Dear doctor, when taking a sharp deep breath in it feels like my heart pauses, this is rather alarming could you shed any light? thank you.

Get eval: A pleuro-pericardial friction can occur when breathing, whereas a possible inflammation of the pericardium (the sac surrounding the heart) can be adversely stimulated when the lungs move against it during inspiration and filling/expansion, possibly causing the sensation of a missed beat, etc. Get an evaluation by a dr. With a stethoscope as a start to be safe. Best wishes to you.