Myocardial Ischemia

1 What is Myocardial Ischemia?

State of reduced blood flow and hence reduced oxygen supply to your heart as a result of partial or complete blockage of coronary arteries is called Myocardial Ischemia or Cardiac Ischemia. It can damage heart muscles and reduce your heart’s contractility.

Myocardial ischemia might progress to heart attack if the coronary supply is severely blocked.

Treatments include medications, a procedure to open blocked arteries or bypass surgery which are primarily aimed at improving blood flow to the heart muscle.

Heart-healthy lifestyle modifications help you prevent and manage myocardial ischemia.

2 Symptoms

Many ischemic people may be unaware of the condition as there may be no any perceivable signs or symptoms (silent ischemia). The most common sign of ischemia is pain on the left side of the chest (angina pectoris).

The signs and symptoms of ischemia, more common among women, elderly and diabetics, are:

• Neck or jaw pain 

• Shoulder or arm pain 

• A fast heartbeat 

Shortness of breath when exerted

• Nausea and vomiting 

• Sweating and Fatigue 

When to see a Doctor?

Seek immediate medical help if the chest pain is severe and prolonged.

3 Causes

Some causes of myocardial ischemia are: 

  • Coronary artery disease (atherosclerosis): Atherosclerosis is a condition in which build-up of plaque on artery walls causes restricted blood flow. 
  • Atherosclerosis is the most common cause of myocardial ischemia.
  • Blood clot: Atherosclerotic plaques can rupture, causing a blood clot. The clot might cause severe arterial blockade and lead to sudden myocardial ischemia, resulting in a heart attack. In rare instances, blood clot from distant part of the body can reach and block coronary arteries.
  • Coronary artery spasm: This is a temporary narrowing of coronary artery which can reduce blood flow to the heart. It is an uncommon cause of myocardial ischemia. 

Myocardial ischemia occurs when blood flow through coronary arteries is decreased. This results into reduced oxygen supply to the heart muscles. Ischemia may progress slowly or rapidly depending upon how fast the arteries get blocked. 

Chest pain associated with myocardial ischemia can be precipitated by physical exertion, emotional stress, cold temperatures and cocaine use.

4 Making a Diagnosis

Myocardial ischemia is diagnosed by performing several tests and procedures.

If you experience any of the above signs and symptoms, seek help from your doctor.

Following medical history and physical examination, your doctor might recommend: 

  • Electrocardiogram (ECG): ECG records the electrical activity of your heart. Certain abnormalities in the electrical activity may be an indicative of myocardial ischemia. 
  • Echocardiogram: Also called Echo, it employs high-pitched sound waves to create video images of your heart. It helps to detect damaged portion of your heart that’s not functioning normally. 
  • Nuclear scan: Radioactive material is first injected into the bloodstream and is monitored to detect abnormalities in the blood flow occurring during stressful situations like exercise. 
  • Coronary angiography: It is a test in which a dye is injected into the blood vessels and an X-ray machine is used to visualize inside of the arteries.
  • Cardiac CT scan: X-rays are used to create detailed images of heart and blood arteries. It helps to detect coronary artery calcification — a sign of coronary atherosclerosis. 
  • Stress test: Stress test monitors cardiac rhythm, blood pressure and breathing during physically demanding activities like walking on a treadmill or riding a stationary cycle. This test helps to detect heart problems which are undetectable during normal physical activity.

5 Treatment

The prime aim of treatment for myocardial ischemia is to improve blood flow to the heart.

Depending on severity, medications, surgery or both may be used: 

Medications

  •  Aspirin: Aspirin is a common drug used for pain and inflammation. A daily low dose of aspirin or other blood thinner helps prevent obstruction of coronary arteries.
  •  Nitrates: Nitrates are the agents that dilate arteries, thereby improving blood flow. 
  •  Beta blockers: These medications reduce heart rate and decrease blood pressure resulting in lower workload on your heart.
  •  Calcium channel blockers: Calcium channel blockers dilate blood vessels, slow pulse and reduce workload on your heart. Consequently, blood flow in your heart is increased.
  •  Cholesterol-lowering medications: These agents decrease the level of cholesterol in your body. Higher cholesterol level is one of the major causes for atherosclerosis.
  •  Angiotensin-converting enzyme (ACE) inhibitors: These blood pressure lowering agents are recommended if you suffer from hypertension or diabetes along myocardial ischemia. 
  •  Ranolazine (Ranexa): It is a coronary artery relaxant and may be prescribed with calcium channel blockers, beta blockers or nitrates.

