lAOla: Heart Sounds & Murmurs
| What causes the first (S1) heart sound?|
What causes the second (S2) heart sound?
|The first heart sound is caused by closure of the mitral and tricuspid valves at the beginning of systole. The second heart sound is caused by closure of the aortic and pulmonic valves (semilunar valves) at the beginning of diastole|
|An S3 heart sound is an indicator of what condition?||An S3 heart sound (gallop rhythm) during mid-diastole is most often heard in the context of congestive heart failure.|
| What is the postulated mechanism(s) that|
produces an S3 heart sound?
|The third heart sound (S3) is thought to reflect a flaccid and inelastic condition of the heart during diastole (Stoelting). Guyton says: "a logical but unproven explanation of this sound (S3) is oscillation of blood back and forth between the walls of the ventricles initiated by inrushing blood from the atria." We favor Guyton's explanation.|
|Describe the murmurs heard and specify the stethoscope location where they are best heard. if the patient has mitral stenosis. If the patient has mitral regurgitation.||Mitral stenosis is recognized by the characteristic opening snap that occurs early in diastole and by a rumbling diastolic murmur. best heard with the chest piece placed over the cardiac apex. The cardinal feature of mitral regurgitation is a blowing holosystolic (heard throughout systole) murmur best heard with the chest piece placed over the cardiac apex. The murmur typically radiates into the axilla as well.|
|Descrihe the murmurs heard and specify the stethoscope location where they are best heard, if the patient has aortic stenosis. If the patient has aortic regurgitation.||Aortic stenosis is recognized by its characteristic systolic murmur best heard in the second right intercostal space (over the aortic arch) with transmission into the neck. Aortic regurgitation is recognized by its diastolic murmur best heard along the left sternal border.|
|How is aortic valvular regurgitation graded?||The severity of aortic valvular regurgitation is graded angiographically after contrast injection into the aortic root as follows: 1+. small amount of contrast material enters left ventricle during diastole. but is cleared from left ventricle during systole; 2+. left ventricle is faintJy opacified by contrast|
media during diastole and not cleared during systole; 3+, left ventricle is progressively opacified; 4+. left ventricle is completely opacified during the first diasto le and remains so for several beats. Note: recognize there are four grades for aortic valvular regurgitation reflecting the severity of the problem.
|What is the problem if the newborn has a systolic and a diastolic murmur?||The patient with patent ductus arteriosus has both a systolic and diastolic murmur. The murmur is more intense during sys tole than during diastole. so that the murmur waxes and wanes with each beat of the heart, creat ing a machinery murmur.|
|A patient is in congestive heart failure and you are listening to the heart sounds. What should be heard? Where on the chest should this be heard?||An S3 gallop should be heard if the patient is in congestive heart failure. Left-sided S3 is best heard with the bell piece of the stethoscope at the left ventricular apex during expiration and with the patient in the left lateral position. Right-sided S3 is best heard at the left sternal border or just beneath the xiphoid and is increased with inspiration|
| What dysrhythmia is most commonly observed|
in the patient with a mitral valve lesion, either stenosis or regurgitation?