Heart Murmurs & Valvular Heart Disease Victor Politi, M.D., FACP Medical Director, SVCMC, School of Allied Health Professions, Physician Assistant Program
What is a Heart Murmur? • A sound produced as blood flows through the chambers and large blood vessels of the heart during the cardiac cycle of contraction and relaxation.
What is a Heart Murmur? • The heart beat normally makes two sounds: • the first is Lub and the second is Dub, these two sounds follow each other (Lub Dub) and are not separated by any extra sounds.
What is a Heart Murmur? • A heart murmur will be heard as a swishing or a whistling sound in addition to the normal Lub-Dub sound. • The moving blood sounds like running water in a garden hose.
What is a Heart Murmur? • A heart murmur is not a diagnosis or disease, it is a sign to alert our attention to check if there is anything wrong. • Heart murmurs come in different sounds which may help indicate whether the murmur is normal or abnormal.
What is a Heart Murmur? • Some murmurs are benign or harmless and are more of a finding than a condition. • A benign murmur is not associated with any significant underlying abnormality of the heart or its vessels.
What is a Heart Murmur? • Many young people can have benign/innocent flow murmurs and still have normal cardiac structure and function.
What causes a heart murmur? • Innocent/Benign Murmur Causes: • Anemia • Fever • Venous Hum • a common innocent murmur heard during childhood. This murmur is heard as a soft humming sound at the base of the neck just above the collarbone. It results from the normal blood flow in the large neck veins (jugular veins).
Innocent/benign Causes: Venous Hum • Light compression of the neck vein will make the murmur transiently disappear, or the murmur will sound louder when turning the child's head to one side or another. • These simple maneuvers help differentiate a Venous Hum from the murmurs resulting from heart disease.
Innocent/benign Causes: Still’s Murmur • This heart murmur is named after the doctor who described it. • It is heard most frequently in active, healthy 3 to 7-year old children. • The murmur represents the normal sound of blood gushing out into the aorta during heart contraction. • It has a musical tone to it and thus is frequently described as "musical murmur"; it usually sounds softer during sitting and may sound very loud during fever, anxiety, or exercise.
Pathologic Murmur • A pathologic heart murmur is one associated with a structural or functional abnormality of the heart.
Pathologic Murmurs • Narrow Valve- stenosis • Valve insufficiency/regurgitation • Septal defects- Hole in the Heart
Valve insufficiency/regurgitation • As the heart valve closes some blood leaks back making a blowing sound. • A leaking valve is called insufficient or regurgitating. • Its importance depends on how much blood is leaking, what valve is involved, and how long it has been going on.
Septal defects – hole in heart • If the pressure in the heart chambers is not the same, the blood will flow from the high to the low-pressure chamber, producing a murmur sounding like a waterfall. • If the hole is small, it will make a very loud sound. • If the hole is large it may make a faint murmur that may go unnoticed for some time; therefore a faint murmur may sometimes indicate a serious problem.
Septal defects – hole in heart • If it is between the upper cardiac chambers, it is called Atrial Septal Defect (ASD), and is called Ventricular Septal Defect (VSD) if it is between the lower cardiac chambers. • The importance of septal defects depends on their size and site.
Mechanisms of Heart Murmurs • Most murmurs are produced as blood flows past the cardiac valves, which separate the chambers of the heart, or through the valves that lead to the great vessels of the lungs and the systemic circulation.
Mechanisms of Heart Murmurs • They are usually caused by one of the following mechanisms: • Flow across partial obstruction (e.g. aortic stenosis) • Flow across valvular or intravascular irregularity w/o obstruction (e.g. bicuspid aortic valve w/o true stenosis) • Increased flow through normal structures (e.g. aortic systolic murmur associated w/anemia)
Mechanisms of Heart Murmurs • Flow into dilated chamber (e.g. aortic systolic murmur associated w/aneurysmal dilatation of the ascending aorta) • Backward or regurgitant flow across an incompetent valve or defect (e.g. mitral regurgitation) • Shunting of blood out of a high pressure chamber or artery through abnormal passage (e.g. ventricular septal defect)
Midsystolic Ejection Murmurs • Most common type of murmur • May be: • 1. Organic • (i.e. secondary to structural cardiovascular abnormality) • 2. Functional • (i.e. secondary to a physiologic alteration w/or w/o heart dx) • 3. Innocent • (i.e. not associated with any functional or structural abnormality)
Midsystolic Ejection Murmurs • Organic causes include: • Aortic stenosis • Pulmonoic stenosis
Pansystolic Regurgitant Murmurs • Heard when blood flows from a chamber of high pressure to one of lower pressure through a valve or other structure that should be closed. • Regurgitation (incompetence or insufficiency) means there is a leak!
