A fast would need to be supervised by a competent fasting expert in a case heart problems.
has this to say...
"In the hundreds of cases of heart disease that I have watched through fasts of various lengths, all but a few have developed stronger and better hearts. Many of them, even so-called incurable ones, have become entirely normal. Rapid hearts have slowed down, abnormally slow hearts have speeded up. weak hearts have greatly improved in vigour, hearts that were irregular have become regular in time and frequency, hearts that were missing pulsations (even as often as one pulsation out of four) have resumed regular pulsation, and many other improvements in heart function have been observed.................
"Since fasting relieves the heart of a great burden, improvement should not be surprising. The heart is nourished from the bodys nutritive reserves just as certainly, and often more adequately, than from raw materials arriving daily from the digestive tract. What more natural than that, given the rest that fasting provides, it should be able to repair itself and renew its functional vigor?."
Fasting Can Save Your Life
. by Dr H M Shelton