ecg interpretations for the ecg interpretations in anesthesia … · 2014. 4. 9. · from...
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ECG Interpretations in Anesthesiology
Brian C. Weiford M.D., FACCPostgraduate Symposium on
AnesthesiologyApril 11, 2014
ECG Interpretations for the Anesthesia Professional
• ECG skills are valuable at every phase of the continuum of care– Preoperative: PAT clinic, etc– Intraoperative– Postoperative
Topics
• The normal ECG• Arrhythmias
– Ectopy– Supraventricular– Ventricular
• Coronary Ischemia, Injury, and Infarct• Pacemakers• Miscellaneous fun with ECGs
Components of the ECG - ReviewP – Wave: Atrial Depolarization.
• Can be positive, biphasic, negative.
QRS Complex: Ventricular Depolarization.
• Q – Wave: 1st negative deflection wave before R-Wave.
• R – Wave: The positive deflection wave.
• S – Wave: 1st negative deflection wave after R – wave.
T – Wave: Ventricular Repolarization.
• Can be positive, biphasic, negative.
Normal Sinus Rhythm with Normal ECG Normal variant Juvenile T wave pattern
From Braunwald’s Heart Disease, 7th Ed.
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Sinus Arrhythmia/Dysrhythmia
Two forms of Sinus Dysrhythmia: 1) more commonly, due to respiratory variability and changes in
vagal tone
2) In elderly subjects with heart disease, and probably related to sinus node dysfunction
Sinus Bradycardia
•Sinus rate < 60 bpm, but usually not clinically significant unless < 50 bpm•Sinus rate is usually > 40 bpm in normal subjects•HR < 40 bpm can be seen commonly in normal subjects during sleep and in well-trained athletes•Sinus rate affected by numerous medications
•Beta blockers, calcium channel blockers, digoxin, antiarrhythmics, clonidine, neostigmine, etc.
•For sinus rates < 40-50 in the absence of medications:•consider sinus node dysfunction (SSS), hypothyroidism, hypothermia, ischemia, and infarction.
Sinus Tachycardia
•Most often, a physiologic reactive phenomenon (to extracardiac stimuli: e.g., hypotension, pain, fever, hypoxia, anemia, anxiety, thyrotoxicosis, etc)•Rarely, “inappropriate sinus tachycardia” observed, with elevated resting sinus rate and exaggerated acceleration of sinus rate with physiologic stimulation.
•Can be treated with radiofrequency ablation/SN modification
Sinus Tachycardia
• Age predicted maximal HR (APMHR) = 220-age
• That rate can be exceeded in intense physiologic exercise, stress, or exaggerated adrenergic stimulation
• Differentiation from supraventricular dysrhythmias (atrial tachycardia, Aflutter) can sometimes be challenging
Premature Atrial Complexes (PACs)
• A supraventricular impulse that occurs earlier than expected and originates in an atrial focus, not in the SA node
• Due to increased automaticity of an atrial focus
• Typically they are clinically insignificant– Can serve as triggers for sustained
dysrhythmias like SVT or AFib/flutter
Premature Atrial Complexes (PACs)
• Based on multiple ambulatory ECG studies, PACs are common findings in healthy subjects, being observed in:– ~15% of infants <10 days old– 13% of 10-13 year old boys– Nearly 2/3 of healthy 22-28 year old women
and > 1/2 of asx male medical students– 100% of 19-29 year old long distance runners– 100% of apparently healthy octogenarians
Wagner, Marriott’s Practical Electrocardiography, 9th ed.
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PAC Generation
Courtesy of St. Jude Medical
PAC Morphology
• QRS complexes, ST segments, and T waves should be normal or unchanged from baseline.
• P wave morphology will be different than sinus P wave.
