Clinical Teaching Case

Anthony Battad MD, FRCPCUniversity of Manitoba

Disclosures

• None

The case of Ms. LM

• 55 year old aboriginal female:– DM II with variable glucose control– HTN, Dyslipidemia– Femoral artery aneurysm (2003) – no sequelae– Hypothyroidism

• Meds: amlodipine, metoprolol, L-thyroxine, glyburide, metformin, pioglitazone

Case…

• 8 Aug – presents to Pauingassi Nursing Station with “chest heaviness”– Discharged home without specific treatment

• 9 Aug – unprovoked syncope with transient LOC at home– Still has 4/10 chest heaviness

• EKG done and faxed to St. Boniface Hospital

EKG – Aug 9

Striking Features?

Deep T wave inversion

Prolonged QT

Case…

• Patient urgently transferred to St. Boniface Hospital ER

• In ER, V-fib arrest: 3-4 minutes CPR restoration of pulse, BP, sinus rhythm

• Rhythm strip is not torsade de pointes

EKG – Aug 9 (ER-post arrest)

594 msec

Wellen’s sign

Repeat EKG – Aug 10

720 msec

biphasic

Wellen’s sign

Case…

• 10 Aug – cardiac cath: no significant stenoses• 11 Aug – echo: mild LV dilation, EF = 50 – 60%• 12 Aug – cardiac MRI: normal• 12 Aug – CT Head: nil acute• 14 Aug – EP consult• 15 Aug – ICD placed

Case…

• 25 Aug – discharged home

• Final Diagnosis: Prolonged QT, likely congenital– note normal QT on an EKG 2 years prior

• Advise given for EKG screening to family members

Prolonged QT

• > 450 msec men• > 470 msec women• > 500 msec “very abnormal”• QTc = QT ÷ √ R-R

Prolonged QT

• Congenital– Jervell & Lange-Nielson

Syndrome– Romano-Ward Syndrome– Idiopathic

• Acquired– Metabolic: hyperkalemia,

hypocalcemia, hypomagnesemia, starvation, anorexia

– Anti-arrythmics: quinidine, amiodorone, sotalol

– Anti-histamines: terfenadine, astemizole

– Psychotropics: TCA, haloperidol– Other meds: SSRI, methadone,

protease inhibitors, levofloxacin, voriconazole

Top 20 Drugs

Sotalol – 4.7%CisaprideAmiodorone – 0.34 %Erythromycin – 0.18 %IbutilideTerfenadineQuinidine – 0.45 %ClarithromycinHaloperidol – 0.14 %Fluoxetine – 0.03 %

Digoxin – 0.1 %ProcainamideTerodilineFluconazoleDisopyramideBepridilFuroseamide – 0.1 %ThioridazineFlecainideLoratidine

Dapro (2001), Eur Heart J

Clinical Features

• Palpitations• Syncope• Seizures• Sudden cardiac death – Torsade de Pointes

V-fib arrest

Diagnosis

• Single ECG not 100 % sensitive– “average” QT– Ambulatory monitoring

• Certain features for congenital QT• EP not part of routine testing

Management: ACC/AHA/ECS

• Lifestyle modification– Avoid QT prolonging drugs– Avoid strenuous exercise

• Beta Blockers (+/-) DDD pacing to reduce QT• Implantable Cardiac Defibrillator (ICD)– Sustained VT and/or syncopal event while on β-

blocker therapy