Recognizing normal heart murmurs: a logic-based mnemonic.

Abstract

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, …