Browse categories and answer follow-up questions to refine your symptom profile.
Approach to the Critical Patient
Initial stabilization
Initial priorities
Airway protection triggers
Depressed consciousness with hypoventilation
Refractory hypoxemia
Breathing support
Oxygen for SpO2 below local target
Noninvasive ventilation for acute pulmonary edema
Circulation actions
If hypotension with altered mentation, immediate synchronized cardioversion
If shock or ischemic chest pain, immediate synchronized cardioversion
If acute pulmonary edema, immediate synchronized cardioversion
Monitoring
Continuous ECG
NIBP every 3 to 5 minutes or arterial line if unstable
Pulse oximetry
Rhythm identification
Atrial fibrillation features
Irregularly irregular R R intervals
No discrete P waves
Atrial flutter features
Regular narrow complex tachycardia with ventricular rate often near 150
Sawtooth flutter waves in inferior leads
Wide complex tachycardia safety assumptions
If wide and irregular, treat as atrial fibrillation with pre-excitation until proven otherwise
If wide and regular, consider ventricular tachycardia until proven otherwise
Hemodynamic instability definition
Instability criteria
Systolic BP below 90 mmHg with hypoperfusion
Ongoing ischemic chest pain
Acute heart failure with pulmonary edema
Altered mental status attributed to arrhythmia
Immediate consult triggers
Cardiology or electrophysiology
Suspected pre-excitation
Refractory rapid ventricular response
Need for urgent rhythm control with complex comorbidity
Critical care
Persistent instability after initial intervention
Need for vasoactive infusion
Key decision points
Management pathway selection
Unstable atrial fibrillation or flutter
Synchronized cardioversion pathway
Peri-procedural anticoagulation consideration
Stable with rapid ventricular response
Rate control pathway
Rhythm control option selection based on onset and stroke risk
Stable without rapid ventricular response
Anticoagulation and outpatient rhythm strategy
Onset timing framework
Onset under 48 hours
Rhythm control option with peri-procedural anticoagulation based on stroke risk
Onset over 48 hours or unknown
Anticoagulation 3 weeks before elective cardioversion
TEE guided cardioversion with immediate anticoagulation alternative
Anticoagulation minimum 4 weeks after cardioversion
Reversible trigger screen
Trigger categories
Sepsis or systemic infection
Hypovolemia or hemorrhage
Hypoxia or COPD exacerbation
Pulmonary embolism
Thyrotoxicosis
Alcohol or stimulant exposure
Postoperative state
Acute coronary syndrome
Decompensated heart failure
History
Presenting features and timing
Symptom characterization
Palpitations
Abrupt onset versus gradual onset
Intermittent versus persistent
Dyspnea
Orthopnea
Reduced exercise tolerance
Chest discomfort
Exertional pattern
Rest pain pattern
Presyncope or syncope
Exertional syncope concern
Injury during event
Neurologic symptoms
Focal weakness
Aphasia
Timing and duration
Symptom onset clock time
Under 48 hours
Over 48 hours
Unknown onset
Prior episodes
Paroxysmal pattern
Persistent pattern
Longstanding persistent pattern
Risk factors and comorbidities
Stroke risk factors
Congestive heart failure history
Hypertension history
Diabetes mellitus history
Prior stroke or TIA
Vascular disease history
Age 65 to 74 years
Age 75 years or older
Female sex
Bleeding risk context
Prior major bleeding
Prior intracranial hemorrhage
Active GI bleed symptoms
Chronic liver disease
Chronic kidney disease
Concomitant antiplatelet use
Structural heart disease
Valvular disease
Cardiomyopathy
Congenital heart disease
Prior cardiac surgery
Potential triggers
Fever
Cough or sputum change
Recent surgery
Alcohol binge
Stimulant use
Thyroid symptoms
Medications and anticoagulation status
Current cardiac medications
Beta blocker use
Non-dihydropyridine calcium channel blocker use
Digoxin use
Antiarrhythmic use
