LECTURE 1 (Auscultation/Heart sounds) Flashcards
How does the heart function?
The heart is a muscular organ and has four chambers that receive and pump blood - right atrium, right ventricle, left atrium, left ventricle
What causes heart sounds?
- Beating heart
- Resultant flow of blood through it
- Turbulence created when the heart valves snap shut
Describe the different sections of the Stethoscope
- TUBE = transmits sounds from chest piece to ear pieces
- EARPIECES = should always face forward
- BELL = used for low frequency
- DIAPHRAGM = used for high frequency sounds
- CHEST PIECE = pressure determining function
What is Systole and Diastole?
Systole = ventricles contract to pump out blood
Diastole = ventricles relax and fill with blood
In a healthy adult, which two sounds can be heard?
‘lub’ and ‘dub’
[third and fourth sounds may be heard in some healthy people but can indicate impairment of the heart function]
What is the difference between S1 & S2 and S3 & S4?
S1 & S2 = High pitched
S3 & S4 = Low pitched
What is the importance of the First heart sound (S1)?
- Produced by closing of AV valves -> Best heard in Mitral and Tricuspid areas on Precordium
- High pitched -> Auscultated using the DIAPHRAGM of stethoscope
- Occurs just after QRS complex -> Marks beginning of systole
- Prolonged & dull in nature
- Frequency: 50-60 Htz Time: 0.15 secs
Describe the Abnormal first heart sound?
- Loud S1 -> Mitral Stenosis
- Soft S1 -> Mitral Regurgitation
- Widened-Split S1 - Right bundle branch block (Delayed T1)
What is the importance of the Second heart sound (S2)?
- Produced by the closing of SEMILUNAR VALVES -> Best heard in Aortic and Pulmonary areas on Precordium
- Occurs after T-wave -> Marks end of systole (beginning of diastole)
- High pitched -> Auscultated using the diaphragm of Stethoscope
- Short and sharp
- Frequency: 80-90 Htz Time: 0.11 sec
Describe the Abnormal second heart sound
- Loud S2 -> Pulmonary hypertension
- Soft S2 -> Pulmonary Stenosis
- Physiological splitting of S2 -> Normal in inspiration (Young patients)
- Fixed splitting of S2 -> Atrial Septal Defect (ASD)
What is the importance of the Third heart sound (S3)?
- Produced by rapid filling and expansion of ventricles -> Occurs just after S2 in diastole when AV valves open
- Normmal in young patients & pregnancy
- Often a sign of systolic heart failure
- Occurs during passive LV filling
- Requires a very compliant LV
- Frequency: 20-30 Htz Time: 0.1 sec
What is the third heart sound (S3) also called?
Ventricular Gallop
What is the importance of the Fourth heart sound (S4)?
- Produced by forceful atrial contractions forcing blood into stiff ventricles
- Occurs immediately before S1 in LATE DIASTOLE
- Low pitched -> Use bell of stethoscope
- Occurs during active LV filling
- Requires a Non-compliant LV
- Indicates atrial hypertrophy (Seen in AS) or stiff ventricles (seen in myocardial infarction -> causes fibrous tissue formation)
Unlike S3, S4 is always ____________
Pathological
Can both S3 and S4 be a sign of systolic congestive Heart Failure?
YES
What are other extra heart sounds?
- Systolic ejection click
- Mitral valve prolapse click
- Opening snap
- Tumor plop
- Pericardial knock
Systolic ejection click
- Indicates a bicuspid aortic valve -> leaflets dome suddenly prior to opening creating the sound
- Heard just after the S1 heart sound
Mitral valve prolapse click
- Mid systolic click followed by a uniform, high pitched murmur
- Heard best at cardiac apex
- Sudden standing -> Preload decreased -> Click moves earlier in systole
- Sudden squatting -> Preload increases -> Click moves later in systole
Opening snap
- Increased left atrial opening pressures cause an opening snap to occur when the mitral valve leaflets suddenly tense and dome into LV in early diastole
- Best heard at apex
Tumour plop
- Early diastolic low-pitched sound just after S2
- May be followed by a low-pitched diastolic murmur
Pericardial knock
- Occurs earlier than a S3 heart sound
- Can be present in patients with Constrictive pericarditis (early filling of LV is limited from the constrictive process)
What are the six different characteristics to be assessed during auscultation?
- Location
- Intensity
- Duration
- Pitch
- Quality
- Timing
Which positions can patients be examined in?
- Lying supine
- Left lateral decubitus position
- Sitting
- Leaning forward
Where are the points for heart auscultation?
APTM
- AORTIC = 2nd Intercostal space to the right sternal border
- PULMONIC = 2nd Intercostal space to the left sternal border
- TRICUSPID = 5th Intercostal space to the lower left sternal border
- MITRAL = Apex, Point of maximum impulse & 5th Intercostal space at Midclavicular line
Where is Erb’s point?
3rd Intercostal space to the left sternal border
