Diagnostic Tests and Approach to ECG Flashcards

Question

What are signs of ECG for a nonspecific intraventricular block

Answer 1

* QRS duration >120 msec | * absence of definitive criteria for LBBB or RBBB

Answer 2

(S in V1) + (R in V5 or V6) >35 mm above for age 40 >40 mm for age 31-40 >45 mm for age 21-30 R in aVL >11 mm (R in I) + (S in III) >25 mm Additional criteria LV strain pattern (asymmetric ST depression and T wave inversion in leads I, aVL, V4-V6) Left atrial enlargement N.B. The more criteria present, the more likely LVH is present. If only one voltage criteria present, it is called minimal voltage criteria for LVH which could be a normal variant

Answer 3

Right axis deviation R/S ratio >1 or qR in lead V1 RV strain pattern: ST segment depression and T wave inversion in leads V1-2

Answer 4

Biphasic P wave with the negative terminal component of the P wave in lead V1 ≥1 mm wide and ≥1 mm deep P wave >100 msec, could be notched in lead II (“P mitrale”)

Answer 5

P wave >2.5 mm in height in leads II, III, or aVF (“P pulmonale”)

Answer 6

■ ST segment depression | ■ T wave inversion (most commonly in V1-V6)

Answer 7

■ transmural (involving the epicardium) - ST elevation in the leads facing the area injured/infarcted ■ subendocardial - marked ST depression in the leads facing the affected area ■ may be accompanied by enzyme changes and other signs of MI

Answer 8

At least 1 mm in 2 adjacent limb leads or at least 1-2 mm in adjacent precordial leads (signifies complete occlusion and transmural ischemic injury)

Answer 9

Diffuse pattern in early pericarditis

Answer 10

Transient ST elevation in patients with coronary artery spasm (e.g. Prinzmetal angina) which can be slight or prominent (>10 mm)

Answer 11

1. hyperacute T waves (tall, symmetric T waves) in the leads facing the infarcted area, with or without ST elevation 2. ST elevation (injury pattern) in the leads facing the infarcted area ◆ usually in the first hours post infarct ◆ in acute posterior MI, there is ST depression in V1-V3 (reciprocal to ST elevation in the posterior leads, that are not recorded in the standard 12-lead ECG) - get a 15-lead ECG 3.significant Q waves: >40 msec or >1/3 of the total QRS and present in at least 2 consecutive leads in the same territory (hours to days post-infarct) ◆ Q waves of infarction may appear in the very early stages, with or without ST changes ◆ non-Q wave infarction: there may be only ST or T changes despite clinical evidence of infarction 4. inverted T waves (one day to weeks after infarction)

Answer 12

■ abnormal Q waves (Q waves may be present in leads III and aVL in normal individuals due to initial septal depolarization) ■ duration >40 msec (>30 msec in aVF for inferior infarction) ■ Q/QRS voltage ratio is >33% ■ present in at least 2 consecutive leads in the same territory ``` ■ abnormal R waves (R/S ratio >1, duration >40 msec) in V1 and occasionally in V2 are found in posterior infarction (usually in association with signs of inferior and/or lateral infarction) ```

Answer 13

Anteroseptal Anterior Anterolateral Extensive anterior

Answer 14

Inferior Posterior MI (assoc. with inf. MI) Right ventricle

Answer 15

Lateral | Isolated posterior MI

Answer 16

V1, V2 V3, V4 I, aVL, V3-6 I, aVL, V1-6

Answer 17

II, III, aVF V3R, V4R (right sided chest leads) V1, V2 (prominent R waves)

Answer 18

I, aVL, V5-6 | V1, V2 (prominent R waves)

Answer 19

■ mild to moderate (K+ 5-7 mmol/L): tall peaked T waves ■ severe (K+>7 mmol/L): progressive changes whereby P waves flatten and disappear, QRS widens and may show bizarre patterns, axis shifts left or right, ST shift with tall T waves, eventually becomes a “sine wave” pattern

Answer 20

■ ST segment depression, prolonged QT interval, low T waves, prominent U waves (U>T) ■ enhances the toxic effects of digitalis

Answer 21

■ shortened QT interval (more extracellular Ca2+ means shorter plateau in cardiac action potential)