Anticoagulation details
DOAC name and last dose time
Warfarin use and last INR value
Missed doses in past 3 weeks
Antiplatelet use
Physical Exam
Focused cardiovascular and volume assessment
Hemodynamics
Blood pressure trend
Hypotension with signs of shock
Hypertension suggesting catecholamine surge
Heart rate
Resting ventricular rate above 110
Ventricular rate near 150 suggesting flutter with 2 to 1 conduction
Peripheral perfusion
Cool extremities
Delayed capillary refill
Cardiac exam
Rhythm regularity
Irregularly irregular pulse
Regular tachycardia with fixed rate
Murmur assessment
Mitral stenosis suspicion
New murmur with heart failure
Volume status
JVP elevation
Right heart strain concern
Fluid overload concern
Peripheral edema
New bilateral edema
Unilateral edema with DVT concern
Pulmonary and neurologic screening
Respiratory status
Work of breathing
Accessory muscle use
Speaking in short phrases
Lung auscultation
Crackles suggesting pulmonary edema
Wheeze suggesting bronchospasm
Neurologic status
Mental status
Acute delirium or confusion
Reduced level of consciousness
Focal deficits
Facial droop
Arm drift
Speech abnormality
PITFALLS
Common misses
Mislabeling atrial flutter as atrial fibrillation on monitor strip
Treating irregular wide complex tachycardia with AV nodal blockers in pre-excitation
Overlooking sepsis or pulmonary embolism as the driver of tachyarrhythmia
Assuming symptom onset time is reliable without corroboration
Differential Diagnosis
Life-threatening and mimics
Dangerous diagnoses
Acute coronary syndrome
ICD-10 I21
SNOMED CT acute myocardial infarction
Pulmonary embolism
ICD-10 I26
SNOMED CT pulmonary embolism
Sepsis
ICD-10 A41.9
SNOMED CT sepsis
Thyroid storm
ICD-10 E05.91
SNOMED CT thyroid storm
Ventricular tachycardia
ICD-10 I47.2
SNOMED CT ventricular tachycardia
Arrhythmia differential
Atrial fibrillation
ICD-10 I48.0 to I48.2
SNOMED CT atrial fibrillation
Typical atrial flutter
ICD-10 I48.3
SNOMED CT atrial flutter
SVT AVNRT or AVRT
ICD-10 I47.1
SNOMED CT supraventricular tachycardia
Multifocal atrial tachycardia
ICD-10 I47.1
SNOMED CT multifocal atrial tachycardia
Atrial tachycardia
ICD-10 I47.1
SNOMED CT atrial tachycardia
Non-arrhythmic causes of tachycardia
Hemorrhage
ICD-10 R58
SNOMED CT hemorrhage
Hypovolemia
ICD-10 E86.1
SNOMED CT hypovolemia
Hypoxia
ICD-10 R09.02
SNOMED CT hypoxemia
Laboratory Tests
Core ED labs
Baseline laboratory panel
Electrolytes and renal function
Sodium mmol/L
Potassium mmol/L
Magnesium mmol/L
Creatinine and eGFR
CBC
Anemia as contributor to demand ischemia
Leukocytosis as infection clue
Glucose mmol/L
Hypoglycemia as altered mentation mimic
Severe hyperglycemia as stress marker
Cause and complication directed labs
Trigger evaluation
Thyroid testing
TSH for new atrial fibrillation without clear trigger
Free T4 if TSH suppressed
Infection evaluation
Lactate mmol/L for suspected sepsis
Blood cultures if febrile with sepsis concern
Cardiac injury evaluation
High sensitivity troponin
Dynamic change supporting ACS
Mild elevation possible in tachycardia and heart failure
BNP or NT-proBNP
Heart failure support in dyspnea
Limited specificity in renal dysfunction
Anticoagulation and procedural labs
Anticoagulation readiness
INR for warfarin users
Therapeutic range 2.0 to 3.0 for nonvalvular atrial fibrillation
Higher target range for mechanical valves per valve type
aPTT for unfractionated heparin titration
Baseline before infusion
Repeat per protocol
Procedure safety
Pregnancy test for patients with pregnancy potential
Medication and imaging implications
Cardioversion generally safe in pregnancy
Diagnostic Tests
Scoring Systems
Risk stratification tools
CHA2DS2-VASc stroke risk
Congestive heart failure 1 point
Hypertension 1 point
Age 75 years or older 2 points
Diabetes mellitus 1 point
Prior stroke or TIA 2 points
Vascular disease 1 point
Age 65 to 74 years 1 point
Female sex 1 point
