Heart sounds and murmurs

A brief description on heart sounds and murmurs

1. Heart sounds and murmurs Dr Jain T Kallarakkal MD, DM, FRCP

2. Heart sounds Sounds produced by the heart during a cardiac cycle Easily detected with a stethoscope or phonocardiograph

3. Types of heart sounds First heart sound - S1 Second heart sound - S2 Third heart sound - S3 Fourth heart sound - S4

4. First heart sound (Lubb) S1: signals the onset of ventricular contraction whish occurs 50-60 msec after the initiation of ventricular systole frequency ranging from 100-120 Hz. Best heard at apex and lower left sternal border Has mitral (M1) and tricuspid (T1) components

5. S1 components Small low frequency muscular vibrations Large high frequency vibrations of mitral valve closure (M1) High frequency tricuspid valve closure (T1) which occurs 20-30 msec after M1 Small low frequency vibrations of accelerated blood flow into great vessels

6. S1 generation theories Luisada : Sound produced by prominent tensing of left ventricular walls, septum and mitral valve apparatus Leatham : Sudden tensing of closed mitral valve apparatus leading sudden deceleration of blood setting the surrounding cardiac structures into vibration

7. Abnormal S1 Loud Soft Variable intensity

8. Loud S1 Tachycardia or Hyper dynamic states Mitral / tricuspid stenosis Short PR interval Atrial myxoma Left to right shunts: Atrial septal defect, Ventricular septal defect, Patent ductus arteriosus Ebstein’s anomaly Hypertension Thin chest wall

9. Soft S1 Low cardiac output states Long PR interval Severe mitral / tricuspid regurgitation Calcified mitral stenosis Flail mitral leaflets Significant aortic stenosis Left bundle branch block

10. Varying S1 Atrial fibrillation Extrasystoles Complete heart block Mobitz type I heart block Pulsus paradoxus

11. Wide S1 Right bundle branch block Ventricular premature ectopic from left ventricle Left ventricular pacing Ideoventricular rhythm from left ventricle Wolss Parkinson White syndrome Tricuspid stenosis Ebstein’s anomaly

12. Single S1 Left bundle branch block Paced beats Ventricular premature ectopic from right ventricle

13. Paradoxical S1 split Left atrial myxoma Mitral stenosis Left bundle branch block Right ventricular pacing

14. Second heart sound (Dubb) S2: Sudden deceleration of retrograde blood flow in the aorta and pulmonary artery which sets the cardiohemic system into vibration Best heard at the base Louder and high pitched than S1 (120-150Hz) Has aortic (A2) and pulmonary (P2) components

15. S2 Hang out interval: Though the right and left ventricular systoles are equal in duration, the pulmonary artery incisura is delayed in relation to the aortic incisura , primarily due to a larger interval separating the pulmonary artery incisura from the right ventricular pressure compared with the same left sided event. This internal is termed as hang out interval

16. Physiological splitting Occurs because left ventricular contraction slightly precedes that of right ventricular contraction Hence aortic valve closes before pulmonary valve Increases at end inspiration because of increased filling of right ventricle which further delays pulmonary valve closure Disappears on expiration

17. Loud S2 Loud A2: Systemic hypertension, Coarctation of aorta, Ascending aortic aneurysm, Tetrology of Fallot , Transposition of great arteries Loud P2: Pulmonary artery hypertension, Pulmonary artery dilatation

18. Soft S2 Low cardiac output Aortic regurgitation Calcific aortic stenosis

19. Enhanced physiological splitting Right bundle branch block Pulmonary stenosis Pulmonary hypertension Ventricular septal defect Acute mitral regurgitation Wide fixed split : Atrial septal defect

20. Reversed Splitting Severe aortic stenosis Hypertrophic cardiomyopathy Left bundle branch block Ventricular pacing Chronic aortic regurgitation

21. S2 in Eisenmenger VSD: Single loud S2 PDA: Close split S2 ASD: Narrow fixed split S2

22. Third heart sound (S3) Low pitched early diastolic sound Best heard at apex with bell Coincides with rapid ventricular filling ( Lub -Dub-Dum) 0.12-0.18 seconds after S2 Usually pathological in elderly

