A long QT interval is more than 440 msec in men, or more than 460 msec in women. If it is more than 500 msec, there is an increase risk of Torsades de pointes.
Causes of QT prolongation include medications, electrolyte disturbances and ischemia.
In overdose, the risk of arrhythmia (Torsades de pointes) is more closely related to the absolute than corrected QT. This is plotted on the QT normogram along with the heart rate and if the result is above the line there is a risk of Torsades.
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Groups of Signs
Variations: QT interval
This ECG is from a dialysis patient who presented with diaphoresis and muscle cramps.
This ECG shows subtly peaked T waves and long ST segments causing a long QT interval. The cause was hyperkalemia (6.6) and hypocalcemia.
This ECG is from a middle aged male who presented with diffuse pain on a background of sickle cell disease.
This ECG shows LVH, diffuse ST depression with ST elevation in aVR and apparrent prolonged QTc due to U waves. The cause was hypokalemia (2.6).
This ECG is from a woman in her 30s who presented with cramping following thyroid surgery.
This ECG shows prolonged QT due to long ST segment, no U waves, but also a prolonged QRS and PR. There was hypocalcemia, mild hyperkalemia and hypermagnesemia.
This ECG is from a patient with a history of diabetes who was found with a GCS of 4.
This ECG shows sinus rhythm with peaked T waves that were so narrow they were mistaken for separate QRS complexes. The cause was hyperkalemia due to acute renal failure.
This ECG is from a middle-aged man who presented with chest pain, tachycardia 130 bpm and BP 50/30. He was alert but cool and clammy. His background was unclear, but he mentioned chronic dyspnoea, 'cancer' and 'chest'. Fluids were started. This ECG was recorded the next day, after the arrhythmia recurred and was treated with ibutilide.
This ECG is from a young woman who presented with status epilepticus seizures and an apparent overdose of bupropion, with possible cocaine ingestion. She was intubated and given propofol and benzodiazepines, which terminated the seizures, and then a PEA arrest was terminated with epinephrine and bicarbonate. This was the repeat ECG the next day.
Where did they come from?
These ECGs were collected from Free Open Access Medical Education (#FOAMed) blogs, with the permission of their authors. You can find out more about each ECG's source by clicking on it.
Why are they here?
This is an experiment in digital curation. The idea is to collect resources to increase awareness and accessibility. Over time, more ECGs in the collection will be tagged to make it easier to find them and reused in new interactive quizzes.
How can I use these ECGs?
You can use these ECGs for your own learning, teaching or research - as long as you abide by the terms of each ECG's copyright licence as stipulated by the original author.