HAS-BLED bleeding risk context
Hypertension uncontrolled 1 point
Abnormal renal function 1 point
Abnormal liver function 1 point
Stroke history 1 point
Bleeding history 1 point
Labile INR 1 point
Elderly age over 65 years 1 point
Drugs predisposing to bleeding 1 point
Alcohol excess 1 point
MRI
MRI roles
Brain MRI
Acute stroke evaluation when CT nondiagnostic and symptoms persistent
Not a prerequisite for anticoagulation decisions in stable patients
Cardiac MRI
Selected cardiomyopathy evaluation in recurrent atrial fibrillation
Not an ED routine test
CT
CT roles
CT pulmonary angiography
PE evaluation when clinical suspicion high
Tachyarrhythmia as possible PE manifestation
CT head noncontrast
New focal neurologic deficit
Head trauma with anticoagulation
CT coronary angiography
Selected chest pain evaluation per local pathways
Ultrasound
Point of care ultrasound
Cardiac POCUS
LV function gross assessment
Pericardial effusion assessment
RV dilation suggesting PE in appropriate context
Lung ultrasound
B lines supporting pulmonary edema
Pleural effusion assessment
Lower extremity venous ultrasound
Proximal DVT assessment when PE suspected
Disposition
Level of care and admission criteria
Admission indications
Persistent hemodynamic instability
Recurrent hypotension
Need for vasoactive support
Acute heart failure
Ongoing oxygen requirement
Need for IV diuresis and monitoring
Suspected ACS
Dynamic troponin rise
Ongoing ischemic symptoms
Stroke or TIA concern
Persistent neurologic deficit
Need for stroke pathway and imaging
Pre-excitation with atrial fibrillation
Need for monitored antiarrhythmic therapy
Electrophysiology evaluation
ICU or stepdown indications
Post cardioversion with ongoing instability
Refractory rate requiring continuous infusion
Significant comorbid decompensation
ED discharge pathway
Discharge candidates
Hemodynamic stability throughout ED stay
Ventricular rate controlled at rest
No active ischemia evidence
No acute heart failure requiring IV therapy
Clear anticoagulation plan with follow-up
Follow-up targets
Primary care or cardiology follow-up within 7 days
Anticoagulation follow-up within 3 to 5 days if warfarin initiation
Electrophysiology referral for typical flutter ablation candidacy
Treatment
Unstable atrial fibrillation or flutter
Synchronized cardioversion
Energy selection
Biphasic 120 to 200 J initial for atrial fibrillation
Biphasic 50 to 100 J initial for typical atrial flutter
Sedation considerations
Etomidate IV 0.1 to 0.2 mg/kg for brief deep sedation
Propofol IV 0.5 to 1 mg/kg with caution in hypotension
Ketamine IV 1 mg/kg for bronchospasm or hypotension risk
Anticoagulation around emergent cardioversion
If onset over 48 hours or unknown, anticoagulation as soon as feasible unless contraindicated
If onset under 48 hours, anticoagulation decision based on stroke risk and clinical context
Stable rate control
Rate control targets
Resting ventricular rate under 110 for stable patients
Resting ventricular rate under 100 for persistent symptoms or LV dysfunction
Beta blocker options
Metoprolol IV
Metoprolol IV 2.5 to 5 mg
Repeat every 5 minutes
Total maximum 15 mg
Avoid in acute decompensated heart failure with hypoperfusion
Avoid in severe asthma with active bronchospasm
Esmolol IV infusion
Esmolol IV bolus 500 mcg/kg over 1 minute
Infusion 50 mcg/kg/min
Titrate every 5 minutes by 50 mcg/kg/min
Maximum 200 mcg/kg/min
Useful when rapid offset desired
Non-dihydropyridine calcium channel blockers
Diltiazem IV bolus then infusion
Diltiazem IV 0.25 mg/kg over 2 minutes
Second bolus 0.35 mg/kg after 15 minutes if inadequate
Infusion 5 to 15 mg/hour
Titrate by 2.5 mg/hour every 15 minutes
Avoid in HFrEF with significant LV systolic dysfunction
Verapamil IV
Verapamil IV 2.5 to 5 mg over 2 minutes
Repeat 5 to 10 mg after 15 to 30 minutes if needed
Maximum 20 mg
Avoid in hypotension
Digoxin
Digoxin IV loading
