eLFH - The Electrocardiogram Part 3 Flashcards

1
Q

ECG features of AF

A

Narrow complex tachyarrhythmia

Absence of P waves

Irregularly irregular ventricular response

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2
Q

Common causes of AF

A

Electrolyte disturbance - especially low K+ or low Mg2+

Dehydration

Valvular (especially mitral) disease

IHD

HTN

Hyperthyroidism

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3
Q

Main considerations of AF patients

A

Consider anticoagulation - risk of thromboembolic events

Rate control - tachycardia may provoke heart failure

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4
Q

ECG features of Atrial Flutter

A

Narrow complex tachyarrhythmia

Saw tooth baseline at rate of 300 bpm

Variable conduction to ventricles - 2:1 = 150 bpm, 3:1 = 100 bpm

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5
Q

Drugs to avoid in WPW with SVT

A

Drugs that slow AV conduction - e.g. Digoxin

Otherwise leads to direct transmission of atrial rate to ventricles via accessory pathway and results in VT

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6
Q

Differentials for broad complex tachycardia

A

Monomorphic ventricular tachycardia

Polymorphic ventricular tachycardia (Torsades de Pointes)

Ventricular fibrillation

SVT with aberrant conduction (i.e. bundle branch block)

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7
Q

Features which may differentiate VT from SVT with aberrant conduction

A

VT more likely if presence of:
- P waves
- Capture beats
- Fusion beats

Above features indicate there is independent atrial and ventricular activity occurring

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8
Q

ECG example of P waves in VT

A
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9
Q

Capture beat definition

A

Independent atrial depolarisation occasionally reaches AV node at appropriate time to ‘capture’ cardiac conduction to produce narrow QRS complex within the VT rhythm

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10
Q

Fusion beat definition

A

Similar to capture beat - atrial depolarisation timed such that it arrives simultaneously with ventricular depolarisation

QRS morphology is part way between broad VT complex and narrow complex

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11
Q

Left atrial hypertrophy causes

A

Aka P mitrale

Mitral valve disease

LAH can predispose to AF

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12
Q

Left atrial hypertrophy ECG changes

A

Increased P wave amplitude > 2.5 mm and duration > 0.12 s

Notched P wave (looks like an M shape - M for P Mitrale)

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13
Q

Right atrial hypertrophy causes

A

Aka P pulmonale

Seen in chronic lung disease tricuspid valve disease

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14
Q

Right atrial hypertrophy ECG changes

A

Only increased P wave amplitude > 2.5 mm
Duration of P wave not prolonged

Best seen in II, III, aVF

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15
Q

Left ventricular hypertrophy causes

A

Hypertensive disease

AS

HOCM

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16
Q

Left ventricular ECG changes

A

Various criteria can be used - most common is:
S wave in V1 + R wave in V5 or V6 (whichever is largest) >=35 mm

LVH can also be associated with LV strain (ST depression)

17
Q

Cause of strain pattern in LVH

A

Likely due to more severe hypertrophic disease

Increased muscle mass causes higher LV diastolic pressures when coronary perfusion occurs - results in less coronary perfusion and myocardial ischaemia

18
Q

Right ventricular hypertrophy causes

A

RV overload

E.g. Pulmonary hypertension

19
Q

Right ventricular hypertrophy ECG changes

A

Dominant R wave in V1

Right axis deviation

20
Q

Coronary blood supply

21
Q

ECG territories associated with Anterior-septal ischaemia and Coronary artery associated

A

V1-V3

Left anterior descending artery

22
Q

ECG territories associated with Anterior-lateral ischaemia and Coronary artery associated

A

V1-V6

Left main stem

23
Q

ECG territories associated with High lateral ischaemia and Coronary artery associated

A

I and aVL

Circumflex

24
Q

ECG territories associated with inferior ischaemia and Coronary artery associated

A

II, III and aVF

Right coronary artery

Most likely to be associated with atrioventricular heart blocks

25
ECG territories associated with posterior ischaemia and Coronary artery associated
V1 and V2 - inverse of usual changes (ST depression, R wave rather than Q wave) Right coronary artery or circumflex depending on which system is dominant May be associated with inferior or lateral infarct depending on affected artery
26
ECG territories associated with Subendocardial ischaemia
Any leads
27
ECG changes with coronary ischaemia seen within first hours
ST elevation
28
ECG changes with coronary ischaemia seen in days
Abnormal Q waves appear T wave inversion may be seen
29
ECG changes with coronary ischaemia seen in weeks
ST segments resolve to normal Q waves remain present
30
ECG changes with high Mg2+
Prolonged PR Wide QRS
31
ECG changes with low Mg2+
Prolonged PR ST depression Flat T waves or Peaked T waves Wide QRS Long QT U waves
32
ECG changes with high Ca2+
Short QT
33
ECG changes with low Ca2+
Long QT
34
ECG changes with high K+
Tall tented T waves Wide QRS Prolonged PR Flattened P waves VT / VF / Asystole
35
ECG changes with low K+
Prolonged PR ST depression Flattened or inverted T waves U waves VF / ventricular ectopics