Chapter 51e - Approach to the Patient with Heart Murmur Flashcards
What are the mechanisms that might explain a heart murmur?
“Heart murmurs are caused by audible vibrations that are due to the increased turbulence from accelerated blood flow through normal or abnormal orifices, flow through a narrowed or irregular orifice into a dilated vessel or chamber, or backward flow through an incompetent valve, ventricular septal defect, or patent ductus arteriosus.”
Continuous murmurs are heard throughout all systole and diastole.
True or False?
False.
“Continuous murmurs are not confined to either phase of the cardiac cycle but instead begin in early systole and proceed through S2 into all or part of diastole.”
Which anatomical and functional characteristics dictate the duration and intensity of a heart murmur?
“The duration of a heart murmur depends on the length of time over which a pressure difference exists between two cardiac chambers, the left ventricle and the aorta, the right ventricle and the pulmonary artery, or the great vessels. The magnitude and variability of this pressure difference, coupled with the geometry and compliance of the involved chambers or vessels, dictate the velocity of flow; the degree of turbulence; and the resulting frequency, configuration, and intensity of the murmur.”
What is the Gallavardin effect?
This effect usually occurs in the elderly with aortic stenosis, in whom one might hear a heart murmur “higher pitched and more acoustically pure at the apex”.
One should distinguish Gallavardin effect from mitral regurgitation, whose heart murmur shares some characteristics.
Mitral valve regurgitation associated with mitral valve prolapse might have an unusual quality as a “honking” sound.
True or False?
True.
How does one explain the higher-pitched aortic valve murmurs comparing to mitral valve murmurs?
The gradient between chambers in aortic valve murmurs is higher comparing to mitral valve murmurs.
A 23-year old patient has a mesosystolic murmur heard in the precordium without irradiation characterized as loud and without a palpable thrill. How do you classify it regarding its intensity?
Grade 3.
Which grade are usually small ventricular septal defects?
Grade 4.
Atrial septal defects usually produces heart murmurs.
True or False?
True and False.
- False: The structural abnormality in itself does not produce any heart murmur, as it is a low-velocity event.
- True: A mid-systolic murmur from “functional” pulmonic stenosis, due to right heart overload, aswell as a mid-diastolic “functional” tricuspid valve stenosis.
A softer murmur is associated with less severe structural heart disease.
True or False?
False.
“Murmurs of grade 3 or greater intensity usually signify important structural heart disease and indicate high blood flow velocit at the site of murmur production.”
“The intensity of a heart murmur may be dimished by any process that increases the distance between the intracardiac source and the stethoscope on the chest wall, such as obesity, obstructive lung disease, and a large pericardial effusion. The intensity of a murmur also may be misleadingly soft when cardiac output is reduced significantly or when the pressure gradient between the involved cardiac structures is low.”
Which characteristics of a carotid murmur would make you suspect of a more severe condition?
Continuous murmur and palpable thrill.
Name four conditions associated with mitral valve prolapse.
Marfan’s syndrome, Ehlers-Danlos syndrome, Straigh-Back syndrome and hyperhyroidism.
Coronary AV fistula, aortic septal defect, anomalous left coronary artery, proximal coronary artery stenosis, pulmonary artery branch stenosis and bronchial collateral circulation include some of the cauyses of continuous murmurs.
True or False?
True.
(other causes include patent ductus arteriousus, ruptured sinus of Valsalva aneurysm, cervical venous hum, mammary souffle of pregnancy, small (restrictive) ASD with MS and intercostal AV fistula)
How does one explain the shorter duration of acute mitral valve regurgitation (MR) in comparison to its chronic disease?
“Acute, severe MR into a normal-sized, relatively noncompliant left atrium results in an early, decrescendo systolic murmur best heard at or just medial to the apical impulse. These characteristics reflect the progressive attenuation of the pressure gradient between the left ventricle and the left atrium during systole owing to the rapid rise in left atrial pressure caused by the sudden volume load into an unprepared, noncompliant chamber and contrast sharply with the auscultatory features of chronic MR.”
