Systolic Murmur

Aka: Systolic Murmur

1. See Also
   1. Heart Murmur
   2. Diastolic Murmur
   3. Pediatric Murmur
2. Causes: Mid-Systolic Murmurs
   1. Innocent Murmur
   2. Physiologic Murmur
      1. Anemia
      2. Hyperthyroidism
      3. Hypothyroidism
   3. Pathologic
      1. Hypertrophic Cardiomyopathy (20 per 10,000 births)
         1. Murmur 2-4/6 at left lower sternal border and apex, increased with Valsalva Maneuver
      2. Atrial Septal Defect (5.4 per 10,000 births)
         1. Murmur 1-3/6 at left upper sternal border, radiating to back, with fixed split S2 Heart Sound
      3. Aortic Coarctation (4 per 10,000 births)
         1. Murmur 1-3/6 at left Scapular region
      4. Aortic Stenosis (3.8 per 10,000 births)
         1. Murmur 2-3/6 at right upper sternal border, radiating to carotid arteries
      5. Pulmonic Stenosis (<1 per 10,000 births)
         1. Murmur 1-3/6 at left upper sternal border, radiating to back and lung fields
3. Causes: Holosystolic Murmur (Pansystolic Murmur, or early murmur)
   1. Ventricular Septal Defect (30 per 10,000 births)
      1. Murmur 3-4/6 (less in larger VSD) harsh, at lower left sternal border, increased with hand grip
   2. Mitral Regurgitation (5 per 10,000 births)
      1. Murmur 2-3/6 at apex radiating to axilla, with possible S3 Heart Sound (pansystolic or early blowing murmur)
   3. Patent Ductus Arteriosus (newborns, 5 per 10,000 births)
      1. Murmur 2-4/6 at left upper sternal border, machinery sound (to and fro), also heard as Diastolic Murmur
   4. Tricuspid Regurgitation (<1 per 10,000 births)
      1. Murmur 2-3/6 at lower left sternal border
4. Exam
   1. See Heart Murmur
   2. Dynamic Maneuvers: Affecting Left Ventricular Preload (most useful single set of dynamic tests)
      1. Decreased Left Ventricular Preload (e.g. Valsalva, stand from squat, forced heavy expiration)
         1. Increases Hypertrophic Cardiomyopathy and Mitral Valve Prolapse Systolic Murmurs
         2. Decreases Aortic Stenosis, Mitral Regurgitation and innocent Systolic Murmurs
      2. Increased left Ventricular Preload (e.g. Squat, passive leg raise)
         1. Increases innocent Systolic Murmurs as well as Mitral Regurgitation and Aortic Stenosis
         2. Decreases Hypertrophic Cardiomyopathy and Mitral Valve Prolapse Systolic Murmurs
   3. Dynamic Maneuvers: Other
      1. Increased Afterload (e.g. hand grip, transient arterial Occlusion with Blood Pressure cuff)
         1. Increases Mitral Regurgitation, pulmonic stenosis and Ventricular Septal Defect Systolic Murmurs
         2. Decreases Hypertrophic Cardiomyopathy, Aortic Stenosis and Mitral Valve Prolapse Systolic Murmurs
      2. Increased venous return and increased left Ventricular Afterload (e.g. deep or exaggerated inspiration)
         1. Increases tricuspid regurgitation, pulmonic stenosis Systolic Murmurs
      3. Decreased jugular venous return (Jugular Vein compression, or transition supine from sitting)
         1. Decreases Venous Hum continuous murmur
5. References
   1. Ford (2022) Am Fam Physician 105(3): 250-61 [PubMed]