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.

A typical day at workA typical day at work

October 29October 29thth, 2009, 2009

So, you get to work, and go to see So, you get to work, and go to see your first patient…your first patient…

21-year-old female with a history of 21-year-old female with a history of "seizure" disorder. She had one of "seizure" disorder. She had one of these events. She has the following these events. She has the following ECG…ECG…

Long QTLong QT

Reading the QT intervalReading the QT interval

CausesCauses

What to watch out forWhat to watch out for

Upper limits of normalUpper limits of normal

Male – 0.44Male – 0.44

Female – 0.46Female – 0.46

Look for longest interval on the ECGLook for longest interval on the ECG

Do it manually!Do it manually!

You’ve been recognized as an You’ve been recognized as an astute diagnostician and astute diagnostician and

prognosticatorprognosticator

As such, in addition to your regular As such, in addition to your regular responsibilities, you’ve been asked to responsibilities, you’ve been asked to predict the future…predict the future…

Uh oh – Diagnosis? Treatment?Uh oh – Diagnosis? Treatment?

Treatment: Torsades de PointesTreatment: Torsades de Pointes

DefibrillationDefibrillation

MagnesiumMagnesium

Overdrive pacingOverdrive pacing

After helping the patient back in to After helping the patient back in to a rhythm more compatible with life, a rhythm more compatible with life,

you do a chart review of you do a chart review of medications. Any concerning?medications. Any concerning?

1. Biaxin1. Biaxin 2. Amiodarone2. Amiodarone 3. Seroquel3. Seroquel 4. Zofran4. Zofran 5. Mefloquine5. Mefloquine

Causes of long QTCauses of long QT 1. Congenital1. Congenital

2. Acquired2. Acquired

AcquiredAcquired A) DrugsA) Drugs

B) LytesB) Lytes

C) Intracranial – CVA, SAHC) Intracranial – CVA, SAH

D) Cardiac pathology (ischemia, CHF, myocarditis)D) Cardiac pathology (ischemia, CHF, myocarditis)

E) Severe bradycardiaE) Severe bradycardia

F) AnorexiaF) Anorexia

G) Thyroid – hyper or hypoG) Thyroid – hyper or hypo (Aust Prescr 2002;25:63–5)(Aust Prescr 2002;25:63–5)

Drugs, drugs, drugsDrugs, drugs, drugs

Lots of drugs implicated in acquired long Lots of drugs implicated in acquired long QT – QT –

1.1. Antibiotics – macrolides, Antibiotics – macrolides, fluoroquinolonesfluoroquinolones

2.2. Antipsychotics – haldol, risperdal, Antipsychotics – haldol, risperdal, seroquel, fluphenazine, clozarilseroquel, fluphenazine, clozaril

3.3. Antiarrhythmic – amiodarone, Antiarrhythmic – amiodarone, sotalol, procainamidesotalol, procainamide

4.4. Antinausea - domperidone, zofranAntinausea - domperidone, zofran

More drugs…More drugs…

Antifungals – fluconazole, Antifungals – fluconazole, ketoconazoleketoconazole

Antidepressants – TCAs, SSRIsAntidepressants – TCAs, SSRIs Antimalarials – quinidine, Antimalarials – quinidine,

mefloquine, chloroquinemefloquine, chloroquine Moral of the story – if it’s Anti Moral of the story – if it’s Anti

Something, it may be Pro – long Something, it may be Pro – long QTc. QTc.

www.QTdrugs.orgwww.QTdrugs.org

You’re asked to take a phone call You’re asked to take a phone call from a hospital administrator. He from a hospital administrator. He

tells you that resources are limited.tells you that resources are limited.

AHS wants you to tighten up your AHS wants you to tighten up your investigations. It has mandated that investigations. It has mandated that you can only do one test on your next you can only do one test on your next patient, who has the following ECG: patient, who has the following ECG:

Lytes and long QTLytes and long QT

1. Hypokalemia1. Hypokalemia

2. Hypomagnesemia2. Hypomagnesemia

3. Hypocalcemia3. Hypocalcemia

Next in the triage list…Next in the triage list…

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

He happens to mention…He happens to mention…

His father died suddenly when he His father died suddenly when he was 30was 30

He’s had multiple fainting spells He’s had multiple fainting spells beforebefore

What do you want to do?What do you want to do?

