What Is Ischemic Cardiomyopathy?

Ischemic cardiomyopathy (ICM) is a special type or advanced stage of coronary heart disease, which refers to long-term myocardial ischemia caused by coronary atherosclerosis, leading to diffuse fibrosis of the myocardium, and the occurrence of primary dilated cardiomyopathy Similar clinical syndromes. With the increasing incidence of coronary heart disease, the harm caused by ICM to human health is becoming increasingly serious. The definition of ischemic cardiomyopathy by the WHO / ISFC in 1995 is: manifested as dilated cardiomyopathy with impairment of systolic function, which is caused by chronic myocardial ischemia, so its incidence is closely related to coronary heart disease.

Basic Information

English name: Ischemic cardiomyopathy
Visiting department: Cardiology
Common locations: Myocardium

Common causes: Long-term myocardial ischemia caused by coronary atherosclerosis
Common symptoms: Congestive ischemic cardiomyopathy is angina pectoris, heart failure, arrhythmia, thrombosis and embolism; restricted type is dyspnea and / or angina pectoris

Causes of ischemic cardiomyopathy

The basic cause of this disease is coronary artery stenosis or occlusive disease caused by coronary dynamics and / or resistance factors. The heart is different from other organs in the human body. In the basic state, the oxygen uptake rate accounts for about 75% of the coronary blood flow. When the oxygen consumption of the heart muscle increases, the oxygen consumption can only be met by increasing the coronary blood flow It is required that myocardial ischemia will be caused when the long-term severe stenosis of the coronary lumen occurs due to various reasons and the local blood flow is significantly reduced. The causes of myocardial ischemia are as follows: Coronary atherosclerosis. Thrombosis. Vasculitis. Other factors that can cause chronic myocardial ischemia include coronary microangiopathy (Syndrome X) and structural abnormalities of coronary arteries.

Clinical manifestations of ischemic cardiomyopathy

According to the different clinical manifestations of patients, ischemic cardiomyopathy can be divided into two categories, namely, congestive ischemic cardiomyopathy and restricted ischemic cardiomyopathy. According to the different types of the disease, the corresponding clinical manifestations are described.

Congestive ischemic cardiomyopathy

(1) Angina pectoris is one of the common clinical symptoms in patients with ischemic cardiomyopathy. There is a clear history of coronary heart disease, and most have a history of more than one myocardial infarction. However, angina pectoris is not a necessary symptom in patients with myocardial ischemia, and some patients can only show asymptomatic myocardial ischemia, and there is no manifestation of angina pectoris or myocardial infarction. However, in such patients, asymptomatic myocardial ischemia persists and damage to the heart muscle persists until congestive heart failure occurs. The symptoms of angina pectoris in patients with angina pectoris may worsen with the progress of the disease, and congestive heart failure will gradually worsen, and the onset of angina pectoris will gradually decrease or even disappear, showing only symptoms such as chest tightness, fatigue, dizziness or difficulty breathing.

(2) Heart failure is often a manifestation of the development of ischemic cardiomyopathy to a certain stage. Early progress is slow, and once heart failure occurs, it progresses rapidly. Most patients present with heart failure at the onset of chest pain or early myocardial infarction. This is due to myocardial diastolic and systolic dysfunction caused by acute myocardial ischemia. It often manifests as exertional dyspnea, and in severe cases can develop left ventricular dysfunction such as sit-to-breath and nocturnal paroxysmal dyspnea, accompanied by fatigue and weakness. The first heart sound of the auscultation of the heart is weakened, and the diastolic galloping rhythm can be heard. Wet murmurs can be heard at the bottom of both lungs. In the later stage, if there is right ventricular failure, symptoms such as lack of appetite, peripheral edema and tightness in the right upper abdomen appear. On physical examination, the jugular vein was filled or swollen, the heart was enlarged, the liver was enlarged, and the tenderness was positive.

(3) Long-term, arrhythmic , chronic myocardial ischemia leads to myocardial necrosis, myocardial stunning, myocardial hibernation, and focal or diffuse fibrosis until scar formation. Can cause exceptions. Various types of arrhythmia can occur during the course of congestive ischemic cardiomyopathy, especially preventricular contractions, atrial fibrillation and bundle branch block.

