Ischemic Heart Disease – Causes, Symptoms, Treatments

What is Ischemic Heart Disease?

Ischemic heart disease (IHD), also known as coronary heart disease (CHD), is a condition that arises when the blood supply to the heart muscle is limited. This limitation is usually caused by a buildup of plaque in the coronary arteries, the vessels that supply blood to the heart. Plaque is a substance made up of fat, cholesterol, calcium, and other substances.

IHD is the leading cause of death for both men and women in many parts of the world. According to the World Health Organization (WHO), IHD caused an estimated 17.9 million deaths in 2019, representing 31% of all global deaths.

Causes of Ischemic Heart Disease

The most common cause of the reduced flow that is iconic of Ischemic Heart Disease is the buildup of plaque inside the coronary arteries. Plaque is a mix of fat, cholesterol, calcium and other debris, which hardens and narrows the arteries over time. This narrowing hinders the flow of oxygen-rich blood to the heart. This results in chest pain (angina) or a heart attack, where a portion of the heart muscle dies due to lack of oxygen. In severe cases, IHD can even lead to heart failure, a condition where the heart struggles to pump blood effectively.

But atherosclerosis, the plaque buildup, isn’t the only cause, only the most common one. Other factors can also contribute to IHD. Coronary artery spasm is a temporary tightening of the muscles surrounding the coronary arteries, akin to a sudden pinch on a hose. This reduces blood flow to the heart and can cause chest pain.

Coronary artery thrombosis occurs when a blood clot forms within a coronary artery, completely blocking blood flow and triggering a heart attack.

There are also underlying conditions that increase your susceptibility to IHD. Chronically high blood pressure damages the delicate lining of the coronary arteries, making them more prone to narrowing. High cholesterol in the blood promotes plaque formation, further constricting the arteries.

Smoking is a double threat, damaging the inner lining of the coronary arteries and increasing the risk of blood clots. Diabetes can also damage blood vessels throughout the body, including the coronary arteries, setting the stage for atherosclerosis. Obesity is a risk factor for high blood pressure, high cholesterol, and diabetes, all of which contribute to IHD. Having a family history of heart disease also increases your vulnerability to IHD.

Symptoms of Ischemic Heart Disease

Ischemic heart disease (IHD) may not always present with clear-cut symptoms, especially in the early stages. However, there are some common signs to watch out for, and they often occur during specific situations. 

Chest Pain (Angina) is the most frequent symptom of IHD, typically described as a pressure, squeezing, tightness, or burning sensation in the chest. The discomfort can radiate to other areas like the shoulders, arms (usually left arm), jaw, back, or even the upper abdomen. Interestingly, women may experience atypical angina, presenting with symptoms like nausea, fatigue, or shortness of breath instead of classic chest pain. Now, when does this pain typically occur? Angina pain is often triggered by physical exertion, emotional stress, or exposure to cold weather. It usually subsides with rest or medication that helps increase blood flow to the heart, typically within minutes.

Shortness of Breath (Dyspnea) can arise due to reduced blood flow to the heart muscle, making it harder for the heart to pump blood effectively. Shortness of breath with IHD often occurs during exertion or when lying flat (especially if it wakes you up at night), and can sometimes be accompanied by a feeling of chest tightness.

Fatigue can be a general symptom and doesn’t solely point to IHD. However, unexplained fatigue that limits your daily activities can be a sign that your heart isn’t getting enough oxygen-rich blood.

Palpitations are sensations of a fluttering or racing heart. While occasional palpitations are common and not necessarily a cause for concern, frequent or bothersome palpitations can be a symptom of IHD, especially if accompanied by other symptoms like chest pain or shortness of breath. Dizziness or Lightheadedness can occur due to a sudden drop in blood pressure caused by IHD. It can also be a warning sign of a more serious event like a heart attack.

