A typical day at work October 29 th, 2009

So, you get to work, and go to see your first patient… 21-year-old female with a history of "seizure" disorder. She had one of these events. She has the following ECG… 21-year-old female with a history of "seizure" disorder. She had one of these events. She has the following ECG…

Long QT Reading the QT interval Reading the QT interval Causes Causes What to watch out for What to watch out for

Upper limits of normal Male – 0.44 Male – 0.44 Female – 0.46 Female – 0.46 Look for longest interval on the ECG Look for longest interval on the ECG Do it manually! Do it manually!

You’ve been recognized as an astute diagnostician and prognosticator As such, in addition to your regular responsibilities, you’ve been asked to predict the future… As such, in addition to your regular responsibilities, you’ve been asked to predict the future…

Uh oh – Diagnosis? Treatment?

Treatment: Torsades de Pointes Defibrillation Defibrillation Magnesium Magnesium Overdrive pacing Overdrive pacing

After helping the patient back in to a rhythm more compatible with life, you do a chart review of medications. Any concerning? 1. Biaxin 1. Biaxin 2. Amiodarone 2. Amiodarone 3. Seroquel 3. Seroquel 4. Zofran 4. Zofran 5. Mefloquine 5. Mefloquine

Causes of long QT 1. Congenital 1. Congenital 2. Acquired 2. Acquired

Acquired A) Drugs A) Drugs B) Lytes B) Lytes C) Intracranial – CVA, SAH C) Intracranial – CVA, SAH D) Cardiac pathology (ischemia, CHF, myocarditis) D) Cardiac pathology (ischemia, CHF, myocarditis) E) Severe bradycardia E) Severe bradycardia F) Anorexia F) Anorexia G) Thyroid – hyper or hypo G) Thyroid – hyper or hypo (Aust Prescr 2002;25:63–5) (Aust Prescr 2002;25:63–5)

Drugs, drugs, drugs Lots of drugs implicated in acquired long QT – 1. Antibiotics – macrolides, fluoroquinolones 2. Antipsychotics – haldol, risperdal, seroquel, fluphenazine, clozaril 3. Antiarrhythmic – amiodarone, sotalol, procainamide 4. Antinausea - domperidone, zofran

More drugs… Antifungals – fluconazole, ketoconazole Antifungals – fluconazole, ketoconazole Antidepressants – TCAs, SSRIs Antidepressants – TCAs, SSRIs Antimalarials – quinidine, mefloquine, chloroquine Antimalarials – quinidine, mefloquine, chloroquine Moral of the story – if it’s Anti Something, it may be Pro – long QTc. Moral of the story – if it’s Anti Something, it may be Pro – long QTc.

You’re asked to take a phone call from a hospital administrator. He tells you that resources are limited. AHS wants you to tighten up your investigations. It has mandated that you can only do one test on your next patient, who has the following ECG: AHS wants you to tighten up your investigations. It has mandated that you can only do one test on your next patient, who has the following ECG:

Lytes and long QT 1. Hypokalemia 1. Hypokalemia 2. Hypomagnesemia 2. Hypomagnesemia 3. Hypocalcemia 3. Hypocalcemia

Next in the triage list… 25 year old guy passed out while he was swimming. He feels fine now and wants to go home. He has the following ECG… 25 year old guy passed out while he was swimming. He feels fine now and wants to go home. He has the following ECG…

He happens to mention… His father died suddenly when he was 30 His father died suddenly when he was 30 He’s had multiple fainting spells before He’s had multiple fainting spells before What do you want to do? What do you want to do?

Congenital - LQTS 1 in people 1 in people Collection of genetically distinct disorders Collection of genetically distinct disorders Results from mutations in cardiac potassium and sodium ion channels (channelopathies) Results from mutations in cardiac potassium and sodium ion channels (channelopathies)

Congenital LQTS forms Romano-Ward Romano-Ward Jervell and Lang-Nielsen Jervell and Lang-Nielsen Andersen Andersen Timothy Timothy

Precipitants of arrhythmias in patients with LQTS Variety of adrenergic stimuli - Variety of adrenergic stimuli - Exercise Exercise Emotion Emotion Loud noise Loud noise Swimming (cold water) Swimming (cold water) Sleep may also precipitate Sleep may also precipitate

Your next patient… Doesn’t have a heart problem! Doesn’t have a heart problem! 40 year old woman with chest pain – turns out it’s a pneumothorax but in the process of working her up, you do an ECG which shows an incidental QTc of 450. Are you worried about this? 40 year old woman with chest pain – turns out it’s a pneumothorax but in the process of working her up, you do an ECG which shows an incidental QTc of 450. Are you worried about this?

Copyright ©2009 BMJ Publishing Group Ltd. Johnson, J N et al. Br J Sports Med 2009;43: Effect of clinical setting on the relative probability of having long QT syndrome (LQTS).

Copyright ©2009 BMJ Publishing Group Ltd. Johnson, J N et al. Br J Sports Med 2009;43: Distribution of QTc values for patients with and without long QT syndrome (LQTS).

LQTS Probability Score (Schwartz score) Clinical history of syncope with stress – 2 points Clinical history of syncope with stress – 2 points Clinical history of syncope without stress – 1 point Clinical history of syncope without stress – 1 point Congenital deafness – 0.5 points Congenital deafness – 0.5 points Family history of long QT syndrome – 1 point Family history of long QT syndrome – 1 point Unexplained sudden death of 1 st degree family member < 30 years – 0.5 points Unexplained sudden death of 1 st degree family member < 30 years – 0.5 points QTc – 1 point QTc – 1 point QTc – 2 points QTc – 2 points QTc >480 – 3 points QTc >480 – 3 points Torsades de Pointes – 2 points Torsades de Pointes – 2 points 3 leads with notched T waves – 1 point 3 leads with notched T waves – 1 point T wave alterans – 1 point T wave alterans – 1 point Bradycardia < 2 nd percentile for age – 0.5 points Bradycardia < 2 nd percentile for age – 0.5 points Schwartz PJ, Moss AJ, Vincent GM, Crampton RS. Diagnostic criteria for the long QT syndrome. An update. Circulation 1993;88:782–784.

On your way to see your next patient you run in to your CCU colleague. He pimps (presents) you with the following scenario… Previously healthy 49-year-old man who presents with progressive muscle weakness and constipation. He has no chest pain or dyspnea. The ECG is most consistent with? Previously healthy 49-year-old man who presents with progressive muscle weakness and constipation. He has no chest pain or dyspnea. The ECG is most consistent with? A) Hypokalemia A) Hypokalemia B) Hyperkalemia B) Hyperkalemia C) Hypocalcemia C) Hypocalcemia D) Hypercalcemia D) Hypercalcemia E) Hypothyroidism E) Hypothyroidism

Short QT Much shorter list: Much shorter list: Hypercalcemia Hypercalcemia Digoxin Digoxin Hereditary short QT Hereditary short QT

Well done, doctor Once again, you’ve stamped out disease. Patients and staff alike cheer as you leave the department. Once again, you’ve stamped out disease. Patients and staff alike cheer as you leave the department.

References 1. European Heart Journal February 20, 2007 Clinical diagnosis of long QT syndrome: back to the caliper. Tom Rossenbacker1 and Silvia G. Priori2 2. Schwartz PJ, Moss AJ, Vincent GM, Crampton RS. Diagnostic criteria for the long QT syndrome. An update. Circulation 1993;88:782– Johnson, J N et al. Br J Sports Med 2009;43: Aust Prescr 2002;25:63–5 6. ECG Wave-Maven 7. Uptodate.com