Internal Medicine - Page 66

Internal MedicineCardiovascular Medicine

Cardiac intervention

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Internal MedicineCardiovascular Medicine

Electrocardiogram

Electrocardiography (ECG) is a technique that uses an electrocardiograph to record the graphical representation of the electrical activity changes produced by the heart during each cardiac cycle from the body surface. During a normal cardiac cycle, each myocardial cell undergoes depolarization followed by repolarization, thereby generating an action potential. Under normal circumstances, myocardial cell depolarization proceeds in an orderly fashion, with the sinoatrial node depolarizing first, then sequentially conducting to the atria, atrioventricular node, and ventricles. The electrical signal propagates throughout the heart in the form of a depolarization wavefront. The small electric fields generated by this wavefront can be detected on the body surface, and the signals recorded by the electrocardiograph constitute the electrocardiogram.

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Blood lipids

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Coronary angiography

Coronary angiography is an interventional diagnostic technique that uses imaging methods to determine the presence of coronary artery lesions and provides a reliable basis for the diagnosis, treatment, and research of coronary heart disease. It is considered the "gold standard" for diagnosing coronary heart disease. Coronary angiography involves injecting a contrast agent to visualize the coronary arteries of the heart, thereby determining the location, extent, and scope of obstructive lesions in the coronary arteries, providing a basis for the diagnosis and treatment of coronary heart disease. Indications: Patients with symptoms of chest tightness and chest pain, suspected of having coronary heart disease, who require a definitive diagnosis. Patients with a confirmed diagnosis of coronary heart disease whose medication treatment is ineffective and who are preparing for further interventional therapy. Patients with a definitive diagnosis of coronary heart disease who are scheduled for coronary artery bypass grafting and require a detailed assessment of coronary artery lesions before surgery. Patients with heart valve disease indicated by ultrasound who are scheduled for surgery, and who are clinically suspected of also having coronary heart disease. Patients who have undergone coronary artery bypass grafting and need to assess the patency of the transplanted vessels. Patients suspected of having coronary artery malformations or other coronary artery diseases. Patients with high-risk factors for coronary heart disease who are scheduled for surgery and require routine preoperative assessment.

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Left bundle branch block

Left bundle branch block (LBBB) refers to a blockage or delay in the electrical conduction of the heart within the left bundle branch. It is often secondary to organic heart diseases such as ischemic heart disease, cor pulmonale, or cardiomyopathy. The incidence of LBBB is age-related, with a higher prevalence in older individuals. Most patients are asymptomatic, while some may experience symptoms like chest tightness or chest pain.

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Left heart failure

Left heart failure refers to left ventricular systolic or diastolic dysfunction caused by abnormal changes in cardiac structure or function due to various reasons, leading to insufficient compensatory function. This disease is characterized by pulmonary congestion and is divided into acute left heart failure and chronic left heart failure based on the time, speed, and severity of heart failure. The main manifestations are respiratory symptoms, such as dyspnea, cough, and expectoration.

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Aortic valve calcification

Aortic valve calcification is a cardiovascular disease caused by the comprehensive action of multiple factors, leading to a large amount of calcium deposition on the heart valves, most notably the aortic valve. This results in thickening, curling, decreased mobility, and narrowing of the valve, causing changes in its morphology and function. It is most commonly seen in isolated aortic stenosis, followed by senile degenerative changes, atherosclerosis, congenital bicuspid aortic valve malformation, and rheumatic aortic valve disease. Approximately 20% of individuals over 60 years old have aortic calcification, which is generally caused by human aging, decreased vascular elasticity, or vascular wall damage.

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Right bundle branch block

Right bundle branch block refers to the obstruction of cardiac impulse conduction to the right ventricle (via the right bundle branch). It is often secondary to other heart diseases and usually presents without clinical symptoms. Isolated right bundle branch block itself does not require specific treatment. The main focus of treatment is on the underlying heart disease. This condition can occur at any age, but the risk of onset increases with age.

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Dextrocardia

Dextrocardia refers to a condition where the main part of the heart is located in the right side of the chest cavity, primarily caused by congenital developmental abnormalities. Dextrocardia can be classified into the following types: Situs inversus totalis with dextrocardia (mirror-image dextrocardia or true dextrocardia): The right atrium, liver, and gallbladder are located to the left of the spine, while the left atrium, spleen, and gastric bubble are located to the right. The left lung has three lobes, and the right lung has two lobes. The morphology of the left and right bronchi is also reversed, resembling a mirror image of a normal person. This type of dextrocardia is the most common. Dextroversion: The heart is in the right chest cavity, while the positions of other organs are normal. Isolated dextrocardia: This is a relatively special type without situs inversus. However, the right atrium is located to the left of the spine, similar to mirror-image dextrocardia. The hepatic segment of the inferior vena cava suddenly turns from the right side of the spine to the left side, entering the right atrium. Dextroposition: This is secondary to thoracic diseases, leading to the heart shifting to the right. Also known as pseudo-dextrocardia, it is not accompanied by visceral transposition. Only the heart is located on the right side of the chest cavity, and the anatomical positions of the left and right heart chambers remain unchanged. Dextroversion and isolated dextrocardia are often accompanied by cardiac malformations, mostly complex ones. If dextrocardia is not accompanied by other cardiovascular malformations, there are generally no uncomfortable symptoms. If it is accompanied by congenital cardiovascular malformations such as atrial septal defect or ventricular septal defect, corresponding symptoms such as chest tightness, shortness of breath, and cyanosis may occur.

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