Ejection Murmurs

Functional systolic ejection murmurs include pulmonic flow murmurs in patients with either normal or increased pulmonary artery or aortic flow. The most common functional systolic ejection murmur in adults is probably a variant of Still's murmur, the so-called innocent murmur of childhood. It is a short, buzzing, pure, medium-pitched, nonradiating, midsystolic murmur heard best along the upper left sternal border. It is thought to result from vibrations set in motion by the pulmonic valve. A less frequently encountered functional pulmonic flow murmur, occurring predominantly in children and adolescents, emanates from the root of the pulmonary artery. It is midsystolic and similar in location, but less uniform than Still's murmur. It is high pitched, often blowing in nature, and is similar to the flow murmur heard in patients with the "straight-back syndrome." Functional systolic ejection murmurs may also result from hyperdynamic blood flow over a normal pulmonic or aortic valve. Such murmurs are commonly associated with high cardiac output states such as thyrotoxicosis, anemia, infection, fever, arteriovenous fistula, beriberi, the hyperkinetic heart syndrome, or pregnancy. They may also be audible after exercise or with anxiety.

Systolic flow murmurs associated with aortic or pulmonic valvular insufficiency may also be included in this category. These murmurs are typically midsystolic. They begin in early systole, peak in early to midsystole, end well before the onset of the second heart sound, have variable intensity, and do not radiate. These murmurs are usually medium pitched and have a crescendo–decrescendo configuration. Although the vibrations that produce these murmurs emanate from both semilumar valves, the murmurs are best (often exclusively) heard at the pulmonic area of the precordium because of the proximity of the pulmonic valve to the chest wall.

The intensity of functional systolic ejection murmurs varies, but generally ranges from grades 1 to 3. The intensity typically increases during phase 3 (release phase) of the Valsalva maneuver, following a post-extrasystolic pause and after inhalation of amyl nitrite. The intensity may decrease with isometric hand grip exercise or intravenous administration of alpha-adrenergic agonists.

Organic systolic ejection murmurs include those associated with valvular aortic stenosis, aortic sclerosis, supravalvular aortic stenosis, subvalvular aortic stenosis, hypertrophic obstructive cardiomyopathy, valvular pulmonic stenosis, pulmonary infundibular stenosis, atrial septal defect, and tetralogy of Fallot.

The murmur of valvular aortic stenosis typically has a crescendo–decrescendo configuration and a low to medium pitch. The murmur is commonly described as harsh, rasping, grunting or rough. Best heard over the primary and secondary aortic area, the murmur is transmitted widely over the precordium and radiates to the carotid arteries. The intensity of the murmur is variable (usually grade 2, 3, or 4), and increases with passive leg raising, sudden squatting, 5 or 6 beats into phase 3 of the Valsalva maneuver (release phase), following a post-extrasystolic pause and after amyl nitrite administration. The murmur tends to fade during phase 2 of the Valsalva maneuver (strain phase), with isometric hand grip exercise and occasionally with intravenous administration of alpha-adrenergic agonists. In elderly persons the murmur may be more intense and high pitched over the mitral area. It commonly takes on a musical or wheezing quality and may be confused with mitral valve regurgitation. The crescendo–decrescendo configuration helps to differentiate aortic stenosis from mitral valve regurgitation. The murmur may peak in either mid or late systole. There is a tendency for the murmur to peak progressively later in systole as stenosis become more severe. Other signs that suggest severity of valvular aortic stenosis include a delayed carotid upstroke (the single best criterion on physical examination), diminished intensity or paradoxical splitting of the second heart sound, and left ventricular hypertrophy. The presence of a systolic ejection click suggests that valve mobility is reasonably well preserved: it mitigates against severe stenosis.

