Discrete Heart Sounds
Differential Overview
Phenomena
❑ S4 gallop
❑ Midsystolic click
❑ S3 gallop
❑ Loud S2
❑ Widely split S1
❑ Widely split S2
❑ Ejection click
❑ Variable S1
❑ Paradoxical splitting of S2
❑ Loud S1
❑ Fixed splitting of S2
❑ Opening snap
❑ Pericardial knock
❑ Tumor plop
❑ Sail sound
Diagnostic Approach
The A2-P2 interval normally increases with inspiration due to decreased intrathoracic pressure and increased venous return, which leads to increased stroke volume.
In my southern medical school I was taught that the cadence of the S3 gallop matches that of the spoken word Kentucky, and of S4, Tennessee.
Clinical Findings
S4 gallop A low-pitched presystolic heart sound (heard best with the bell), it may be palpable at the left heart border. Caused by atrial contraction into a noncompliant ventricle, a fourth heart sound is often heard in hypertension with left ventricular hypertrophy, and in aortic stenosis, ischemic heart disease, and acute mitral regurgitation. Increased ventricular filling during atrial contraction, caused by anemia, thyrotoxicosis, or prolonged PR interval, can also produce an S 4.
Midsystolic click Heard in mitral valve prolapse, it may be a single click or multiple midsystolic clicks, often followed by a mitral regurgitant murmur. It moves in placement with maneuvers that change ventricular volume, such as positional change.
S3 gallop The third heart sound is a low-pitched early diastolic sound heard best at the apex with the bell. It is associated with the rapid ventricular
filling phase of the cardiac cycle, and its presence correlates with left ventricular dysfunction in congestive heart failure (ischemia, cardiomyopathy, myocarditis, cor pulmonale) or overload (acute valvular regurgitation, high output state, left-to-right shunt, complete heart block). In young adults, an S3 may be a normal finding (a filling sound) due to a hyperkinetic heart or increased filling volume with mitral regurgitation.
Loud S2 A2 is increased in systemic hypertension. P2 is increased in pulmonary hypertension.
Widely split S1 Splitting may be produced by electrical delay of atrioventricular conduction in right bundle branch block, ventricular tachycardia, or left ventricular pacing.
Widely split S2 If splitting is present both recumbent and standing, and is increased with inspiration, it suggests right bundle branch block, pre-
excitation, atrial septal defect, right ventricular pressure overload (pulmonary hypertension with right ventricular failure, severe pulmonary stenosis, or massive pulmonary embolism), or decreased resistance to left ventricular outflow (mitral regurgitation).
Ejection click A sharp, high-pitched early systolic sound, it is associated with a bicuspid aortic valve, pulmonic stenosis, and aortic dilation.
Variable S1 Beat-to-beat variation in intensity occurs with a variable PQ interval, such as occurs in Wenckebach, complete heart block, or atrial fibrillation.
Paradoxical splitting of S2 Splitting decreases with inspiration, and is due to delayed aortic valve closure with left bundle branch block, severe aortic stenosis, hypertrophic cardiomyopathy, or severe left ventricular dysfunction, especially early in myocardial infarction. Differentiate A2-P2 from
A2-OS by having the patient stand. A2-OS widens, while A2-P2 narrows or is unchanged.
Loud S1 An accentuated first heart sound occurs in hemodynamically significant mitral stenosis, hyperadrenergic states, and left atrial myxoma.
Fixed splitting of S2 Splitting is not affected by Valsalva. It is found in atrial septal defect and severe right heart failure.
Opening snap It is a high-pitched sound occurring shortly after the second heard sound. Usually associated with mitral stenosis, it is also heard in tricuspid stenosis. The greater the degree of stenosis, the closer the snap moves toward the second heart sound. It can be distinguished from a split S2 by audibility over the sternal notch.
Pericardial knock Caused by sudden restriction of ventricular filling by a thickened nondistensible pericardium, it occurs earlier in diastole than an S3.
Tumor plop The hallmark of an atrial myxoma, it occurs in the same part of the cardiac cycle as an S3, but its timing varies.
Sail sound This loud sound is produced by delayed tricuspid valve closure in Ebstein anomaly.
Book Source Details
- Book Title: Field Guide to Bedside Diagnosis
- Author(s): David S. Smith
- Year of Publication: 2007
- Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2007 Lippincott Williams & Wilkins.
Other Book Chapters Related to Heart symptoms
Read excerpts from these other book chapters related to Heart symptoms:
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- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2008 Williams & Wilkins.
More About Causes of Heart symptoms
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More About This Book:
Title: Field Guide to Bedside Diagnosis
Authors: David S. Smith
Publisher: Lippincott Williams & Wilkins
Copyright: 2007
ISBN: 0-78178-165-5
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