Tachyarrhythmia
1. Mechanism
* 2 mx i) disorders of impulse propagation = reentry
ii) disorders of impulse formation = enhanced automaticity, triggered activity
1) Reentry
- sustained paroxysmal tachyarrhythmiaÀÇ mc mx
- reentry¸¦ ½ÃÀÛÇϱâ À§Çؼ´Â ´ÙÀ½ »çÇ×µéÀÌ ÇÊ¿äÇÏ´Ù.
i) electrophysiologic inhomogeneity°¡ ÇϳªÀÇ circuitÇü¼º
: closed loopÀ¸·Î ¿¬°áµÇ¾î ÀÖ´Â 2°÷ À̻󿡼 conduction and/or refractorinessÀÇ
Â÷À̰¡ ÀÖ¾î¾ß ÇÑ´Ù.
ii) unidirectional block in one pathway
iii) slow conduction over an alternative pathway
óÀ½¿¡ blocked pathway°¡ ÈïºÐ¼ºÀ» ȸº¹ÇÒ ½Ã°£À» Á¦°øÇÑ´Ù.
iv) ÇѹÙÄû activationÀ» ¸¶Ä£ initially blocked pathwayÀÇ reexcitation
- reentrant arrhythmia´Â premature complex³ª rapid stimulation¿¡ ÀÇÇØ ½ÃÀ۵ǰųª
Á¾·áµÉ¼ö ÀÖ´Ù.
2) Enhanced automaticity
- myocardial cellÀº Á¤»óÀûÀ¸·Î´Â pacemaker activity¸¦ °®Áö ¾Ê´Â´Ù.
- ´ÙÀ½°ú °°Àº pathophysiologic state¿¡¼ latent pacemaker fiberÀÇ normal automaticity
°¡ Áõ°¡µÇ°Å³ª potential depolarization¿¡ ÀÇÇÑ resting membraneÀÇ abnormal
automaticity°¡ ¹ß»ýÇÒ¼ö ÀÖ´Ù.
i) endogenous or exogenous catecholamine¡è
ii) electrolyte disturbance(¿¹, hypokalemia)
iii) hypoxia or ischemia
iv) mechanical effect(¿¹, stretch)
v) drug(¿¹, digitalis)
- automaticity¿¡ ÀÇÇØ À¯¹ßµÈ tachycardia´Â pacing¿¡ ÀÇÇØ ½ÃÀ۵ǰųª ÁߴܵÇÁö ¾Ê´Â´Ù.
3) Triggered activity
early afterdepolarizationȤÀº delayed afterdepolarization¿¡ ÀÇÇØ ¹ß»ýÇÒ¼ö ÀÖ´Ù.
¨ç early afterdepolarization
action potential phase 2,3µ¿¾È¿¡ ¹ß»ý
´ÙÀ½ »óȲ¿¡¼ triggered activity°¡ ¹ß»ýÇÒ¼ö ÀÖ´Ù.
: bradycardia, hypokalemia, or action potentialÀ» ¿¬Àå½ÃŰ´Â »óÅÂ
¿¹> TdP
¨è delayed afterdepolarization
phase 3°¡ Á¾·áµÈ ÀÌÈÄ¿¡ ¹ß»ý
´ÙÀ½ »óȲ¿¡¼ ¹ß»ýÇÒ¼ö ÀÖ´Ù.
: local catecholamine concentration¡è, hyperkalemia, hypercalcemia,
digitalis intoxication
¿¹> tachycardia associated with digitalis intoxication
accelerated idioventricular rhythm in acute infarction and/or reperfusion
exercise-induced VT
2. Premature complexes
1) APC (Fig 230-2)
- 24h Holter monitoring»ó Á¤»ó¼ºÀÎÀÇ 60% À̻󿡼 ¹ß°ßµÈ´Ù.
- susceptible pt´Â PSVT·Î °¡±âµµ ÇÑ´Ù.
