Answer (a) Dilation, Volume overload is correct!

3. Volume overload. Shunts, Aortic regurgitation, and congestive heart failure are all are examples of volume overload that dilate the heart. The pressure is not necessarily high: it just has to pump lots of blood. But according to Laplace's law, it cannot generate as much pressure as a hypertrophied heart.

An LV that is dilated too thin could rupture - according to Laplace's law. So some hypertrophy thickens the wall to keep the ratio of wall thickness to LV radius normal. For this reason, we seldom see pure dilatation. Dilation is a "series" replication of myofibrils. As increasing volume stretches the LV, it adds myofibrils onto the ends of others (in series) and thus lengthens them.

See: Todd's, Vol I, #629 and Braunwald, chapter on "Pathology of Heart Failure."
Keywords: CHF, Pressure & volume overload, dilatation

Answer (b) Dilation, Pressure overload is wrong.

You are correct in saying #3 is dilated. Its diameter is much increased from the other hearts shown. But pressure overload does not cause this. According to Laplace's law, dilation weakens the heart so it cannot generate pressure as well as a normal or hypertrophied heart. Eg. A thin dilated balloon is much easier to blow up (generates less pressure) than a thick small balloon.

Answer (b) Hypertrophy, Volume overload is wrong.

2. Hypertrophy is a parallel replication of myofibrils associated with Pressure overload (picture #2 on left) not volume overload. In pressure overload Increased LV pressure, leads to a thick muscular LV - like pumping iron. The LV wall is disproportional thickened. This thickening is due to parallel (side by side) building of sarcomeres.

Answer (d) Hypertrophy, Pressure overload is wrong.

2. Hypertrophy is a parallel replication of myofibrils that thickens the LV. It is associated with Pressure overload not volume overload as shown in diagram #2. In pressure overload, Increased LV pressure leads to a thick muscular LV - like pumping iron. The LV wall is disproportional thickened. This thickening is due to parallel (side by side) building of sarcomeres.

Answer: a. Aortic Stenosis. Note the "pulsus tarvus" with reduced dP/dT and pulse pressure. Note the anacrotic notch seen on the arterial upstroke. These are due to the slowed ejection of blood out the tight stenotic aortic valve. Arterial pulse tracings may be recorded via invasive catheters or external transducers placed on the carotid artery.

Answer:
a. Swan-Ganz thermodilution catheter.

Note the deflated balloon on the end. The catheter passes through RA, RV and PA.

Other Structures Seen Are:
1. Swan Ganz IVC-RA-RV-PA (loop coiled in Right Atrium)
   
2. Right coronary artery
   
3. Pigtail catheter in ascending Aorta
   
4. Left coronary artery
   
5. pigtail catheter is descending Aorta
   
6. Aortic insufficiency jet regurgitating backwards through aortic valve