Palpitations

Key considerations: Ventricular tachycardia, Atrial fibrillation with rapid ventricular response, Wolff-Parkinson-White (WPW) with pre-excited AF

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history: Onset, duration, frequency, regularity; Associated symptoms: chest pain, dyspnea, syncope, diaphoresis; Triggers: caffeine, alcohol, exercise, stress, position changes; Medications: stimulants, decongestants, thyroid meds, QT-prolonging drugs; Substance use: cocaine, amphetamines, energy drinks; Family history: sudden cardiac death, cardiomyopathy, channelopathies; exam: Heart rate and rhythm, blood pressure; Cardiac: murmurs, irregular rhythm, S3; Thyroid: goiter, tremor, exophthalmos; Signs of heart failure: JVD, peripheral edema, crackles; labs: CBC (anemia as cause of sinus tach); BMP (electrolytes — K, Mg, Ca); TSH; Troponin if chest pain present; Magnesium level; Drug screen if clinically indicated; imaging: CXR if dyspnea or heart failure suspected; Echocardiogram if structural heart disease suspected; CT or MRI if cardiomyopathy concern; bedside: 12-lead ECG — assess rhythm, intervals (PR, QRS, QTc), delta waves (WPW); Continuous telemetry monitoring; Point-of-care echo if concerned for structural disease

immediate: IV access, cardiac monitor, pulse oximetry; Identify and treat hemodynamic instability — synchronized cardioversion if unstable; Correct electrolyte abnormalities (K >4, Mg >2); general: Reassurance if benign etiology (PACs, PVCs, sinus tachycardia); Avoid triggers: caffeine, alcohol, stimulants; Outpatient Holter or event monitor for recurrent symptoms; Electrophysiology referral if recurrent SVT or concerning arrhythmia; specific: diagnosis: SVT; steps: Vagal maneuvers: modified Valsalva, carotid massage; Adenosine 6mg rapid IV push, repeat 12mg if needed; If refractory: diltiazem 0.25mg/kg IV or metoprolol 5mg IV; Cardioversion if hemodynamically unstable; diagnosis: Atrial Fibrillation; steps: Rate control: diltiazem, metoprolol, or digoxin; Assess need for anticoagulation (CHA₂DS₂-VASc); Cardioversion if <48 hours onset or TEE-guided; Unstable AF → synchronized cardioversion; diagnosis: Ventricular Tachycardia; steps: Stable: amiodarone 150mg IV over 10 min; Unstable or pulseless: defibrillation per ACLS; Correct electrolytes, identify underlying cause; Cardiology consult

admit: Sustained VT or concerning ventricular arrhythmia; Syncope with arrhythmia; New atrial fibrillation with rapid rate requiring IV meds; Hemodynamic instability; Structural heart disease with new arrhythmia; discharge: Isolated PACs/PVCs with normal ECG and labs; SVT converted with adenosine, stable, reliable follow-up; Sinus tachycardia with identified benign cause; consults: Cardiology: sustained arrhythmias, syncope, structural heart disease; Electrophysiology: recurrent SVT, WPW, VT for ablation evaluation

Wide complex tachycardia is VT until proven otherwise — treat as VT if unsure
Adenosine is safe as a diagnostic tool in wide complex tachycardia — it will not harm VT but will reveal SVT with aberrancy
WPW with atrial fibrillation: NEVER give AV nodal blockers (adenosine, diltiazem, digoxin) — can cause VF
Correct K to >4.0 and Mg to >2.0 in any arrhythmia
Modified Valsalva (blow into syringe for 15 sec, then immediately lie flat with legs elevated) has ~40% conversion rate for SVT