- early P wave´Â ÇüŰ¡ sinus P wave¿Í´Â ´Ù¸£°í, cardiac cycleÀÇ Èı⿡´Â ventricle
·Î Àüµµ°¡ °¡´ÉÇÏÁö¸¸ early APCs´Â relative refractory period¿¡ °É¸®°Ô µÇ¾î Àüµµ°¡
Áö¿¬µÇ¾î PR intervalÀÌ prolongationµÇ¾î ³ªÅ¸³´Ù.
- pre- & post extrasystolic PP intervalÀº two sinus PP intervalÀÇ ÇÕº¸´Ù °£°ÝÀÌ ÀÛ´Ù.
- ´ëºÎºÐ ¹«Áõ»óÀ̸ç Ä¡·á°¡ ÇÊ¿ä¾ø´Ù.
- palpitation or PSVT¸¦ À¯¹ßÇϸé Ä¡·á°¡ ÇÊ¿äÇÒ¼ö ÀÖ´Ù.
- À¯¹ßÀÎÀÚ(alcohol, tobacco, or adrenergic stimulation)¸¦ ¾ø¾Ö°í, ¾ø´Ù¸é mild sedation
½ÃÄѺ¼¼ö ÀÖ°í, ¥â-blocker¸¦ »ç¿ëÇØ º¼¼öµµ ÀÖ´Ù.
2) AV junctional complexes
- normal AV node´Â automaticity°¡ ¾ø±â ¶§¹®¿¡ AV junctional complexÀÇ ±â¿øÀº
His bundle·Î »ý°¢µÈ´Ù.
- APC³ª VPCº¸´Ù´Â ´ú ÈçÇϸç ÈçÈ÷ cardiac disease or digitalis intoxication°ú °ü·Ã
ÀÖ´Ù.
- antegradely & retrogradely µÑ´Ù Àüµµ °¡´ÉÇÏ´Ù.
- premature AV junctional complexes´Â ¼±ÇàÇÏ´Â P wave¾øÀÌ normal appearing QRS
complexes¿¡ ÀÇÇØ ÀÎÁöµÇ±âµµ Çϰí retrograde P wave(lead II, III, aVF¿¡¼ inverted)
°¡ ³ªÅ¸³ª±âµµ ÇÑ´Ù.
- ÁÖ·Î asymptomaticÇÏÁö¸¸ palpitation°ú cannon a wave¿Í °ü·ÃµÇ±âµµ Çϸç ÀÌ´Â neck
pulsationÀ¸·Î ³ªÅ¸³ª±âµµ ÇÑ´Ù. Áõ»óÀÌ ÀÖÀ¸¸é APCó·³ Ä¡·áÇÑ´Ù.
3) VPCs
: wide(>0.14s), bizarre QRS complex, P wave(-)
- °¡Àå ÈçÇÑ ºÎÁ¤¸ÆÁß ÇϳªÀ̸ç, heart dsÀ¯¹«¿¡ »ó°ü¾øÀÌ ¹ß»ýÇÒ¼ö ÀÖ´Ù.
- ¼ºÀÎ ³²¼ºÀÇ 60% À̻󿡼 VPCs°¡ º¸ÀδÙ.
- heart disease°¡ ¾ø´Ù¸é mortality, morbidityÁõ°¡¿Í °ü·ÃÀÌ ¾ø´Ù.
- previous MIȯÀÚÀÇ 80%°¡±îÀÌ VPC°¡ ¹ß»ýÇϴµ¥ À̶§
frequent(>10ȸ/1hr) and/or complex(couplets) VPCÀ϶§´Â mortalityÁõ°¡¿Í °ü·ÃÀÖ´Ù.
±×·¯³ª ±×·± ȯÀÚ¿¡¼ cardiac mortality´Â ÈçÈ÷ impaired LV dysfunction°ú °ü·ÃÇÏ¿©
¹ß»ýÇÑ´Ù.
