QTc less than 350 ms = short QT syndrome in absence of 2ndry cause .Hypercalcemia shorten QT .
QTc more than 470 ms = long QT .If no acquired cause = long QT syndrome.Hypicalcemia , hypokalemia and hypomagnesemia prolong QT .
RBBB pattern and ST elevation in V1-V3 in a patient with syncope = Brugada syndrome
Late potential or Epsilon wave in ECG or fibrofatty infiltration of the RV on MRI = Arrhythmigenic RV dysplasia.Treatment is ICD if with VT or after surviving cardiac arrest
Only short PR interval in a patient with palpitation = LGL syndrome
ST elevation in mid precordial leads in an otherwise asymptomatic subject = Normal variant early repolarization >>reassure .
Bidirectional VT = digitalis toxicity or a patient with catecholaminergic polymorphic VT >>> beta blockers or CCB .
Long QT with deafness = Nielsen syndrome (AR) .
Long QT with event during swimming or exercise = long QT 1
Long QT with event during auditory stimuli = Long QT2
Long QT with event during sleep or rest = long QT 3 .