(4) Thrombosis and embolism The formation of thrombus and embolism in the cardiac chamber is more common: the cardiac chamber is significantly enlarged; atrial fibrillation without anticoagulation therapy; the cardiac output is significantly reduced.
Patients who have been bedridden for a long time without physical activity are prone to venous thrombosis of the lower extremities, and pulmonary embolism occurs after shedding.

2. Restricted ischemic cardiomyopathy

Although the majority of patients with ischemic cardiomyopathy behave similarly to dilated cardiomyopathy, the clinical manifestations of a few patients are mainly dominated by left ventricular diastolic dysfunction, while myocardial contractile function is normal or only mildly abnormal, similar to restrictive cardiomyopathy The symptoms and signs are called restricted ischemic cardiomyopathy or hard heart syndrome. Patients often have dyspnea on exertion and / or angina pectoris and therefore have limited mobility. Often see a doctor for recurrent pulmonary edema.

Ischemic cardiomyopathy

Laboratory inspection

Complicated with acute myocardial infarction, white blood cell count may increase.

2. Auxiliary inspection

(1) Congestive ischemic cardiomyopathy Many abnormalities in the electrocardiogram can be manifested as various types of arrhythmia, with sinus tachycardia, frequent multi-source pre-ventricular contractions, atrial fibrillation, and left bundle branch Conduction blocks are the most common. At the same time, there are often pathological Q waves of ST-T abnormalities and old myocardial infarction. X-ray examination can show signs of whole heart enlargement or left ventricular enlargement, which may include pulmonary congestion, pulmonary interstitial edema, alveolar edema, and pleural effusion. Coronary and aortic calcification are sometimes seen. Echocardiography shows the general enlargement of the heart, and the left ventricular enlargement is the main cause. The diameter of the ventricular cavity increases at the end of diastole and end of systole. The left ventricular ejection fraction decreases with the increase of end-systolic and end-diastolic volume. Segmental movements weaken, disappear or become stiff. Sometimes a mural thrombus in the heart cavity is seen. Ventral radionuclide angiography showed enlarged heart cavity, wall dyskinesia, and decreased ejection fraction. Myocardial imaging showed a multi-segment myocardial radionuclide perfusion abnormal area. Cardiac catheter examination showed increased left ventricular end diastolic pressure, left atrial pressure, and pulmonary wedge pressure. Ventricular angiography showed that local or diffuse multi-segment and multi-regional abnormal wall motion abnormalities significantly reduced left ventricular ejection fraction, mitral regurgitation, etc. . Patients with coronary angiography often have more than 70% stenosis of multiple vascular lesions.

(2) Restrictive ischemic cardiomyopathy X-ray chest radiograph has pulmonary interstitial edema, pulmonary congestion, and pleural effusion. The heart is small, and there is no dilatation of the heart cavity. Coronary and aortic calcification are sometimes seen. The electrocardiogram can show various arrhythmias, sinus tachycardia, early atrial fibrillation, atrial fibrillation, ventricular arrhythmia, and conduction block. Echocardiography often manifests as a general diminished contractility of diastolic restricted ventricular muscles, without local wall motion disorders of the wall tumors. No mitral regurgitation. Even after the pulmonary edema subsided, the cardiac catheter still showed a slight increase in left ventricular end-diastolic pressure, an increase in end-diastolic volume, and a slight decrease in left ventricular ejection fraction. Coronary angiography often has more than 2 diffuse vascular lesions.

Diagnosis of ischemic cardiomyopathy

1. Have a clear history of coronary heart disease, at least one or more myocardial infarctions (with or without Q-wave myocardial infarction;

2. The heart is significantly enlarged;

3. Signs of cardiac insufficiency and / or laboratory basis; 2 negative conditions are:

(1) Exclude certain complications of coronary heart disease, such as ventricular septal perforation, ventricular wall tumors, and mitral regurgitation caused by papillary muscle dysfunction.

(2) Excluding heart enlargement and heart failure caused by other heart diseases or other causes.

Ischemic cardiomyopathy treatment

1. Reduce or eliminate risk factors for coronary heart disease

Risk factors for coronary heart disease include smoking, elevated blood pressure, diabetes, hypercholesterolemia, overweight, a family history of coronary heart disease, and men. Among them, other risk factors can be treated or prevented in addition to family history and gender.

