CVS: Arrhythmia Flashcards
Outline the pathophysiology of Arrhythmias
Disturbance of cardiac rhythm
Common, often benign, often intermittent
Outline the Aetiology of Arrhythmias
Cardiac = MI, coronary artery disease, LV aneurysm, mitral valve disease, cardiomyopathy, pericarditis, myocarditis, aberrant conduction pathways
Caffeine
Smoking
Alcohol
Pneumonia
Drugs = beta 2 agonists, digoxin, L-dopa
Metabolic imbalance = K, Ca, Mg, hypoxia, hypercapnia, metabolic acidosis
Pheochromocytoma
What are the signs and symptoms of arrhythmias
Asymptomatic
Palpitations
Chest pain
Presyncope/syncope
Hypotension
Pulmonary oedema
How would you investigate an arrhythmia?
Bloods = FBC, U+Es, glucose, Ca, Mg, TSH
ECG
24h ECG monitoring
ECHO = any structural heart disease
Provocation tests = exercise ECG
How would you manage SVT
Acute management = Valsalva/carotid massage, IV adenosine (blocks conduction through AV = remove QRS and only see atrial activity) or verapamil
DC (direct current) shock if compromised
Maintenance = beta blockers, verapamil
How would you manage VF
Acute management = IV amiodarone, IV lidocaine, if no response DC shock
Amiodarone
Permanent pacing may be used to overdrive tachyarrhythmias, to treat bradyarrhythmia’s, or prophylactically in conductance disturbances
What are the complications of arrhythmias
Formation of blood clots = stroke
Sudden cardiac arrest
Heart failure
How would you manage bradycardia?
If asymptomatic and >40bpm = no treatment
Stop drugs that may be contributing = beta blockers, digoxin
If <40bpm and symptomatic = atropine, if no response insert pacing wire
Atropine = increases HR by reducing vagal stimulation
How does bradycardia present on ECG?
Rate below 60bmp
Normal P wave with proceeding QRS
How does atrial fibrillation present on ECG?
Irregularly irregular
Absent P waves (wavy baseline)
Rapid ventricular rhythm, (majority >100bpm)
How does atrial flutter present on ECG?
Baseline - saw tooth appearance II, III, aVF
How does VT present on ECG and how is it managed?
> 3 consecutive ventricular beats with a rate of 100-250bpm (100-120 = slow tachy, >250 = ventricular flutter)
Wide QRS complexes (> 3 small boxes)
More controlled appearance than VF
Mx =
- unstable = DC cardioversion
- stable = amiodarone
How does a STEMI present on ECG?
(full thickness - endocardium to epicardium)
Acute = ST elevation
Late = ST elevation normalises, T wave inverts, Q wave deepens and persists
How does a LBBB present on ECG?
Wide QRS (> 3 small boxes)
V1 - W, broad S wave
V6 - M
How does a RBBB present on ECG?
Wide QRS (> 3 small boxes)
V1 - M
V6 - W
How does 1st degree heart block present on ECG?
(slow conduction at AV node and bundle of His)
PR interval prolonged (>5 small squares)
Normal QRS
How does 2nd degree heart block type 1 present on ECG?
Progressive lengthening of PR interval
Until 1 P wave is not transmitted
How does 2nd degree heart block type 2 present on ECG?
PR interval normal
Sudden non-conduction of a beat = dropped QRS
How does 3rd degree heart block present on ECG?
No relationship between P and QRS
Wide QRS
Rate is very slow = 30-40bpm
How does a ventricular ectopic beat present on ECG?
Wide QRS complex
What is the difference between SVT and VT?
SVT = improper electrical activity arising from the atria
- AVNRT = palpitations, SOB, chest pain, syncope
VT = improper electrical activity arising from the ventricles
What are the indications for DC cardioversion?
Restore sinus when other treatments have failed
Haemodynamic compromise
SVT, AF, atrial flutter, VT
What is wolff-parkinson-white syndrome?
Extra electrical pathway between the atria and ventricles (typically the left) = tachycardia
ECG = delta wave with narrow QRS
How is AF managed?
Anticoag =
- structural heart disease = warfarin
- no heart disease = DOAC
Rate control = beta blocker (bisoprolol) or Ca channel blocker (verapamil)
Rhythm control =
- synchronised DC shock
- amiodarone, flecanide
What scoring systems are helpful in determining whether a pt with AF should be taking long-term anticoag?
CHADSVASC (>2 offer anti-coag)
HAS-BLED
What is a ‘Reveal’?
Chip inserted under the skin on the chest
Records ECG
Loops every 7 1/2 mins
Pt activates recording with controller
Lasts 3 years
Programmed to detect specific factors
Indications = syncope, dizziness, symptoms that aren’t frequent
What is a pacemaker?
Indications = AF, sinus node dysfunction, AV block, after MI, prevent tachycardia
Lasts 6-15 years
Incision in vein, then insertion of of electrode lead into heart chamber/s
Guided by fluoroscopy
Function = if it doesn’t detect a normal beat-to-beat period it will stimulate the ventricle with a short low voltage pulse
What causes AF?
Thyrotoxicosis
Previous IHD
Alcohol
Elderly
How is atrial flutter managed?
- rhythm control - cardioversion
- rate control
- ablation catheter = procedure used to remove or terminate a faulty electrical pathway
- anti-coag
- ECHO
- Consider DC cardioversion
