What is the approach to managing patients with arrhythmias?

Approach to Managing Patients with Arrhythmias

Initial Assessment and Documentation

The cornerstone of arrhythmia management is obtaining ECG documentation of the rhythm disturbance, which should guide all subsequent therapeutic decisions. 1

Essential Initial Workup

• Obtain a 12-lead ECG during the arrhythmia whenever possible - this is the single most critical diagnostic step, though it should not delay cardioversion in hemodynamically unstable patients 1
• Document the clinical presentation: palpitations, syncope, presyncope, chest pain, dyspnea, or cardiac arrest 1
• Assess hemodynamic stability immediately - blood pressure, mental status, signs of shock or heart failure 1, 2
• Perform focused physical examination for irregular pulse, jugular venous pulsations, variable S1 intensity, and signs of structural heart disease 1

Risk Stratification Elements

• Evaluate for structural heart disease with echocardiography - this determines prognosis and guides therapy selection 1
• Obtain resting 12-lead ECG in sinus rhythm to identify pre-excitation (WPW), conduction abnormalities, LVH, or channelopathy patterns 1
• Assess for underlying conditions: coronary disease, heart failure, hypertension, valvular disease, cardiomyopathy 1
• Screen for reversible triggers: electrolyte abnormalities, hyperthyroidism, anemia, sepsis, sleep apnea 1

Mechanism-Based Classification

Supraventricular Arrhythmias

For narrow complex tachycardias (QRS <120ms), the rhythm is almost always supraventricular in origin 1

• Regular narrow complex without visible P waves = AVNRT most likely - look for pseudo-r' in V1 or pseudo-S waves in inferior leads 1
• P wave in ST segment separated from QRS by >70ms = AVRT 1
• RP interval longer than PR interval = atypical AVNRT, PJRT, or atrial tachycardia 1
• Atrial fibrillation presents with irregularly irregular rhythm and absent discrete P waves 1

Ventricular Arrhythmias

For wide complex tachycardias (QRS ≥120ms), presume ventricular tachycardia until proven otherwise 1, 2

• Search for AV dissociation - this is diagnostic of VT 1
• Assess QRS duration >140ms, extreme axis deviation, and specific morphologic criteria 1
• Consider SVT with aberrancy or pre-excitation only after excluding VT 1
• Obtain esophageal or intracardiac recordings if diagnosis remains uncertain 1

Acute Management Algorithm

Hemodynamically Unstable Patients

Immediate synchronized cardioversion is mandatory for any hemodynamically unstable arrhythmia, without delay for diagnostic workup 1, 2

• Deliver cardioversion at maximum output initially 1
• Provide brief sedation if patient is conscious but hypotensive 1
• This applies to both supraventricular and ventricular arrhythmias 1, 2

Hemodynamically Stable Supraventricular Tachycardia

Follow this stepwise approach for stable narrow complex tachycardia: 1, 2

1. Vagal maneuvers first - Valsalva, carotid massage (safe, quick, effective for most SVTs) 1, 2
2. Adenosine 6mg rapid IV push if vagal maneuvers fail - terminates ~95% of AVNRT 2
3. IV diltiazem, verapamil, or beta-blockers if adenosine unsuccessful or contraindicated 1
4. IV esmolol particularly useful when concurrent hypertension present 1

Hemodynamically Stable Ventricular Tachycardia

Electrical cardioversion remains first-line even for stable wide complex tachycardia 1

• IV procainamide or flecainide may be considered in patients without severe HF or acute MI 1
• IV amiodarone is preferred in patients with HF or suspected ischemia 1
• IV lidocaine has only moderate efficacy for monomorphic VT 1
• IV verapamil or beta-blockers specifically for LV fascicular VT (RBBB morphology with left axis) 1

Long-Term Management Strategy

Pharmacologic Therapy

Beta-blockers are first-line therapy for both supraventricular and ventricular arrhythmias 1

