ECG Case 076

Rate:

• 66

Rhythm:

• Sinus Arrhythmia

Axis:

• Inferior (+90 deg)

Intervals:

• PR – Normal (~120ms)
• QRS – Normal (~80ms)
• QT – 560-600ms (QTc Bazett ~ 610-630 ms)
  • Note absolute QT interval greater than 1/2 of R-R interval

Segments:

• Up-stroked ST segment I, V2-4

Additional:

• T Wave Inversion aVL, aVR

Interpretation:

• Marked QT Prolongation
  • Secondary to toxic ingestion
  • Using QT-RR Nomogram as described by Chan et al. this patient is ‘at risk’ of developing torsades de pointes

LITFL

• The QT Interval
• Drugs Causing QT Prolongation
• Clinical cases of drug-induced QT prolongation
  • Quetiapine
  • Citalopram
• Polymorphic VT & TdP
  

Article

• Chan A, Isbister GK, Kirkpatrick CMJ, Duffu SB. Drug-induced QT prolongation and torsades de pointes: evaluation of a QT nomogram. QJM2007 100(10):609-615 PMID: 17881416 Full text here