Aortic sclerosis results from degeneration and calcification of the aortic cusps, predominantly at their base. This abnormality produces a murmur that is identical in character to aortic valvular stenosis but does not result in a pressure gradient over the aortic valve. The murmur typically peaks in midsystole and is accompanied by a normal second heart sound and carotid pulse upstroke. The responses to physiologic and pharmacologic interventions are identical to those of functional systolic ejection murmurs. Echocardiographic studies suggest that aortic sclerosis is common in the elderly and may be the single most common cause of systolic murmur in this population.

Discrete subaortic stenosis, resulting from a fibrous web or fibromuscular tunnel, produces a murmur that is indistinguishable from aortic stenosis. An ejection click is typically absent. The absence of calcium and poststenotic dilatation of the aorta on chest x-ray or fluoroscopic examination of a patient with apparently "severe aortic stenosis" suggests the diagnosis.

Supravalvular aortic stenosis also produces a murmur indistinguishable from valvular aortic stenosis. The murmur is typically most intense over the primary aortic area and radiates to both carotid arteries, but the amplitude of the carotid and brachial pulses may be unequal (greater on the right side) due to the orientation of the jet of blood that traverses the area of stenosis. An ejection click is typically absent. Supravalvular aortic stenosis usually becomes apparent early in childhood, and may be associated with mental retardation and elfin facies.

The systolic murmur associated with hypertrophic obstructive cardiomyopathy (HOCM), also known as idiopathic hypertrophic subaortic stenosis, results from dynamic left ventricular outflow tract obstruction. Left ventricular outflow obstruction is probably related to systolic anterior motion of the anterior mitral valve leaflet caused by a Venturi (suction) effect in the outflow tract resulting from rapid ejection of blood. Recent evidence suggests that concurrent mitral valve regurgitation may contribute to the murmur in some cases. The murmur of HOCM is typically medium pitched, has a crescendo–decrescendo configuration, and is heard best along the left sternal border. There is radiation to the base of the neck, but not into the carotid arteries. The murmur is similar in quality to that of aortic valve stenosis, but is somewhat less harsh and slightly higher pitched. The intensity of the murmur is quite variable. The murmur of HOCM becomes louder during phase 2 of Valsalva's maneuver (strain phase), with standing, after a post-extrasystolic pause, and following amyl nitrite inhalation. All of these maneuvers or interventions reduce left ventricular volume, increasing the subaortic pressure gradient. The murmur decreases in intensity with recumbency, passive leg raising, squatting, isometric hand grip, or following intravenous administration of alpha-adrenergic agonists. The murmur of HOCM is commonly accompanied by a fourth heart sound, a double or triple apical impulse, and a bisferiens (spike and dome) carotid pulse. A thrill is occasionally palpable over the left sternal border.

Valvular pulmonic stenosis is usually congenital in origin. Severe cases are apt to be encountered more in childhood than adulthood. The murmur of valvular pulmonic stenosis is midsystolic (with respect to right heart events). It begins well after the first heart sound and ends before the pulmonic component of the second heart sound (which may be delayed in severe cases), but often extend through the aortic component of the second heart sound. The murmur has a crescendo–decrescendo configuration. There is a strong tendency for the murmur to peak later in systole as stenosis becomes more severe. The murmur is best heard over the second intercostal space at the left sternal border and does not radiate. Its quality is similar to that of valvular aortic stenosis. The intensitv of the murmur is variable but is generally grade 3 or higher; it increases during phase 3 of the Valsalva maneuver (release phase), with inhalation of amyl nitrite, and occasionally with passive leg raising and following a post-extrasystolic pause. The murmur is commonly accompanied by a right ventricular lift and thrill palpable along the upper left sternal border. A fourth heart sound (right sided) may be audible at the lower left sternal border. A pulmonic ejection click is frequently audible (during expiration) over the pulmonic area except in very severe cases. Patients with congenital pulmonary valvular stenosis commonly, but not invariably, have moon facies and hyperteleorism.

Infundibular pulmonic stenosis is present in approximately 10% of cases of right ventricular outflow obstruction. It is usually accompanied by a ventricular septal defect, but may also occur as an isolated abnormality. The murmur of isolated infundibular pulmonic stenosis is identical to that of valvular pulmonic stenosis except that it is best heard lower along the left sternal border (third intercostal space) and is rarely accompanied by an ejection click.

