases, these conditions can also lead to swellings in organs. Tiredness is also a common symptom for patients suffering from heart valve disease and heart failure conditions. Patients with heart infections experience severe fever and tiredness. Even though these symptoms are warning signs of heart disease, other mild health conditions apart from heart disease can also cause similar symptoms in the human body. Because of that, a clinical examination is extremely necessary in order to differentiate heart diseases from false alarms. A prudent and comprehensive examination is essential to analyze health conditions and assess the reason for as well as the intensity of symptoms. A detailed examination conducted in the clinic by a licensed physician or cardiologist can detect whether heart disease is the cause of underlying symptoms. If it is, they can refer the patient for further advanced examination to assess the individual risk of heart disease and provide immediate medication.

      The physician or cardiologist initially explores the patient’s family history, past medical history, and lifestyle along with examining the symptoms being experienced by the patient. Further examination includes inspection of cyanosis (bluish discoloration commonly found in nails), and scrutiny of faces to look for unexpected color changes and movement of the eyeballs. The examination is then extended to check blood pressure and perform blood tests, along with advanced procedures including electrocardiography, echocardiography, chest roentgenography, etc.

      This chapter briefly describes the various clinical examination methods traditionally used by cardiologists in detecting heart diseases. It also explains various symptoms and physiological factors related to heart diseases and their clinical significance. In addition, the chapter also discusses the works in the literature that have integrated artificial intelligence and machine learning methods along with the clinically observed physiological values for improved detection of heart disease conditions.

      2.2 Physical Assessments

      As in past years, experts and doctors rely on many physical techniques as a path to early diagnosis of heart diseases. Physical assessments for diagnosing heart diseases include the technique, palpation, auscultation, electrocardiography, treadmill test, and cardiac biomarker examination. Each type of examination is chosen based on the result observed in the previous type. Usually, the inspection technique is conducted first and, based on its results, the licensed physician or cardiologist further proceeds with other types of examination.

      2.2.1 Inspection Examination

This technique focuses on the visual appearance of the human patients, where the skin color, general health, face expressions, and nutritional status of the patient are taken into consideration. For instance, sweatiness, paleness, or cyanosis can be the initial signs of a possible heart attack in an acutely ill patient. Cyanosis is a medical condition where a bluish discoloration is seen in the lips, ears, nose, fingernails, as well as toenails. This condition is usually known as “blue hands or feet” due to hypoxemia. Hypoxemia is a condition where oxygen levels are lower than normal in the blood. The bluish color is caused by the excess amount of deoxyhemoglobin in the blood when various heart-related conditions prevent blood flow from tissues to the heart and backward. Excess amounts of deoxyhemoglobin in the blood can be due to various heart-related diseases including heart failure, myocardial infections, congenital heart diseases, valvular heart conditions, etc. Moreover, malar flush, corneal arcus, xanthomata, and proptosis are manifestations in the face of the patient suffering from heart disease. Malar flush is a facial manifestation where the cheeks turn a plum-red color. The malar flush symptom is closely related to valvular heart disease called mitral stenosis. Mitral stenosis is a condition where the mitral valve’s area is less than 2 cm² (the normal area is about 5 cm²) during diastole. Reduction in the area causes carbon dioxide retention and leads to vasodilation (widening of blood vessels) of the arterioles present in the cheek. In the xanthomata condition, the eyes, palms, or tendons will experience a yellowish deposit of lipids. The excess yellowish deposit is due to high-level blood lipids and fats. The tendon xanthomata is a sign of high-level LDL (low-density lipoprotein) cholesterol in the blood as well as atherosclerosis. Proptosis refers to a change in the eyeball movement, especially to a protruded eyeball. In non-acute patients, one important sign is cachexia, as it is a clear sign for the prognosis of heart failure [1]. Cachexia is a wasting disorder where the patient experiences severe weight loss as well muscle loss.

      2.2.2 Palpation Examination

      Palpation examination involves pulse tracing of patients’ jugular veins, arterial pulses, precordial impulses, etc. This includes examination using the fingers or hands to