Atrial Arrhythmias - Cardiovascular

Snapshot
- A 66-year-old man presents to the emergency deparment with palpitations and lightheadedness. The patient has been experiencing these symptoms for the past few days. He reports mild chest discomfort. Medical history is significant for hypertension, type 2 diabetes mellitus, and rheumatic heart disease. An electrocardiogram is immediately performed, which demonstrates a narrow QRS complex tachyarrhythmia that is irregularly irregular. (Atrial fibrillation)

                        Introduction
                    
                        Aberrant rhythms can occur anywhere along the cardiac conduction system (SA node to a single cardiomyocyte)
                    
                        these aberrant rhythm can originate from the
                    
                        atrium (thus a supraventricular arrhythmia)
                    
                        ventricles
                    
                        Etiology
                    
                        there are a number of causes and they include
                    
                        myocardial infarction
                    
                        cardiac scarring can interrupt the cardiac conduction system
                    
                        atrial stretch
                    
                        alters the cardiac conduction system (e.g., significant mitral stenosis)
                    
                        reentrant circuit
                    
                        accessory pathway (e.g., atrioventricular re-entry tachycardia)
                    
                        normal atrioventricular node (e.g., atrioventricular nodal reentrant tachycardia)
                    
                        Symptoms
                    
                        asymptomatic
                    
                        palpitation
                    
                        light headedness
                    
                        syncope
                    
                        sudden cardiac death
                    
                        Atrial Arrhythmias
Type
Electrocardiogram Findings
TreatmentComments
Atrial fibrillationA tachyarrhythmia that isirregularly irregular rhythm and has absent P-waves
Stable patientsrate controle.g.,β-blockers and non-dihydropyridine calcium channel blockers
rhythm controle.g.,amiodarone
Unstable patientssynchronized cardioversion
Anticoagulationoptions includeaspirin
warfarin
new oral anticoagulant (NOAC)e.g., dabigatran
Most common type of atrial arrhythmia
A dilated left atrium can result in atrial fibrillatione.g., mitral stenosis
Can result in a thromboembolic event (e.g., stroke)
The ventricular rate is determined by the AV node refractory period
Often originates in thepulmonary veins
Atrial flutter
A tachyarrhythmia with a"sawtooth"appearance
Stable patientstreat similarly as atrial fibrillation
Unstable patientssynchronized cardioversion
Definitive treatment is with catheter ablation
Caused by are-entrant circuit in the right atrium
Sick sinus syndromeA bradyarrhythmia with episodes of tachycardia
acute patients
assess for reversible causes such as medications (calcium channel blockers, digoxin, lithium)
chronic patientsanticoagulation
pacemaker placement

Atrial Arrhythmias
Type	Electrocardiogram Findings	Treatment	Comments
Atrial fibrillation	A tachyarrhythmia that isirregularly irregular rhythm and has absent P-waves	Stable patients rate control e.g.,β-blockers and non-dihydropyridine calcium channel blockers rhythm control e.g.,amiodarone Unstable patients synchronized cardioversion Anticoagulation options include aspirin warfarin new oral anticoagulant (NOAC) e.g., dabigatran	Most common type of atrial arrhythmia A dilated left atrium can result in atrial fibrillation e.g., mitral stenosis Can result in a thromboembolic event (e.g., stroke) The ventricular rate is determined by the AV node refractory period Often originates in thepulmonary veins
Atrial flutter	A tachyarrhythmia with a"sawtooth"appearance	Stable patients treat similarly as atrial fibrillation Unstable patients synchronized cardioversion	Definitive treatment is with catheter ablation Caused by are-entrant circuit in the right atrium
Sick sinus syndrome	A bradyarrhythmia with episodes of tachycardia	acute patients assess for reversible causes such as medications (calcium channel blockers, digoxin, lithium) chronic patients anticoagulation pacemaker placement

Action	Numeric Key	Letter Key	Function Key
Show Bullets		S	Enter (frontside only)
20%	1	N
40%	2	H
60%	3	F	Enter (backside only)
80%	4	E
100%	5	M
Toss	0	T