Congenital - LQTSCongenital - LQTS

1 in 2500-5000 people1 in 2500-5000 people Collection of genetically distinct Collection of genetically distinct

disorders disorders Results from mutations in cardiac Results from mutations in cardiac

potassium and sodium ion channels potassium and sodium ion channels (channelopathies)(channelopathies)

Congenital LQTS formsCongenital LQTS forms

Romano-WardRomano-Ward Jervell and Lang-NielsenJervell and Lang-Nielsen AndersenAndersen TimothyTimothy

Precipitants of arrhythmias in Precipitants of arrhythmias in patients with LQTSpatients with LQTS

Variety of adrenergic stimuli -Variety of adrenergic stimuli - ExerciseExercise EmotionEmotion Loud noiseLoud noise Swimming (cold water)Swimming (cold water) Sleep may also precipitateSleep may also precipitate

Your next patient…Your next patient…

Doesn’t have a heart problem!Doesn’t have a heart problem! 40 year old woman with chest pain – 40 year old woman with chest pain –

turns out it’s a pneumothorax but in turns out it’s a pneumothorax but in the process of working her up, you do the process of working her up, you do an ECG which shows an incidental an ECG which shows an incidental QTc of 450. Are you worried about QTc of 450. Are you worried about this?this?

Copyright ©2009 BMJ Publishing Group Ltd.

Johnson, J N et al. Br J Sports Med 2009;43:657-662

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;43:657-662

Distribution of QTc values for patients with and without long QT syndrome (LQTS).

LQTS Probability Score LQTS Probability Score (Schwartz score)(Schwartz score)

Clinical history of syncope with stress – 2 pointsClinical history of syncope with stress – 2 points Clinical history of syncope without stress – 1 pointClinical history of syncope without stress – 1 point Congenital deafness – 0.5 pointsCongenital deafness – 0.5 points Family history of long QT syndrome – 1 pointFamily history of long QT syndrome – 1 point Unexplained sudden death of 1Unexplained sudden death of 1stst degree family member < degree family member <

30 years – 0.5 points30 years – 0.5 points QTc 450-460 – 1 pointQTc 450-460 – 1 point QTc 460-480 – 2 pointsQTc 460-480 – 2 points QTc >480 – 3 pointsQTc >480 – 3 points Torsades de Pointes – 2 pointsTorsades de Pointes – 2 points 3 leads with notched T waves – 1 point3 leads with notched T waves – 1 point T wave alterans – 1 pointT wave alterans – 1 point Bradycardia < 2Bradycardia < 2ndnd percentile for age – 0.5 points 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 On your way to see your next patient you run in to your CCU colleague. He pimps (presents) you to your CCU colleague. He pimps (presents) you

with the following scenario…with the following scenario… Previously healthy 49-year-old man who Previously healthy 49-year-old man who

presents with progressive muscle presents with progressive muscle weakness and constipation. He has no weakness and constipation. He has no chest pain or dyspnea. The ECG is most chest pain or dyspnea. The ECG is most consistent with? consistent with? 

A) HypokalemiaA) Hypokalemia B) HyperkalemiaB) Hyperkalemia C) HypocalcemiaC) Hypocalcemia D) HypercalcemiaD) Hypercalcemia E) Hypothyroidism E) Hypothyroidism

Short QTShort QT

Much shorter list:Much shorter list:

HypercalcemiaHypercalcemia DigoxinDigoxin Hereditary short QTHereditary short QT

Well done, doctorWell done, doctor

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

ReferencesReferences 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;88:782–784.

3. www.QTdrugs.org

4. 4. Johnson, J N et al. Br J Sports Med 2009;43:657-662

5. Aust Prescr 2002;25:63–5

6. ECG Wave-Maven www.ecg.bidmc.harvard.edu/maven

7. Uptodate.com