Yes, it harmful for anyone's health if they inhale smoke for a long time.
In your case, as you said that you are a heart patient so yes it is harmful for you because small particles you are inhaling which are negligible,are harming your heart as well as your rest body organs.
So, please try to avoid that.
Next Steps
For further queries, consult me through practo app.
Health Tips
Try to use hot water bottles if you have to use for long.
Try to wear more layers of warm clothes.
Try to use heating pad but for a very short time as it also increases heart rate.