• Shorter PR intervals than sinus PR interval– Due to location of the foci– Shorter routes for
their depolarization waves
Junctional beats/escape Ectopic Atrial Rhythm
Note negatively directed P wave in II
Ectopic Atrial Rhythm
• Often transient• Can occur in individuals with and without
structural heart disease• Distinguish from sinus rhythm by
comparing P wave morphologies, P wave vector
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PVC(Premature Ventricular Complex)
Frequency of PVCs in General Population
• Based on the ARIC study (of almost 16000 45-65 year olds in 4 US communities), overall prevalence was– 8% in African American males– 7% in white males– 7% in African American females– 5% in white females– In older, African American males with heart disease,
prevalence ~20%– Strong association between HTN and prevalence of
PVCsSimpson: Am Heart J 2002;143:535-40
Frequency and Significance of PVCs in General Population
• In the ARIC study, there was a more than 3x increase in coronary heart disease (CHD) mortality in subjects with PVCs
• After controlling with CV risk factors and therapy, subjects with PVCs were twice as likely to die from CHD than those without PVCs
Massing: Am J Cardiol 2006;98:1609 –1612
Quadrigeminal PVCs Actual Advertisement
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Functional LBBB (with underlying sinus tachycardia and HR 115 bpm)
Atrial Fibrillation with elevated ventricular response
Note irregularly irregular and rapid R-R pattern with absence of P waves
Ventricular pacing with underlying Atrial Flutter
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2nd Degree AV block (Mobitz II)
•Note predominant 2:1 association of P waves and QRS complexes•Note wide complex QRS
2nd Degree AV block
• Mobitz I (Wenckebach) 2nd degree AV block can be seen in normals and in subjects with heart disease– 2nd degree AV block present in 11% of healthy 10-13
year old boys and 40% of distance runners based on holter/ambulatory ECG studies
• QRS is prolonged 80% of the time with Mobitz II block (infranodal block—within or below bundle of His)
• 2:1 AV block can be due to to a Mobitz I or Mobitz II block mechanism
Sinus rhythm with complete heart block (in setting of acute inferior MI)
Note regular R-R intervals and lack of 1:1 association with P waves (plus ST elevation in inferior leads)
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Atrial Fibrillation with complete heart block
Note absence of P waves and coarse baseline with regular R-R intervals
Note marked bradycardia, scalloped/sagging ST depression in inferior leads, flattened T waves in lateral leads, and prominent U waves in V2-3.
Digoxin effect and toxicity: complete heart block with junctional escape rhythm
WPW (underlying sinus rhythm)
From Braunwald’s Heart Disease, 7th Ed.
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• Aberrant conduction of supraventricular impulses. Note association of P waves with QRS
• Refractory period of bundle branches is related to preceding R-R interval. – Long-short initiation sequence finds right bundle in
refractory period and QRS is conducted aberrantly (RBBB)
• Ashman’s phenomenon– Common cause of “pseudo VT”
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Multifocal Atrial Tachycardia
•Irregularly irregular tachycardia with 3 or more distinct P wave morphologies•Important to differentiate from atrial fibrillation•Highly associated with lung disease such as COPD
From Braunwald’s Heart Disease, 7th Ed.
ECG Changes in Acute Coronary Syndromes (ACS)
• ST depression = Ischemia– Digoxin effect, Repolarization changes with LVH
• ST elevation = Injury (threatened infarction)– Pericarditis, Coronary vasospasm
• Q waves = Infarction– Pseudo Q waves
Prevalence of ECG post surgery• Based on the VISION study
– New T wave inversions most common (in 23%), but not likely clinically significant
– New ST depression of > or =1mm (in 16%)– New ST elevation of > or =1mm (in 2.3%)– New LBBB (in 0.5%)
• Three findings independently associated with 30 day mortality: ST elevation, anterior ST depression, and new LBBB
• Most new ischemic ECG changes in POD#1
Biccard: Curr Opin Anesthesiol 2014, 27:000–000
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Pseudo-infarct Patterns (Q-waves in absence of MI)
• WPW• Hypertrophic CM• LVH• LBBB• RVH• LAFB• Chronic lung disease• Amyloid, sarcoid, & infiltrative
cardiomyopathies• Chest deformity• Pulmonary Embolus• Myocardial contusion• Acute CNS ischemia
• Myocarditis• Myocardial tumors• Hyperkalemia• Pneumothorax• Pancreatitis• Lead reversal• Corrected transposition• Muscular dystrophy• Mitral valve prolapse• Left/right atrial enlargement• Atrial flutter• Dextrocardia
Ischemia
Diffuse Ischemia Ischemia?
• 23 year old with hypertrophic cardiomyopathy• Note high QRS voltage Injury Pattern
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Location in Acute ST-Segment elevation MI (STEMI)
• Anterior:- rS complex in V1 followed by ST segment elevation in leads V2-V4
• Anteroseptal:– abnormal Q or QS deflection in V1-V3 and sometimes V4 with ST
segment elevation• Anterolateral:
– abnormal Q waves with ST segment elevation in leads V4-V6• Lateral/High Lateral:
– abnormal Q wave in lead I and aVL with ST segment elevation• Inferior:
– abnormal Q wave in at least 2 of leads II, III, aVF with ST segment elevation
• Posterior:– initial R wave in V1-V2 >0.04s with R>S, and ST segment
depression (usually >2mm) with upright T waves.
Location
Diffuse Mild ST elevation: Pericarditis
Note PR segment depression in multiple leads, and PR elevation in aVR
Anteroseptal STEMI Inferior STEMI
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Inferior STEMI (with probable RV involvement) Inferior STEMI (with probable posterior involvement)
Lateral STEMI Extensive Injury (posterior, inferior, lateral, and anterolateral)
True Posterior Injury/Infarct Criteria Extensive Injury (anteroseptal, anterolateral, lateral and inferior)
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Extensive inferior and anterolateral STEMI
Acute MI with chronic LBBB
Single Chamber Pacing System
AAI Pacemaker VVI Pacemaker
Dual Chamber pacing
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Real or Artifactual?
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Thanks