Small PPT on How to measure QT & How to calculate corrected QT. To get value of cube root of RR(in second) please use google online calculator (search bar) or a scientific calculator

1. How to calculate QTc interval
• 1 small squares in EGG = 40 ms
• 25 small squares in ECG = 1 sec
Normal value = 350-450 ms
Long QT:
• Males: > 450 ms
• Females > 470 ms
Abnormal QTc: Repeat ECG and calculations

2. Exercise-I
24 years old male
QT=16x40=640ms
QTfc= 640/cube root of (40X23ms) = 640/cube root of 0.92 = 640/0.97= 695 ms
X
BDQ to be avoided

3. Exercise-II
60 years old male
QT=10x40=400ms
QTfc= 400/cube root of (40X20ms) = 400/cube root of 0.8 = 400/0.928= 431 ms

BDQ containing
regimen can be
initiated/continued

4. Exercise –III
42 year female patient
QT=11x40=440ms
QTfc= 440/cube root of (40X18ms) = 440/cube root of 0.72 = 440/0.896= 490 ms
X
BDQ to be avoided

5. Exercise IV
55yr old female
QT=9x40=360ms
QTfc= 400/cube root of (40X31ms) = 360/cube root of 0.8 = 400/1.1= 327 ms

BDQ containing regimen
can be initiated/continued
But etiology of short QT to
be explored & treated
accordingly