1. Arrhythmias Flashcards
What are arrhythmia?
An abnormal heart rhythm caused by abnormal electrical activity
Types of arrhythmias
Arrhythmias are classified in accordance to where they start in the heart
Supraventricular - start above the ventricles in the atria
* Atrial fibrillation
* Atrial flutter
* Paroxysmal superventriclar tachycardia
Ventricular - start in the ventricles and more deadly type of arrythmias
* Ventricular tachycardia
* Ventricular fibrillation
* Torsade de pointes
Atrial fibrillation
Most common type of arrhythmia. A fast and irregular heart rhythym that orginates in the atria
Atrial fibrillation types
Paroxysmal - episodes last < 7 days
Persistent - episodes last > 7 days
Permanent - Present all the time
Atrial fibrillation symptoms
- Palpitations
- Dyspnoea
- Dizziness, Tiredness
Atrial fibrillation complications
- heart failure; as bloood is being pumped inefficiently around the body
- stroke; as an irregular heart rhythm causes blood to pool in the atrium, causing a clot, which can be expelled from the heart, to the brain and lead to a stroke
Arrhythmia treatment determining factors
Two types:
-
Rate control aims to reduce the ventricular rate
Usually first line, UNLESS:
* new onset atrial fibrillation with symptoms < 48 hrs and NO haemodynamic instability
* reversible cause
* atrial flutter suitable for ablation - Rhythym control aims to restore sinus rhythm
Rate control treatment
- Beta blocker (not SOTALOL)
- Rate-limiting CCB (diltiazem, verapamil) - not to be used in heart failure
- Digoxin (ONLY FOR sedentary patients and non-paroxysmal)
If monotherapy does not work,
2nd line: combination therapy bUT cannot combined VERAPAMIL and DIGOXIN together = interaction
If dual therapy is infeffective, rhythym control should be considered
Stroke prevention assesment
CHA(2)DVAS(2)S
C - chronic heart failure or left ventricular systolic dysfunction [1]
H - Hypertension [1]
A(2) - AGE 75+ [2]
D - diabetes mellitus [1]
S(2) - Stroke/TIA/VTE [2]
V - vascular disease [1]
A - 65-74 years [1]
S - sex i.e female 1[1]
2 points or more = high risk = Anticoagulant
Warfarin or DOAC (only for patients who do not have issues with their heart valves)
Rhythm control tretament
Through the use of anti-arrhythmic drugs:
* Amiodarone
* Flecainide and Propafenone - avoid in ischaemic heart disease, e.g angina
For paroxysmal atrial fibrillation <48 hrs:
Pill-in-pocket approach can be used
For patients post-cardioversion: standard beta-blocker NOT sotaolol
Atrial flutter: managed in a similar way HOWEVER these patients respond better to catheter ablation
Beta blockers aree used as they reduce sympathomomimetic activity which
Risk of bleeding
O - older 75+ [1]
R - reduced haemoglobin, haematocrit, anaemia [2]
B - bleeding history [2]
I - insufficient kidney function [1]
T - treatment with antiplatelet [1]
Paroxysmal supraventricular tachycardia
When the heart rate beats super fast in a short while, short circuit in the atrium causes the atrium to contract over and over agin
Paroxysmal supraventricular tachycardia treatment treatment
Usually stops spontaenously, can also be managed with:
-
Vagal nerve stimulation - when the parasympathetic nervous system is activated to reduce the heart rate
e.g face in cold water, valsalva manoevure - IV adenosine, Verapamil
If the episodes are recurring:
catheter ablation OR anti-arrhythmic drugs
Ventricular arrhythmias
Includes ventricular tachycardia and ventricular fibrillation.
Ventricualr arrthymias are the worst type, as the ventricles pump blood directly out of the body and to lungs, so has a greater impact on bodily function when changes occur in their rhythym
Ventricular tachycardia - ventricles contract very quickly over again. This can also lead to ventricular fibrillation
Ventricular fibrillation - when the heart beats so fast, it stops working and goes into cardiac arrest = MEDICAL EMERGNECY = DEFRIBRILLATOR
Ventricular arrhythmias management
Ventricular fibrillation - cardiopulmonary resuscitation and defribrilator
Most patients at risk of a cardiac arrest are fitted with a defribillator implant
Patients whom are haemodynamically unstable:
* Require diect current
* Stable and sustained: IV anti-arrhythmic drug
Torsade de pointes
Life-threatening type of ventricular tachycardia with a long QT interval
Hypokalaemia is a risk factor for a prolonged QT interval = torsade de pointes
Torsade de pointes symptoms and treatment
Symptoms
* Fainting
* Seizures
* Palpitations
* Dyspnoea
Treatment:
IV magnesium sulphate
Classes of anti-arrhythmic drugs
Class I:
Na+ channel blockers
(membraine stabilising drugs)
* Lidocaine
* Flecainide
* Propafenone
* Disopyramide
Class IV
Rate-limiting Ca2+ channel blockers
* Diltiazem
* Verapamil
Class III
K+ Channel blockers
* Amiodarone
* Sotalol
* Dronedarone
Class II:
* Beta-blockers
Other:
* Adenosine (CI Asthma/COPD)
* Digoxin (Sedentary patients with non-paroxysmal atrial fibrillation and heart failure)
Amiodarone mechanism of action
Blocks K+ channels that repolarise the heart during phase 3 of the cardiac action potential
Amiodarone uses
Treats most types of arrhythmias and used during CPR to revive a patient with pulsless ventricular tachycardia or ventricular fibrillation
Amiodarone oral loading dose
200mg TDS for 1 week, then BD for 1 week, then OD as maintenance
Amiodarone key counselling
Patients should on amiodarone should be provided an alert card
Amiodarone side effects
P -pulmonary toxicity, prolonged QT interval
H - hyper/hypothyroidism, hepatotoxicity
O - optic neuritis
N - neuropathy in limbs
E - eyes corneal micordeposits
S - slate-grey skin, sensitive to light
Amiodarone side effects
As amiodarone has a long half life, the dangerous effects can persist for a month or more after stopping treatment
Corneal micro-deposits
Can affect driving at night as the lights can cause dazzling
Grey skin, phototoxicity
Patients should use high SPF sunscreen and protect skin
Optic neuropathy
Amiodarone can damage the topic nerve, patients should report impaired vision
Peripheral neuropathy
Can present as pins and needles, numbness, tremors
Thyroid dysunfction resulting in high or levels of thyroid levels
monitor: TFT, TSH, T3, T4
Hepatotoxicity
Patients should report signs of liver toxicity - abdominal pain, dark urine, jaundice, persistent vomiting
Monitor: LFT’s
STOP: if 3x increase in AST and ALT
Pulmonary toxicity
Patients should report shortness of breath or cough
QT prolongation:
Monitoring: Potassium
Patients should report signs of an erratic, irregular or slow heartbeat
Bradycardia
