cardiovascular disorders
Cardiac Auscultation
Introduction
Auscultation of the heart requires excellent hearing and the ability to distinguish subtle differences in pitch and timing. Hearing-impaired health care practitioners can use amplified stethoscopes. High-pitched sounds are best heard with the diaphragm of the stethoscope. Low-pitched sounds are best heard with the bell. Very little pressure should be exerted when using the bell. Excessive pressure converts the underlying skin into a diaphragm and eliminates very low-pitched sounds. The entire precordium is examined systematically, typically beginning over the apical impulse with the patient in the left lateral decubitus position. The patient rolls supine, and auscultation continues at the lower left sternal border, proceeds cephalad with auscultation of each interspace, then caudad from the right upper sternal border. The clinician also listens over the left axilla and above the clavicles. The patient sits upright for auscultation of the back, then leans forward to aid auscultation of aortic and pulmonic diastolic murmurs or pericardial friction rub. Major auscultatory findings include Heart sounds Murmurs Rubs Heart soundsare brief, transient sounds produced by valve opening and closure; they are divided into systolic and diastolic sounds. are produced by blood flow turbulence and are more prolonged than heart sounds; they may be systolic, diastolic, or continuous. They are graded by intensity and are described by their location and when they occur within the cardiac cycle. Murmurs are graded in intensity on a scale of 1 to 6 (see table Heart Murmur Intensity ). Rubsare high-pitched, scratchy sounds often with 2 or 3 separate components, which may vary according to body position; during tachycardia, the sound may be almost continuous. The clinician focuses attention sequentially on each phase of the cardiac cycle, noting each heart sound and murmur. Intensity, pitch, duration, and timing of the sounds and the intervals between them are analyzed, often providing an accurate diagnosis. Historically, a diagram of the major auscultatory and Palpation of the precordium was drawn in the patient’s chart each time the patient’s cardiovascular system was examined (see figure Murmur, character, intensity, and radiation are depicted. Sound of pulmonic closure exceeds that of aortic closure. Left ventricular (LV) thrust and right ventricular (RV) lift (heavy arrows) are identified. A 4th heart sound (S4) and systolic thrill (TS) are present. a=aortic closure sound; p=pulmonic closure sound; S1=1st heart sound; S2=2nd heart sound; 3/6=grade of crescendo-diminuendo murmur (radiates to both sides of neck); 2/6=grade of pansystolic apical crescendo murmur; 1+=mild precordial lift of RV hypertrophy (arrow shows direction of lift); 2+=moderate LV thrust (arrow shows direction of thrust). 