Heart Sounds & Murmurs Flashcards
heart auscultation points
*AORTIC valve = right upper sternal border (2nd intercostal space)
*PULMONIC valve = left upper sternal border (2nd intercostal space)
*TRICUSPID valve = left lower sternal border (4th/5th intercostal space)
*MITRAL valve = left 5th intercostal space, midclavicular line
S1 heart sound
*“lub” sound
*represents closure of mitral and tricuspid valves (beginning of SYSTOLE)
*usually single, may be split
*best heard at apex and left lower sternal border
S2 heart sound
*“dub” sound
*represents closure of aortic and pulmonic valves (END of systole)
*often split
*best heard at base of heart (upper sternum)
systole/diastole relative to S1/S2
*systole = between S1 and S2
*diastole = after S2
S1 and S2 on Wigger’s Diagram
*recall: S1 = closure of atrioventricular valves (mitral/tricuspid); S2 = closure of semilunar valves (aortic/pulmonic)
S1 and S2 on pressure-volume loops
*recall: S1 = closure of atrioventricular valves (mitral/tricuspid); S2 = closure of semilunar valves (aortic/pulmonic)
split S2 heart sound
*S2 is divided into A2 and P2
*A2 = closure of the aortic valve
*P2 = closure of the pulmonic valve
*can have normal variation based on the respiratory cycle
respiratory cycle and heart sounds: inspiration
*inspiration → decreased thoracic pressure → increased venous return → increased blood in right ventricle → delay in closure of pulmonic valve (delay in P2)
respiratory cycle and heart sounds: expiration
*expiration → increased thoracic pressure → decreased venous return → less blood in right ventricle → P2 and A2 much closer together
normal physiologic splitting of S2
*INSPIRATION → decreased thoracic pressure → increased venous return → increased blood in right ventricle → delay in closure of pulmonic valve (delay in P2)
*inspiration can result in normal physiologic splitting of S2 heart sound, in which A2 sound occurs just before P2 sound
wide physiologic splitting of S2
*seen in conditions that delay RV emptying (RIGHT BUNDLE BRANCH BLOCK or PULMONIC STENOSIS)
*causes delayed pulmonic sound (delayed P2), especially on inspiration
*an exaggeration of normal splitting
fixed physiologic splitting of S2
*due to ATRIAL SEPTAL DEFECT (ASD)
*ASD → left-to-right shunt → increased RA and RV volumes → increased flow through pulmonic valve → delayed pulmonic valve closure
*does NOT vary with respiration
paradoxical splitting of S2
*heard in conditions that delay aortic valve closure (AORTIC STENOSIS or LEFT BUNDLE BRANCH BLOCK)
*due to delayed A2
*normal order of semilunar valve closure is REVERSED (in paradoxical splitting, P2 occurs before A2)
S3 heart sound
*rapid filling sound in early to mid diastole
*single, dull, and soft
*heard at apex or left lower sternal border
*caused by VOLUME OVERLOAD in heart failure
*comes after S2
*sounds like “Kentucky”
S4 heart sound
*atrial kick sound in late diastole
*single, dull, and soft
*heart at apex or left lower sternal border
*caused by stiff ventricle, such as caused by hypertension
*sounds like “Tennessee”
*comes immediately before S1
note - if atrial fibrillation present, you CANNOY have S4
effect of pressure on S4 & S3 gallop sounds
*light pressure: gallop sounds heard
*firm pressure: gallop sounds DISAPPEAR
*best to hear in left lateral decubitus position
summation gallops
*at slower heart rates, you may be able to appreciate both S3 and S4
*however, at higher heart rates, they may blur together - this is called a summation gallop
differentiating split S2 from S3/S4
*split S2 is heard at the upper sternal borders (right and left 2nd intercostal spaces)
*S3/S4 are better heard at the apex and left lower sternal border
*S3/S4 disappear with increased pressure; S2 does not
important factors to consider when auscultating for murmurs
*location of murmur
*grade of murmur
*onset and duration (midsystolic vs. holosystolic vs. late systolic)
*timing of peak intensity
*radiation of murmur