Stages of Ischemic Heart Disease

Ischemic heart disease (IHD) itself doesn’t typically progress through distinct stages like some other chronic conditions. However, there are ways to categorize the severity of the disease based on symptoms and the presence or absence of complications. Here’s a breakdown of how IHD might be classified:

1. Asymptomatic Stage: In this early stage, there may not be any noticeable symptoms. Plaque buildup might be present in the coronary arteries, narrowing them slightly, but blood flow to the heart muscle is still sufficient. People in this stage might not even be aware they have IHD.
2. Stable Angina: This stage is characterized by the presence of angina pectoris, the chest pain symptom of IHD. This pain typically occurs predictably with exertion or stress and resolves with rest or medication that improves blood flow to the heart.
3. Unstable Angina: This is a more concerning stage where the angina pectoris symptoms become unpredictable. The chest pain may occur at rest, be more frequent or intense, and not necessarily relieved by rest or medication alone. This can be a sign that a coronary artery blockage is worsening and there’s a higher risk of a heart attack.

Complications of IHD

Ischemic heart disease (IHD) can lead to a cascade of complications if left untreated or if the blood flow to the heart remains compromised. 

Myocardial infarction (heart attack) is the most serious complication of IHD. When a coronary artery becomes completely blocked by a blood clot, the heart muscle supplied by that artery starts to die due to lack of oxygen and nutrients. The severity of the heart attack depends on the size and location of the blockage.

Over time, if the heart muscle is weakened by repeated episodes of ischemia (reduced blood flow), it may not be able to pump blood as efficiently as it should. This condition, known as heart failure, can cause fatigue, shortness of breath, and swelling in the legs and ankles.

When the heart muscle is damaged by IHD, the electrical signals that coordinate the heartbeat can become disrupted. This can lead to various arrhythmias (irregular heartbeats), such as atrial fibrillation (a quivering or irregular heartbeat in the upper chambers of the heart) or ventricular tachycardia (fast heartbeats originating in the lower chambers). Some arrhythmias may cause only mild symptoms, while others can be life-threatening.

In some cases, especially if a large area of the heart muscle is damaged by IHD, the electrical signals can become completely chaotic, leading to sudden cardiac arrest. This is a condition where the heart stops beating effectively and blood flow ceases. Without immediate medical intervention, sudden cardiac arrest is fatal.

How is Ischemic Heart Disease Diagnosed?

Diagnosing Ischemic Heart Disease (IHD) often involves a multi-pronged approach, combining information from various methods to get a clear picture of your heart health. Here’s a breakdown of the usual diagnostic methods employed:

1. Medical History Evaluation: Your doctor will first delve into your medical background, including any symptoms you’re experiencing, such as chest pain, shortness of breath, or fatigue. They’ll also inquire about risk factors like high blood pressure, cholesterol, diabetes, smoking history, and family history of heart disease.
2. Physical Examination: During a physical exam, your doctor will listen to your heart for any abnormal sounds, such as murmurs, which can indicate narrowed arteries. They may also check your blood pressure and pulse.
3. Imaging Techniques: Several imaging techniques can provide valuable insights into your heart’s health:
   • Electrocardiogram (ECG): This painless test measures the electrical activity of your heart. While a normal ECG doesn’t rule out IHD, an abnormal ECG might indicate problems with the heart’s rhythm or damage from a previous heart attack.
   • Stress Test: This test evaluates how your heart responds to physical exertion or medication that increases blood flow to the heart muscle. There are different types of stress tests, such as treadmill exercise tests or pharmacological stress tests using dobutamine medication. During the test, an ECG is monitored to detect any abnormalities in the heart’s electrical activity that might suggest IHD.
   • Echocardiogram (Echo): This painless ultrasound examination uses sound waves to create images of your heart’s structure and function. An echo can reveal abnormalities in the heart wall movement, heart valve function, and estimate the pumping efficiency of your heart.
   • Coronary artery CT angiography (CTA): This non-invasive imaging test uses X-rays and computer technology to create detailed images of your coronary arteries. It can help identify blockages or narrowing in the arteries.
4. Blood Tests: Blood tests can measure levels of cardiac enzymes, such as troponin, which are released into the bloodstream when heart muscle is damaged. While not definitive for IHD diagnosis, elevated cardiac enzymes can raise suspicion of a heart attack, especially in conjunction with other symptoms and tests.

How is IHD Treated?

Ischemic heart disease (IHD) treatment typically involves a two-pronged approach: addressing the underlying causes and managing symptoms to prevent complications. Lifestyle Modifications are often the cornerstone of IHD management. Making healthy lifestyle changes can significantly improve your heart health and reduce your risk of complications.

A diet rich in fruits, vegetables, whole grains, and lean protein can help lower cholesterol, control blood pressure, and promote a healthy weight. Limiting saturated and trans fats, added sugar, and salt is also crucial.

