OHCEPS - ECG Flashcards

Question

Second degree heart block - Mobitz I?

Answer 1

1. PR interval becomes progressively longer after each P wave until an impulse fails to be conducted at all. 2. The interval then returns to the normal length and the cycle is repeated. 3. Also known as the Wenkenbach phenomenon.

Answer 2

1. PR interval is fixed but NOT EVERY P wave is followed by a QRS. 2. The relationship betweenP waves and QRS complex may be 2:1, 3:1, or random.

Answer 3

Also called complete heart block. 1. There is no conduction of the impulse through the AV junction. 2. Atrial and ventricular depolarization occur independently of one another. 3. Each has a separate pacemaker triggering electrical activity at different rates.

Answer 4

The QRS complex is an abnormal shape as the electrical impulse does not travel through the ventricles via the normal routes (see ventricular escape).

Answer 5

In 3rd degree heart block P waves may be seen "merging" with QRS complexes if they coincide.

Answer 6

If in doubt about the pattern of P waves and QRS complexes, mark out the P wave intervals and the R-R intervals separately, then compare.

Answer 7

Leads II and V1.

Answer 8

Conduction through the AV node, bundle of His, and left bundle branch will be normal but depolarization of the RV occurs BY THE SLOW ELECTRICAL CURRENT THROUGH THE MYOCARDIAL CELLS.

Answer 9

The result is delayed right ventricular depolarization giving a second R wave known as "R prime" (R').

Answer 10

Pathology in the right side of the heart, but can be a normal variant.

Answer 11

1. "RSR" pattern seen in V1. 2. Cardiac axis usually remains normal unless left anterior fascicle is also blocked ("bifascicular block") which results in left axis deviation. 3. T wave is DOWN in anterior chest leads (V1-V3).

Answer 12

1. Hyperkalemia 2. Congenital heart disease (Fallot) 3. Pulmonary embolus 4. Cor pulmonale 5. Fibrosis of conduction system

Answer 13

Conduction through the AV node, bundle of His, and right bundle branch will be normal but depolarization of the LV occurs by the slow spread of electrical current through myocardial cells.

Answer 14

The result is delayed LV depolarization.

Answer 15

ALWAYS PATHOLOGICAL.

Answer 16

1. M pattern seen in V6. | 2. T wave down in lateral chest leads (V5-V6).

Answer 17

1. HTN 2. IHD 3. Acute MI 4. AV stenosis 5. Cardiomyopathies 6. Fibrosis of the conducting system

Answer 18

1. Drugs 2. Sick sinus rhythm 3. Hypothyroidism 4. Inferior MI 5. Hypothermia 6. Incr. intracranial pressure 7. Physiological (athletes)

Answer 19

1. Beta blockers 2. Verapamil 3. Amiodarone 4. Digoxin

Answer 20

1. Ventricular rate >100 (usually 100-150 beats per minute). | 2. Normal P wave before each QRS.

Answer 21

1. Epinephrine 2. Caffeine 3. Nicotine

Answer 22

1. Drugs 2. Pain 3. Exertion 4. Anxiety 5. Anemia 6. Thyrotoxicosis 7. Pulmonary embolus 8. Hepatic failure 9. Cardiac failure 10. Hypercapnia 11. Pregnancy 12. Constrictive pericarditis

Answer 23

Tachycardias (>100) arising in the atria or in the AV node. --> As conduction through the bundle of His and ventricles will be normal (unless there is other pathology in the heart), the QRS complexes appear normal.

Answer 24

1. A-fib 2. A-flutter 3. Junctional tachycardia 4. Re-entry tachycardia

Answer 25

Disorganized contraction of the atria in the form of rapid, irregular twitching. There will, therefore, be NO P WAVES on the ECG.

Answer 26

Electrical impulses from the twitches of the atria arrive at the AV node randomly, they are then conducted via the normal pathways to cause ventricular contraction. --> Characteristic rhythm that is irregularly irregular with no discernable pattern.

Answer 27

1. No P waves. Rhythm is described as irregularly irregular. 2. Irregular QRS complexes. 3. Normal appearance of QRS. 4. Ventricular rate may be UP ("fast AP") - typically 120-160 per minute.

Answer 28

1. Idiopathic 2. IHD 3. Thyroid disease 4. HTN 5. MI 6. Pulmonary embolus 7. Rheumatic mitral or tricuspid valve disease

Answer 29

Abnormally rapid contraction of the atria. 1. The contractions are NOT DISORGANIZED/RANDOM, unlike AF, but are fast and inadequate for a normal movement of blood. 2. Instead of P waves, the baseline will have a typical "saw-tooth" appearance - sometimes known as F waves.

Answer 30

1. The AV node is unable to conduct impulses faster than 200/min. 2. Atrial contraction faster than that leads to impulses failing to be conducted --> Atrial rate of 300 --> HR 150. --> Called 2:1 block. 3. Other ratios of atrial to ventricular contractions may occur.