Digoxin IV 0.25 mg
Repeat 0.25 mg every 6 hours
Total 1 mg over 24 hours
Slower onset
Useful in sedentary patients with hypotension limiting other agents
Combination therapy cautions
Beta blocker plus calcium channel blocker risk
Hypotension
AV block
Stable rhythm control
Rhythm control selection
Pharmacologic cardioversion options
Ibutilide IV for flutter and atrial fibrillation
Ibutilide IV 1 mg over 10 minutes if weight 60 kg or more
Second dose 1 mg over 10 minutes after 10 minutes if needed
Continuous telemetry minimum 4 hours
Torsades risk increased with low potassium or low magnesium
Procainamide IV for atrial fibrillation with pre-excitation
Procainamide IV 15 to 17 mg/kg over 30 to 60 minutes
Stop if QRS widens over 50 percent
Stop if hypotension develops
Avoid in severe heart failure
Amiodarone IV for atrial fibrillation with structural heart disease
Amiodarone IV 150 mg over 10 minutes
Infusion 1 mg/min for 6 hours
Infusion 0.5 mg/min for 18 hours
Slower cardioversion than class IC agents
Electrical cardioversion in stable patient
Suitable when symptom burden high and onset under 48 hours
Suitable when TEE excludes atrial thrombus
Pre-excitation and irregular wide complex tachycardia
Avoid AV nodal blockers
Adenosine
Diltiazem
Verapamil
Beta blockers
Digoxin
Preferred agents
Procainamide IV protocol
See procainamide dosing section
Continuous ECG for QRS widening
If unstable, synchronized cardioversion
Immediate pathway
Anticoagulation and stroke prevention
Anticoagulation indication framework
Nonvalvular atrial fibrillation or flutter
CHA2DS2-VASc 0 in men
No anticoagulation usually
CHA2DS2-VASc 1 in men
Anticoagulation consideration based on shared decision making
CHA2DS2-VASc 1 in women from sex alone
No anticoagulation usually
CHA2DS2-VASc 2 or more in men
Long term anticoagulation recommended
CHA2DS2-VASc 3 or more in women
Long term anticoagulation recommended
Valvular atrial fibrillation
Moderate to severe rheumatic mitral stenosis
Warfarin preferred
Mechanical heart valve
Warfarin required
DOAC options for nonvalvular atrial fibrillation
Apixaban
Apixaban 5 mg PO twice daily
Reduce to 2.5 mg PO twice daily when dose reduction criteria met
Rivaroxaban
Rivaroxaban 20 mg PO daily with food
Dose reduction for renal impairment per product monograph
Dabigatran
Dabigatran 150 mg PO twice daily
Dose reduction for renal impairment per product monograph
Edoxaban
Edoxaban 60 mg PO daily
Dose reduction for renal impairment per product monograph
Warfarin
Warfarin initiation
INR target 2.0 to 3.0 for nonvalvular atrial fibrillation
Bridging not routinely required for nonvalvular atrial fibrillation
Peri-cardioversion anticoagulation
Onset over 48 hours or unknown
Anticoagulation minimum 3 weeks before elective cardioversion
Anticoagulation minimum 4 weeks after cardioversion
TEE guided strategy
Immediate anticoagulation then TEE to exclude thrombus
Cardioversion after negative TEE
Anticoagulation minimum 4 weeks after cardioversion
Evidence and guideline signals
Guideline classes
Hemodynamic instability with atrial fibrillation or flutter
Synchronized cardioversion Class I recommendation
Anticoagulation for elevated CHA2DS2-VASc
Long term oral anticoagulation Class I recommendation
AV nodal blocking agents for acute rate control in stable patients
Beta blockers or non-dihydropyridine calcium channel blockers Class I recommendation
Special Populations
Pregnancy
Pregnancy considerations
Maternal stabilization priority
Synchronized cardioversion safe when unstable
Left lateral tilt for late pregnancy hypotension risk
Rate control medication selection
Beta blockers preferred for acute control with fetal monitoring as indicated
Avoid atenolol for chronic use due to fetal growth restriction association
Anticoagulation selection
LMWH preferred for therapeutic anticoagulation in pregnancy
Warfarin teratogenicity risk in first trimester
