Nursebob's MICU/CCU Survival Guide
Cardiology In Critical Care
Sounds of the Heart


There are several principles which must be involved when listening to heart sounds. First primacy should be provided for all patients. The room should be warm, the patient draped, , and as much extranious noise removed as possible. Always explain to the patient what you’re going to do. You should have a stethoscope which fits your ears comfortably and proper bell and diaphragm for your patient. be time for examination is important also, it is best to examine the patient when he is not had any procedures recently, has not had a full meal recently, and is not in any claim or discomfort. The nurse should practice listening to heart sounds every chance possible. You must learn to recognize the normal before you can recognize the abnormal.

Remember, when listing the hard sounds it is always timing, location, pitch.

Listening at the mitral area, of the patient’s chest, you can hear the sound of the mitral and tricuspid valves closing. At the apex, you can hear the normal heart sounds of S1 and S2. Normally, the timing between the first heart sound (S1) and a second hard sound (S2) is shorter than the time between the second heart sound and the next first sound. The shorter interval is a systolic time while longer interval is a diastolic time. The major audible components of the first sound are related to the mitral and tricuspid valves closing.

The sound of the mitral valve closure normally occurs before the sound of the tricuspid closure. It can be heard at any sight of ausculation, but it is best heard at the apex with a diaphragm firmly pressed against the patient's chest.the second component of the first heart sound is a tricuspid closure, it is less nutrients and is usually only arable at the left lateral sternal border. It is a high frequency sound and is also best heard with the diaphragm firmly pressed against the patient.

With increased respiration the S2 splits, this is normal. These sounds are best heard in the second left intercostal space. This is also called a physiological split of S2 and is usually caused by changes in the intrathoracic pressure created by ventilation. Closure of aortic and pulmonic valves, sound of semilunar valves closing. On the other hand, a paradoxical split of S2, may be caused by right ventricular pacemaker or ectopy, severe aortic valve disease, or patent ductus arteriosus. A wide, fixed, split of S2 may be caused by an atrial septal defect, acute pulmonary hypertension, our pulmonic stenosis.

A normal third heart sound or S3 may be hard at the apex. This sound usually occurs approximately 0.15 sec. after the second heart sound. It is a low pitched soft blowing. It may be caused by congestive heart failure, fluid overload, cardiomyopathy, or ventricular septal defect. It can be found in youngsters, pregnant women or anemia. A locates all sounds usually lasted approximately 0.15 sec. after the second sound, usually occurs whenever there is a rapid heart rate (over 100 bpm). It is best heard at the apex by having the patient lay on his left side and using the bell portion of the stethoscope applying very light pressure to the chest. it sounds like lub-da-da with the second da being S3.

A pericardial friction rub is often found in pericarditis. There are other sounds which may be herd. A midsystolic click at the apex in which the exact position may change with body position, is often associated with a light systolic murmur diagnosed as a mitral valve prolapse. A low-end post systolic murmur heard at the apex which might be rough or musical in quality, may also be associated with mitral regurgitation.

Normal Heart Sounds: the first sound, S1, is the sound of the mitral valve closing. The second sound S2 is a sound of the tricuspid valves closing.These sounds are the closing of the mitral and tricuspid valves. They are Loudest in the mitral area. Split S1 is best heard at the tricuspid area.

Reference: Nursebob's Notes.

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