The murmur associated with atrial septal defect is caused by increased blood flow in the right ventricular outflow tract. Accordingly, it is identical in character to the functional pulmonic ejection murmurs previously described. The presence of fixed and wide splitting of the second heart sound, not the nonspecific pulmonic flow murmur, confirms the presence of atrial septal defect.

The murmur associated with tetralogy of Fallot (ventricular septal defect, infundibular pulmonic stenosis, right ventricular hypertrophy, and overriding aorta) emanates predominantly from the ventricular septal defect when pulmonic stenosis is mild, but from the pulmonary outflow tract when pulmonic stenosis is moderate to severe. Tetralogy of Fallot with mild pulmonic stenosis is characterized by a loud (usually grade 4 or higher), harsh, midsystolic, crescendo–decrescendo murmur. The murmur is widely audible over the precordium arid peaks in late midsystole. With moderate to severe pulmonic stenosis, the murmur peaks progressively earlier in systole as much of the blood flow is shunted through the ventricular septal defect into the aorta. In extreme cases a short early systolic aortic flow murmur may be all that is audible. Tetralogy associated with mild pulmonic stenosis may be accompanied by a delayed and diminished pulmonic component of the second heart sound. The pulmonic component is not audible when pulmonic stenosis is moderate to severe. When extreme pulmonic stenosis is present, an aortic ejection click may be audible.

Regurgitant Murmurs

Systolic regurgitant murmurs include the many variations of mitral valve regurgitation, tricuspid valve regurgitation, and ventricular septal defect. Depending on its etiology and pathogenesis, mitral regurgitation may produce four discrete auscultatory patterns. Classic mitral valve regurgitation is typified by the systolic murmur of a rheumatic mitral valve. Other variations include mitral regurgitation associated with papillary muscle dysfunction, acute mitral regurgitation, and mitral valve prolapse.

The murmur of rheumatic mitral valve regurgitation is high pitched, blowing, and best heard at the cardiac apex with radiation to the axilla. It is holosystolic, starting with the first heart sound and extending to and sometimes through the aortic component of the second heart sound. Typically plateau in configuration, the murmur occasionally has late systolic accentuation. The intensity of classic mitral valve regurgitation is quite variable. The intensity increases with squatting, isometric hand grip exercise, and intravenous administration of alpha-adrenergic agonists. It typically decreases with amyl nitrite inhalation. As a result of the volume overload state associated with valvular mitral regurgitation, a third heart sound is commonly audible at the apex. Dilated cardiomyopathy can produce a mitral regurgitation murmur similar in character to rheumatic mitral valve regurgitation.

Mitral regurgitation associated with papillary muscle dysfunction is typically a midsystolic, crescendo–decrescendo, nonradiating murmur localized to the lower left sternal border. The murmur is medium to high pitched and commonly has a musical or cooing quality. The intensity is generally less than grade 4. Mitral regurgitation murmurs associated with left ventricular dilatation (e.g., from dilated cardiomyopathy) may occasionally present in this fashion.

Mitral valve prolapse (idiopathic or secondary) is a common cause of mitral regurgitation. Classically, mitral valve prolapse is characterized by a medium-pitched late systolic murmur ushered in by a midsystolic click. The murmur is best heard over the apex and generally does not radiate. The murmur commonly, but not invariably, has a crescendo configuration as it reaches the aortic component of the second heart sound. The intensity is quite variable. The intensity increases and the murmur starts earlier in systole with maneuvers or interventions that decrease left ventricular volume (and therefore increase the severity of prolapse), for example, standing, phase 2 (strain phase) of the Valsalva maneuver, and following amyl nitrite inhalation. These interventions also cause the midsystolic click to migrate closer to the first heart sound. Maneuvers and interventions that increase left ventricular volume decrease the intensity of the murmur. These include passive leg raising, recumbency, a post-extrasystolic pause, squatting, isometric hand grip exercise, and intravenous administration of alpha-adrenergic agonists. Such maneuvers and interventions cause the click to return to its original location in midsystole. Not infrequently, the murmur of mitral valve prolapse is holosystolic (either spontaneously or following interventions to decrease left ventricular volume). Such a murmur generally retains a medium pitch, but may radiate to the axilla. It may reach an intensity of grade 5 or 6 and may have a musical whooping or honking quality.

