This is due to the system abuse that we all saw in Season 1 - players of 70+ Skill rating partying up with 20-30 SR players to get easier games and win more often then not. This new feature will certainly limit that system abuse and the games will feel much more balanced.
HCM is the second most common form of cardiomyopathy. If you have HCM, it means that the walls of your heart are thicker than they should be. Some thickening is normal for healthy people who exercise or who play competitive sports. But with HCM, the thickening becomes extreme. In time, the thickening of the heart muscle can cause the heart to get bigger, or enlarge.
Pericardial Effusion. Pericardial effusion is abnormal fluid build up in the membrane surrounding the heart called the pericardial sac. The clinical signs owners report depends on the amount of fluid accumulation as well as the rate of development of the fluid. Slowly accumulating fluid allows time for the pericardial sac to stretch and expand. Since the heart has time to adjust to the new fluid accumulation the intracardiac pressure does not increase to affect the filling ability of the heart until a critical point is reached.