Pharm D
Someone in the U.S. has a heart attack every 40 seconds, affecting about 805,000 people every year. In this article, let’s discuss angina pectoris, which can lead to myocardial infarction and serious consequences.
Angina pectoris is choking of the chest characterized by paroxysmal and usually recurring substernal or precordial chest pain or discomfort. It is a symptom of ischemic heart disease caused by varying combinations of increased myocardial demand and decreased myocardial perfusion. The imbalance between blood supply and demand is caused by a primary decrease in coronary blood flow or a disproportionate increase in myocardial oxygen requirements.
Angina can be classified as:
Chronic exertional angina usually occurs because of obstructive coronary artery disease that causes the heart to be vulnerable to further ischemia whenever there is increased demand or workload. Unstable angina occurs with changing character, duration, and pain intensity.
Stable angina occurs due to a reduction of coronary perfusion due to chronic stenotic coronary atherosclerosis, which is relieved by rest and related to activities that increase myocardial demand. Chest discomfort occurs because of exertion; pain may occur after eating or experiencing emotional tension. Often, the duration of stable angina is three to 25 minutes. Rest or nitroglycerin helps ease chest pain.
Prinzmetal variant angina occurs because of coronary artery spasm without increased myocardial oxygen demand. It happens at rest, often during sleep in the early morning hours, and is associated with elevation of the ST segment of the electrocardiogram, which indicates transmural ischemia. It tends to last longer than other forms of angina. Sometimes, it may subsidize exercise.
Unstable angina occurs when an atherosclerotic plaque vasospasm, or both, are disrupted. The pain increases with increasing frequency and is precipitated with decreasing effort. The duration of unstable angina is longer than that of stable angina and may not be relieved with nitroglycerin or rest. Untreated patients with unstable angina often progress to myocardial infarction.
Cardiac syndrome X is caused by normal coronary arteries without any known causes. It can happen due to inadequate flow reserve in the heart’s microvascular circulation, causing chest pain, heaviness, squeezing, and pressure that is triggered by exertion and travels to the back, jaw, shoulder, and arm. It lasts longer than 10 minutes and is usually relieved with rest and nitrates.
Silent ischemia doesn’t have any exact mechanism. However, possible explanations include autonomic dysfunction, high threshold, and excessive quantities of endorphin production. It can also be described as angina without pain, may result in problems with contractility, and causes transient ST depression persisting for at least one minute. Silent ischemia is usually unrecognized by patients as it doesn’t cause any symptoms.
The most common cause of angina pectoris is atherosclerosis: the most common cause of coronary artery disease, which is the leading cause of death in the USA for men and women. However, it can also occur in patients with normal coronary arteries because of conditions such as cardiac dysrhythmias, increased metabolic demand, marked anemia, severe myocardial hypertrophy, severe aortic stenosis or regurgitation, or inadequate flow reserve in the microcirculation.
Coronary artery spasms, fixed stenotic plaques, disrupted plaques, thrombosis, platelet aggregation, and embolization cause blood flow in the coronary arteries to become partially or completely blocked. This leads to ischemia, or a lack of oxygen supply to the heart, which eventually causes chest pain.
During an angina attack, the patient shows up with chest discomfort, commonly described as chest pain or heaviness, with a feeling of tightness or pressure. The patient may feel it as a squeezing sensation accompanied by indigestion.
Angina pain often occurs in the substernal region or across the anterior upper chest. The discomfort may radiate to the upper abdomen, tongue, neck, jaw, and either elbow, wrist, hand, or arm. Anginal pain is often short, usually lasting between three to five minutes. Sometimes it can last up to 30 minutes or longer.
Angina pain may occur due to exposure to frigid temperatures or sometimes after a heavy meal. The discomfort may be subsidized upon the termination of the precipitation factor. With anginal pain, the patient gets anxious, pale, lightheaded, with increased sweating, tachycardia, loss of breath, and nausea. On auscultation, you may observe atrial or ventricular gallops.
Angina itself is a symptom of an underlying heart disease. Therefore, diagnostic tests are not done for it. But if anginal pain occurs, the diagnostic tests help know about myocardial infarction and if any tissue damage has occurred during the episode.
ECG, or electrocardiogram, assesses the electrical conductivity of the heart that is often disturbed by a myocardial infarction. Usually, the PQRST pattern is delicate, but in abnormal conditions, ST segment depression, T wave inversion, or transient ST elevation may occur. If you notice any ECG changes, promptly discuss the case with the physician and follow their orders.
CK-MB, or creatine kinase isoenzyme, is a cardiac biomarker that helps determine myocardial ischemia, which causes its levels to elevate. Normally, the levels of CK-MB are 0 to 5% of total CK or 5 to 25 IU/L.
Troponin I helps differentiate between angina and myocardial infarction. The typical result is less than 3.1 mg/L and elevated in MI. Troponin T, a protein found in heart muscle cells, helps measure the troponin levels in your blood. When elevated, it indicates damage to the heart muscle. The expected results of troponin I are less than 0.2 mg/L.
If these tests show some abnormality, other essential tests are done, such as:
Drugs are given in angina to provide relief from acute pain, prevent or lower ischemia, prevent future ischemic attacks, and decrease the heart preload and afterload.
Nitrates, such as nitroglycerin, are used in the dose of 0.3 to 0.6 mg sublingually as required for stable angina. However, the dose for unstable angina may vary when given intravenously. Nitrates relieve the symptoms of ischemia by dilating the coronary arteries and reducing left ventricular preload and afterload.
Aspirin is also given to inhibit platelet aggregation to reduce the risk of coronary artery blockage in the dose 75 to 325 mg orally as immediate relief tablets.
Beta-blockers may also be used, such as propranolol, metoprolol, atenolol, and others, as they help reduce myocardial oxygen demands by decreasing heart rate, contractility, and blood pressure.
Various other drugs are also used to relieve and manage angina, such as intravenous nitroglycerin, narcotics, calcium channel blockers, long-acting nitrates, vasodilators, diuretics, antihypertensives, anticoagulants, and antihyperlipidemics.
The goal in patients with angina is to decrease the heart’s oxygen demand. Therefore, encourage the patient to take plenty of bed rest until the pain subsides. Bedrest may be prescribed for a short time, but keeping heel pads, a mattress, or a foot cradle can help reduce the incidence of skin breakdown and increase patient comfort. They should wear compression stockings to maintain efficient blood circulation.
Throughout the hospital stay, ask the patient to rest well. With the occurrence of heart disease, anxiety is common among patients and their caregivers. Have an in-depth discussion with them about the lifestyle and dietary changes that the patient might require. Let them discuss their concerns with you and clear up any confusion. Be open to their questions and answer patiently. If the patient smokes, ask them to quit smoking. Refer them to rehabilitation for smoking cessation.
Also, the patient should be referred to the cardiac rehabilitation clinic, which helps reduce risk factors for heart disease and provides guidance, encouragement, and social support. Compel the patient to adhere to the prescribed therapy and treatment plan. Tell them little changes can add days, months, and even years to their life. Otherwise, angina can lead to myocardial infarction and serious consequences.
Angina pectoris is chest pain and is a symptom of any underlying heart disease such as atherosclerosis or myocardial infarction. If a patient presents with angina, make sure to get their complete diagnostic tests done. Otherwise, it can lead to life-threatening consequences, such as myocardial infarction or sudden death due to arrhythmia.
Compel your patients to monitor their blood pressure, eat a healthy diet, follow the treatment as prescribed, and attend follow-up visits. Patients with angina pectoris are often tense and anxious. Counseling, listening to their concerns, and helping calm them would be best.
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