Answer 31

May lead to an irregularly irregular pulse indistinguishable from that of AF on clinical examination.

Answer 32

1. "Saw-tooth" appearance baseline. | 2. Normal appearance of QRS complexes.

Answer 33

Similar to A-fib.

Answer 34

1. The area in or around the AV node depolarizes spontaneously, the impulse will be immediately conducted to the ventricles. 2. The QRS complex will be of normal shape but no P waves will be seen.

Answer 35

1. No P waves 2. QRS complexes are regular and normal shape. 3. Rate may be fast or may be of normal rate.

Answer 36

1. Sick sinus syndrome (including drug-induced). 2. Digoxin toxicity 3. Ischemia of the AV node, especially with acute INFERIOR MI 4. Acutely after cardiac surgery 5. Acute inflammatory processes (acute RF) which may involve the conduction system. 6. Diphtheria 7. Other drugs (most anti-arrhythmics)

Answer 37

There is an extra conducting pathway between the atria and the ventricles --> The bundle of Kent. A break in the normal electrical insulation. --> Not specialized to delay the impulse as the AV node does. --> Not linked to the normal conduction pathways of the bundle of His.

Answer 38

A fusion beat - Normal + Abnormal ventricular depolarization combine to give distortion of the QRS complex.

Answer 39

The accessory pathway may allow electrical activity to be conducted from the ventricles back up to the atria. --> Electrical activity may be conducted down the bundle of His, across the ventricles and UP THE ACCESSORY PATHWAY into the atria causing them to contract again...and the cycle is repeated.

Answer 40

1. The bundle of Kent may connect the atria with either the right or the left ventricle. 2. Thus WPW is classically divided into 2 groups according to the resulting appearance of the QRS complex in the anterior chest leas. 3. In practice, this classification is rather simplistic as 11% of patients may have more than one accessory pathway.

Answer 41

1. Upright delta wave and QRS in V1. | 2. May be mistaken for RBBB or posterior MI.

Answer 42

1. Downward delta wave and QRS in V1, positive elsewhere. | 2. May be mistaken for LBBB or anterior MI.

Answer 43

Most of them originate outside the usual conduction pathways meaning that excitation spreads by an abnormal path through the ventricular muscle to give broad or unusually shaped QRS complexes.

Answer 44

Here, there is a focus of ventricular tissue depolarizing rapidly within the ventricular myocardium.

Answer 45

3 or more successive ventricular extrasystoles at a rate of >120/min. Sustained VT lasts for > 30sec.

Answer 46

Monomorphic VT --> Repetitive QRS shape. | Polymorphic VT --> Unstable with varying patterns of the QRS complex.

Answer 47

SVT + bundle branch block.

Answer 48

1. Wide QRS complexes which are irregular in rhythm and shape. 2. AV dissociation - independent atria/ventricular contraction. 3. May seen FUSION and CAPTURE beats on ECG as signs of atrial activity independent of ventricular activity --> Said to be pathognomonic. 4. Rate can be up to 130-300/min. 5. QRS concordance: all the QRS complexes in the chest leads are either mainly positive or mainly negative --> ventricular origin of the tachycardia. 6. EXTREME axis deviation (far negative or far positive).

Answer 49

1. Ischemia (AMI) 2. Electrolyte abnormalities (Low K, Low Mg) 3. Aggressive adrenergic stimulation (eg cocaine use) 4. Drugs - especially antiarrhythmics.

Answer 50

Disorganized, uncoordinated depolarization from multiple foci in the ventricular myocardium.

Answer 51

1. No discernible QRS complexes. | 2. A completely disorganized ECG.

Answer 52

1. Coronary artery disease 2. Cardiac inflammatory disease 3. Abnormal metabolic states 4. Pro-arrhythmic toxic exposures 5. Electrocution 6. Tension pneumothorax, trauma, and drowning 7. Large pulm. embolism 8. Hypoxia and acidosis

Answer 53

This is VF with a small amplitude waveform. It may resemble asystole on the ECG monitor, particularly in an emergency situation. --> You should remember to increase the gain on the monitor to ensure what you think is asystole is not really fine VF as the management for each is very different.

Answer 54

These are ventricular contractions originating from a focus of depolarization within the ventricle. As conduction is via ABNORMAL PATHWAYS, the QRS complex will be unusually shaped.

Answer 55

They are COMMON + HARMLESS if there is no structural heart disease. --> If they occur at the same time as a T wave, the "R on T" phenomenon --> VF.

Answer 56

This occurs as a back-up when conduction between the atria and the ventricles is interrupted (as in complete heart block).

Answer 57

30-40/min.

Answer 58

The ventricular beats will be abnormal and wide with abnormal T waves following them. --> This rhythm can be stable but may suddenly fail.

Answer 59

This is complete absence of electrical activity and is not compatible with life.

Answer 60

There may be a slight wavering of the baseline which can be easily confused with fine VF in emergency situations.

Answer 61

This is a slow, irregular rhythm with wide ventricular complexes which vary in shape.