(1) Reduce blood pressure and control the increase of diastolic or systolic blood pressure, reduce left ventricular ejection resistance, can prevent the deterioration of heart failure, and prevent progressive damage to left ventricular function.

(2) Decreasing the risk factors for lowering serum cholesterol coronary heart disease is directly related to the magnitude and duration of the decrease in serum cholesterol levels. Those with elevated total cholesterol and / or low-density lipoprotein (LDL) should be prevented and treated with a reasonable diet, and if necessary, combined with lipid-lowering drugs

(3) Diabetes should be actively treated to control blood sugar levels within a reasonable range.

(4) Controlling or reducing weight and obesity is positively correlated with overweight and total cholesterol, triacylglycerol, LDL, VLDL, plasma insulin, glucose levels, and blood pressure in plasma; it is negatively correlated with HDL levels. You can achieve this goal by reducing calorie intake and increasing exercise.

(5) Smoking cessation studies have shown that smoking is an independent risk factor for coronary heart disease, and if it coexists with other risk factors, it plays a synergistic role.

2. Improve myocardial ischemia

For patients with angina pectoris or an ischemic change in the electrocardiogram without significant reduction in blood pressure, the use of vasodilators can be considered to improve myocardial ischemia.

3. Treatment of congestive heart failure

Once heart failure occurs in ischemic cardiomyopathy, emphasis should be placed on correcting dyspnea, peripheral edema, and prevention of primary disease, preventing further deterioration of heart function, improving activity tolerance, and improving quality of life and survival.

(1) General treatment should be given light digestible food, liquid or semi-liquid is appropriate, eat less and eat more to reduce the burden on the heart and help the recovery of heart failure. Patients with significant exertional dyspnea should rest in bed, intermittently inhale oxygen, and be given sedative drugs.

(2) The indications for water and electrolyte disorders should be well grasped to avoid the abuse of diuretics, especially fast and powerful diuretics, so as to avoid serious electrolyte disorders, hypovolemia or shock and other serious consequences. During the application of diuretics, we should closely observe changes in clinical symptoms, blood pressure, fluid input and output, electrolyte and acid-base balance, and renal function.

(3) Angiotensin-converting enzyme inhibitors (ACEI) can block the renin-angiotensin-aldosterone system (RAAS), reduce the production of angiotensin and aldosterone, expand the peripheral arteries, and dilate the veins. Effect, reduce peripheral resistance, reduce sodium and water retention, thereby reducing the load before and after the heart, and increase cardiac output.

(4) Digitalis and other positive inotropic drugs

(5) -receptor blockers are not ideal for heart failure through digitalis control, and those with increased sympathetic nerve activity can be treated with -receptor blockers. Therefore, -blockers should be started from a small dose and gradually adjusted to an effective dose.

4. Management of restricted ischemic cardiomyopathy

The main pathological changes were fibrosis and focal scars caused by myocardial ischemia, which manifested as ventricular diastolic dysfunction and heart failure. Therefore, we must focus on the application of drugs that improve diastolic function, and mainly treat them with nitrates, beta-blockers, and calcium channel antagonists. This type of patients should not use digitalis and sympathomimetic positive inotropic drugs.

5. Prevention and treatment of complications

(1) Arrhythmia In patients with ischemic cardiomyopathy, various arrhythmias are very common. Arrhythmia will aggravate the symptoms and signs of the original heart dysfunction, and attention should be paid to prevention and treatment. In the application of antiarrhythmic drugs, it should be taken into account that the negative inotropic effect of some antiarrhythmic drugs on the myocardium can affect cardiac function.

(2) Thrombosis and embolism Patients with dilated heart cavity and associated atrial fibrillation, especially those with a past history of thromboembolism, are prone to embolism of mural thrombus and other organs. Anticoagulation and antiplatelet therapy can prevent thromboembolism.

6. Percutaneous coronary angioplasty (PTCA)

The percutaneous puncture of the femoral artery is used to retrogradely deliver the balloon catheter to the lesion of the coronary arteries. The balloon is pressurized and filled to expand the stenosis and enlarge the lumen of the blood vessel, thereby improving myocardial blood supply and alleviating symptoms.

7. Heart Transplantation