Answer 22

■ prolonged QT interval (less extracellular Ca2+ means longer plateau in cardiac action potential)

Answer 23

* sinus bradycardia * when severe, prolonged QRS and QT intervals * AFib with slow ventricular response and other atrial/ventricular dysrhythmias * Osborne J waves: “hump-like” waves at the junction of the J point and the ST segment

Answer 24

* early: diffuse ST segment elevation ± PR segment depression, upright T waves * later: isoelectric ST segment, flat or inverted T waves * ± tachycardia

Answer 25

• Demand pacemaker has discharge (narrow vertical spike on ECG strip) prior to widened QRS • Atrial pacemaker has discharge prior to P wave • Triggered pacemaker has discharge following the P wave but prior to the widened QRS • Atrial and ventricular pacing have discharge before the P wave and widened QRS wave

Answer 26

Palpitations, fatigue, visual changes (yellow vision), decreased appetite, hallucinations, confusion, and depression

Answer 27

■ therapeutic levels may be associated with “digitalis effect” ◆ ST downsloping or “scooping” ◆ T wave depression or inversion ◆ QT shortening ± U waves ◆ slowing of ventricular rate in AFib ◆ toxic levels associated with: – arrhythmias: paroxysmal atrial tachycardia (PAT) with conduction block, severe bradycardia in AFib, accelerated junctional rhythms, PVCs, ventricular tachycardia (see Arrhythmias, C16) – “regularization” of ventricular rate in AFib due to a junctional rhythm and AV dissociation

Answer 28

■low voltage, right axis deviation (RAD), poor R wave progression in precordial leads ■ RAE and RVH with strain ■ multifocal atrial tachycardia (MAT)

Answer 29

■ sinus tachycardia and AFib/atrial flutter are the most common arrhythmias ■ RAD, RVH with strain ■ most specific sign is S1Q3T3 (S in I, Q and inverted T wave in III) but rather uncommon

Answer 30

• the P wave represents atrial contraction; best leads: II, VI ■ lead II: the P wave should be rounded, <120 msec and <2.5 mm in height ■ lead VI: the P wave is biphasic with a negative phase slightly greater than the positive phase

Answer 31

sawtooth P wave (Hint: flip the ECG upside-down to see it better if unclear)

Answer 32

absent P wave, may have fibrillatory wave, irregular rhythm

Answer 33

tall P wave (>2.5 mm) in II or V1 (P pulmonale)

Answer 34

negative deflection >1 mm deep or >1 mm wide in V1, wide (>100 msec) notched P wave in II may be present (P mitrale)

Answer 35

the P-R interval shows the delay between atrial and ventricular contraction that is mediated by the AV node; the magnitude of the delay is referred to as “dromotropy” ``` positive dromotropy increases conduction velocity (e.g. epinephrine stimulation), negative dromotropy decreases velocity (e.g vagal stimulation) ```

Answer 36

120-200 ms

Answer 37

■heart block ◆ first degree: fixed, prolonged P-R interval ◆ second degree Mobitz I/Wenckebach: steadily prolonging P-R interval to eventual dropped beat ◆ second degree Mobitz II/Hay: fixed P-R interval with ratio of beat to dropped beat (e.g. for every 3 beats, there is one dropped beat [3:1]) ◆ third degree/complete: variable P-R intervals, P-P and R-R intervals individually constant but not in sync ■ atrial flutter ■ sinus bradycardia (normal to have long P-R if heart rate slow) ■ hypokalemia ■ “trifascicular” block -1st degree AV block with LAHF and complete RBBB

Answer 38

■ pre-excitation syndrome (delta wave: upswooping of the P-R segment into the QRS complex indicating pre-excitation) ◆ accessory pathways ◆ WPW ■ low atrial rhythm

Answer 39

if Q wave ≥1 small square (≥40 msec) or >33% of the total | QRS

Answer 40

Where ventricular contraction is visualized

Answer 41

* Septal depolarization by the left bundle * Seen in leads I II, III, aVL, V5, V6 * <40 msec

Answer 42

• rate - check the R-R interval to see if it matches the P-P interval * amplitude: check for hypertrophy * narrow width (<120 msec) QRS means that the His-Purkinje system is being used * wide width (>120 msec) QRS means that the His-Purkinje system is being bypassed or is diseased

