OVERVIEW
Continuous murmurs are produced by uninterrupted flow of blood from a vascular bed of higher pressure or resistance into a vascular bed of lower pressure or resistance, with unphased interruptions between systole and diastole of the heart. These murmurs arise mainly because of (i) communication between the main and pulmonary arteries; (ii) arteriovenous communication; (iii) impaired blood flow patterns in the arteries; and (iv) impaired blood flow patterns in the veins. Continuous murmurs are common in congenital arterial ductus arteriosus, main-pulmonary septal defects, ruptured aortic sinusoidal aneurysm, pulmonary venous malformation drainage, congenital pulmonary arteriovenous fistula. In mild cases, there are no symptoms or only exertional palpitation, chest tightness and angina pectoris, if the aortic sinus tumor breaks into the right atrium or right ventricle, there may be lack of appetite, abdominal distension, lower limb edema. Its treatment principle is mainly to target the original disease.
Etiology
Continuous murmur is common in the following diseases. 1. Shunt between high-pressure vessels or cardiac chambers and low-pressure vessels or cardiac chambers: e.g. arterial catheterization, main-pulmonary septal defect, aortic sinus aneurysm ruptured into the heart, entrapped arteries ruptured into the cardiac chambers, coronary arteriovenous fistulae, or pulmonary aneurysms. 2. Localized arterial stenosis: e.g. aortic stenosis, multiple aortitis, renal artery stenosis, coronary artery stenosis, etc. 3. High-flow or high-velocity blood flow to normal or dilated blood vessels: e.g. pregnancy, hyperthyroidism, breast vascular murmur in perinatal women, ectopic reflux in pulmonary veins, etc. 4. physiologic murmurs of the jugular veins and carotid arteries, etc.
Symptoms
1. Symptoms: mild cases are asymptomatic or only have exertional palpitation, chest tightness and angina pectoris; if the aortic sinus tumor breaks into the right atrium or right ventricle, there may be lack of appetite, abdominal distension, lower limb edema; if the aortic sinus tumor breaks into the left ventricle, there may be respiratory difficulty, cough and shortness of breath. 2. Signs The murmur is rough, loud, low, medium or high pitched. Signs of heart failure include dry and wet lung? tones, hepatomegaly, lower extremity edema, etc.
Examination
1. Electrocardiogram
To understand the changes of electrical activity of the heart.
2.Echocardiography
To clarify the structure of the heart and blood flow.
3. Chest X-ray
To understand the structure of the heart. To clarify the presence of pulmonary stasis, pleural effusion, etc.
4. Cardiac catheterization
To observe the dynamics of blood flow in the heart.
Differential Diagnosis
1. Arterial ductus arteriosus
The murmur is often grade 4/6 to 5/6. If there is a continuous murmur throughout the systolic and diastolic phases, it indicates that the aortic pressure is high and the pulmonary artery pressure may be low; if the aortic pressure is low or the blood shunt causes pulmonary arterial hypertension, the continuous murmur accounts for a small portion of the diastolic phase or is only a systolic murmur. The murmur is often transmitted to the interscapular region and the upper chest, and is often accompanied by a continuous tremor.
2. Arterial Ductus Arteriosus
The murmur is mostly in the pulmonary valve area.
3. Main pulmonary artery septal defect
The location of the murmur is lower than that of arterial ductus arteriosus.
4. Coronary arteriovenous fistula and aortic sinus aneurysm breaking into the right heart.
The murmurs are mostly in the 3rd to 4th intercostal spaces of the left sternal border and the precordial area.
5. The murmur of pulmonary arteriovenous fistula is in the lung field part.
Treatment principle
1. Heart failure
Diuretics, cardiotonic agents and vasodilators can be given.
2. Treatment of primary disease
Main and pulmonary arterial septal defects, entrapment aneurysm breaking into the heart cavity, aortic sinus aneurysm breaking into the heart cavity, surgery is recommended; arterial catheter failure, coronary arteriovenous fistula, femoral arteriovenous fistula, local arterial stenosis, subclavian arteriovenous fistula, interventional therapy is recommended.