- frequent & complex VPC°¡ independent risk factorÀÌÁö¸¸ impaired LV dysfx¸¸Å
°ÇÑ risk factor´Â ¾Æ´Ï´Ù.
- spontaneous ectopy¿Í life-threatening VT or VF¿ÍÀÇ ¿øÀÎ-°á°ú »çÀÌÀÇ °ü·Ã¼ºÀº
È®¸³µÇ¾î ÀÖÁö ¾Ê´Ù.
- very early cycle(R-on-T) VPCs´Â sudden deathÀÇ risk°¡ ³ô´Ù°í ÇÏ¿´´Ù.
- ºñ·Ï R-on-T°¡ acute ischemia¿Í QT prolongation¶§ º¼¼ö ÀÖÁö¸¸ ÈçÈ÷ VT or VF°¡
prior beatÀÇ T waveÈÄ¿¡ ¹ß»ýÇÏ´Â VPC¿¡ ÀÇÇØ À¯¹ßµÈ´Ù.
- ¼±ÇàÇÏ´Â sinus complex¿Í fixed relationshipÀÌ ÀϹÝÀûÀÌÁö¸¸ VPC»çÀÌ¿¡ °£°ÝÀÌ ÀÏÁ¤
ÇÑ °æ¿ìµµ ÀÖ´Ù.(=ventricular parasystole, Fig 230-4)
ÀÌ·± °æ¿ì VPC´Â ventricular focus¿¡¼ abnormal automaticity¸¦ º¸ÀδÙ.
* VPCÀÇ ÇüÅÂ
singly
bigeminy : sinus beat-VPC°¡ ¹ø°¥¾Æ ³ª¿È
trigeminy : sinsu beat-sinus beat-VPC
2 successive VPCs = pairs or couplets
3°³ ÀÌ»ó ¿¬¼ÓÇØ ³ª¿À¸é¼ rate°¡ 100/minÀÌ»óÀ϶§ = VT
* ¸ð¾ç¿¡ µû¶ó : monomorphic(=uniform) or polymorphic(=multiformed)
- ÈçÈ÷ VPC´Â retrograde·Î´Â ÀüµµµÇÁö ¾Ê°í SA node¸¦ reset½ÃŰÁöµµ ¾Ê´Â´Ù.
±×·¯¹Ç·Î VPC´Â fully compensated pause¸¦ ¸¸µç´Ù.
Áï, 2 basic RR interval = RR¡Ç
- ventricular impulse°¡ retrograde conductionÇÏ¿© inverted P wave¸¦ ¸¸µé±âµµ ÇÑ´Ù
(lead II, III, aVF).
À̶§´Â sinus node¸¦ reset½ÃÄÑ less compensatory result¸¦ ÃÊ·¡ÇÑ´Ù.
- ¸¹Àº ¿¹¿¡¼, VPC´Â retrograde VA conduction°ú´Â °ü·ÃÀÌ ¾ø°í AV node¿¡¼
retrogradely blockµÈ´Ù.
- subsequent sinus beat¿¡ ´ëÇÑ AV node refractoriness´Â slowed conductionÀ» À¯¹ß
ÇѰųª(=PR prolongation) or next P wave¸¦ block½ÃŲ´Ù.
ÀÌ·¯ÇÑ prolonged PR intervalÀº ventricular impulseÀÇ AV node·ÎÀÇ concealed
retrograde conductionÀ» ÀǹÌÇÏ´Â °ÍÀÌ´Ù.
* interpolated VPC : retrograde concealed conductionÀ» ÀÏÀ¸Å°Áö ¾Ê°í, oncoming sinus
impulse¿¡ ¿µÇâÀ» ÁÖÁö ¾Ê¾Æ¼.
- VPCs´Â palpitation ¶Ç´Â cannon a wave, ventricular contractility·Î ¼öÃà·ÂÀÌ
Áõ°¡µÇ¾î neck pulsationÀ» ÀÏÀ¸Å³¼ö ÀÖ´Ù.
