Your physician is absolutely correct, you do need to keep hydrated to have a healthy heart and keep other bodily functions healthy as well.
Just because we don't feel thirsty doesn't mean we don't need water. A rule of thumb is to drink 8 glasses of 8oz of water a day. If you are thirsty, that means the dehydration is already starting to set in.
The best way to get this liquid is in water form. Try making a little chart and put it on the wall where you drink most of your water, then when you reach the required 8 glasses, you can cut back for that day. I would start earlier in the morning so you are not drinking a lot at night, you certainly don't want to be getting up all night to wee.
My son is this same way. It has taken some health issues to convince him that even if not thirsty, he has to work drinking like a day job. He has a water bottle and his phone. He drinks at intervals. So, every hour, on the hour, he drinks a certain amount of his water bottle. It helps to get a water bottle you like. :>) If he is somewhere where he can't drink every hour or he forgets, he will drink the whole water bottle or half the water bottle's contents at that time. This has helped him tremendously. One of the main things to improve is his GI tract. He was frequently constipated and had a slow GI tract overall and this regime has done wonders. Good luck!!
There are water bottles that actually remind you to drink water. The prices range dramatically, as to some of the features, but since you need it for your heart, it would be worth the investment.
I haven't used one so I'm not endorsing any of these products, but for people who have a hard time remembering to drink water, they could be worth it.
I have kidney stones, so my urologist is always telling to me "drink up" as well. I have a 20 oz water bottle that I carry with me and I try to make sure to I fill that up 3-4 times/day. My uro says I don't really need that much, but it's a goal to aim for because I, too, tend not to drink as much as I should. I just keep the bottle close and make a point to sip often.
I hadn't heard about the bottles that remind one to drink - I'll check it out. Thanks.