1. atrial fibrillation 2. atrial flutter 3. AV nodal re-entry tachycardia (AVNRT) 4. AV reciprocating tachycardia (AVRT)

cardiac arrhythmias Flashcards by Areej Shahid

what is a cardiac arrhythmia

An abnormality of cardiac rhythm

How well did you know this?

Not at all

Perfectly

what can cardiac arrhthymias lead to

sudden death, syncope, HF, dizziness, palpitations or no symptoms at all

How well did you know this?

Not at all

Perfectly

describe the route of cardiac conduction

Sinoatrial node (pacemaker)
Atrioventricular node
Bundle of His
Right and left bundle branches
Purkinje fibres

How well did you know this?

Not at all

Perfectly

2 types of Cardiac Dysrhythmias

bradycardia

tachycardia

How well did you know this?

Not at all

Perfectly

what is bradycardia

Slow heart rate
<60 BPM

How well did you know this?

Not at all

Perfectly

does bradycardia cause symptoms

yes
More likely to cause symptomatic arrhythmias

How well did you know this?

Not at all

Perfectly

when is bradycardia normal

Normal during sleep and in well-trained athletes due to increased vagal tone and PS activity

How well did you know this?

Not at all

Perfectly

what is tachycardia

Fast heart rate
>100 BPM

How well did you know this?

Not at all

Perfectly

what is tachycardia divided into

Supraventricular tachycardias

Ventricular tachycardias

How well did you know this?

Not at all

Perfectly

what is sinus tachycardia

> 100 BPM
Physiological response to exercise and excitement

How well did you know this?

Not at all

Perfectly

what can sinus tachycardia occur in

Anaemia
Fever
Heart failure
Thyrotoxicosis
Acute PE
Hypovolaemia
Atropine

How well did you know this?

Not at all

Perfectly

management of sinus tachycardia

Correction of cause
Beta blockers

How well did you know this?

Not at all

Perfectly

what are Supraventricular tachycardias (SVT)

Any tachycardia which arises from the atrium or AV junction

How well did you know this?

Not at all

Perfectly

4 types of SVT

atrial fibrillation
atrial flutter
AV nodal re-entry tachycardia (AVNRT)
AV reciprocating tachycardia (AVRT)

How well did you know this?

Not at all

Perfectly

what is atrial fibrillation

Chaotic, irregular atrial rhythm 300-600BPM

How well did you know this?

Not at all

Perfectly

what. is the most common cause of arrhthymias

atrial fibrilaltion

How well did you know this?

Not at all

Perfectly

pathophysiology of atrial fibrillation

Atrial activation 300-600/minute

Only a proportion of these impulses are conducted to the ventricles (due to refractory period of AVN)
HR 120-180 BPM

How well did you know this?

Not at all

Perfectly

causes of atrial fibrillation

any condition that causes raised atrial pressure:

Heart failure
Hypertension
Coronary artery disease
Rheumatic Heart Disease
Valvular Heart Disease
Thyrotoxicosis

How well did you know this?

Not at all

Perfectly

what would ECG of atrial fibrillation show

Irregularly irregular
F waves
No clear P waves
Rapid and irregular QRS complex

How well did you know this?

Not at all

Perfectly

symptoms of atrial fibrillation

Asymptomatic
Palpitations
Fatigue
Dyspnoea and/or chest pain
Heart failure

management of atrial fibrillation

rate control
rhythm control
Anticoagulation with warfarin

what does rate control do

aims to reduce HR at rest and during exercise but patient remains in AF

how to do rate control

Beta blockers (bisoprolol) or calcium channel blockers (verapamil) preferred

Digoxin used in sedentary patients

Anti-arrhythmic - Amiodarone

what does rhythm control do

generally used in patients who are <65, highly symptomatic, patients with HF and individuals with recent onset AF

how to do rhythm control

Electrical DC cardioversion by defibrillator followed by beta blockers to suppress arrhythmia Other agents used on presence of underlying heart disease

how to calculate stroke risk with atrial fibrillaton

CHADS2VASc score

what is atrial flutter

Often associated with AF Atrial HR = 300 BPM Ventricular rate = 150 BPM (due to AV node conducting every second “flutter beat”

causes of atrial flutter

Idiopathic Coronary artery disease HTN Pericarditis Obesity

presentation of atrial flutter

Palpitations Chest pain Syncope Fatigue

ecg of atrial flutter

sawtooth flutter waves (F waves)

treatment of atrial flutter

IV amiodarone (to restore rhythm) and beta blocker (to suppress further arrhythmias) Radiofrequency catheter ablation of re-entry circuit

what is AV nodal re-entry tachycardia (AVNRT)

most common SVT Due to the presence of a “ring” of conducting pathways in the AV node, of which the “limbs” have different conduction times and refractory periods This allows a re-entry circuit and an impulse to produce a circus movement tachycardia

risk factors for AVRNT

Exertion Caffeine Alcohol

presentation of AVRNT

Regular rapid palpitations – abrupt onset and sudden termination Neck pulsation – JV pulsations Polyuria – due to release of ANP in response to increased atrial pressure during tachycardia Chest pain and SOB

ECG of AVRNT

P waves are either not visible, or are seen immediately before or after the QRS complex QRS complex is a normal shape because the ventricles are activated in the normal way (down bundle of His)

what is AV reciprocating tachycardia (AVRT)

Due to the presence of an accessory pathway connecting the atria and ventricles and is capable of antegrade or retrograde conduction (or both).

how to differ AVRNT and AVRT on ecg

in AVRT P wave is usually clearly seen between the QRS complex and T wave.

best known type of AVRT

Wolff-Parkinson-White syndrome (WPW)

what is WPW

There is an accessory pathway (bundle of Kent) between the atria and ventricles When the SAN depolarises, the impulse can travel to the AVN via the atria as well as the accessory pathway

symptoms of AVRT

Palpitations Dizziness Dyspnoea Central chest pain Syncope

ECG of AVRT

The early depolarisation of part of the ventricle leads to a shortened PR interval and a slurred start to the QRS (delta wave) and the QRS is narrow Patients are also prone to atrial and occasionally ventricular fibrillation

how to manage stable AVRT an AVRNT

If stable, vagal manoeuvres - Breath-holding - Carotid massage - Valsalva manoeuvre

what to do if If manoeuvres unsuccessful for AVRT and AVRNT treatment

IV adenosine Causes a complete heart block for a fraction of a second Effective at terminating AVNRT and AVRT

intrinsic causes of bradycardia

Acute ischaemia Infarction of SAN Sick sinus syndrome

what is sick sinus syndrome

Bradycardia caused by intermittent failure of SAN depolarisation due to failure of sinus node to propagate to the atria (sinoatrial block)

ecg of sick sinus syndrome

severe sinus bradycardia or intermittent long paused between consecutive P waves

how to treat intrinsic bradycardia

Treat with atropine, permanent pacemaker or temporary pacing in acute cases

extrinsic causes of bradycardia

Drug therapy – beta blockers, digoxin Hypothyroidism Hypothermia Raised intracranial pressure Treat underlying cause