Welch Allyn Means ECG Physicians Manual for CP Series Electrocardiographs - User Manual - Manual (Page 16)

MEANS Physicians Manual
Welch Allyn
16
2.11 Low QRS voltage
Say: “low QRS voltage in extremity leads”
if: top-top QRS amplitude

500 µV in all extremity leads
Say:
“low QRS voltage in precordial leads”
if: top-top QRS amplitude

1000 µV in all precordial leads
Say:
“low QRS voltage”
if: both previous tests passed
2.12 QT abnormalities
The QT interval is measured from the beginning of the Q wave until the end of the T wave. In
the case of intraventricular conduction delay, the excess QRS duration (>106 ms) is
subtracted from
the measured QT. A correction is made for the heart rate, using Bazett’s
equation: corrected QT interval = QT interval *

(heart rate/60). The corrected QT interval
renders the QT interval for a standard heart rate of 60 beats per minute. The upper limit of
470 ms is increased to 500 ms in case of infarct.
Skip tests
if:
WPWB and QRS duration < 126 ms
or heart rate

110 BPM
Say:
“short QT interval, consider hypercalcaemia”
if: corrected QT interval < 330 ms
Say:
“long QT interval, consider hypocalcaemia or quinidine-like drug”
if: corrected QT interval  470 ms
and no infarct test passed
or corrected QT interval

500 ms
and any infarct test passed