Bonnie,
Do you mean scrunching up as in roaching up in the back?
Here are some links and quotes from them:
Heart Failure In Dogs - Congestive Cardiomyopathy
"Signs of Heart Failure:
Dogs in the later stages of congestive heart failure become much less active and tire easily. Their appetite usually falls of and they show signs of difficult respiration, panting and coughing while at rest. Their tummy enlarges and takes on a pear-shape as fluid accumulates in the liver and abdomen. Electrocardiograms taken of these dogs are always abnormal. When I examine these dogs, the color of the membranes of the mouth are grayish rather than healthy pink and blood vessels on the surface are abnormally congested with blood. These dogs often have a condition called a jugular pulse in which the beating of the heart can be seen in the large jugular veins of the neck. The sounds of heartbeat that I hear through my stethoscope are always abnormal to some degree."
Congestive Heart Failure in Dogs - Mitral Valve
"Symptoms of Heart Failure:
At this late stage of the disease all forms of heart failure have the same signs. Dogs in the later stages of congestive heart failure become much less active and tire easily. Their appetite usually falls of and they show signs of difficult respiration, panting and coughing while at rest. Electrocardiograms taken of these dogs are always abnormal. When I examine these dogs, the color of the membranes of the mouth are grayish rather than healthy pink and vessels on the surface are abnormally congested with blood. These dogs often have a condition called a jugular pulse in which the beating of the heart can be seen in the large jugular veins of the neck. The sounds of heartbeat that I hear through my stethoscope are always abnormal to some degree.
Congestive heart failure develops over many months and years. Its effects on blood flow also develops slowly. As heart function declines, the body is able to compensate for several weeks or months. However, at some point, the body's ability to compensate is no longer effective. At this point, dogs can go into severe heart failure in what appears to be a matter of hours. Rapid, heavy breathing, blue tongue (cyanosis), excessive drooling, or collapse may be the first signs that anything is wrong.
By the time dogs develop ascites cyanosis and pulmonary edema they rarely live beyond a year or two. Many die sooner despite the use of many medications. The disease is known to run in families so dogs with this problem should not be bred."
And a few more:
Canine Dilated Cardiomyopathy and Heart Failure ~ Pawprints and Purrs, Inc.
Canine Congestive Heart Failure - LoveToKnow Dogs
Congestive Heart Failure in Dog
Maybe the answer will be in these.
Debbie