Answer 62

Often seen in the later stages of unsuccessful resuscitation attempts as the heart dies.

Answer 63

The complexes become progressively broader before all recognizable activity is lost (asystole).

Answer 64

Literally meaning "twisting of points. A form of polymorphic VT characterized by a gradual change in the amplitude and twisting of the QRS axis. In the US, it is known as "cardiac ballet".

Answer 65

Usually terminates spontaneously but frequently recurs and may degenerate into sustained VT and VF.

Answer 66

Results from prolonged QT interval. 1. Congenital long-QT syndromes 2. Drugs (antiarrhythmics 3. K and Mg may also be down.

Answer 67

1. In sinus rhythm each P wave is closely associated with a QRS complex. 2. P waves are usually upright in most leads EXCEPT aVR. 3. P waves are <3 small squares high.

Answer 68

1. Right atrial hypertrophy --> Tall, peaked P waves (P pulmonale) 2. Left atrial hypertrophy --> Wider and twin-peaked or "bifid" P wave. (P mitrale).

Answer 69

Ischemic changes.

Answer 70

Inversion, which has a number of causes.

Answer 71

1. Commonly inverted in V1 and aVR. | 2. May be inverted in V1-V3 as normal variant.

Answer 72

Non-Q wave MI can cause T wave inversion. Changes need to be interpreted in light of clinical picture.

Answer 73

Ventricular hypertrophy causes T inversion in those leads focused on the ventricle in question. --> For example, LV hypertrophy will give T changes in V5, V6, II, aVL.

Answer 74

Causes abnormal QRS complexes due to abnormal pathways of ventricular depolarization. --> The corresponding abnormal repolarization gives unusually shaped T waves which have no significance in themselves.

Answer 75

Digoxin causes a characteristic T wave inversion with a downsloping of the ST segment known as the "reverse tick" sign. --> This occurs at therapeutic doses and it NOT a sign of digoxin toxicity.

Answer 76

1. UP K --> Tall tented T waves. 2. DOWN K --> Small T waves and U waves (broad, flat waves occurring after the T waves). 3. DOWN Ca --> Small T waves with prolongation of the QT interval. (UP Ca has the reverse effect).

Answer 77

1. Subarachnoid hemorrhage | 2. Lithium use

Answer 78

The degree + extent of ST elevation is of crucial importance in ECG interpretation as it determines whether reperfusion therapy (thrombolysis or PCI) is considered in AMI.

Answer 79

1. AMI - Convex ST elevation in affected leads (the "tomb-stone" appearance), often with reciprocal ST depression in opposite leads. 2. Pericarditis - Widespread concave ST elevation ("saddle-shaped"). 3. LV aneurysm - ST elevation may persist over time.

Answer 80

Can be horizontal, upward sloping, or downward sloping.

Answer 81

1. Myocardial ischemia - Horizontal ST depression and an upright T wave. May be the result of CAD or other causes (anemia, AV stenosis). 2. Digoxin toxicity - downward sloping ("reverse tick"). 3. "Non-specific" changes - ST depression which is often upward sloping may be a normal variant and is NOT thought to be associated with any underlying significant pathology.

Answer 82

Test looks to induce ischemic changes --> Extent + Timing + Nature of ST changes can help quantify the probability of ischemic heart disease.

Answer 83

ECG can remain normal.

Answer 84

In order: 1. ST elevation and T waves become peaked. 2. Pathological Q waves develop. 3. ST returns to baseline and T waves invert.

Answer 85

The leads in which these changes take place allow you to identify which part of the heart has been affected and, therefore, which coronary artery is likely to be occluded.

Answer 86

I, aVL, V5, V6

Answer 87

III, aVF (sometimes also II)

Answer 88

The usual depolarization of the posterior of the LV is lost, giving a dominant R wave in V1. Imagine it as a mirror image of the Q wave you would expect with an anterior MI.

Answer 89

Often no changes on the 12-lead ECG. If suspected clinically, leads are placed on the right of the chest, mirroring the normal pattern and are labeled V1R, V2R, V3R, and so on.

Answer 90

Changes to the P wave.

Answer 91

This can lead to changes to the cardiac axis, QRS complex height/depth, and the T wave.

Answer 92

1. Tall R wave in V6 and deep S wave in V1. 2. May also see left axis deviation. 3. T wave inversion in V5, V6, I, aVL.

Answer 93

1. R wave > 25mm (5 large squares) in V6. | 2. R wave in V6 + S wave in V1>35mm (7 large squares).

Answer 94

1. "Dominant" R wave in V1 (ie R wave bigger than S wave). 2. Deep S wave in V6. 3. May also see right axis deviation. 4. T wave inversion in V1-V3.

Answer 95

In the CORONAL plane: 1. aVR --> Looking at the right atrium. 2. aVF, II, III --> Inferior septum and anterior aspects of LV. 3. I, aVL --> Left lateral aspect.

OHCEPS - ECG Flashcards

(120 cards)