DOACs generally avoided due to limited safety data
Geriatric
Geriatric considerations
Presentation patterns
Fatigue and dyspnea more common than palpitations
Delirium as primary manifestation
Medication risks
Hypotension sensitivity with diltiazem and beta blockers
Bradycardia risk with combination therapy
Anticoagulation emphasis
Higher baseline stroke risk
Fall risk alone not a contraindication to anticoagulation
Pediatrics
Pediatric considerations
Epidemiology
Atrial fibrillation rare in structurally normal hearts
Congenital heart disease and postoperative states as common contexts
Workup focus
Structural heart disease screening
Toxicology consideration in adolescents
Management
Early cardiology involvement
Weight based dosing for rate control agents per pediatric protocols
Background
Epidemiology
Epidemiology basics
Prevalence
Most common sustained arrhythmia in adults
Prevalence increases markedly with age
Atrial flutter context
Often coexists with atrial fibrillation
Typical flutter is cavotricuspid isthmus dependent
Outcomes
Increased stroke risk without anticoagulation
Increased heart failure risk with uncontrolled rates
Pathophysiology
Mechanisms
Atrial fibrillation mechanism
Multiple wavelet reentry and triggers
Pulmonary vein ectopy contribution
Atrial flutter mechanism
Macroreentrant circuit in right atrium for typical flutter
Fixed atrial rate leading to predictable ventricular conduction ratios
Complications
Left atrial appendage thrombus formation
Tachycardia induced cardiomyopathy
Therapeutic Considerations
Rate versus rhythm strategy
Rate control advantages
Rapid symptom improvement for many patients
Lower procedural risk than cardioversion
Rhythm control advantages
Symptom relief when rate control inadequate
Potential reduction in tachycardia induced cardiomyopathy
Early rhythm control concept
Potential long term benefit in selected patients with recent onset atrial fibrillation
Anticoagulation rationale
Stroke risk driven by comorbidity more than rhythm pattern
Typical flutter carries thromboembolic risk similar to atrial fibrillation in many patients
Ablation considerations
Typical flutter ablation high success with low recurrence
Atrial fibrillation ablation considered for symptomatic recurrent atrial fibrillation despite medical therapy
Patient Discharge Instructions
copy discharge instructions
Discharge education
Diagnosis and expectations
Atrial fibrillation or atrial flutter explanation in simple language
Heart rate control goal
Medication instructions
Exact dose and schedule
Missed dose instructions per medication type
Anticoagulation safety
Bleeding precautions
Avoid NSAIDs unless clinician approved
Inform dentist and clinicians about anticoagulant use
Return to ED now triggers
Chest pain
Shortness of breath at rest
Fainting
New weakness or speech trouble
Uncontrolled bleeding
Black stools or vomiting blood
Severe headache or head injury while on anticoagulant
Follow-up plan
Appointment date or timeframe
ECG reassessment plan
Anticoagulation monitoring plan if warfarin
References
Clinical guidelines and key sources
Guideline sources
AHA ACC HRS guideline for atrial fibrillation management
Class I recommendations for urgent cardioversion in instability
Class I recommendations for anticoagulation by CHA2DS2-VASc
ESC guideline for atrial fibrillation management
Integrated care approach and anticoagulation guidance
Cardioversion anticoagulation duration guidance
Evidence and tools
CHA2DS2-VASc validation studies
Stroke risk stratification support
Broad external validation
HAS-BLED development and validation studies
Bleeding risk identification for modifiable factors
Not a reason alone to withhold anticoagulation
Trials comparing rate versus rhythm control strategies
Symptom driven selection support
Early rhythm control evidence in selected populations
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.