Murmurs Flashcards
(16 cards)
What types of murmurs are common in children?
Innocent murmurs, also known as flow murmurs, caused by fast blood flow during systole.
What are the typical features of innocent murmurs?
Soft, short, systolic, symptomless, and situation dependent (the murmur gets quieter with standing, or only appears when the child is unwell or feverish).
What features would prompt referral for innocent murmurs?
Murmur louder than 2/6, diastolic murmurs, louder on standing, and other symptoms such as failure to thrive, feeding difficulty, cyanosis, or SOB.
When do pan systolic murmurs occur?
Throughout the systolic contraction of the heart, between S1 and S2.
What are some causes of pan systolic murmurs in children?
Mitral regurgitation, heard loudest in the mitral area; tricuspid regurgitation, heard loudest in the tricuspid area; ventricular septal defect, heard loudest at the left lower sternal border.
When do ejection systolic murmurs occur?
During systole between S1 and S2.
What type of character do ejection systolic murmurs have?
A crescendo-decrescendo character, building and then falling in intensity with a peak in the middle.
What are some causes of ejection systolic murmurs?
Aortic stenosis, heard loudest in aortic area; pulmonary stenosis, heard loudest in pulmonary area; hypertrophic obstructive cardiomyopathy, heard loudest in the 4th intercostal space at the left sternal border.
What is S2 caused by?
The closure of the aortic and pulmonary valves at the end of systole.
When does a ‘split’ second heart sound occur?
When the aortic and pulmonary valves close at different times.
What are some causes of a split second heart sound?
Normal during inspiration; atrial septal defect (fixed split); pulmonary valve stenosis (wide split).
Why can a split second heart sound be normal during inspiration?
- during inspiration, the chest wall and diaphragm expand and create negative intrathoracic pressure → this pulls the heart and lungs open
- negative intrathoracic pressure causes increased filling of the RA and ventricle from the systemic venous circulation
- it takes longer for the RV to empty the greater volume of blood, causing a slight delay in the pulmonary valve closing compared to the aortic valve
- therefore, there is ‘split’ second heart sound during inspiration
How can an ASD cause a ‘fixed split’?
- this allows blood to flow from the left atrium to the right → increasing the volume of blood that the RV has to empty before the pulmonary valve can close
- this ASD causes a ‘fixed split’ second heart sound, that doesn’t vary during inspiration and expiration
How can pulmonary valve stenosis cause a ‘widely split’ second heart sound?
It takes longer for the RV to empty through the narrow pulmonary valve compared with the LV.
What is the gold standard investigation for structural heart disease?
Echocardiogram.
What are other investigations for heart disease?
ECG to diagnose arrhythmia; CXR to diagnose other pathology related to symptoms.