23. Causes of S3 Physiological: Children, Athletes, Pregnancy, Fever Pathological: Left ventricular failure, Severe mitral / tricuspid regurgitation, Severe aortic regurgitation, Large left to right shunts

24. Fourth heart sound (S4) Soft and low pitched Pre systolic or atrial gallop Best heard at apex with bell 0.11 seconds prior to S1 Caused by atrial kick into a non compliant ventricle

25. Causes of S4 Always pathological LVH (Hypertension, Aortic stenosis , Hypertrophic obstructive cardiomyopathy ) Coronary artery disease Cannot occur in atrial fibrillation

26. Gallop Three or four sounds resembling the center of a horse S3 gallop S4 gallop Summation gallop

27. Pericardial friction rub Scratchy leathery high pitched sound Best heard at end inspiration leaning over Three phases: mid systolic, mid diastolic and pre systolic Confusing with Hamman’s sign

28. Pericardial rub - causes Viral pericarditis Pyogenic pericarditis Tuberculous pericarditis Dressler’s syndrome Acute rheumatic fever Systemic lupus erythematosus / Rheumatoid arthritis Uremia

29. Prosthetic sounds Ball valves: Opening sound louder than closing sound Tilting disc valves: Only closure sound heard Bileaflet valves: Closure sound well heard

30. Early systolic sounds Usually high frequency Ejection sound Seen with bicuspid aortic valve, pulmonic stenosis and mechanical prosthetic valves

31. Mid - late systolic sounds High frequency Click Seen with mitral valve prolapse Occurs earlier with Valsalva maneuver or squatting

32. Early diastolic sounds Opening snap: seen with mitral stenosis . Occurs when movement of anterior mitral leaflet suddenly stops at point when LV pressure drops below left atrial pressure Pericardial knock: seen with chronic constrictive pericarditis

33. Opening snap - causes Mitral stenosis Tricuspid stenosis Severe mitral regurgitation Atrial septal defect Large ventricular septal defect Tetrology of Fallot

34. Murmurs Abnormal or ectopic heart sound Produced by turbulent flow across an abnormal valve, septal defect or outflow obstruction Also occur when stroke volume is increased

35. Description of murmur Where best heard Systolic or diastolic Timing and character Intensity Pitch Best heard with bell or diaphragm Conducted or not Variation with respiration Variation with posture Dynamic auscultation

36. Grading - systolic murmur I – Very soft II – Soft III – Loud IV – Loud with thrill V – Very loud with thrill VI – Very loud even heard when stethoscope is slightly away from chest wall

37. Systolic murmurs Occur during whole or part of systole Early systolic murmurs: Small ventricular septal defect, Acute severe mitral regurgitation, Acute severe tricuspid regurgitation Ejection systolic murmurs: Atrial septal defect, aortic stenosis , pulmonary stenosis , severe aortic regurgitation, Hypertrophic obstructive cardiomyopathy Late systolic murmurs: Mital valve prolapse , Tricuspid valve prolapse , Papillary muscle dysfunction Pan systolic murmurs: mitral regurgitation, tricuspid regurgitation, Ventricular septal defect

38. Grading – diastolic murmur I – Very soft II – Soft III – Loud IV – Loud with thrill

39. Diastolic murmurs Early diastolic murmurs: Aortic regurgitation, Pulmonary regurgitation Mid diastolic murmurs: Mitral stenosis , Tricuspid stenosis Late diastolic murmurs: Mitral stenosis , Tricuspid stenosis , Atrial myxoma

40. Continuous murmurs Patent ductus arteriosus Aorto pulmonary window Tricuspid / pulmonary atresia Anomalous left coronary artery from pulmonary artery Pericardial friction rub Mammary soufflé Rupture of sinus of Valsalva Venous hum

41. Functional murmur Usually ejection systolic murmur Normal S1 and S2 Normal cardiac impulse No hemodynamic abnormality

42. Changing murmurs Carey- coomb’s murmur Infective endocarditis Atrial thrombus Atrial myxoma

43. Named murmurs Carey- coomb’s murmur – Acute rheumatic valvulitis Austin Flint murmur – Chronic aortic regurgitation Graham Steel murmur Ritan’s murmur – in complete heart block Docks murmur Mill wheel murmur Stills murmur Gibson’s murmur – Patent ductus arteriosus murmur

44. Thank you