Arrhythmias Flashcards

1
Q

sinus bradycardia

A

originates in SA node

rate less than 60

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2
Q

sinus tacchycardia

A

originates in SA node

rate greater than 100

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3
Q

causes of sinus arrhythmias

A

resp: the P-P interval lengthens and shortens with inspiration and expiration
non-resp: where the process occurs seemingly for no reason
sometimes seen in association with complete heart block

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4
Q

Dilatation

A

the distension of an individual heart chamber

can be acute or chronic

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5
Q

hyptrophy

A

a chronic condition of the heart characterised by an increase in the thickness of a chamber’s myocardial wall
increase in its workload over time

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6
Q

Right atrial enlargement

A

usually caused by increased pressure and/or volume in the right atrium - right atrial overload
occurs in:
pulmonary valve stenosis, tricuspid valve stenosis and insufficiency, pulmonary hypertension from various causes

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7
Q

Left atrial enlargement

A

usually caused by an increased pressure and/or volume in the left atrium - left atrial overload
occurs in:
mitral valve stenosis and insufficiency, acute myocardial infarction, left heart failure, left ventricular hypertrophy

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8
Q

Right ventricular hypertrophy

A

caused by increase pressure in the right ventricle

occurs in: pulmonary valve stenosis, tricuspid valve insufficiency, pulmonary hypertension

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9
Q

ECG changes in right ventricular hypertrophy

A

QRS 0.12 secs or less
R waves: tall R waves in leads II and III and V1
S waves: relatively deeper than normal in lead I and V4-5
ST segments: downsloping ST depression in leads II, III, aVF and V1
T waves: T wave inversion in leads II, III, aVF, V1

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10
Q

left ventricular hypertrophy

A

caused by increased pressure in the left ventricle

occurs in: mitral insufficiency, aortic stenosis, systemic hypertension, MI, hypertophic cardiomyopathy

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11
Q

ECG changes in left ventricular hyptrophy

A

QRS 0.12 or less
slight QRS deviation to the left
R waves: tall in leads I and aVL and V5,6
S waves: deep S waves in lead III and V1,2

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12
Q

pericarditis

A

inflammatory disease of the pericardium, directly involving the epicardium with deposition of inflammatory cells and a variable amount of serous, fibrous, purulent or haemorrhagic exudate within the pericardial sac

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13
Q

causes of pericarditis

A
infectious agents
acute MI
trauma
connective tissue diroders
allergic and hypersensitivity disease
metabolic disorders
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14
Q

Hyperkalaemia

A

excess of serum potassium above the normal levels of 3.5 to 5mEg/l
causes: kidney failure and certain duiretics
peaky T waves

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15
Q

Hypokalaemia

A

deficiency of serum potassium below the normal 3.5 to 5

common causes vomiting, gastric suction, excessive use of diuretics

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16
Q

hypercalaemia

A

excess serum calcium above the normal levels of 2.1 to 2.6

17
Q

causes of hypercalcaemia

A
adrenal insufficiency
hyperparathyroidism
immobilisation
kidney failure
malignancy
sarcoidosis
thyrotoxicosis 
vitamin A and D intoxication
18
Q

hypocalcaemia

A

shortage of serum calcium below the normal levels

19
Q

causes of hypocalcaemia

A
chronic stetorrhea 
diuretics
hypomagnesemia 
osteomalacis in adults and rickets in children
hypoparathyroidism
pregnancy
resp alkalosis and hyperventilation
20
Q

digitalis

A

administered within therapeutic range produces characteristic changes in the ECG

excitatory: premature atrial contractions, atrial tachycardia, nonparyoxysmal junctional tachy, premature ventricular contractions, ventricular tachy, ventricular fibrillation
inhibitory: sinus tachy, SA exit block, AV block

21
Q

ECG characteristics of digitalis

A

PR intervals: prolonged over 0.20 seconds
ST segments: depressed in many leads
T waves: flattened, inverted, biphasic
QT intervals: shorter than normal for the HR

22
Q

Patho of preexcitation syndromes

A

occurs when electrical impulses from the atria or AV junction into the ventricles through accessory conduction pathways
accessory conduction pathways are abnormal strands of myocardial fibers that conduct electrical impulses
can conduct impulses backwards

23
Q

Accessory AV pathways (bundles of Kent)

A

accessory tracts responsible for WPW conduction
pathways conduct electrical impulses from atria to the ventricles, bypassing AV junction, producing premature depolarisation of ventricles

24
Q

ECG changes: WPW

A

PR intervals shortened to less than 0.12

QRS greater than 0.12 seconds and abnormally shaped

25
Atrio-His fibers (James FIbers)
an accessory conduction pathway connects the atria with the lowermost part of the AV node, bypassing slower conducting AV node
26
ECG characteristics: Atrio-his fibers
PR intervals are usually shortened to less than 0.12 | QRS normal
27
Nodoventricular/fasiculoventricular fibers (Mahaim fibers)
rare accessory conduction pathways provide bypass channels between the lower part of the AV node and the ventricles and the between the bundle of His and the ventricles
28
ECG characteristics of nodoventricular/fasiculoventricular fibers
PR intervals normal | QRS greater than 0.12 seconds adn abnormally shaped
29
Brugada Syndrome
pts presenting with ST segment elevation in leads V1-3, right branch block, suscpetibility to ventricular tachy arrhythmias
30
ECG changes: brugada syndrome
QRS complexes in V1-3 resemble a right bundle branch block without typical RR pattern
31
QT
Qt interval prolongation increases potential for lethal ventricular arrhythmias such as torsades short QT are rare but when found are due to genetic disorders
32
Calculation for QT
QTc= QT (milliseconds) + 1.75 (ventricular rate - 60)
33
chronic cor pulmonale
enlargement of the right ventricle commonly accompanied by right heart failure usually end stage result of prolonged pulmonary hypertension
34
early repolarisation
describes a form of myocardial repolarisation in which ST segment is elevated or depressed 1 to 3mm above or below the baseline respectively
35
Acute pulmonary embolism
occurs when a blood clot or other foreign matter lodges in a pulmonary artery and causes obstruction of blood flow to the lung segment supplied by the artery
36
hypothermia
causes a positive wave, the osborn wave | occurs at the junction of the QRS complex and ST segment