Transcript ECG Practice Cases: Part 2 Arrythmias

ECG PRACTICE CASES:
PART 2 ARRHYTHMIAS
Megan Chan, PGY-1
UHCMC 2015
ttp://thepracticalpsychosomaticist.com/2013/04/01/qtc-interval-prolongation-andantipsychotics-by-elysha-elson-pharm-d-mph/
71 Y/O FEMALE WITH SOB
DIAGNOSIS?
WHAT CAN CAUSE AFIB?
Afib with RVR (HR 140)
Nonspecific ST & T wave changes
ATRIAL FIBRILLATION
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Etiology
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HTN
CAD
Valvular heart disease
Thyrotoxicosis
ETOH abuse
Pericarditis
Post-operative state
Treatment
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http://www.riversideonline.com/source/images/image_popup/hb7_afib.jpg
Medication
Rate control: beta blockers, diltiazem, digoxin
 Rhythm control: amiodarone, quinidine, procainamide
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DC-Synchronized Cardioversion
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Esp if associated with MI, hypotension, or pulmonary
edema
43 Y/O FEMALE IN CLINIC FOR FOLLOW UP
HER ECG 2 YEARS AGO
DIAGNOSIS?
HER ECG 2 YEARS AGO
Sinus tach (HR ~100) with RBBB and a PVC
HER CURRENT ECG
DIAGNOSIS?
New Aflutter with 2:1 conduction
Old RBBB
AFLUTTER
http://www.medicine-on-line.com/html/ecg/e0001en_files/08.htm
http://www.learntheheart.com/ecg-review/ecg-topic-reviews-and-criteria/atrial-flutter-review/
ATRIAL FLUTTER
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Etiology:
Pulmonary disease—e.g. pulmonary HTN, PE
 Valvular/ischemic heart disease
 ETOH abuse
 Pericarditis
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Treatment:
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Cardioversion
Medications—similar to Afib tx but don’t use quinidine or
procainamide as these can decrease atrial conduction to 1:1
 DC cardioversion
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Ablation—esp if sawtooth is down-going
67 Y/O FEMALE WITH PALPITATIONS
DIAGNOSIS?
SVT with LVH
(Narrow complex tachycardia, HR 165)
(R in I > 14, R in aVL > 12, S in V2 + R in V6 > 35)
SUPRAVENTRICULAR TACHYCARDIA
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Pathophysiology:
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AV nodal reentrant tachycardia (AVNRT)
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2 pathways (1 fast, 1 slow) within the AV node
 Common “slow-fast” AVNRT = anterograde conduction via slow
pathway, retrograde conduction via fast pathway
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Uncommon “fast-slow” AVNRT = anterograde conduction via
fast pathway, retrograde conduction via slow pathway
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ECG: no discernible P waves (inverted P buried within QRS complex)
because the atria and ventricles activate simultaneously. Pseudo R
waves in V1 or V2.
ECG: inverted P wave that falls after the QRS because the atria
activation is delayed
Orthodromic AV reentrant tachycardia (AVRT)
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An accessory pathway between the atria and ventricle that conducts
retrogradely
ECG: P waves may or may not be discernable depending on the
rate. Accessory pathway is far enough from the AV node that there is
a difference in timing of activation of the atria and ventricles.
AVNRT vs AVRT
2 pathways within the
AV node
Accessory pathway
between atrium and
ventricle
http://en.wikipedia.org/wiki/File:AV_nodal_reentrant_tachycardia.png
Common AVNRT
No pseudo R
waves during
sinus rhythm
Pseudo R
waves in V1
Uncommon AVNRT
P waves in
yellow falling
after QRS
http://lifeinthefastlane.com/ecg-library/svt/
http://imgarcade.com/1/avrt-vs-avnrt-ecg/
WHAT TYPE OF SVT IS THIS?
WHAT TYPE OF SVT IS THIS?
Pseudo R waves
Common AVNRT
SUPRAVENTRICULAR TACHYCARDIA
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Etiology
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Ischemic heart disease
Digoxin toxicity
Excessive caffeine/amphetamine
Excessive ETOH
Atrial flutter with RVR
WHAT IS YOUR NEXT STEP IN MANAGEMENT?
SUPRAVENTRICULAR TACHYCARDIA
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Treatment
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Maneuvers to increase vagal tone and delay AV
conduction to block reentry
Valsalva maneuver
 Carotid sinus massage
 Breath holding
 Head immersion into cold water
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Pharmacotherapy
IV adenosine = agent of choice
 Decreases sinoatrial and AV nodal activity
 IV verapamil, IV esmolol/propranolol/metoprolol, digoxin
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DC cardioversion if unstable or meds ineffective
Prevention
Digoxin = drug of choice
 Verapamil, Beta-blockers
 Radiofreqency ablation
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http://www.emedu.org/ecg/images/ans/2adeno_1a.jpg
http://www.emedu.org/ecg/images/ans/2adeno_2a.jpg
ATRIAL TACHYCARDIA WITH ADENOSINE
P waves with blocked AV conduction
http://www.heartpearls.com/tag/adenosine
72 Y/O FEMALE WITH PALPITATIONS
DIAGNOSIS?
WHAT IS YOUR NEXT STEP IN MANAGEMENT?
NSR with PVC
(PVC resembles LBBB because originating from right tract)
PREMATURE VENTRICULAR CONTRACTIONS
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Etiology
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Variation of normal
Excessive caffeine
Anemia
Anxiety
Organic heart disease (ischemic, valvular, hypertensive)
Medications (e.g. epinephrine, digitalis toxicity)
Metabolic abnormalities (hypoxia, hypokalemia, acidosis,
alkalosis, hypomagnesemia)
Treatment
None if asymptomatic.
 ↑ mortality if treated. However, >10 PVCs per hour ↑ risk
of death in those with heart disease.
 If symptomatic, treat with beta-blockers and possibly
ablation.
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85 Y/O FEMALE ADMITTED FOR FALLS
DIAGNOSIS?
DIAGNOSIS?
Sinus Bradycardia (HR 50) with PAC
PREMATURE ATRIAL CONTRACTIONS
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Pathophysiology
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Etiology
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Early beat fires on it’s own from a focus in the atria
Variant of normal
Adrenergic excess
ETOH/Tobacco
Electrolyte imbalances
Ischemia
Infection
No significance in a normal heart, but may be a
precursor of ischemia in a diseased heart.
REFERNCES
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Agabegi SS, Agabegi ED. Step up to Medicine, 3rd ed.
2013. Lippincott Williams & Wilkins. Philadelphia,
PA.
Gomella LG, Haist SA. Basic EKG reading. In:
Clinician’s Pocket Reference. McGraw-Hill; 2007.
http://flylib.com/books/en/2.569.1.27/1/. Accessed Nov
18, 2014.
Longo DL, Fauci AS, Kasper DL, et al.
Electrocardiography. In: Harrison’s Principles of
Internal Medicine, 18th ed. 2012. McGraw Hill. New
York, NY.
University of Illinois at Chicago. Online ICU
Guidebook. 2013.
http://chicago.medicine.uic.edu/UserFiles/Servers/Ser
ver_442934/Image/1.1/residentguides/final/icuguidebo
ok.pdf. Accessed December 1, 2014.