- frequent VPC or bigeminy´Â syncope or lightheadedness¸¦ °ÅÀÇ ÀÏÀ¸Å°Áö ¾Ê´Âµ¥
ÀÌ´Â VPC°¡ HR¸¦ "halving"(¹ÝÀ¸·Î) ÇÔÀ¸·Î½á S.V & C.OÀ» °¨¼Ò½ÃŰÁö ¾Ê±â ¶§¹®ÀÌ´Ù.
<Ä¡·á>
¨ç cardiac disease°¡ ¾ø°í, isolated asymptomatic VPC : Ä¡·á Çʿ䡿
¨è symptomatic
i) anxiety¶§¹®À¸·Î »ý°¢
ii) ¥â-blocker : ³·¿¡ ÁÖ·Î »ý±â°Å³ª, stressful situationÀÏ ¶§,
MVP & thyrotoxicosisÀ϶§ È¿°úÀû
¨é cardiac dsÀÖÀ» ¶§
frequent VPC = sudden & nonsudden cardiac death risk¡è
¿¹¹æÀû Ç׺ÎÁ¤¸Æ ¾àÁ¦´Â Àüü »ç¸Á·üÀ» ¿ÀÈ÷·Á Áõ°¡(¡ñproarrhythmic effect)
½ÃŰ¹Ç·Î »ç¿ë±ÝÁö(Cardiac Arrhythmia Suppression Trial, CAST)
¨ê EPS & ICD
high risk of sudden death
LVEF<40% & nonsustained VTȯÀÚ¿¡¼ Ä¡·á
¨ë IV ¥â-blocker : primary VT ºóµµ¸¦ °¨¼Ò½ÃÄ×´Ù°í º¸°í
3. Tachycardia
1) Sinus tachycardia
HR > 100/min, primary arrhythmia°¡ ¾Æ´Ï´Ù.
¿©·¯ °¡Áö stress¿¡ ´ëÇÑ physiologic responseÀÌ´Ù.
: fever, volume depletion, anxiety, exercise, thyrotoxicosis, hypoxemia
hypotension, congestive heart failure
P wave°¡ QRS complex¾Õ¿¡ Ç×»ó ¼±ÇàÇÑ´Ù.
*Ä¡·á : primary arrythmia¸¦ Ä¡·áÇØ¼± ¾ÈµÇ°í primary disorder¸¦ Ä¡·áÇØ¾ß ÇÑ´Ù.
¿¹> HF¿¡ ´ëÇØ¼± digitalis or diuretics
hypoxemia -> O2, thyrotoxicosis tx
fever -> aspirin, emotional upset -> tranquilizer
2) Atrial fibrillation
- paroxysmal form & persistent form
- Á¤»óÀο¡¼µµ º¼¼ö ÀÖ´Ù.
: ƯÈ÷ emotional stress, ¼ö¼úÈÄ, exercise, vagal tone¡è(vasovagal response)
- heart or lung disease pt¿¡¼µµ º¼¼ö ÀÖ´Ù.
: hypoxia, hypercapnea, metabolic or hemodynamic derangement
- Persistent AF : cardiovascular dsȯÀÚ¿¡¼ ÈçÇÏ´Ù.
: RHD, nonrheumatic MV ds, hypertensive cardiovascular ds, chronic lung ds, ASD
- lone AF : underlying heart disease¾øÀÌ AF´Üµ¶À¸·Î ¿Ã¶§.
- thyrotoxicosisÀÇ Ã¹ ¼Ò°ßÀϼöµµ ÀÖ´Ù.
* AF¿Í °ü·ÃÇÑ morbidity 5°¡Áö
i) excessive ventricular rate -> hypotension, pul. congestion, angina pectoris
ii) AF cessationÈÄÀÇ pause -> syncope
iii) systemic embolization : RHD¿¡¼ °¡Àå ÈçÈ÷ ¹ß»ý
iv) C.O¿¡ atrial contractionÀÇ ±â¿©¡¿ -> fatigue
v) palpitation -> secondary anxiety
- persistnent rapid rate¿¡¼´Â ¶ÇÇÑ cardiomyopathy¸¦ ÀÏÀ¸Å³¼ö ÀÖ´Ù.