Answer 43

BBB VT ventricular hypertrophy cardiomyopathy WPW ectopic ventricular beat hyperkalemia drugs (e.g. TCAs, antiarrhythmics)

Answer 44

corresponds to the completion of ventricular depolarization

Answer 45

lateral ST depression (leads I, aVL, V5, V6) may actually indicate a STEMI in the right heart

Answer 46

this is the repolarization phase of the ventricles (repolarization of the atria are obscured by the QRS complex)

Answer 47

• pathology when T wave variation occur in consecutive leads ■ inversion: BBB, ischemia, hypertrophy, drugs (e.g. digitalis), pulmonary embolism (lead III as part of S1Q3T3 sign) ■ elevation: infarction (STEMI, Prinzmetal, hyperacute), hyperkalemia (wider, peaked) ■ flattened: hypokalemia, pericarditis, drugs (e.g. digitalis), pericardial effusion ■ variations: T wave alterans; beat-to-beat variations due to PVC overlap (R on T phenomenon which may precipitate VT or VFib) ``` • appropriate T wave discordance: in BBB, T wave deflection should be opposite to that of the terminal QRS deflection (i.e. T wave negative if ends with R or R’; positive if ends with S) ``` ■ inappropriate T wave concordance suggests ischemia or infarction

Answer 48

this represents the duration of ventricular depolarization and repolarization and is often difficult to interpret

Answer 49

• corrected QT (QTc) is often used instead in practice to correct for the repolarization duration; QTc = QT ÷ √RR • normal QTc is 360-450 msec for males and 360-460 msec for females

Answer 50

■ increased (>450 msec for males and >460 msec for females): risk of Torsades de Pointes (a lethal tachyarrhythmia)

Answer 51

◆ genetic Long QT Syndrome (often a channelopathy) ◆ drugs: antibiotics, SSRIs, antipsychotics, antiarrhythmics ◆ electrolytes: low Ca2+, low Mg2+, low K+ ◆ others: hypothyroidism, hypothermia, cardiomyopathy

Answer 52

■ decreased (<360 msec) ◆ electrolytes: high Ca++ ◆ drugs: digoxin ◆ others: hyperthyroidism

Answer 53

Risk of VFib

Answer 54

origin unclear but may be repolarization of Purkinje fibres or delayed/prolonged repolarization of the myocardium • more visible at slower heart rates • deflection follows T wave with <25% of the amplitude

Answer 55

• variations from norm could indicate pathologic conditions: ■ prominent (>25% of T wave): electrolyte (low K+), drugs (digoxin, antiarrhythmics) ■ inverted (from T wave): ischemia, volume overload

Answer 56

ST Elevation I HELP A PAL Ischemia with reciprocal changes ``` Hypothermia (Osborne waves) Early repolarization (normal variant, need old ECGs to confirm) LBBB Post-MI ``` Acute STEMI Prinzmetal’s (Vasospastic) angina Acute pericarditis (diffuse changes) Left/right ventricular aneurysm

Answer 57

ST Depression WAR SHIP WPW syndrome Acute NSTEMI RBBB/LBBB STEMI with reciprocal changes Hypertrophy (LVH or RVH) with strain Ischemia Post-MI

Answer 58

1-2 days Up to 2 weeks

Answer 59

1 day 3 days

Answer 60

■ AST and LDH also increased in MI (low specificity) ■ BNP and NT-proBNP: secreted by ventricles in response to increased end-diastolic pressure and volume ◆ DDx of elevated BNP: CHF, AFib, PE, COPD exacerbation, pulmonary HTN

Answer 61

check troponin I at presentation and 8 h later ± creatine kinase-MB

Answer 62

In patients with acute dyspnea, measurement of B-type natriuretic peptide improves clinical outcomes (need for hospitalization or intensive care) and reduces time to discharge and total cost of treatment.

