Notes
Ischemic Heart Disease: Symptoms & Treatments
Sections
Ischemic Heart Disease: Symptoms & Treatments
Angina pectoris is the hallmark of ischemic heart disease.
Characterized by pain or discomfort in the chest, which often radiates through the upper extremities, face, and other areas of the body, and is due to the heart's inability to meet its metabolic needs.
Stable angina is characterized by predictable triggers, duration, and frequency.
Unstable angina is unpredictable and is a medical emergency, as it can lead to myocardial infarction.
Non-ischemic causes of angina include aortic stenosis, anemia, arrhythmias, and hypertrophic cardiomyopathy.
Other indicators of Ischemic Heart Disease include discomfort or pain in other areas of the body, fatigue, etc.
These symptoms are sometimes described as "atypical angina," or "angina equivalents."
Silent ischemia refers to asymptomatic ischemic heart disease; be aware that "silent" does not mean "harmless," and silent ischemia is associated with increased morbidity and mortality.
Diagnosis of ischemic heart disease may involve ECG, echocardiogram, stress testing, angiograms, and CT scans.
Although angina is often due to obstructive coronary artery disease, angina can also occur in the absence of clinically significant blockage.
Angina Types
Stable angina
Sometimes called "effort" angina because it is triggered by physical or mental exertion, such as climbing a flight of stairs or a psychologically stressful event.
This type of angina resolves with rest and/or nitrates.
Unstable angina
New onset or worsening angina that is unpredictable; it occurs spontaneously during activity or rest, and does not resolve with rest or medications.
Unstable angina is a form of acute coronary syndrome, and, as mentioned earlier, is a medical emergency that can lead to myocardial infarction.
Vasospastic angina
Also known as variant and Prinzmetal angina
Occurs when vasospasm contracts the vessel and reduces blood flow.
Occurs spontaneously, and often at rest.
A hallmark of vasospastic angina is occurrence at night or early morning – early morning exercise is a common trigger.
Vasospastic angina is most common in women and cigarette smokers.
Responds to nitrates, and can be suppressed by calcium-channel blockers (but not beta-blockers, which can exacerbate this type of angina).
Microvascular angina
This is the result of coronary microvascular dysfunction or vasospasm.
Microvascular angina accounts for chest pain in up to half of patients who do not have obstructive coronary artery disease.
Occurs with exertion and at rest, but, may respond less well to nitrates.
- Difficult to distinguish from epicardial angina, and, that positron emission tomography (PET) or cardiac magnetic resonance (CMR) can be used to assess coronary microvascular blood flow.
Common Symptoms of Ischemic Heart Disease
Sex, age, and race may influence which symptoms are present and how they are interpreted.
Angina
Many patients experience chest discomfort or pain, which is variably described as: tightness, dull, sharp, or stabbing pain, squeezing, or pressure on the heart.
We show the patient displaying Levine's sign, a clenched fist held over the sternum, because many patients will describe their chest discomfort with this gesture or one similar to it.
Patients also report discomfort in the shoulders, arms, neck, and jaw; pain is often described as "radiating".
Other S/Sx:
Some patients, particularly those of African descent, often experience gastrointestinal discomfort that may be interpreted as indigestion or heart burn, abdominal pain or burning.
Thus, practitioners should consider ischemic heart disease in patients who report such symptoms when gastrointestinal causes are ruled out.
Some patients, especially women with ischemic heart disease, experience light-headedness or dizziness, and persistent fatigue.
Other commonly-reported symptoms include dyspnea (difficulty breathing) and excessive sweating.
Treatments
Life-style modifications, such as smoking cessation and a heart-healthy diet are generally recommended.
Anti-angina medications can be prescribed to reduce oxygen consumption and/or increase cardiac blood flow.
Notice that many of these are addressed in our tutorial on hypertension treatments.
Medications can work on the heart, blood vessels, or other targets; surgery is also an option.
Nitroglycerin, which is often administered as a tablet that dissolves under the tongue, dilates vessels and prevents spasms. Nitroglycerins can be taken as prophylaxis of or in response to an angina episode.
Beta-blockers slow the heart rate (which reduces myocardial oxygen demands).
Calcium channel blockers promote vessel dilation.
Sodium channel inhibitors, such as Ranolazine, increase myocardial relaxation (which reduces oxygen demand and increases blood flow).
ACE-inhibitors promote vessel dilation.
Statins reduce hyperlipidemia, vessel inflammation, and endothelial dysfunction.
Daily aspirin may be prescribed for patients with elevated risk of ischemic heart disease, but benefits must be weighed against the risk of bleeding.
Surgery: In some patients, additional procedures may be necessary to reestablish blood flow.
There are different means to coronary revascularization, which opens the coronary arteries:
Percutaneous coronary intervention, aka, angioplasty, is performed by using a catheter to place a balloon in the obstructed vessel; when the balloon is inflated, the plaque is pushed outward, widening the lumen.
A stent may be added to help keep the vessel open.
Coronary artery bypass grafting (CABG), as its name suggests, involves grafting a portion of another vessel to bypass an obstruction.
In our drawing, we show that a portion of the saphenous vein has been used to re-route blood around a blockage in the right coronary artery. The saphenous vein, radial artery, and left internal mammary artery are commonly used in this procedure.
Refractory angina refers to ischemia with angina that persists despite medical intervention; innovative treatments for these "no-option" patients are eagerly sought.
Clinical Cases
Case 1: Myocardial Infarction Management
A 62-year-old male is brought to the emergency department by his wife. He is a farmer, and developed a "twinge" in his chest a few hours ago. She reports that he refused to come to the hospital at that time, and continued shoveling snow. He insisted on staying at home until he collapsed on the floor approximately 1 hour ago. Even then, he wanted to stay home and rest, but his wife insisted on bringing him to the emergency department. He states the pain is almost gone, and that his wife is "making a fuss" about nothing. The patient smokes two packs of cigarettes per day, and drinks "a couple of beers" every evening. He does not take any medications and does not see a doctor regularly.
On physical examination, he is sweating (diaphoretic), and has vomited twice since coming into the emergency department. His blood pressure is 160/100 mm Hg, heart rate 120/min, respiratory rate 20/min, oxygen saturation is 94 percent, and temperature is 37.2 degrees Celsius (98.9 degrees Fahrenheit). As you arrived to see the patient, an electrocardiogram (EKG) was just being completed by a technician (see below).
Given the history and physical examination findings, what is the next best step in the management of this patient?
Answer
- Provide morphine, oxygen, sublingual nitroglycerin, and one adult aspirin
Explanation
This patient is suffering from an acute myocardial infarction (MI) as evident from his presentation history and changes on his electrocardiogram (EKG). After establishing the patency of his airway and adequate ventilation (confirmed in this case by noting the patient is speaking clearly and his pulse oximetry readings), the next appropriate steps are administration of morphine (5mg IV), 100 percent oxygen via facemask, sublingual nitroglycerin, and 1 adult aspirin tablet orally (325 mg). The acronym MONA (morphine, oxygen, nitroglycerin, aspirin) is helpful to remember this regimen. The EKG demonstrates negative deflection of the QRS complex (Q waves) and ST segment elevation in leads V1 to V4, which is highly suggestive of an anterior wall MI. In this scenario, the primary goal of therapeutic intervention is to relieve his chest pain, reduce cardiac workload, revascularize the coronary artery, and to preserve myocardial tissue.
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