someone stands still long enough, you will get an EKG on...
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9/26/2013 1 Jennifer Carlquist PA‐C, CAQ ER Cardiology Physician Assistant, Central Coast Cardiology ER Physician Assistant, Salinas Valley Memorial “If someone stands still long enough, you will get an EKG on them.” – Dr. Fajardo Learning objectives What is a qt interval ? How do you calculate it? What prolongs it (causes)? What does the public know? What does the evidence say? What is the reality? Who is really high risk? This is what all the fuss is about.
Transcript of someone stands still long enough, you will get an EKG on...
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Jennifer Carlquist PA‐C, CAQ ERCardiology Physician Assistant, Central Coast CardiologyER Physician Assistant, Salinas Valley Memorial
“If someone stands still long enough, you will get an EKG on them.” –Dr. Fajardo
Learning objectives
What is a qt interval ? How do you calculate it? What prolongs it (causes)? What does the public know? What does the evidence say? What is the reality? Who is really high risk?
This is what all the fuss is about.
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You can’t find it if you don’t look for it.
High index of suspicion
Syncope/Near syncope/Lightheadedalgorithm
4 Things you need to look for every time.
Without fail. HOCM
WPW
Prolonged QT
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Psyche clearance
38 y/o femaleSuicidal
Meds: Paxil
Can you rely on the machine interpretation?
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Corrected Qt Formula
Bazett's Formula = QT Interval / √ (RR interval)
or…..
http://www.mdcalc.com/corrected‐qt‐interval‐qtc/
The DL on the QT
30‐50% of patients are symptomatic
How long is too long? ‐Men: > 450ms‐Women: >460ms
Even the experts can’t be pinned down
“Bazett’s over corrects at fast heart rates.Fredericia over corrects at slow heart rates.There is no perfect correction factor.All agree that uncorrected QT > 500 is distinctly abnormal.”
Richard J Kovacs MDProfessor of Clinical Medicine
Associate Dean for Clinical ResearchIndiana University School of Medicine
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Sean Nordt, MD
“Qt greater than 600 is when I worry The machine actually calculates it “pretty well” For most patients, let the machine do it!”
QTC is where the money is
Is the hr correct? The most prolonged qt ever…
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Or was it?
Focusing on correctable causes
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Congenital: epidemiology
Congenital long QT syndrome (LQTS) is an inherited disease characterized by prolongation of ventricular myocyte repolarization
QT prolongation, syncopal episodes, VT/VF 1 in 2000 ‐ 7000 live births Causes 3000 deaths a year
There are usually clues…
Seizures
LOC teen years
Syncope during fright
This is a bad sign….
“These data establish a mechanism linking T‐wave alternans of the ECG to the pathogenesis of sudden cardiac death….”
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Theories
Imbalance in cardiac sympathetic innervation And/or intra cardiac abnormality prob related to K currents
And/or inadequate shortening of qt with Increase of HR
Lancet:1136‐1138 1988
It may be easier to say what’s not on the list…
Known/possible offenders
• Biaxin• Zithromax• Oxafloxacin
Antibiotics
• Zofran• Inapsine• Pepcid
Gi Meds
Known/possible offenders
• Amiodarone• Sotolol• RanexaCardiac
• Geodon/Lithium• Haldol• Effexor/SeroquelPsyche
Misc: Tamoxifen, Quinidine
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Known/possible offenders
• Benadryl• FluconazoleMisc
• Grapefruit juice• Energy drinksFoodMeds that inhibit the P450
Common combos we give
Amiodarone and Quinalones Zithromax and Zofran Pepcid and Zofran
Here’s a different way to look at it…
http://www.azcert.org/
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This can work for us…or against us
Yet one more substance to worry about
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Case 1 ‐ 51 year old Felt unwell “like the water ran out of me” Under stress HX: HTN, psyche, chronic neck pain Drank alcohol, etoh, did cocaine
Called 911…
EMS says… “Had an episode of urinary incontinence, pt felt weak”
Dizzy, dyspnea, chest discomfort Field EKG: Sinus tachycardia with borderline stelevation in V1, V2 with one PVC
Then goes into torsades….
