ECG Interpretations for the ECG Interpretations in Anesthesia Professional Anesthesiology

• ECG skills are valuable at every phase of Brian C. Weiford M.D., FACC the continuum of care Postgraduate Symposium on – Preoperative: PAT clinic, etc Anesthesiology – Intraoperative April 11, 2014 – Postoperative

Topics Components of the ECG - Review P – Wave: Atrial Depolarization. • The normal ECG • Can be positive, biphasic, negative. QRS Complex: Ventricular Depolarization. • • Q – Wave: 1st negative deflection wave before R-Wave. – Ectopy • R – Wave: The positive deflection wave. st – Supraventricular • S – Wave: 1 negative deflection wave after R – wave. T – Wave: Ventricular Repolarization. – Ventricular • Can be positive, biphasic, negative. • Coronary , Injury, and Infarct • Pacemakers • Miscellaneous fun with ECGs

Normal Sinus Rhythm with Normal ECG Normal variant Juvenile pattern

From Braunwald’s Heart Disease, 7th Ed. Sinus /Dysrhythmia Sinus

•Sinus rate < 60 bpm, but usually not clinically significant unless < 50 bpm •Sinus rate is usually > 40 bpm in normal subjects Two forms of Sinus Dysrhythmia: •HR < 40 bpm can be seen commonly in normal subjects during sleep 1) more commonly, due to respiratory variability and changes in and in well-trained athletes vagal tone •Sinus rate affected by numerous medications •Beta blockers, calcium channel blockers, , antiarrhythmics, clonidine, neostigmine, etc. 2) In elderly subjects with heart disease, and probably related to •For sinus rates < 40-50 in the absence of medications: sinus node dysfunction •consider (SSS), hypothyroidism, , ischemia, and infarction.

Sinus

• Age predicted maximal HR (APMHR) = 220-age • That rate can be exceeded in intense physiologic exercise, stress, or •Most often, a physiologic reactive phenomenon (to extracardiac exaggerated adrenergic stimulation stimuli: e.g., hypotension, pain, fever, hypoxia, anemia, anxiety, • Differentiation from supraventricular thyrotoxicosis, etc) •Rarely, “inappropriate sinus tachycardia” observed, with elevated dysrhythmias (, Aflutter) resting sinus rate and exaggerated acceleration of sinus rate with can sometimes be challenging physiologic stimulation. •Can be treated with radiofrequency ablation/SN modification

Premature Atrial Complexes Premature Atrial Complexes (PACs) (PACs) • A supraventricular impulse that occurs • Based on multiple ambulatory ECG earlier than expected and originates in an studies, PACs are common findings in atrial focus, not in the SA node healthy subjects, being observed in: – ~15% of infants <10 days old • Due to increased automaticity of an atrial – 13% of 10-13 year old boys focus – Nearly 2/3 of healthy 22-28 year old women • Typically they are clinically insignificant and > 1/2 of asx male medical students – Can serve as triggers for sustained – 100% of 19-29 year old long distance runners dysrhythmias like SVT or AFib/flutter – 100% of apparently healthy octogenarians

Wagner, Marriott’s Practical , 9th ed. PAC Generation 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

Courtesy of St. Jude Medical

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 PVC (Premature Ventricular Complex)

Frequency of PVCs in General Frequency and Significance of Population PVCs in General Population • Based on the ARIC study (of almost 16000 45- 65 year olds in 4 US communities), overall • In the ARIC study, there was a more than prevalence was 3x increase in coronary heart disease – 8% in African American males (CHD) mortality in subjects with PVCs – 7% in white males – 7% in African American females • After controlling with CV risk factors and – 5% in white females therapy, subjects with PVCs were twice as – In older, African American males with heart disease, likely to die from CHD than those without prevalence ~20% PVCs – Strong association between HTN and prevalence of PVCs Massing: Am J Cardiol 2006;98:1609 –1612 Simpson: Am Heart J 2002;143:535-40

Quadrigeminal PVCs Actual Advertisement Functional LBBB (with underlying sinus tachycardia and HR 115 bpm)

Atrial with elevated Ventricular pacing with underlying ventricular response

Note irregularly irregular and rapid R-R pattern with absence of P waves 2nd Degree AV block (Mobitz II) 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)

•Note predominant 2:1 association of P waves and QRS complexes • 2:1 AV block can be due to to a Mobitz I or •Note wide complex QRS Mobitz II block mechanism

Sinus rhythm with complete (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) Digoxin effect and toxicity: complete heart block with junctional escape rhythm with complete heart block

Note marked bradycardia, scalloped/sagging ST depression in inferior leads, flattened T waves in lateral leads, and prominent U waves in V2-3. Note absence of P waves and coarse baseline with regular R-R intervals

WPW (underlying sinus rhythm)

From Braunwald’s Heart Disease, 7th Ed. • 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” 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 Prevalence of ECG post surgery Syndromes (ACS) • Based on the VISION study • ST depression = Ischemia – New T wave inversions most common (in 23%), but not likely clinically significant – Digoxin effect, Repolarization changes with LVH – New ST depression of > or =1mm (in 16%) • ST elevation = Injury (threatened – New ST elevation of > or =1mm (in 2.3%) infarction) – New LBBB (in 0.5%) – , • Three findings independently associated with 30 • Q waves = Infarction day mortality: ST elevation, anterior ST – Pseudo Q waves depression, and new LBBB • Most new ischemic ECG changes in POD#1

Biccard: Curr Opin Anesthesiol 2014, 27:000–000 Pseudo-infarct Patterns (Q-waves in absence of MI) Ischemia

•WPW • • Hypertrophic CM • Myocardial tumors •LVH • Hyperkalemia • LBBB • Pneumothorax •RVH • Pancreatitis •LAFB • Lead reversal • Chronic lung disease • Corrected transposition • Amyloid, sarcoid, & infiltrative • Muscular dystrophy • prolapse • Chest deformity • Left/right • Pulmonary Embolus • Atrial flutter • Myocardial contusion • Dextrocardia • Acute CNS ischemia

Diffuse Ischemia Ischemia?

• 23 year old with hypertrophic • Note high QRS voltage Injury Pattern Location in Acute ST-Segment Location 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.

Diffuse Mild ST elevation: Pericarditis

Note PR segment depression in multiple leads, and PR elevation in aVR

Anteroseptal STEMI Inferior STEMI (with probable posterior Inferior STEMI (with probable RV involvement) Inferior STEMI involvement)

Extensive Injury (posterior, inferior, Lateral STEMI lateral, and anterolateral)

True Posterior Injury/Infarct Criteria Extensive Injury (anteroseptal, anterolateral, lateral and inferior) Extensive inferior and anterolateral STEMI

Acute MI with chronic LBBB

Single Chamber Pacing System Dual Chamber pacing

VVI Pacemaker AAI Pacemaker Real or Artifactual? Thanks