: tachycardia-induced cardiomyopathy
* EKG
i) disorganized atrial activity ; ºÐ¸íÇÑ P wave°¡ ¾ø´Ù.
ii) undulating baseline
iii) sharply inscribed atrial deflection of varying amplitude & frequency(350-600 bpm)
iv) ventricular response : irregulary irregular
¡ñ AV node¸¦ Áö³ª´Â ¸¹Àº atrial impulse°¡ refractory period¿¡ °É¸®±â ¶§¹®
nonconducted atrial impulse´Â ´ÙÀ½ atrial impulse¿¡ ¿µÇâÀ» ¹ÌÄ¡´Âµ¥ ÀÌ·¯ÇÑ È¿°ú¸¦
"concealed conduction"À̶ó ÇÑ´Ù.
±× °á°ú ventricular response´Â atrial rateº¸´Ù ´À¸®´Ù.
- AF°¡ atral flutter·Î ÀüȯµÇ±âµµ ÇÑ´Ù. ƯÈ÷ quinidineÀ̳ª flecainide°°Àº antiarrhythmic
drug¿¡ ¹ÝÀÀÇØ¼.
- AF°¡ atrial flutter·Î Àüȯ½Ã atrial rate´Â ´À·ÁÁø´Ù. ±× °á°ú concealed conductionÀÌ °¨¼Ò
ÇÏ°Ô µÇ°í ventricular responseÀÇ paradoxic increase°¡ ¹ß»ý³´Ù.
- AFÁ¸ÀçÇÏ¿¡¼ ¸¸¾à ventricular rhythmÀÌ regular & slow(30-60 bpm)ÇÏ´Ù¸é
=> complete heart blockÀǽÉÇϰí
regular & rapid(100 bpm¡è)ÇÏ´Ù¸é
=> AV junction or ventricle¿¡¼ À¯¹ßµÈ tachycardia¸¦ ÀǽÉÇÑ´Ù.
: À§ µÎ°¡Áö Çö»óÀÇ ÈçÇÑ ¿øÀÎÀº digitalis intoxication ÀÌ´Ù.
- JVP : a wave¼Ò½Ç
- LA enlargement : LA >4.5cmÀ϶§ sinus rhythmÀ¸·ÎÀÇ ÀüȯÀº ºÒ°¡´É
*Ä¡·á : i) precipitating factor ã¾Æ¼ Á¦°Å
- fever, pneumonia, alcoholic intoxication, thyrotoxicosis, pul. emboli,
CHF, pericarditis
ii) ÀÓ»ó»óŰ¡ ½ÉÇÏ°Ô À§Å·οì¸é electrical cardioversion : TOC
iii) severe cardiovascular compromise°¡ ¾ø´Ù¸é
ventricular rate¸¦ ³·Ãß´Â °ÍÀÌ Ã³À½ Ä¡·áÀÇ ¸ñÇ¥
: ¥â-blocker and/or Ca channel blocker = AV refractory period¡è
catecholamine levelÀÌ Áõ°¡ÇÑ °æ¿ì¿£ ¥â-blocker°¡ ´õ ÁÁ´Ù.
digitalis : less effective
iv) cardioversion to sinus rhythm
drug : type IA(quinidine-like) or flecainide-like type IC drug
electrical : medical tx¿¡ ½ÇÆÐ½Ã. 200J
anticoagulation½ÃÇà, 3ÁÖÀüºÎÅÍ cardioversion 4ÁÖÈıîÁö.
v) cardioversion ¾ÈµÉ¶§ÀÇ Ä¡·á¸ñÇ¥ : ventricular response control
: digitalis, ¥â-blocker, Ca channel blocker
¾à¹°·Î ¾ÈµÉ¶§´Â radiofrequency catheter ablationÀ¸·Î complete AV block
À¯¹ßÈÄ permanent pacemaker implantation
vi) sinus rhythmÀ¸·Î Àüȯ½Ã Àç¹ß¹æÁö
: quinidine, Ic(flecainide), amiodarone
vii) anticoagulation (Tab 230-1,3)
viii) Ablation tx
3) Atrial flutter
- ÈçÈ÷ organic herat ds°¡ ÀÖ´Ù.
