Normal Murmurs Research Articles

Cardiology patient pages. Innocent murmurs: a parent's guide.

Murmurs are sounds or noises made by blood as it flows through the heart and blood vessels of the body. Murmurs can be caused by abnormal flow patterns that occur when there are abnormalities of the heart valves, holes within the heart, or abnormal communications between blood vessels or between blood vessels and the heart. In infants and children, most murmurs originate through normal flow patterns, however, and are referred to as innocent, physiological, or normal murmurs. By innocent , we mean that there are no structural (anatomic) or functional (physiological) abnormalities of the heart and that the murmur comes from normal flow within a normal heart. Innocent is the preferred term because it strongly conveys that nothing is wrong, as opposed to the older term functional , which is not always clearly understood as being normal by parents and patients. Although murmurs termed innocent may be heard in virtually anyone, they are most often heard in childhood. Although innocent murmurs may be prevalent mostly in childhood, the presence of murmur does not imply the presence of structural heart disease. Congenital heart defects, which are responsible for most of the heart problems in children in the developed world, are structural abnormalities caused by errors in the development of the heart while the child is still in the womb. The heart starts out as a single tube and, during the first eight …

Recognizing normal heart murmurs: a logic-based mnemonic.

A logic-based mnemonic for the auscultory diagnosis of nonpathologic murmurs, which I developed for teaching medical students and house staff, is presented with the hope of improving the auscultatory skills of primary care pediatric practitioners. The objective is positive identification of nonpathologic murmurs rather than diagnosis by exclusion. The auscultatory features of these murmurs are largely determined by their causative mechanisms. The logic, therefore, is based on an understanding of these mechanisms so that the listener will know why these murmurs have their characteristic sound features and specifically what to listen for. The logic can also be used in explaining nonpathologic murmurs to parents. The mnemonic device should reduce the need for rote memorization. Heart murmurs are present in most pediatric patients, and almost all are nonpathologic. Yet, the most common reason for referral to many pediatric cardiologists is for the evaluation of a heart murmur, two thirds of which are deemed normal.1,2 I believe that improving the accuracy of auscultation by primary care practitioners and improving their confidence in recognizing normal murmurs will decrease referrals to pediatric cardiologists, without underreferral of patients with heart disease. This outcome would be of significant psychologic and economic benefit to patients and their families. In referring to nonpathologic murmurs, the commonly used terms are innocent, functional, and normal. I prefer the latter. Perhaps, because “normal” is a less technical, more familiar word to parents, to me it seems easier for them to understand and accept the benign nature of these murmurs with this terminology. The formulation of the logic begins with a consideration of causative mechanisms. A heart murmur is a continuous series of sounds, with a variable number of different sound wave frequencies present at each instant. The wave frequency content of a murmur determines, to a large extent, …

Consultation with the Specialist

Introduction As many as 90% of children will have an audible heart murmur at some point in time. However, the prevalence of nontrivial heart disease in this age group is less than 4 per 1000. The practitioner's task is to distinguish the ubiquitous innocent or normal murmur from the murmur indicating heart disease. Normal murmurs include vibratory and pulmonary flow murmurs, venous hums, carotid bruits, and the murmur of physiologic branch pulmonary artery stenosis. Mislabeling of a normal murmur as pathologic may have adverse psychological effects on the family and the child, including unwarranted exercise restrictions and problems later with insurability and employment. Alternatively, failure to identify a pathologic murmur may delay appropriate intervention, especially in early infancy. Recent well-publicized sudden cardiac deaths of professional athletes have augmented the anxiety caused by the specter of heart disease in the young. Because less than 5% of heart murmurs in children denote cardiac pathology and because each practitioner is likely to see no more than five patients per year who have important heart disease, distinguishing normal from organic murmurs is not always simple. Nevertheless, given the high prevalence of murmurs in the young and because nearly 50% of the patients who have murmurs referred to pediatric cardiologists do have underlying heart disease of variable severity, most clinicians can recognize normal murmurs.