Acute mitral valve regurgitation is most commonly caused by chordae tendineae rupture, but may also result from papillary muscle rupture, infective endocarditis, or trauma. The murmur of acute mitral regurgitation is typically decrescendo and of variable intensity (usually grade 3 or higher). It begins with the first heart sound and decreases in intensity throughout systole, occasionally terminating before the aortic component of the second heart sound. Best heard at the cardiac apex, the murmur typically radiates to the axilla and may be audible along the cervical spine or at the top of the head in selected cases. The murmur is lower pitched than that of rheumatic mitral regurgitation, often possessing a harsh quality reminiscent of valvular aortic stenosis. A third and fourth heart sound may be audible at the apex.

The murmur of tricuspid valve regurgitation is typically a high-pitched, blowing, holosystolic, plateau, nonradiating murmur best heard at the lower left sternal border. The intensity is variable, but tends to increase during inspiration (Carvallo's sign), with passive leg raising, after a post-extrasystole pause, and following amyl nitrite inhalation. The intensity of the murmur tends to correlate positively with the severity of regurgitation. Right ventricular enlargement may displace the location of the murmur leftward. Right ventricular failure may abolish respiratory variation. When tricuspid regurgitation is caused by pulmonary hypertension, a pulmonic ejection click may be audible. Severe tricuspid regurgitation is commonly accompanied by a third heart sound emanating from the right ventricle and best heard at the lower left sternal border. Severe tricuspid regurgitation typically produces an accentuated jugular "cv" wave and may produce hepatic congestion with a pulsatile liver.

The murmur of acute tricuspid valve regurgitation (due to infective endocarditis or trauma) is similar in character to that previously described, but often possesses a decrescendo configuration (similar to acute mitral regurgitation) and may terminate before the second heart sound.

The auscultatory findings associated with ventricular septal defect are variable, depending on a variety of morphologic and hemodynamic considerations. The systolic murmur associated with a Roger's-type ventricular septal defect (regurgitant jet flows directly into the right ventricular outflow tract) in patients with low pulmonary vascular resistance is a low to medium pitched, holosystolic murmur with midsystolic accentuation. The murmur is heard best over the third and fourth intercostal space at the left sternal border but is widely audible over the entire precordium. The intensity of the murmur is typically grade 3 or higher. Amyl nitrite inhalation causes the murmur of an uncomplicated ventricular septal defect to decrease, whereas alpha-adrenergic agonists cause no change or an increase in intensity. A precordial thrill and third heart sound (from left ventricular volume overload) frequently accompany the murmur. The pulmonic component of the second heart sound is occasionally delayed.

If pulmonary hypertension produces equalization or reversal of shunt flow in a Roger's-type ventricular septal defect (Eisenmenger's complex), the systolic murmur emanating from the septal defect may disappear entirely or be replaced by an early-peaking, medium-pitched, midsystolic murmur emanating from a dilated aortic root. Other auscultatory signs of pulmonary hypertension, including a loud pulmonic component of the second heart sound, a pulmonary ejection click, the early diastolic murmur of pulmonary valve insufficiency (Graham-Steel murmur), and right-side Austin-Flint murmur, may accompany the relatively nondescript systolic murmur. Physiologic maneuvers and pharmacologic interventions have little effect on small defects when pulmonary hypertension is present. With large defects, the murmur intensity may increase with amyl nitrite inhalation, but shows no change or decreases following intravenous administration of alpha-adrenergic agonists.

