Is congestive heart failure the same thing as a heart attack?

No. Congestive heart failure is used to describe a progression of the heart losing its ability to pump. It can be from several reasons, but basically the blood is not being pumped well and it pools or congests (is congests a word?). Eventually, someone can die from congestive heart failure, but they can live for a while with their heart not pumping well also. It depends on the specific situation and severity.

A heart attack is sudden.

No, Congestive heart failure or cardiomyopathy is a disease of the heart muscle and not being able to properly pump blood throughout the body. I don’t know what they do for dogs, but for people It can be treated with drugs, surgery, pacemakers. ventricular assist devices or in severe cases a heart transplant.

@JLeslie While a heart attack may seem sudden, my understanding is that the underlying cause is also a gradual and progressive disease (like buildup of plaque in the arteries), so I wasn’t sure how it differed from CHF.
Thank you and @sebb for explaining.

@2davidc8 That is true. People who have plaque might have “heart disease.” My father would be classified as having heart disease, but not congestive heart failure. He had bypass surgery at age 46 and had a stent put in at age 70. He has never had a heart attack. His heart is in great shape, but everything around his heart puts him at risk. I am no authority on the specifics of the terms though. There probably is some overlap, depending on the condition. When I think of congestive heart failure I think of someone who is very aware their heart is not functioning well. They have physical symptoms that let them know things are not perfect. My dad was basically a ticking time bomb before his surgery. Arteries clogging since childhood probably, but he had no symptoms until it was very bad and risk of heart attack was immenent. He became short of breath and luckily got it checked.

With congestive heart failure for a dog, it can be the beginning of a lot of issues. For some reason it usually is linked to fluid in the lungs as well. My dog had congestive heart failure and it caused fluid to build in his lungs. There are treatments for it but the dog will usually only last 6 months to a year after diagnosed. And that is if he has treatment.
The treatment usually involves a diuretic that will cause kidney problems and lead to kidney failure. When my dog went into kidney failure I opted to have him put down.

There is a treatment but with his heart problems they said it was a delicate balance and they could not assure its success. Plus they could only treat his kidney and prolong his life for only a few weeks if successful.
Sounds as if they opted not to treat his heart and he probably passed away of heart failure or fluid in the lungs or they just opted to have him put down.