Venous hum | |
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Other names | cervical venous hum |
Specialty | Vascular surgery |
Symptoms | Audible humming sound from the upper chest |
Causes | Insufficiency, regurgitation, stenosis |
Venous hum is a benign auscultatory phenomenon caused by the normal flow of blood through the jugular veins. [1] At rest, 20% of cardiac output flows to the brain via the internal carotid and vertebral arteries; this drains via the internal jugular veins. The rush of blood from these veins to the brachiocephalic vein can cause the vein walls to vibrate, creating a humming noise which can often be heard by the subject.
Typically, a peculiar humming sound is heard in the upper chest near the clavicle, emanating from the supraclavicular fossa just lateral to the sternocleidomastoid muscle, usually more obviously on the right side than on the left. The sound may radiate to the upper sternal border on either side. [2] Though the exact mechanism is still unclear, it has been suggested that the hum occurs when otherwise silent laminar flow through the internal jugular vein is disturbed by deformation of this vessel at the level of the transverse process of the atlas during head rotation. [3]
The venous hum is heard throughout the cardiac cycle, though is typically louder during diastole. It may be easier to hear when sitting, when the chin is elevated, or when the head is rotated contralaterally (away from the location of the sound); deep inspiration and hyperkinetic circulatory states (e.g. hyperthyroidism) can also increase its intensity. [2] It may be loud enough to result in audible pulsatile tinnitus. It is by far the most common type of normal continuous murmur, universal in healthy children, and frequently present in healthy young adults, especially during pregnancy. [4]
The humming may be confused with a heart murmur, which may be a symptom of a potentially serious condition. The difference is easily detected by placing light pressure on the internal jugular vein when listening to the heart, which will immediately abolish or change the venous hum, whereas a true heart murmur will be unaffected by this maneuver. The murmur also disappears when the patient is in the supine position or may disappear if the subject turns their head to one side. It is also known by the names "nun's murmur" and "bruit de diable" (noise of devils).
While a venous hum may provoke consultation with a healthcare professional, the hum itself is entirely harmless and is the product of ordinary cardiac physiology. Abnormal and potentially serious conditions such as thyrotoxicosis and anemia, by augmenting blood flow through the jugular veins, can nonetheless initiate or reinforce the venous hum, making it more noticeable, [4] and manipulation of the sound with various maneuvers has often helped physicians discover and diagnose cardiovascular disorders. [5]
Veins are blood vessels in humans, and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. In contrast to veins, arteries carry blood away from the heart.
The blood circulatory system, is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels. The circulatory system has two divisions, a systemic circulation or circuit, and a pulmonary circulation or circuit. Some sources use the terms cardiovascular system and vascular system interchangeably with the circulatory system.
Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut. In cardiac auscultation, an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the condition of the heart.
Heart murmurs are unique heart sounds produced when blood flows across a heart valve or blood vessel. This occurs when turbulent blood flow creates a sound loud enough to hear with a stethoscope. Turbulent blood flow is not smooth. The sound differs from normal heart sounds by their characteristics. For example, heart murmurs may have a distinct pitch, duration and timing. The major way health care providers examine the heart on physical exam is heart auscultation. A murmur is a sign found during the cardiovascular exam. Murmurs are of various types and are important in the detection of cardiac and valvular pathologies.
The Valsalva maneuver is performed by a forceful attempt of exhalation against a open airway, usually done by closing one's mouth and pinching one's nose shut while expelling air out as if blowing up a balloon. Variations of the maneuver can be used either in medical examination as a test of cardiac function and autonomic nervous control of the heart, or to clear the ears and sinuses when ambient pressure changes, as in scuba diving, hyperbaric oxygen therapy, or air travel.
Mitral stenosis is a valvular heart disease characterized by the narrowing of the opening of the mitral valve of the heart. It is almost always caused by rheumatic valvular heart disease. Normally, the mitral valve is about 5 cm2 during diastole. Any decrease in area below 2 cm2 causes mitral stenosis. Early diagnosis of mitral stenosis in pregnancy is very important as the heart cannot tolerate increased cardiac output demand as in the case of exercise and pregnancy. Atrial fibrillation is a common complication of resulting left atrial enlargement, which can lead to systemic thromboembolic complications like stroke.
Kussmaul's sign is a paradoxical rise in jugular venous pressure (JVP) on inspiration, or a failure in the appropriate fall of the JVP with inspiration. It can be seen in some forms of heart disease and is usually indicative of limited right ventricular filling due to right heart dysfunction.
The jugular venous pressure is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections and two downward deflections have been described.
Mitral regurgitation(MR), also known as mitral insufficiency or mitral incompetence, is a form of valvular heart disease in which the mitral valve is insufficient and does not close properly when the heart pumps out blood. It is the abnormal leaking of blood backwards – regurgitation from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts. Mitral regurgitation is the most common form of valvular heart disease.
Cardiac catheterization is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes.
Beck's triad is a collection of three medical signs associated with acute cardiac tamponade, a medical emergency when excessive fluid accumulates in the pericardial sac around the heart and impairs its ability to pump blood. The signs are low arterial blood pressure, distended neck veins, and distant, muffled heart sounds.
The atrium is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
The internal jugular vein is a paired jugular vein that collects blood from the brain and the superficial parts of the face and neck. This vein runs in the carotid sheath with the common carotid artery and vagus nerve.
The external jugular vein receives the greater part of the blood from the exterior of the cranium and the deep parts of the face, being formed by the junction of the posterior division of the retromandibular vein with the posterior auricular vein.
Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart. These conditions occur largely as a consequence of aging, but may also be the result of congenital (inborn) abnormalities or specific disease or physiologic processes including rheumatic heart disease and pregnancy.
In medicine, the cardiac examination, also precordial exam, is performed as part of a physical examination, or when a patient presents with chest pain suggestive of a cardiovascular pathology. It would typically be modified depending on the indication and integrated with other examinations especially the respiratory examination.
The abdominojugular test, also known as abdominojugular reflux (AJR), is a physical examination test useful in diagnosing right ventricle dysfunction, particularly right ventricular failure.
Venous return is the rate of blood flow back to the heart. It normally limits cardiac output.
Right atrial pressure (RAP) is the blood pressure in the right atrium of the heart. RAP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system. RAP is often nearly identical to central venous pressure (CVP), although the two terms are not identical, as a pressure differential can sometimes exist between the venae cavae and the right atrium. CVP and RAP can differ when venous tone is altered. This can be graphically depicted as changes in the slope of the venous return plotted against right atrial pressure.
The cardiovascular examination is a portion of the physical examination that involves evaluation of the cardiovascular system. The exact contents of the examination will vary depending on the presenting complaint but a complete examination will involve the heart, lungs, belly and the blood vessels.