If you’re overweight or obese, losing weight can take a significant burden off your heart. Aim for at least 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise per week. Exercise helps improve blood flow, strengthen the heart muscle, and manage weight. Smoking is another major risk factor for IHD. Quitting smoking significantly reduces your risk of complications like heart attack and stroke.

Chronic stress can worsen IHD symptoms. Techniques like meditation, yoga, or deep breathing exercises can help manage stress.

Several medications can play a role in managing IHD and preventing complications.

• Antiplatelet medications: These medications, like aspirin, help prevent blood clots from forming in the coronary arteries.
• Cholesterol-lowering medications: Statins are the mainstay for lowering LDL (“bad”) cholesterol and reducing the risk of plaque buildup.
• Blood pressure medications: Medications can help control high blood pressure, a significant risk factor for IHD.
• Beta-blockers: These medications can help slow the heart rate and reduce blood pressure, lowering the heart’s workload.
• Nitrates: These medications help relax and widen blood vessels, improving blood flow to the heart and relieving angina symptoms.

In some cases, minimally invasive procedures or surgeries might be necessary to address narrowed or blocked coronary arteries.

• Percutaneous coronary intervention (PCI): Also known as angioplasty and stenting, this procedure involves inserting a tiny balloon into a narrowed artery to open it up and placing a stent to keep it open.
• Coronary artery bypass grafting (CABG): In this surgery, a healthy blood vessel from another part of the body is grafted to bypass a blocked coronary artery, creating a new pathway for blood flow to the heart muscle.

Cardiac Rehabilitation helps individuals with IHD recover from a cardiac event or surgery and improve their overall heart health. It typically involves exercise training, education about managing IHD, and counseling to promote healthy lifestyle changes.

What Medications are Most Often Prescribed for Ischemic Heart Disease?

While there are several medications used to treat Ischemic Heart Disease (IHD), some categories are more commonly prescribed than others. Doctors typically employ a multi-pronged approach with medications from various categories to address different aspects of the disease.

1. Antiplatelet medications: These medications prevent blood clots from forming in the coronary arteries, reducing the risk of heart attack and stroke.
   • Example: Aspirin is a common first-line medication for preventing blood clots in people with IHD.
2. Cholesterol-lowering medications: These medications target lowering LDL (“bad”) cholesterol and reducing plaque buildup in the arteries.
   • Example: Statins are the mainstay for lowering LDL cholesterol. Some commonly prescribed statins include atorvastatin (Lipitor), rosuvastatin (Crestor), simvastatin (Zocor), and pravastatin (Pravachol).
3. Blood pressure medications: High blood pressure is a significant risk factor for IHD. Here are some medication classes used to control it:
   • ACE inhibitors (angiotensin-converting enzyme inhibitors) and ARBs (angiotensin II receptor blockers): These medications help relax blood vessels and lower blood pressure.
     • Examples of ACE inhibitors: Lisinopril (Zestril), ramipril (Altace), enalapril (Vasotec).
     • Examples of ARBs: Losartan (Cozaar), valsartan (Diovan), irbesartan (Avapro).
   • Calcium channel blockers: These medications relax the muscles surrounding the blood vessels, allowing them to dilate and lower blood pressure.
     • Examples: Amlodipine (Norvasc), nifedipine (Procardia XL), felodipine (Plendil).
   • Diuretics: These medications help the body get rid of excess fluid through urination, which can help lower blood pressure.
     • Examples: Hydrochlorothiazide (HCTZ), chlorthalidone (Thalitone), furosemide (Lasix).
4. Beta-blockers: These medications help slow the heart rate and reduce blood pressure, lowering the heart’s workload and oxygen demand.
   • Examples: Metoprolol (Lopressor), bisoprolol (Zebeta), atenolol (Tenormin).
5. Nitrates: These medications help relax and widen blood vessels, improving blood flow to the heart and relieving angina symptoms. They come in various forms:
   • Sublingual tablets: Placed under the tongue for fast relief of angina attacks. Ex: Nitroglycerin (Nitrostat).
   • Sprays: Similar to sublingual tablets but act faster. Ex: NitroMist.
   • Patches: Worn on the skin to provide sustained release of nitrates. Ex: Nitro-Dur, Transderm-Nitro.