• Beta-blockers reduce SCD across the spectrum of cardiac disorders through sympathetic blockade and calcium channel modulation 1
• Avoid beta-blockers in patients with ≥2 shock risk factors (age >70, HR >110, SBP <120) as they increase mortality 1
• For symptomatic PVCs in structurally normal hearts, beta-blockers or non-dihydropyridine calcium channel blockers are first-line 1
• Amiodarone has broad-spectrum efficacy but showed no survival benefit vs placebo in SCD-HeFT trial (LVEF ≤35%) 1

Antiarrhythmic Drug Cautions

Never initiate Class I or III antiarrhythmic drugs without documented arrhythmia due to proarrhythmia risk 1

• Discontinue any potentially pro-arrhythmic medications immediately 1
• Class Ic agents (flecainide, propafenone) are potentially harmful in asymptomatic VA with congenital heart disease 1
• When transferring from another antiarrhythmic, allow 2-4 half-lives before starting flecainide 3
• When combining flecainide with amiodarone, reduce flecainide dose by 50% and monitor plasma levels 3

Atrial Fibrillation-Specific Management

Stroke prevention with anticoagulation takes absolute priority over rhythm control 1

• Offer oral anticoagulation to all AF patients except CHA₂DS₂-VASc score 0 (males) or 1 (females) 1
• Initial rate control target is HR <110 bpm, with stricter control if symptomatic or LV function deteriorates 1
• Address uncontrolled hypertension (SBP >160 mmHg) to minimize bleeding risk 1
• Consider RAAS blockade (ACE inhibitors/ARBs) in patients with LVH 1

Device and Ablation Therapy

Catheter ablation should be considered for symptomatic arrhythmias refractory to or intolerant of medical therapy 1

• Ablation is highly effective for AVNRT, AVRT, atrial flutter, and focal atrial tachycardia 1
• For RVOT ventricular arrhythmias, ablation has far higher success than medical therapy 1
• Urgent catheter ablation is recommended for refractory polymorphic VT 1
• ICD implantation for secondary prevention after cardiac arrest or sustained VT with structural heart disease 1

Diagnostic Testing for Paroxysmal Arrhythmias

Ambulatory Monitoring Strategy

• 24-hour Holter monitor for frequent symptoms (several episodes per week) 1
• Event recorder or wearable loop recorder for less frequent arrhythmias 1
• Implantable loop recorder for rare symptoms (<2 episodes/month) with severe hemodynamic instability 1
• 30-day event monitoring to detect rare arrhythmias; 6-minute cutoff most widely used for device-detected AF 1

Exercise Testing and Electrophysiology Study

• Exercise testing indicated when arrhythmia is clearly triggered by exertion 1
• Invasive EP study with catheter ablation may be used for diagnosis and therapy in patients with clear history of paroxysmal regular palpitations 1
• Transesophageal atrial recordings/stimulation for selected cases when other measures fail 1

Critical Management Pitfalls

What to Avoid

• Never delay cardioversion to obtain diagnostics in unstable patients - hemodynamic stability takes absolute priority 2
• Never use verapamil in acute decompensated heart failure due to negative inotropic effects 2
• Never use AV nodal blockers (adenosine, verapamil, diltiazem) in pre-excited AF - may precipitate VF 1
• Avoid empiric antiarrhythmic therapy without documented arrhythmia 1
• Do not ignore resting HR >80-85 bpm - investigate for occult HF, AF, anemia, hyperthyroidism 1

Special Populations

• Patients with severe renal impairment (CrCl ≤35 mL/min) require initial flecainide dose of 100mg once daily with frequent plasma level monitoring 3
• Therapeutic flecainide trough levels are 0.2-1 mcg/mL; levels >1 mcg/mL increase cardiac adverse events 3
• In children, flecainide dosing is weight-based (50-200 mg/M²/day) with mandatory plasma level and ECG monitoring 3

Underlying Disease Optimization

Optimize treatment of underlying cardiovascular disease before and during arrhythmia management 1

• Treat heart failure, coronary disease, hypertension, and valvular disease per current guidelines 1
• Control modifiable triggers: correct electrolytes, treat thyroid disease, manage sleep apnea 1
• Address conduction disturbances particularly in hypertensive patients with LVH 1