Physical diagnosis secret 2ed

heart murmurs

HEART MURMURS

Salvatore Mangione, MD

That the stethoscope will come in general use notwithstanding its value I am extremely doubtful, because its beneficial application requires much time and gives a great deal of trouble both to the patient and the practitioner, and because its whole hue and character is foreign and opposed to our habits and associations. It must be confessed that them is something even ludicrous in the picture of a grave physician actuallylistening through along tube to the patient's thorax as if the disease within were a &Mg being that could communicate its conditions to the sense without. Besides, there is in this method a sort of bold claim and pretension to certainty, which cannot, at first sight, but be somewhat startling to a mind deeply versed in the knowledge and uncertainties of our art, and to the calm and cautious habits of philosophizing to which the physician is accustomed. On all these accounts and others that might be mentioned, I conclude that the new method will only in a few cases be speedily adopted, and never generally." -John Forbes, preface to his translation of R.T.H. Laannec, De L'Auscuttatione Mediate. London, T. & J. Underwood, 1821.

INTRODUCTION AND BASIC ISSUES

Cardiac auscultation is the centerpiece of physical diagnosis, and recognizing murmurs is its most challenging aspect. It requires the identification of sounds jam-packed in less than 0.8 second, often overlapping, and not infrequently at the threshold of audibility. Stethoscopy is like learning a musical instrument and similarly rewarding. Hence, despite being as old as the battle of Waterloo, this lisle tool and its skilful use still occupy an important role in 21st-century medicine.

1. What are the auscultatory areas of murmurs? The classic ones are shown in Fig. 12-1 and Table 12-1. Auscultation typically starts in the aortic area, continuing in clockwise fashion: first over the pulmonic, then the mitral (or apical), and finally the tricuspid areas. Since murmurs may radiate widely, they often become audible in areas outside those historically assigned to them. Hence, "inching" the stethoscope (i.e., slowly dragging it from site to site) can be the best way not to miss important findings.

2. What is Erb's point? It is an additional and important area, located over the third/fourth interspace-just left of the sternum. It is named after the German neurologist (and pathologist) Wilhelm Heinrich Erb (1840-1921), who is otherwise more famous for his contributions in the field of neuromuscular dystrophies (Erb was to Germany what Charcot was to France, and bowers to England. In fact, he was the first clinician to routinely use the reflex hammer in bedside examinations.) His homonymous point is an important site for the detection of aortic sounds and murmurs.

3. How accurate is physical examination in detecting asymptomatic valvular disease? Suite accurate: in fact, highly specific (98%), fairly sensitive (70%), and with positive and negative predictive values of 92%. Still, accuracy depends on the valve. For example, sensitivity