Which of the following can be used to calculate hea rate from an ECG?: (A) Number of large squares in one R-R interval/300, (B) 300/ (Number of large squares in one Q-T interval), (C) 300/ (Number of large squares in one R-R interval), (D) (Number of large squares in one Q-T interval) / 300
Answer is C. For calculating hea rate: HR-300/ Number of large squares(0.20 secs) in one R-R interval HR-1500/no of small squares (0.04 secs) in one R-R interval