Dr Andrew Grace, Consultant Cardiologist at Papworth Hospital in Cambridge discusses the subcutaneous implantable cardioverter defibrillator (S-ICD) in this Arrhythmia Alliance video. An S-ICD might be implanted in patients who have experienced or at be at risk of experiencing an abnormal, fast heart rhythm. An S-ICD is different from a standard ICD: no leads are placed into the heart.
Arrhythmias cause heart rate to drop in the 20's...cause for concern?
ICD/Pacemaker 
Does anyone use an Apple Watch or similar to monitor Heart Rhythm? 
Help! I need answers now.
Was this sharp pain an ectopic, pvc or a muscle spasm of the heart?
