From the Guidelines
Heart murmurs can be classified into three main types: systolic murmurs, diastolic murmurs, and continuous murmurs, with systolic murmurs further divided into holosystolic, midsystolic, early systolic, and mid to late systolic murmurs, as outlined in the 2008 focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease 1. The main types of heart murmurs include:
- Systolic murmurs, which occur during ventricular contraction and can be further classified into:
- Holosystolic (pansystolic) murmurs
- Midsystolic (systolic ejection) murmurs
- Early systolic murmurs
- Mid to late systolic murmurs
- Diastolic murmurs, which occur during ventricular filling and can be further classified into:
- Early high-pitched diastolic murmurs
- Middiastolic murmurs
- Presystolic murmurs
- Continuous murmurs, which span both systole and diastole Murmurs are characterized by their timing, location, radiation, intensity (graded I-VI), pitch, and quality, and can be caused by various factors, including high blood flow rate through normal or abnormal orifices, forward flow through a narrowed or irregular orifice into a dilated vessel or chamber, and backward or regurgitant flow through an incompetent valve, as discussed in the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease 1. Innocent or physiologic murmurs can occur in healthy individuals, especially children, and typically don't indicate heart disease, whereas diastolic murmurs virtually always represent pathological conditions and require further cardiac evaluation, as do most continuous murmurs, as noted in the 2008 focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease 1. The underlying mechanism of murmurs involves blood flowing at high velocity through narrowed valves (stenosis), backward through incompetent valves (regurgitation), or through abnormal connections between heart chambers or vessels, creating vibrations that are audible with a stethoscope, as explained in the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease 1.
From the Research
Types of Heart Murmurs
- Systolic murmurs: common and can be caused by various conditions, including aortic stenosis, mitral regurgitation, and ventricular septal defect 2
- Diastolic murmurs: can be a sign of pathologic heart disease, such as aortic regurgitation 3, 4
- Innocent heart murmurs: physiologic in nature and not associated with structural heart disease, common in children and adolescents 5, 6
- Accidental murmurs: occur in anatomically and physiologically normal hearts, include classic vibratory parasternal-precordial Stills murmur, pulmonary ejection murmur, and others 5
- Organic murmurs: caused by structural heart disease, such as mitral valve prolapse, hypertrophic obstructive cardiomyopathy, and ventricular septal defect 2
Characteristics of Heart Murmurs
- Timing in the cardiac cycle: systolic, diastolic, or holosystolic 3
- Intensity: graded from I to VI 3
- Shape: described as vibratory, ejection, or regurgitation 5
- Pitch: described as high-pitched or low-pitched 3
- Location: described as precordial, parasternal, or apical 3
- Radiation: described as radiating to the carotids, axilla, or back 3
Diagnosis and Evaluation
- Cardiac examination: can reliably determine the cause of systolic murmurs in some cases, but limited in assessing the exact cause, especially if multiple lesions are present 2
- Echocardiography: recommended for patients with systolic murmurs of unknown cause, suspected of having significant heart disease 2, 3
- Auscultation: permits distinction between innocent and pathologic murmurs, characteristics of pathologic murmurs include holosystolic or diastolic murmur, maximal murmur intensity at the upper left sternal border, and increased intensity when the patient stands 3