Answer 63

■ extended ambulatory ECG of 24 or 48 h or 14 or 28 d duration ■ provides a view of only two or three leads of electrocardiographic data over an extended period of time ■ permits evaluation of changing dynamic cardiac electrical phenomena that are often transient and of brief duration

Answer 64

◆ a small, lightweight, battery operated recorder that records two or three channels of ECG data ◆ patient activated event markers ◆ minimum of 24-48 h

Answer 65

◆ subcutaneous monitoring device for the detection of cardiac arrhythmias ◆ typically implanted in the left pectoral region and stores events when the device is activated automatically according to programmed criteria or manually with magnet application ◆ can be used for months to years

Answer 66

None other than patient refusal and adhesive allergy

Answer 67

■ should be performed as the initial test in certain life-threatening situations, (e.g. aortic dissection) when other tests contraindicated (e.g. CT angiography in patient with renal failure) ■ intracardiac thrombi, tumours, valvular vegetations (infective endocarditis), aortic dissection, aortic atheromas, prosthetic valve function, shunt, technically inadequate transthoracic study ■ evaluation for left atrial/left atrial appendage thrombus in a patient with atrial fibrillation/atrial flutter to facilitate clinical decision making regarding electrical cardioversion or ablation

Answer 68

■ serious complications are extremely rare (<1 in 5,000) ■ esophageal perforation ■ gastrointestinal bleeding ■ pharyngeal hematoma

Answer 69

■ useful alternative to other stress imaging modalities ■ when ECG cannot be interpreted appropriately ■ intermediate pre-test probability with normal/equivocal exercise ECG ■ post-ACS when used to decide on potential efficacy of revascularization ■ To evaluate the clinical significance of valvular heart disease ■ evaluation of myocardial viability, dyspnea of possible cardiac origin, mitral valve disease, aortic stenosis, mitral regurgitation, pulmonary hypertension, and patients with hypertrophic cardiomyopathy (for LVOT obstruction

Answer 70

■ contraindications to exercise testing ■ contraindications to dobutamine stress echocardiography: tachyarrhythmias and systemic hypertension ■ AAA has been considered as a relative contraindication to exercise testing or dobutamine stress echocardiography

Answer 71

■ improves resolution and provides real-time assessment of intracardiac blood flow ■ conventional agent is agitated saline (contains microbubbles of air) ■ allows visualization of right heart and intracardiac shunts, most commonly patent foramen ovale (PFO) and intrapulmonary shunt

Answer 72

description: newer contrast agents are capable of crossing the pulmonary bed and achieving left heart opacification following intravenous injection these contrast agents improve visualization of endocardial borders and enhance evaluation of LV ejection fraction and wall motion abnormalities (in patients with technically inadequate echocardiograms), and intracardiac mass

Answer 73

■ risk of non fatal MI and death are rare ■ ultrasound contrast agents may cause back pain, headache, urticaria, and anaphylaxis

Answer 74

■ patients with intermediate (10-90%) pretest probability of CAD based on age, gender, and symptoms ■ ST depression <1 mm at rest, no left bundle branch block, no digoxin or estrogen use ■ exercise test results stratify patients into risk groups 1. low risk patients can be treated medically without invasive testing 2. intermediate risk patients may need additional testing in the form of exercise imaging studies or cardiac catheterization 3. high risk patients should be referred for cardiac catheterization

Answer 75

■ acute myocardial infarction (within 2 days) ■ unstable angina pectoris ■ uncontrolled arrhythmias causing symptoms of hemodynamic compromise ■ symptomatic severe valvular stenosis ■ uncontrolled symptomatic heart failure ■ active endocarditis or acute myocarditis or pericarditis ■ acute aortic dissection ■ acute pulmonary or systemic embolism ■ acute non-cardiac disorders that may affect exercise performance or may be aggravated by exercise

Answer 76

◆ patient’s desire to stop ◆ drop in systolic blood pressure of >10 mmHg from baseline despite an increase in workload, when accompanied by other evidence of ischemia ◆ moderate to severe angina ◆ ST elevation (>1 mm) in leads without diagnostic Q-waves (other than V1 or aVR) ◆ increasing nervous system symptoms (e.g. ataxia, dizziness, or near syncope) ◆ signs of poor perfusion (cyanosis or pallor) ◆ technical difficulties in monitoring ECG or systolic blood pressure ◆ sustained ventricular tachycardia

Answer 77

CI = CO/body surface area ◆ cardiac index is a measure of cardiac function ◆ <1.8 L/min/m2 usually means cardiogenic shock ◆ 2.6-4.2 L/min/m2 is considered normal