Pansystolic Regurgitant Murmurs • The murmur begins immediately with the 1st heart sound and continues up to the 2nd heart sound. • Causes include: • Mitral regurgitation LV LA • Tricuspid regurgitation RV RA • Ventricular septal defect LV RV
Diastolic Murmurs • Unlike systolic murmurs, diastolic murmurs are almost always indicative of heart disease. • Two general types may be distinguished: • The diastolic rumble originating in atrioventricular valves • The early diastolic murmurs of semilunar valve incompetence
Diastolic Murmurs • Diastolic rumbling murmurs are caused by: • Flow across distorted or stenotic mitral or tricuspid valves • Increased blood flow across normal mitral or tricuspid valves
Diastolic Murmurs • Because these valves open only after the aortic and pulmonic valves close, a short period of silence separates S2 from the beginning of diastolic rumbles. • These murmurs are low in pitch, rumbling in quality, and heard best with the bell of the stethoscope in light skin contact.
Diastolic Murmurs • Semilunar valve incompetence may result either from valvular deformity or from dilatation of the valvular ring. • In either case blood regurgitates from the great vessel back into the ventricle.
Diastolic Murmurs • Murmurs of aortic regurgitation, together with most murmurs of pulmonic regurgitation, start immediately after the second sound and then diminish in intensity • In contrast to the rumbling atrioventricular valve murmurs, they are high pitched and blowing and best heard with the diaphragm pressed firmly on the chest.
Diastolic Murmurs • The most common examples of these two types of diastolic murmurs are: • Mitral stenosis • Aortic regurgitation
Points to Remember ! • If the flow is excessive or turbulent, a murmur may be manifest. • Blood flowing through a tight valve will produce a murmur. • Blood that is leaking back across an improperly sealing valve also can cause a murmur. • Occasionally, abnormal communications (holes) between chambers of the heart can result in the presence of a murmur.
Diagnosing a Murmur • Diagnosing a heart murmur begins with auscultation of the heart. • The location, quality, pitch and variation in the sound are all important clues to whether the murmur is benign or pathologic.
Murmur Evaluation • One of the most useful tests in evaluating a murmur is an echocardiogram. • Other tests – • EKG • Chest x-ray
Valvular Heart Disease • 90% of valvular disease is chronic, with decades between the onset of the structural abnormality and symptoms
The four heart valves prevent retrograde flow of blood during the cardiac cycle, allowing efficient ejection of blood with each contraction of the cardiac chambers
The mitral valve has two cusps, while the other three heart valves normally have three cusps
The right and left papillary muscles promote effective closure of the tricuspid and mitral valves, respectively.
Valvular Heart Disease • Mitral Stenosis • Mitral Regurgitation • Aortic Stenosis • Aortic Regurgitation • Tricuspid Stenosis • Tricuspid Regurgitation
Mitral Stenosis- Pathophysiology • Despite its declining frequency, rheumatic heart disease is still the most common cause of mitral valve stenosis • Due to progressive dilation of the atria, many patients with mitral stenosis will go on to develop atrial fibrillation
Mitral Stenosis • Normal mitral valve 4-6cm2 • When the valve narrows <1.5cm2, left atrial pressure must rise to maintain normal flow across the valve and a normal cardiac output • This results in a pressure difference between the left atrium and the left ventricle during diastole
Mitral Stenosis • In mild cases of mitral stenosis, the patient may be asymptomatic and cardiac output and left atrial pressure may be normal • In moderate cases (valve area < 1.5cm2) as left atrial pressure rises - dyspnea and fatigue appear
Mitral Stenosis • With severe stenosis, pulmonary venous congestion at rest and reduced cardiac output occur resulting in dyspnea, fatigue, and right sided heart failure
Mitral Stenosis - Clinical Findings • Dyspnea • In 80% of cases, most common presenting symptom • Paroxysmal nocturnal dyspnea • hemoptysis • 2nd most common symptom • Orthopnea • Symptoms often precipitated by onset of pregnancy or atrial fibrillation
Mitral Stenosis - Clinical Findings • Murmur • duration varies - severity of stenosis & heart rate • middiastolic rumble, crescendos into S2 • Heart Sounds • long snapping S1 • apical impulse is small and tapping due to underfilled left ventricle
Mitral Stenosis - Murmur • The pressure gradient and the length of the diastolic murmur reflect the severity of mitral stenosis
Mitral StenosisDiagnostic Studies • Echocardiography • reveals thickened valve that opens poorly, closes slowly • rather than moving in opposite directions, the anterior and posterior leaflets are fixed, moving together • rule out atrial myxoma (clinical presentation similar to mitral stenosis) • left atrial size can be accurately measured • increased size - increased risk of atrial fibrillation or systemic emboli