Hi Thanks for posting on HCM Spasm on left hand could be caused by many medical condition.It may not also be linked to your defibrillator/pacemaker, however, your underlying heart problem may be a risk factor.Possible causes may include: -Stress from the work you did -Peripheral neuropathy -Diabetic neuropathy -Ionic imbalances like low calcium, low magnesium.. Inadequate blood supply -Vitamin deficiency I will suggest you try the following: *Rest well *Continue with pain drug tylenol *A myorelaxant like miorel *Apply heat or cold *Stretch and massage *Eat well and healthy with enough vegetables *B complex vitamins If these measures do not help, you see the Doctor for evaluation.In this case, you will need tests like full blood count, ESR, serum electrolyte, fasting blood sugar and if need be, other tests may be requested depending on the Doctor s diagnostic orientation. Hope this will help Best regards