Answer 78

◆ obtained by advancing the catheter to wedge in the distal pulmonary artery ◆ records pressure measured from the pulmonary venous system ◆ in the absence of pulmonary venous disease reflects left atrial pressure

Answer 79

■ obtain direct measurements of central venous, right-sided intracardiac, pulmonary artery, and pulmonary artery occlusion pressures ■ can estimate cardiac output, systemic and pulmonary vascular resistance as well as mixed venous oxyhemoglobin saturation, oxygen delivery, and oxygen uptake

Answer 80

■ unexplained or unknown volume status in shock ■ severe cardiogenic shock (e.g. acute valvular disease, suspected pericardial tamponade) ■ suspected or known pulmonary artery hypertension ■ severe underlying cardiopulmonary disease (e.g. congenital heart disease, left-to-right shunt severe valvular disease, pulmonary hypertension) and undergoing corrective or other surgery

Answer 81

■ lack of consent ■ infection at the insertion site ■ the presence of a right ventricular assist device ■ insertion during cardiopulmonary bypass

Answer 82

accomplished by introducing a catheter into the brachial or femoral artery and advancing it through the aorta, across the aortic valve, and into the left venricle

Answer 83

evaluates mitral and aortic valvular defects and myocardial disease systolic and end-diastolic pressure tracings recorded LV size, wall motion and ejection fraction can be assessed by injecting contrast into the LV (left ventriculography) via femoral/radial artery catheterization cardiac output

Answer 84

■ identification of the extent and severity of CAD and evaluation of left ventricular function ■ assessment of the severity of valvular or myocardial disorders (e.g. aortic stenosis or insufficiency, mitral stenosis or insufficiency, and various cardiomyopathies) to determine the need for surgical correction ■ collection of data to confirm and complement noninvasive studies ■ determination of the presence of CAD in patients with confusing clinical presentations or chest pain of uncertain origin

Answer 85

1-8 (15-30) mm Hg

Answer 86

4-12 mm Hg (15-30)

Answer 87

4-12 mm Hg

Answer 88

4-12 mm Hg

Answer 89

■ severe uncontrolled hypertension ■ ventricular arrhythmias ■ acute stroke ■ severe anemia ■ active gastrointestinal bleeding ■ allergy to radiographic contrast ■ acute renal failure ■ uncompensated congestive failure (so that the patient cannot lie flat) ■ unexplained febrile illness or untreated active infection ■ electrolyte abnormalities (e.g. hypokalemia) ■ severe coagulopathy

Answer 90

Informally: ■ to define the coronary anatomy and the degree of luminal obstruction of the coronary arteries ■ to determine the presence and extent of obstructive CAD ■ to assess the feasibility and appropriateness of various forms of therapy, such as revascularization by percutaneous or surgical interventions ■ can also be used when the diagnosis of CAD is uncertain and CAD cannot be reasonably excluded by noninvasive technique ACC/AHA: • Disabling (CCS classes III and IV) chronic stable angina despite medical therapy * High-risk criteria on clinical assessment or non-invasive testing * Serious ventricular arrhythmia or CHF * Uncertain diagnosis or prognosis after non-invasive testing * Inability to undergo non-invasive testing

Answer 91

Coronary angiography

Answer 92

■ radiographic visualization of the coronary vessels after injection of radiopaque contrast media ■ coronary vasculature accessed via the coronary ostia

Answer 93

severe renal failure (due to contrast agent toxicity – must check patient’s renal status)

Answer 94

defined as 70% or more narrowing of the luminal diameter

Answer 95

■ fluid loading may unmask latent pericardial constriction ■ afterload reduction or inotropic stimulation may be used to increase the outflow tract gradient in HCM ■ coronary vasoreactive agents (e.g. methylergonovine, acetylcholine) ■ a variety of pulmonary vasoreactive agents in primary pulmonary HTN (e.g. oxygen, calcium channel blockers, adenosine, nitric oxide, or prostacyclin)

Answer 96

often used to assess coronary artery and previous graft stenosis/viability that could not be seen during coronary angiography

Answer 97

Valuable in assessment of congenital cardiac anomalies, abnormalities of the aorta, assessment of viable myocardium, and assessment of cardiomyopathies