Procedures to improve blood flow 

Apart from medications, your doctor might recommend more aggressive treatments: 

  •  Angioplasty and stenting: A long, thin tube (catheter) with tiny balloon is guided into the blocked part of the artery. The balloon is inflated to open the artery and restore normal blood flow. A small wire mesh coil called stent is inserted to keep the artery open. 
  •  Coronary artery bypass surgery: By its name, the bypass surgery is used to bypass the severely narrowed or blocked arteries with vessel from another part of your body. This is generally used when arteries are severely narrowed or blocked. 
  •  Enhanced external counterpulsation: This noninvasive outpatient treatment might be recommended if other treatments haven't worked. Cuffs that have been wrapped around your legs are gently inflated with air then deflated. The resulting pressure on your blood vessels can improve blood flow to the heart.

6 Prevention

Heart-healthy lifestyle that includes healthy diet and sufficient physical activity can help you prevent and manage myocardial ischemia.

7 Lifestyle and Coping

Maintaining a heart-healthy lifestyle is the best way to cope with myocardial ischemia.

Tips for Heart-healthy Lifestyle:

  • Quit smoking: Quit smoking starting from now. Learn more about smoking cessation strategies from your doctor. 
  • Diabetes, high blood pressure and high blood cholesterol all may increase your risk for myocardial ischemia. Manage these conditions, talk to your doctor about how you can treat them or manage them.
  • Follow a Healthy diet. Don’t take too much saturated fat and feast on whole grains, fruits and vegetables. Keep your cholesterol level in check. 
  • Exercise: Consult your doctor about which types of exercises are good for you. Plan a exercise schedule and follow strictly. 
  • Maintain a healthy weight: Being overweight or obese dramatically increases your risk of myocardial ischemia or any other cardio-metabolic disorders. Work out to attain a healthy weight.
  • Decrease stress: Stress is another risk factor for this condition. Keep stress levels low with managing stress techniques such as muscle relaxation and deep breathing. 

Many risk factors such as high cholesterol, high blood pressure and diabetes can remain unnoticeable for a long period of time. Early detection followed by prompt treatment ensures a better heart health.

8 Risks and Complications

There are several risks and complications associated with myocardial ischemia.

Risks

  • Tobacco: Smoking (first-hand or second-hand) damages arterial walls making them more inelastic. Fatty substances like cholesterol get deposited on these damaged parts of the arteries and slow blood flow in the coronary arteries. 
  • Moreover, smokers are more likely to have blood clots as compared to non-smokers.
  • Diabetes: A clear link has been established between diabetes and increased risk of cardiovascular conditions like myocardial ischemia, heart attack and other heart problems. 
  • High blood pressure. Hypertension can enhance the development of Atherosclerosis, resulting in damage to the coronary arteries. 
  • High blood cholesterol level: High level of Bad Cholesterol (LDL) in blood is associated with narrowing of arteries.
  • High blood triglyceride level: Like cholesterol, triglycerides are a major factor contributing to atherosclerosis. 
  • Obesity: Obesity is associated with many conditions like high blood pressure and high blood cholesterol levels. It is found that a waist measurement of more than 35 inches (89 centimeters) for women and 40 inches (102 cm) in men increases the risk of high blood pressure and heart disease
  • Lack of physical activity: Sedentary lifestyle can result in obesity, high blood pressure and higher cholesterol and triglyceride levels. Regular aerobic exercise decreases your risk for myocardial ischemia, heart attack and hypertension.

Complications

  • Heart Attack: Myocardial ischemia can lead to various complications, heart attack being the most important one to watch for. Complete or severe blockage of coronary artery reduces oxygen supply to a dangerous level causing heart attack, a potentially fatal condition in which portion of heart that is deprived of oxygen gets destroyed.  
  • Irregular heart rhythm (arrhythmia): Irregular heart rhythm can weaken your heart and may be life-threatening especially if the beats are too high or too low. 
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