Long QT

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.

Featured Example

References

Related

ECG Library (58)

Sort by:
TitleDate
ASCDESC
Show:
31230
Columns:
In the ECGquest archives, this ECG has been tagged with: - 12-Lead Long QT Tall U waves Hypokalemia Dr Smith's ECG Blog CC BY-NC
“Long QT” after droperidol

This ECG is from a patient who presented wuth altered mental status and falls soon after treatment for intractable hiccups.

This ECG shows large U waves and long QU interval due to hypokalemia (1.7).

In the ECGquest archives, this ECG has been tagged with: - Muscle pains 12-Lead Long QT Peaked T waves Hyperkalemia Hypocalcaemia Dr Smith's ECG Blog CC BY-NC
Patient with Dyspnea. You are handed a triage ECG interpreted as “normal” by the computer. ‘Baseline’ ECG

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.

In the ECGquest archives, this ECG has been tagged with: - 12-Lead Long QT Hypokalemia Dr Smith's ECG Blog CC BY-NC
Potassium and Magnesium: how low is too low?

This ECG is from a woman in her 30s who presented with vomiting, diarrhoea and cough for 2-3 days.

This ECG shows long QTc due to hypokalemia. She was found unresponsive in VF shortly after and required defibrillation.

In the ECGquest archives, this ECG has been tagged with: - Vomiting Weakness 12-Lead Long QT Hypocalcaemia Dr Smith's ECG Blog CC BY-NC
A Pathognomonic ECG. What is it?

This ECG is from a patient of unknown age who presented with weakness, decreased urine output and vomiting.

This ECG shows long QT due to a long ST segment without altering the T wave, caused by hypocalcemia.

In the ECGquest archives, this ECG has been tagged with: - 12-Lead Long QT ST elevation in aVR Tall U waves Widespread ST depression Hypokalemia Dr Smith's ECG Blog CC BY-NC
Diffuse ST depression, and ST elevation in aVR. Left main, right?

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).

In the ECGquest archives, this ECG has been tagged with: - 12-Lead Long PR Long QT Wide QRS Hyperkalemia Hypocalcaemia ECG of the Week CC-BY-NC-SA
ECG of the Week – 31st December 2018 – Interpretation

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.

In the ECGquest archives, this ECG has been tagged with: - Loss of consciousness 12-Lead Long QT Peaked T waves Hyperkalemia Hypocalcaemia Dr Smith's ECG Blog CC BY-NC
Found comatose with prehospital ECG showing “bigeminal PVCs” and “Tachycardia at a rate of 156”

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.

In the ECGquest archives, this ECG has been tagged with: - Weakness 12-Lead Long QT T-U waves Tall U waves Hypokalemia Dr Smith's ECG Blog CC BY-NC
A young man with back spasms

This ECG is from a young man who presented with weakness and back pain on a background of an eating disorder and chronic kidney disease.

In the ECGquest archives, this ECG has been tagged with: - 12-Lead Serial 12-lead Long QT Regular Short QRS Tachycardia Sinus tachycardia Pericardial effusion Dr Smith's ECG Blog CC BY-NC
A Middle-Aged Man with Chest pain, Hypotension and Tachycardia: Next day, after ibutilide

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.

In the ECGquest archives, this ECG has been tagged with: - Weakness 12-Lead Long QT Tall U waves Hypokalemia Dr Smith's ECG Blog CC BY-NC
A pathognomonic ECG you should recognize instantly

This ECG is from a patient of unknown age who presented with generalised weakness and malaise.

In the ECGquest archives, this ECG has been tagged with: - Cardiac arrest 12-Lead Anterior ST elevation Long QT R in aVR Dr Smith's ECG Blog CC BY-NC
Bupropion Overdose Followed by Cardiac Arrest and, Later, ST Elevation. Is it STEMI? Repeat ECG the next day

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.