You can watch a quick video where I explain it all:
When it comes to understanding murmurs of the heart, we have a hard time remembering what Early systolic, Mid Systolic, Late Systolic, Pan Systolic, Early Diastolic, Mid Diastolic, Late Diastolic is, and what is Continuous murmur.
Annnnnd… with SEO stuff out of the way, let me simplify the cardiac cycle and its murmurs to the best of my abilities.
Now, let’s help you read the cycle better. Think of the image like a clock. Start from the 12 o’ clock position and go clockwise. Start with
- S1: Closure of AV Valves (Mitral and Tricuspid),
- Clicks: Opening of Semilunar valves (Aortic and Pulmonary) causes sounds called clicks.
- S2: Closure of Aortic and Pulmonary valves.
- Snaps: Opening of AV Valves.
So remember as Snap S1, Click S2.
Some other info I thought to drop in here: The closer the Mid diastolic murmur of Mitral stenosis is to S2, the faster the Mitral valve has opened and the more severe the case of MS is. Now you may wonder how that’s possible. You see, the shorter the time between them, the faster the Left Atrial pressure was able to open the MV. Meaning the smaller the pressure difference between LV and LA is. Meaning that LA pressure has risen a lot. Which in turn causes back pressure to the Pulmonary veins and you know the rest (Pulmonary Hypertension, Right Ventricular Hypertrophy (RVH), Features of RVH: Hepatomegaly, Ascites, Edema…)
Also, a side note as you from the example above. These murmurs can move up and down the cycle based on their severity. So a MDM can become LDM to an extent.