Final answer:
To measure ventricular rate on an ECG, count the number of QRS complexes per minute. Each QRS complex represents one ventricular contraction, or heartbeat, which allows for the determination of heart rate.
Step-by-step explanation:
To measure the ventricular rate on an ECG, you count the number of QRS complexes per minute. The QRS complex indicates ventricular depolarization, which corresponds to ventricular contraction. Each QRS complex on an electrocardiogram (ECG) represents one heartbeat. In a standard ECG, the lead II potential is most often graphed, and the voltage between the right arm and left leg provides crucial data on heart muscle function.
To calculate the heart rate, determine the time interval between successive QRS complexes and divide it into 60 seconds (one minute). For an accurate heart rate, assume a constant time between beats, count the number of QRS complexes in a given time frame (typically 6 seconds), and then multiply by 10 to extrapolate to one minute.