MEDICINE
CARDIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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hypercalcemia
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digitalis
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Adrenaline
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hypoxia
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Hypothermia
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Detailed explanation-1: -Recipients of digoxin also may be at higher risk of torsades de pointes, although digoxin itself does not prolong the QT interval.
Detailed explanation-2: -Corrected QT interval (QTc) Fridericia formula: QTC = QT / RR. Framingham formula: QTC = QT + 0.154 (1 – RR) Hodges formula: QTC = QT + 1.75 (heart rate – 60)
Detailed explanation-3: -Mechanism. The ECG features of digoxin effect are seen with therapeutic doses of digoxin and are due to: Shortening of the atrial and ventricular refractory periods-producing a short QT interval with secondary repolarisation abnormalities affecting the ST segments, T waves and U waves.
Detailed explanation-4: -After-depolarization can initiate a sequence of ventricular extra beats. Digoxin treatment also increases [Ca2+]i but shortens QT (via vagal activation).