Norwegian Forest Cat HCM DNA Research Project

 

Cardiac Acronyms

useful data compiled from various sources as noted below

submitted by Colleen McGrady/Finnishline, NY

 

• IVSd: IntraVentricular Septum in Diastole
  Meaning the measurement of the septum between the ventricles (the septum is the wall that separates the left ventricle from the right ventricle)
• LVIDd: Left Ventricle Inner Diameter in Diastole
  Meaning how large the actual ventricle - the space - is. This is first measured in diastole, and later in systole (and usually in the M-Mode)
• LVFWd: Left Ventricle Free Wall in Diastole
  The free wall is the wall of the ventricle that is on the outer part of the heart

• IVSs: IntraVentricular Septum in systole
  Meaning the measurement of the septum between the ventricles (the septum is the wall that separates the left ventricle from the right ventricle)
• LVIDs: Left Ventricle Inner Diameter in systole
  Meaning how large the actual ventricle - the space - is. This is first measured in diastole, and later in systole (and usually in the M-Mode)
• LVFWs: Left Ventricle Free Wall in systole
  The free wall is the wall of the ventricle that is on the outside of the heart
• SF: Shortening Fraction (expressed in %)
  This is the calculation of how much the heart contracts. It is calculated from the difference between the LVIDd and LVIDs (which are already measured), divided by LVIDd. This will give a percentage that shows how many percent smaller does the ventricle get in systole compared to when it is in diastole.
  Note: the contractions are not that powerful in a sedated cat.
• Ao: aorta
  This is a measurement of the aorta, i.e. the diameter of the aorta. The blood goes from the ventricle out though the aorta and supplies the body with oxygenated blood.
• LA: left atrium
  The diameter is measured.
  Ao and LA are always done in 2-D Mode.
• LA/Ao: meaning LA divided by Ao
  This measurement gives the subjective LA size (i.e. the comparison between the LA size subjectively to the size of the heart as a whole).
  These two (LA and Ao) are normally fairly equal in size; it is more common to be slightly over than slightly below though (so 1, 1.2 and 1.3 are fairly normal; when you get more than 1.4 there might be a reason to worry).
• Subjective Left Atrial Size:
  There are no clear limits here (as far as I know), but an enlarged atrium could be a sign of HCM or RCM.
• SAM: Systolic Anterior Motion of the Mitral Valve
  The mitral valve is supposed to close when the heart contracts, thus preventing blood to flow back into the left atrium. SAM means that the mitral valve does not close fully and this causes abnormal flows, turbulence and also leakages can occur. The most common reason why the mitral valve does not close properly is that it sticks to a local thickening of the septum. Not all of the blood can leave the left ventricle during the contractions and will leak back into the left atrium. This is why SAM also leads to an enlarged left atrium.
  At autopsies you can sometimes see a spot of scar tissue or something where the mitral valve used to hit back against the wall again - SAM! So SAM can sometimes be seen even at autopsy, in this way.
• End systolic Cavity Obliteration:
  This means that in the systolic phase - when the heart is in contraction - there is no room left in the left heart chamber (ventricle) caused by thickened walls or enlarged papillary muscles. There is always - in normal hearts - some room left. The walls thicken on the inside of the heart, not on the outside.
• Papillary muscles:
  Those are the muscles located inside the left and right ventricle, at the walls and attached to "threads" which are in the other end attached to the mitral valve. These threads show on the screen as white lines. Papillary muscles can be enlarged, but they can also be longer than average. This is easy to confuse with thickening but is entirely different. Some cats can have split papillary muscles or extra small ones. These anomalies do not seem to affect the cats at all, contrary to enlarged papillary muscles.