Question

4. To interpret an ECG, we must look at the regularity of heart beats (regular, irregular), rhythm (sinus or other), heart rate, cardiac axis, duration, a description of the P wave, QRS complexes, Enlargement Figure 1-4. Standard graph paper measurements A Graph paper. conduction intervals. of one square of graph paper The ECG paper speed is 25 mm/sec. Calculate from the heart rate shown in the ECG tracing (a). Show your work. (3) a. b. Lead 1 ii) Which is showing tachcardia (a, b, or c)? (1)

Answer 1

i. In regular rhythm ECG, the formula of Heart rate calculation is calculate large boxes between two QRS and divide it with 300.

In image a. There are 3 and a half large boxes inside 2 QRS.

So, $300\div 3.5 Large Box = 85$ Beats per min

Ans - The hear rate is 85 beats/min

b. There is approx 5 and a half large boxes in between two QRS complexes.

So, $300\div 5.5 Large Box = 54$ beats per min

Ans The Heart rate is 54beats/min

c. There is approx 2 large boxes in between two QRS complexes.

So, $300\div 2 Large Box = 150$ beats per min

Ans - The Heart rate is 150beats/min

ii.

Image c is showing tachycardia. Because the heart rate is 150 bpm (>100 bpm)