Small, slit-like ventricular septal defects typically produce an early systolic murmur that ends during the early portion of midsystole.

Extracardiac Sounds

Extracardiac sounds that may simulate systolic murmurs include the innocent subclavian murmur, carotid murmurs, the internal mammary souffle, coarctation of the aorta, and murmurs associated with a dilated aortic or pulmonic trunk and patent ductus arteriosus associated with pulmonary hypertension.

The innocent subclavian murmur (supraclavicular or brachiocephalic systolic murmur) is detected most frequently in children and adolescents. It has a crescendo–decrescendo configuration, an abrupt onset and brief duration in early to midsystole, and is medium to high pitched. Its origin is the brachiocephalic artery, and it is best heard over that region, but it may be heard with attenuation over the aortic and pulmonic areas of the precordium. The murmur disappears with compression of the brachiocephalic artery or hyperextension of the ipsilateral shoulder, a maneuver accomplished by bringing the elbows well behind the back, causing the shoulder girdle muscles to be taut. This murmur is frequently mistaken for an organic systolic murmur. Consequently some children who have it are unnecessarily kept from athletic or other strenuous physical activities.

A soft, high-pitched, early to midsystolic murmur may occasionally be audible along the sternal borders in pregnant women and appears to emanate from one of the internal mammary arteries. It is termed the internal mammary souffle and is of no pathological significance.

Bruits that originate in the carotid arteries may occasionally be mistaken for systolic heart murmurs. They are consistently heard best over the carotid arteries and are heard only with attenuation over the aortic and pulmonic areas.

Coarctation of the aorta typically is associated with a systolic murmur. In 50% of the cases a bicuspid aortic valve is present. When the murmur is not caused by valvular stenosis, it is thought to result from rapid blood flow across the stenotic segment of aorta. The murmur of coarctation is medium to high pitched and peaks rather late in systole. It is heard best over the left interscapular area and faintly if at all over the aortic areas of the precordium. The typical peripheral manifestations of coarctation permit relatively easy detection when a thorough examination is performed.

Systolic murmurs may also emanate from a dilated aortic or pulmonary trunk. Most commonly, this occurs in association with hypertension in the respective vascular circuit. The murmur is similar in character to that of aortic sclerosis or mild pulmonic stenosis.

Patent ductus arteriosus produces a continuous murmur in patients with normal pulmonary vascular resistance. As pulmonary vascular resistance increases, the diastolic portion of the murmur attenuates. With equalization of pressures in the systemic and pulmonary circuits, the systolic component of the murmur remains, extends through the second heart sound, and ends in early diastole. When pulmonary hypertension produces a right-to-left shunt, the murmur emanating from the ductus disappears and is replaced by a systolic flow murmur emanating from the root of the pulmonary artery.

The cause of a systolic murmur can accurately be ascertained in most cases from the physical examination. The medical history, resting electrocardiogram, and chest x-ray may provide valuable information concerning the impact of the underlying cardiac abnormality on the patient's cardiopulmonary status, but rarely provide specific information useful in characterizing the systolic murmur. Phonocardiography and recording of pulse tracings may be used to confirm clinical suspicions. In this regard, they are most useful as teaching tools. Echocardiography is well suited to the characterization of systolic heart murmurs. A complete examination, employing M-mode, two-dimensional, and Doppler echocardiographic techniques, can accurately identify the cause of virtually any organic systolic heart murmur (and by exclusion confirm the presence of a functional systolic ejection murmur). Limitations exist in the ability of echocardiography reliably to quantify the severity of most cardiac abnormalities that produce systolic murmurs. Despite its potential usefulness in identifying underlying causes of systolic murmurs, echocardiography is too expensive to use as a screening tool. It should be considered only when the diagnosis is in question following examination by an experienced clinician. Cardiac catheterization is rarely needed to define the cause of a systolic heart murmur, but may be of great value in assessing the severity of the cause of the murmur and determining its impact on the heart and circulation.