Consultation withthe Specialist

Introduction As many as 90% of children will have an audible heart murmur at some point in time. However, the prevalence of nontrivial heart disease in this age group is less than 4 per 1000. The practitioner9s task is to distinguish the ubiquitous innocent or normal murmur from the murmur indicating heart disease. Normal murmurs include vibratory and pulmonary flow murmurs, venous hums, carotid bruits, and the murmur of physiologic branch pulmonary artery stenosis. Mislabeling of a normal murmur as pathologic may have adverse psychological effects on the family and the child, including unwarranted exercise restrictions and problems later with insurability and employment. Alternatively, failure to identify a pathologic murmur may delay appropriate intervention, especially in early infancy. Recent well-publicized sudden cardiac deaths of professional athletes have augmented the anxiety caused by the specter of heart disease in the young. Because less than 5% of heart murmurs in children denote cardiac pathology and because each practitioner is likely to see no more than five patients per year who have important heart disease, distinguishing normal from organic murmurs is not always simple. Nevertheless, given the high prevalence of murmurs in the young and because nearly 50% of the patients who have murmurs referred to pediatric cardiologists do have underlying heart disease of variable severity, most clinicians can recognize normal murmurs.

Screening for Heart Murmurs.

In brief In preparticipation screening, auscultation is a key component of a rapid but thorough cardiovascular exam. A systematic approach allows an examiner to identify the normal murmurs that occur among young athletes as well as the sounds that might signify underlying cardiac pathology. Keeping in mind the factors that influence murmur audibility helps ensure accurate differentiation between normal and pathologic murmurs. The goals are to identify athletes at risk for sudden death, to flag those who may need treatment for other cardiac conditions, and to allow athletes who have normal murmurs to remain active.

Diagnosis and Management of Heart Murmurs in Children

The physician taking care of children must meet the problem of an easily audible heart murmur almost every day. In order to do so, the physician must be able to perform an excellent cardiovascular examination, should have an approach to making the differential between abnormal and normal murmurs, and should be able to figure out what the common cardiac lesions sound like. If one places an intracardiac phonocatheter at the root (origin) of the pulmonary artery or root of the aorta in all nondiseased people, a heart murmur will be documented (Figs 1 and 2).1-3 This murmur is present for two reasons: (1) because the origin of each great artery is narrower than the ventricle which ejects the blood into it, and (2) because each great artery arises from the ventricle at an angle. A useful analogue to explain the normal murmur to families is to suggest that they go to the basement of their home, find a water pipe, and listen with ears close to the pipe. As the water goes through the pipe it can easily be heard, and, of course, that is a murmur. If one finds the input to that water pipe and turns the spigot such that the space for the entering stream is narrowed, that murmur will become louder; and if then one finds an angle in the pipe where turbulence is likely, the murmur is again recognized to be louder.

Maximal exercise capacity of children with heart defects

Maximal treadmill tests following the Bruce protocol were performed by 830 children with heart defects and the endurance times compared with normal values from 327 children seen in the same clinic because of normal murmurs and from 388 normal children randomly selected and tested in the schools. When values in the normal clinic children were used as the reference, only 21 percent of the patients with heart defects had endurance times below the 10th percentile line. This line was 14 percent higher in the normal school children, and 47 percent of the patient group had values below the 10th percentile when values in the school children were used as the reference. Maximal heart rate in children with heart defects was almost always in the normal range (180 to 210 beats/min) except in patients with cyanosis or severe valve disease and, when encouraged to continue exercising, even these children had a mean maximal heart rate of 175 beats/min. When comparing the exercise capacity of children with heart defects with that of normal children, the source of the normal children is important; body build needs to be considered, as well as physical activity habits. Clinic patients without heart defects probably serve as a better normal control group than children obtained from the school system. Maximal exercise tests do not necessarily distinguish between children with mild or severe heart disease. Only children with lesions causing cyanosis or children with obviously severe disease have consistent reductions in exercise capacity.

Cardiovascular Problems: Perspectives and Progress

In this volume are 36 chapters, grouped in 13 subdivisions, with three lively panel discussions. About one half of the text is devoted to different aspects of coronary heart disease. Some contributions review selected topics (eg, rheumatic fever, cardiac transplantation, or normal murmurs), others survey the literature (eg, myocardial imaging or pharmacokinetics of the antiarrhythmic agents and of digoxin and digitoxin), and others summarize original work by the author and co-workers (eg, alcoholic cardiomyopathy or systolic time intervals and echocardiography in coronary heart disease). In general, the quality of these presentations is good, sometimes excellent. Admittedly, I must differ from some of the expressed opinions, and I am more moderate in the enthusiastic acceptance of some procedures. Various contributors also maintain contrasting opinions regarding the importance of congenital vs environmental factors in the pathogenesis of atherosclerosis. These differences of opinion do not detract but rather increase the value of the