An answer from the Rebbe to someone who had a heart condition, and after the doctors performed a cardiac catheterization – they scheduled an operation for after Pesach.
לכן כדאי שלאחרי חה”פ [=חג הפסח] (ואכילתו מיכלא דאסוותא) יבדקו אותו הרופאים (מהנ”ל, ואולי גם עוד מומחה אחד), אבל לא לעשות עוה”פ [=עוד הפעם]
וידונו עוה”פ בכ”ז [עוד הפעם בכל זה] ויחליטו סופית.
…It is therefore worthwhile that after Pesach (and him eating Matza, the food of healing) the doctors should check (for the condition mentioned above, and maybe also by one more specialist), but don’t do an additional cardiac catheterization.
They, the doctors, should discuss the entire case again and make a final decision. ■