Is shocked at 200 j once, brief CPR
Post shock in ER Off the QT prolonging meds
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What were her risks?
K was 2.7 Qt prolonging meds Did cocaine Double methadone
Hx of previous long qt…. Female
At clinic visit
“I think I need something stronger for pain… I didn’t take my blood pressure medication as it was too expensive…
I did take my nieces medication, it starts with an L
I did take two methadone that day for pain”
Clinic EKG Her med list…
Prozac Methadone Trazadone Pepcid Risperidal
Xanax, Neurontin
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They had to rule out structural causes
Cath neg Echo: moderate LAE ef 65%
“No structural reason for Vtach…”
Review of a prevER visit last year
Had prolonged qt of 550 Had a low K of 3.1
“My doctor told me that I show work on my potassium, but I was too busy…”
Routine EKG in 2012
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You bought yourself an ICD…
If you are….
‐A post cardiac arrest survivor with this‐ Persistently above 550 ms‐ Persistent sx despite beta blockade
Case 2 ‐ 53 year old Vomiting x 3 d “every hour” Felt weak HX: HTN. No chest pain, dyspnea. But….
Called 911…
Case #3 Repeat EKG
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Case 4 ‐54 year old Syncope during dialysis, preceded by a headache VS: 213/106, HR 113, RR 19, RA 100% HX: HTN. Labs: K – 2.7. Head CT WNL. Trop ‐
Called 911… “Code 3”
DX: Hypo K post dialysis
Case 5Case 6 ‐22 year old
“Still coughing.” Cough is better. “But I REALLY think I need antibiotics.”
Bounceback
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Feels worse today.Cough better, but feels
“weak and lightheaded”.
VS: 130/80, 90, 98% RA. RR: 16
“Pt. asked for abx, 3 d of sx. 2 day recheck, agreed if not feeling better, would rx abx.”
Impression: Bronchitis
Plan::Avelox Samples
Given
Her EKG Case 7 –29 y/o fever
Fever x 2 weeks (Tmax 104.5) ROS: Abd pain, diarrhea, (hx ulcerative colitis) anxiety, fatigue, dry cough, orthopnea
VS: 130/66, HR 111, RR 18 02 sat 99% Exam: Tender abd x 4, no rash, no edema
Differentials: Lyme, PE, PNA Acute abd, colitis, pericarditisand…
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Why would a 29 year old have 3 conduction abnormalities?
CXR: “water bottle” heart, no PNA CT abd: descending and sigmoid colitis with no abscess formation
Labs: Hgb 8.8, + guaic, CBC, CMP normal, CRP 190, mono negative, BNP 4884, Trop .71
EKG #2 –done 3 hours later Myocarditis!
Heart block + troponin BNP 4884 (CXR water bottle) Elevated CRP 190 Fever x 2 weeks (Tmax 104) Prolonging Intervals over a 2 hour span
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Case 8 ‐ 30 y/o female “palpitations”
If there is a bad outcome, who will be at fault?
Where does that leave us?
How do they know who not to give the drug to? How can you determine who the 1 patient in 7,000 is?
Will an EKG be required before its use? Will providers write fewer prescriptions? Will hospitals revert to inferior antiemetic drugs?
Lawyers now have free reign. Who suffers?
Can we give ZMAX?
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FDA Statement regarding azithromycin(Zithromax) and the risk of cardiovascular death 05‐17‐2012] The U.S. Food and Drug Administration (FDA)
is aware of the study published in the New England Journal of Medicine, onMay 17, 2012, that compared the risks of cardiovascular death in patients treated with azithromycin (Zithromax), amoxicillin, ciprofloxacin (Cipro), levofloxacin (Levaquin), and no antibacterial drug. The study reported a small increase in cardiovascular deaths, and in the risk of death from any cause, in persons treated with a 5‐day course of azithromycin (Zithromax) compared to persons treated with amoxicillin, ciprofloxacin, or no drug.
