tachycardia and bradicardia. difference of heart pulsating, fast and slow rhythm of heart. normal heart rhythm.

tachycardia beat bradycardia disease heart irregular medical medicine rhythm pulse rapid arrhythmia background blood cardio cardiogram control danger fast frequency graph health illness illustration life slow rate sinus cardiology doctor ecg ekg electrocardiogram emergency hospital pathology normal science scheme healthcare monitoring pharmacy cover line cardiovascular lecture university heartrhythm complex diagnosis