Which conditions are associated with acute mitral valve regurgation?
Acute myocardial infarction, rupture of chordae tendineae in the setting of myxomatous mitral valve disease, infective endocarditis and blunt chest wall trauma.
How does one distinguish between acute mitral valve regurgitation and ventricular septal rupture following acute myocardial infarction?
“Acute, severe MR from papillary muscle rupture usually accompanies an inferior, posterior, or lateral MI and occurs 2-7 days after presentation. It is often signaled by chest pain, hypotension, and pulmonary edema, but a murmur may be absent in up to 50% of cases. The posteromedial papillary muscle is involved 6 to 10 times more frequently than the anterolateral papillary muscle. The murmur is to be distinguished from that associated with post-MI ventricular septal rupture, which is accompanied by a systolic thrill at the left sternal border in nearly all patients and is holosystolic in duration.”
“The disctinction between acute MR and ventricular septal rupture also can be achieved with right heart catheterization, sequential determination of oxygen saturations, and analysis of the pressure waveforms (tall v wave in the pulmonary artery wedge pressure in MR).”
Mitral regurgitation in the context of infective endocarditis is always the result of chordae tendinae rupture.
True or False?
False.
It might be also due to destruction of leaflet tissue.
Blunt thoracic trauma can result in papillary muscle contusion and rupture, chordal detachment, or leaflet avulsion.
True or False?
True.
How does one explain the fact that a small congenital muscular ventricular septal defect (VSD) is characterized by a early systolic murmur and no signs of pulmonary hypertension and congestion whereas a large defect is usually holosystolic and might have pulmonary vascular involvement?
“A congenital, small muscular VSD may be associated with an early systolic muyrmur. The defect closes progressively during septal contraction, and thus, the murmur is confined to early systole.”
How come a large ventricular septal defect (VSD) might have a heart murmur that becomes shorter with increasing severity?
“Anatomically large and uncorrected VSDs, which usually involve the membranous portion of the septum (…) associated with the left-to-right shunt, which earlier may have been holosystolic, becomes limited to the first portion of systole as the elevated pulmonary vascular resistance leads to an abrupt rise in right ventricular pressure and an attenuation of the interventricular pressure gradiente during the remainder of the cardiac cycle. In such instances, signs of pulmonary hypertension (right ventricular lift, loud and single or closely split S2) may predominate.”
How do you descibre Carvallo’s sign?
Incrasing intensity of tricuspid regurgitation murmur.
What is the most common cause of mid-systolic murmur in an adult?
Aortic stenosis.
How does one distinguish between aortic valve stenosis (Gallavardin effect) and mitral regurgitation?
Aortic valve stenosis is associated with a mid-systolic murmur with a late-peak, is graded 3-4, A2 might be decreased or absent, S2 can be paradoxically splitten, and might have S4.
Other features include pulsus parvus et tardus, ECG criteria for left ventricular hypertrophy and ejection sound, mostly on bicuspid noncalcified aortic valves.
Regarding a patient with aortic valve stenosis, an ejection sound is a marker of better prognosis.
True or false?
True.
The presence of ejection sound signifies a flexible, noncalcified bicuspid valve (or one of its variants).
Name the causes of reversed splitting of S2.
Aortic stenosis, myocardial infarction, hypertrophic cardiomyopathy (rarely) and right ventricular pacing.
Obstructive form of hypertrophic cardiomyopathy is usually accompanied with bisferians pulse.
True or False?
False.
Although this pulse is associated with this condition, the carotid pulse is usually normal.
Name the findings in hypertrophic obstructive cardiomyopathy (HOCM).
HOCM is associated with a mid-systolic heart murmur, usually loudest along the left sternal border or between this point and the apex. The intensity of the murmur increases with maneuvers that decrease preload and/or afterload, aswell as medications that increase the inotropism. It usually does not excede grade 3.
Rarely, there might be reversed splitting of S2.
Other features include ECG criteria for left ventricular hypertrophy, S4 and rarely, bisferians pulse.
What is the most common cause of shunting?
Ostum secundum atrial septal defect.
