Congestive Heart Failure

ODE TO MY MASTER: I once was a puppy/ All happy and helpless/ I’d pee on the floor/ Just before you had your breakfast/ ...Chewed up your best shoes/ They tasted so good/ You weren’t too enthused/ ‘Cause I lost my manhood!!!/ But you’ll always be my buddy/ No matter what...!/ I was the silly putty/ That filled in life’s ruts/ ..My cold-nose started your day/ It budged you from your warm repose/? Then I fetched your paper/ As you watched my tail go!/ And when you were down and feelin’ sad/ I’d be around, my head in your lap/ And when you came home late/ After a hot date/ I’d never judged/ Or second guessed you/ Or demanded how life should be/ ‘Cause I love you too much/ God bless you!/ Even in pain and infirmity.../ So now when I begin to pee too soon/ My heart starts skipping beats/ And life gets so out of tune/ I can barely stand on my "feet"/ I’ll still wag my tail for you/ And remember those old times/ Even when you must do what you’ve gotta do/ I’ll kiss those tears from your eyes../ c.2001 Ed Ryan, DVM

When his "heart starts skipping beats" is never a welcome occurrence; yet heart disease spells the end of many dog’s and cat’s lives; just as it does with people; The disease, commonly referred to as "congestive heart failure," can be very insidious in its early stages distinguished only by an imperceptible cough in the morning that disappears within an hour after the animal rises, only to occur the following morning like a "smoker’s cough." Later, excessive panting, lethargy and increased sleeping may be noted. If left untreated, the dog or cat will eventually get kidney failure and/or pneumonia and subsequently die.

The reason for the intermittent nature of the cough is that lungs retain fluid during the dog or cat’s sleep when the heart must work doubly hard to circulate the blood through inactive tissue. In some cases, the already serious heart condition is exacerbated by valve disease. The valve won’t close completely after each beat creating a "murmur." Whether the underlying cause is a murmur or old age, the added burden to the heart causes the heart to grow larger like any other muscle under strain; but unlike other muscle, the blood vessels which feed the heart don’t increase proportionately, causing poor circulation and, later, infarcts (scar tissue) that predispose to arrhythmias ("skipped beats"). In time, not only the heart but the kidneys fail due to the lack of oxygen from poor blood flow.

When the kidney lacks oxygen, it secretes a hormone called angiotensin converting enzyme (ACE) which, in turn, summons the adrenal gland to secrete another hormone called aldosterone which increases the blood’s sodium level thereby increasing the blood volume and increasing blood pressure.

Since the heart’s muscle contracts only in response to the volume of blood filling it, the more volume, the greater the squeeze. The heart doesn’t contract just because you want it to, as does the muscle in your arm. Instead it’s always on "automatic pilot," always contracting with as much force as the force of the blood filling its chambers, as long as the heart is healthy. This is called Starling’s Law. When the heart is unhealthy due to age or valve disease, this increased blood pressure results in increased panting and exercise intolerance, as more and more fluid gets backed up into the lungs because the heart can’t handle the overload. The heart muscle stretches beyond physiological limits and gets "dilated." This stage is noted on ultrasound, as the machine’s sound waves echo off the heart’s inner chambers signifying how overstretched the heart has become. If the heart is too dilated, successful treatment becomes impossible. Treatment must begin before this occurs.

One class of drugs which is used alone or in combination therapy is the ace inhibiter. This drug prevents the kidney from secreting angiotensin converting enzyme (ACE) which causes the high blood pressure and all the attendant damage that ensues. When should treatment be instituted? Certainly if there’s any morning cough, excessive panting or exercise intolerance. This should be followed up with

X-Rays and a blood profile. The usual age of onset is between 8 and 11 years of age.

E.J. Ryan, D.V.M., 474-7771, Loving Care Animal Hospital