Clear as mudAntibiotic AzithromycinWon't Harm Healthy Hearts: Study –may 1, 2013
Our study shows no increased risk in the general population of young and middle‐aged adults," he said. That, he added, "would reinforce the hypothesis that any increased risk of cardiovascular [death] associated with azithromycin is restricted to high‐risk patients ‐‐ for instance [those] with a history of cardiovascular disease.“
The risk for those with existing heart disease is still unclear, he said. Fonarow said
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Lets talk antibiotics
85 deaths for every 1 million Zithromax courses of treatment
32 deaths for every 1 million amoxicillin courses of treatment
30 deaths for every 1 million courses of non‐antibiotic treatment
JpnJ Pharmacol. 2001 Nov; 87(3):231‐4.
Who gives 32 mg anyway?
ISSUE: The U.S. Food and Drug Administration (FDA) is informing healthcare professionals and the public that preliminary results from a recently completed clinical study suggest that a 32 mg single intravenous dose of ondansetron (Zofran, ondansetron hydrochloride, and generics) may affect the electrical activity of the heart (QT interval prolongation), which could pre‐dispose patients to develop an abnormal and potentially fatal heart rhythm known as Torsadesde Pointes.
The use of a single 32 mg intravenous dose of ondansetron should be avoided. New information indicates that QT prolongation occurs in a dose‐dependent manner, and specifically at a single intravenous dose of 32 mg.
Patients who may be at particular risk for QT prolongation with ondansetron are those with congenital long QT syndrome, congestive heart failure, bradyarrhythmias, or patients taking concomitant medications that prolong the QT interval
Electrolyte abnormalities (e.g., hypokalemia or hypomagnesemia) should be corrected prior to the infusion of ondansetron.
no single intravenous dose of ondansetron should exceed 16 mg due to the risk of QT prolongation.
The new information does not change any of the recommended oral dosing regimens for ondansetron, including the single oral dose of 24 mg for chemotherapy induced nausea and vomiting.
Pic of zofran and bullets flying in
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Droperidol
“Newer data suggest that the incidence of prolongation of the QT interval and the occurrence of torsades de pointes is similar to more expensive alternative medications used to treat postoperative nausea and vomiting”
CurrOpinAnaesthesiol. 2010 Jun;23(3):423‐7.
Zofran 3 clinical studies Each study included very small numbers of patients, mostly following general anesthesia (which itself impacts QT intervals)
no one in any of the trials was harmed by the drug.
Study #2
85 patients under going anaesthetic not randomized and there were no placebo groups 13% had QT after > 500 ms No one had adverse effects At highest doses 120 minutes max No healthy volunteers
Anesthesiology. 2005 Jun;102(6):1094‐100.
BUT…
Just because it is prolonged…doesn’t mean the risk for torsades is increased.
WHAT???
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Lets take amiodaronefor example
2878 people in a trial Less than 0.7% torsades Amiodarone up to 80 ms Sotolol 10–40 ms
Cases of torsades?
(with non‐antiarrhythmics) less than one case per 10 000 or 100 000
(with antiarrhythmics) (including dofetilide, quinidine, and sotalol)
up to 3% of all patients who receive them
European Society of Cardiology. Eur Heart J. 2000;21:1216–31.
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Drug ordering alerts –warranted?
If ECGs were recorded before and after QTcoverrides, clinically relevant QTc prolongation was
found in one‐third of cases (31%)
Br J Clin Pharmacol 2009 Mar;67(3):347‐54
What’s the actual risk?
Risk is actually low for torsades Risk increases if: female, hypokalemia, hypomagnesium, bradycardic , polypharmacy
Biggest risk: Congenital prolonged QT + QT prolonging agent
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Pearls
1. Replete K before QT prolonging meds2. Review med reconciliation forms3. Risk vs benefit ratio4. Ask history 5. Document the conversation
Which ones can we fix?
DRUGS
Hypo • Thermia
Hypo• Ca++• K+• Mag+
Drugs
• MI, Raised ICP, Long QT syndrome
3 minutes. 3 questions. Final thoughts…When all else fails, do nothing.
Dead People Don’t get Bronchitis
“Musings of a DistractableMind” – Dr. Rob
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Electronic Resources
EKG Wave Maven 12 Lead EKG Challenge App (by: Limmer) ECG Guide App (by: QxMD) Cardiology Draw MD Azcert.org
