367.4 📋 章末速蚘 Summary

367.4.1 🔑 䞀句話瞜結

Syncope = transient LOC + global cerebral hypoperfusion + spontaneous complete recovery; distinguish from seizure (aura + tonic-clonic + lateral tongue bite + post-ictal confusion minutes) + drop attacks (no LOC) + psychogenic non-epileptic spells; three major categories — (1) Reflex (neurally mediated) ~ 60-70% — vasovagal (most common with prodrome of warmth/nausea/diaphoresis/blurred vision, triggers emotion/pain/prolonged standing/heat), situational (cough, micturition, defecation, deglutition, post-exercise), carotid sinus syndrome (older, shaving/tight collar); (2) Orthostatic ~ 15% — drug-induced (antihypertensives, TCAs, antipsychotics), volume depletion (dehydration, hemorrhage, adrenal insufficiency), autonomic failure (primary PD/MSA/PAF/DLB, secondary DM/amyloidosis/paraneoplastic); (3) Cardiac ~ 10-15% MOST CONCERNING — arrhythmia (brady SSS/AV block, tachy VT/SVT, pacemaker malfunction, inherited LQTS/Brugada/CPVT/ARVC), structural (severe AS, HCM with obstruction, massive PE, AMI, tamponade, aortic dissection, atrial myxoma, pulmonary HTN); history key features for cardiac — sudden without prodrome + during exertion + palpitations + FHx sudden death + known cardiac disease; workup all syncope — ECG mandatory (long QT, Brugada, WPW, heart block, HCM, old MI, ARVC) + orthostatic vitals (SBP ↓ ≥ 20, DBP ↓ ≥ 10, HR ↑ > 30 = POTS); selective echo (structural), tilt table (reflex/POTS), Holter/loop recorder (arrhythmia), ILR for recurrent unexplained (ASSURE 2023 superior yield), EP study, stress test exertional, cardiac MRI ARVC/sarcoidosis, CTA PE, genetic testing FHx; risk stratification — San Francisco Syncope Rule (CHESS — CHF, Hct < 30, ECG abnormal, SOB, SBP < 90), OESIL, EGSYS; admit high-risk — cardiac suspected, abnormal ECG, structural disease, exertional, FHx sudden death, severe injury, ↑ troponin; treatment — vasovagal reassurance + education + hydration + counter-pressure maneuvers + tilt training, refractory midodrine + fludrocortisone, severe with bradycardia pacemaker rarely; orthostatic treat cause + fluid/salt + compression stockings + midodrine α1 agonist + fludrocortisone mineralocorticoid + pyridostigmine + droxidopa Northera FDA 2014 (PD/PAF/MSA); cardiac pacemaker (brady/AV block) + ICD (VT, structural, high-risk channelopathies) + AVR for AS + HCM specific therapy + treat underlying; inherited arrhythmia syndromes — LQTS (β-blocker + ICD), Brugada (ICD if symptomatic), CPVT (β-blocker + ICD + flecainide), ARVC (ICD); POTS HR ↑ ≥ 30 within 10 min standing without BP drop, young women, salt + fluid + exercise + compression + propranolol + ivabradine。

367.4.2 💊 治療粟芁

  • vasovagalreassurance + education + hydration + counter-pressure (squat, leg crossing) + tilt training; refractory midodrine 5-10 mg TID + fludrocortisone 0.1-0.2 mg/d; pacemaker rare (severe cardioinhibitory documented)
  • orthostatic hypotensionfluid 2-3 L/d + salt 6-10 g/d + compression stockings + head-of-bed elevation 30°; midodrine 5-10 mg TID + fludrocortisone 0.1-0.3 mg/d; pyridostigmine 30-60 mg TID for neurogenic OH; droxidopa (Northera) 100-600 mg TID FDA 2014 for symptomatic neurogenic OH in PD/PAF/MSA
  • POTSsalt 6-10 g/d + fluid 3 L/d + compression + exercise (especially recumbent); propranolol 10-20 mg TID + ivabradine 5-7.5 mg BID + fludrocortisone + midodrine
  • bradyarrhythmia syncopepermanent pacemaker (SSS, AV block II/III)
  • VT/structural disease high-riskICD (primary or secondary prevention)
  • AS syncopeTAVR or surgical AVR (Class I)
  • HCM syncopeβ-blocker + disopyramide + septal reduction (surgical myectomy or alcohol septal ablation) + ICD for high-risk
  • LQTSβ-blocker (propranolol, nadolol) + avoid QT-prolonging drugs + ICD for high-risk (Schwartz score, family history SCD) + LCSD for refractory
  • Brugada syndromeICD if symptomatic (syncope, aborted SCD) or high-risk; avoid sodium channel blockers + treat fever aggressively
  • CPVTβ-blocker + flecainide + ICD + LCSD

367.4.3 🎯 盧醫垫的考前提醒

  1. Three categories (memorize): reflex (vasovagal most common ~ 60-70%) + orthostatic ~ 15% + cardiac ~ 10-15% (MOST CONCERNING) — cardiac may indicate SCD risk
  2. Distinguish syncope from seizure: vasovagal has prodrome (warmth, nausea, diaphoresis) + brief LOC + quick recovery + may have brief myoclonic jerks (benign convulsive syncope); seizure has aura + tonic-clonic + lateral tongue bite + post-ictal confusion minutes
  3. Cardiac syncope features: sudden onset without prodrome + during exertion + palpitations + FHx sudden death + known heart disease + abnormal ECG → urgent workup + admit
  4. ECG mandatory for all syncope — look for: long QT (LQTS) + Brugada pattern (coved ST V1-V3) + WPW (delta wave) + heart block + HCM (LVH + Q-waves) + old MI + ARVC (epsilon waves + T inversion V1-V3)
  5. Orthostatic definition: SBP ↓ ≥ 20 or DBP ↓ ≥ 10 within 3 min standing; POTS = HR ↑ ≥ 30 within 10 min without BP drop (young women, treatment salt/fluid/compression/exercise + propranolol/ivabradine)
  6. High-risk admission criteria (SFSR CHESS): CHF + Hct < 30 + ECG abnormal + SOB + SBP < 90 = any present → admit
  7. Cardiac syncope workup: echo (structural) + Holter/loop recorder + ILR (recurrent unexplained, ASSURE 2023 superior) + EP study + stress test (exertional) + cardiac MRI (ARVC/sarcoidosis) + genetic testing (FHx, channelopathies)
  8. Vasovagal treatment: reassurance + education + hydration + counter-pressure (squat, leg crossing) + tilt training; refractory midodrine + fludrocortisone; routine CT head NOT useful without trauma/focal deficit
  9. Orthostatic hypotension treatment: fluid + salt + compression stockings + midodrine + fludrocortisone + droxidopa (Northera, neurogenic in PD/PAF/MSA) + pyridostigmine
  10. Inherited arrhythmia syndromes: LQTS (β-blocker + ICD) + Brugada (ICD if symptomatic) + CPVT (β-blocker + flecainide + ICD) + ARVC (ICD) + HCM (β-blocker + disopyramide + septal reduction + ICD for high-risk) + HOCM