- paroxysmalÇÑ °æ¿ì¿£ ÈçÈ÷ À¯¹ßÀÎÀÚ°¡ ÀÖ´Ù: pericarditis, acute resp. failure
- AF, Atrial flutterµÑ´Ù open heart surgeryÈÄ 1ÁÖÀϵ¿¾È ¾ÆÁÖ ÈçÇÏ´Ù.
- Atrial flutter°¡ 1ÁÖÀÌ»ó Áö¼Ó½Ã AF·Î ÀüȯÇϸç systemic embolizationÀº AFº¸´Ù ´ú ÈçÇÏ´Ù.
- atrial rate : 250-350 bpm
typical ventricular rate : 1/2 ¡¿ atrial rate(´ë·« 150 bpm)
- quinidine°°Àº Ç׺ÎÁ¤¸Æ ¾à¹°·Î atrial rate¸¦ 220ȸ ÀÌÇÏ·Î ¶³¾î¶ß¸®¸é ventricular rate°¡
°©ÀÚ±â Áõ°¡ÇÑ´Ù. ¡ñ 1:1 conduction¶§¹®
- ÀüÇüÀûÀÎ flutter wave ; regular sawtooth-like atrial activity(inf. lead¿¡¼ °¡Àå Àú¸í)
*Ä¡·á
i) °¡Àå È¿°úÀûÀÎ Ä¡·á: direct-current(DC) cardioversion (25-50J) under mild sedation
100-200Jµµ »ç¿ë
ii) ȯÀÚ»óŰ¡ Áï°¢ÀûÀÎ cardioversionÀ» ÇÒ¼ö ¾øÀ»¶§
AV node¸¦ block½ÃÄÑ ventricular rate¸¦ ´À¸®°Ô ÇÑ´Ù.
: ¥â-blocker, Ca antagonist, digitalis cf. digitalis - least effect, °¡²û AF·Î Àüȯ
ÀÏ´Ü rate¸¦ ´À¸®°Ô ÇÑÈÄ sinus rhythmÀ¸·Î ÀüȯÀ» ½Ãµµ: class IA or IC, or
amiodarone
iii) Àç¹ß¹æÁö: quinidine, or other IA, flecainide, propafenone, amiodarone, sotalol
iv) radiofrequency ablation - highly effective
4) PSVT (Fig 230-7)
- AV nodeÀÇ conduction & refractorinessÀÇ Â÷ÀÌ(AVNRT) ȤÀº bypass tract(AVRT)¿¡ ÀÇÇØ
PSVT°¡ ¹ß»ýÇÑ´Ù(Á¾Àü¿¡´Â paroxysmal atrial tachycardia¶ó°í ºÎ¸§).
- PSVTÀÇ ´ëºÎºÐÀº reentry°¡ ¿øÀÎÀÌ´Ù.
- conduction
: AV node¸¦ ÅëÇÑ antegrade conduction, bypass tractÀ» ÅëÇÑ retrograde conduction
- WPW syndrome¿¡¼´Â bypass tractÀ» ÅëÇÏ¿© antegrade conductionµÉ¼ö ÀÖ´Ù.
- bypass tractÀ¸·Î retrograde conduction¸¸ µÉ¶§¸¦ "concealed bypass tract"À̶ó ÇÑ´Ù.
- WPW syndromeÀÌ ¾øÀ»¶§, AV node¸¦ ÅëÇÑ reentry ȤÀº concealed bypass tractÀ» ÅëÇÑ
reentry°¡ Àüü PSVTÀÇ 90%ÀÌ»óÀ» Â÷ÁöÇÑ´Ù.
5) AVNRT - PSVTÀÇ °¡Àå ÈçÇÑ ¿øÀÎ (Fig230-8)
- Àß ¹ß»ýÇÏ´Â ¿¬·ÉÀ̳ª disease predispositionÀº ¾øÀ¸³ª(¾îµð¼³ª ¹ß»ýÇÑ´Ù) ¿©¼º¿¡¼
´õ ÈçÇÏ´Ù.
- SVTÀÇ °¡Àå ÈçÇÑ ÇüÅÂÀ̸ç 120-150 bpmÀÇ regular narrow QRS complex tachycardia·Î
³ªÅ¸³´Ù.
- retrograde P wave´Â ¾ø°Å³ª ¹¯Çô ÀÖ°í ȤÀº QRS ³¡ºÎºÐ¿¡ ³ªÅ¸³¯¼ö ÀÖ´Ù.
: retrograde atrial activation°ú antegrade ventricular activationÀÌ µ¿½Ã¿¡ ÀϾ¸é
P wave´Â surface ECG¿¡¼ º¸ÀÌÁö ¾Ê°Ô µÈ´Ù.
- AVNRT°¡ ½ÃÀÛÇÏ´Â APCs´Â °ÅÀÇ Ç×»ó PR intervalÀÌ prolongationµÇ¾î ÀÖ´Ù.
ÀÌ´Â APCÈÄ¿¡ ½ÉÇÑ AV nodal conduction delay(prolonged AH interval)°¡ ¿À±â ¶§¹®À̸ç
AVNRT¹ß»ý¿¡ ¾ÆÁÖ Áß¿äÇÏ´Ù.
ÀÌ·¯ÇÑ AH intervalÀÇ °©ÀÛ½º·± ¿¬ÀåÀº dual AV nodal pathway·Î ÀÌÇØÇØ¾ß ÇÑ´Ù.
: reentry circuit = AV node, HR = 120-250ȸ
dual AV nodal pathway
¥á pathway = slow but short refractory period
¥â pathway = rapid but long refractory period
* Fig 230-8
A. NSR¿¡¼´Â ¥á,¥â pathway·Î ¸ðµÎ conductionÇÏÁö¸¸ ¥â(fast) pathway°¡ ¿ì¼¼ÇÏ´Ù.
¡Å PR intervalÀº normalÀÌ´Ù. 0.16sec
B. atrial premature depolÀÌ ¿Â´Ù¸é ¥â pathway´Â refractory period°¡ ±æ±â ¶§¹®¿¡ block
µÇ°í ¥á pathway¸¦ ÅëÇÏ¿© slow conductionµÉ°ÍÀÌ´Ù.
C. ¸¸¾à ¥á pathway·ÎÀÇ conductionÀÌ ³Ê¹« ´À·Á refractory ¥â pathway°¡ excitability¸¦
ȸº¹ÇÒ ½Ã°£À» °®´Â´Ù¸é impulse´Â ¥â pathway·Î retrograde conductionµÇ¾î single atrial
echoȤÀº sustained tachycardia¸¦ Çü¼ºÇÑ´Ù.
* ÀÓ»óƯ¡
: palpitation, syncope & heart failure
ventricular filling¿¡ ±â¿©ÇÏ´Â atrial contributionÀÌ °©ÀÚ±â ¼Ò½ÇµÇ¾î ¹ß»ýÇÑ´Ù.
-> atrial pr»ó½Â, acute pul. edema
ventricular filling°¨¼Ò¸¦ ÀÏÀ¸Å³¼ö ÀÖ´Ù.
atrial & ventricular contractionÀÌ µ¿½Ã¿¡ ÀϾ¼ cannon a wave°¡ »ý±æ¼öµµ ÀÖ´Ù.
* Ä¡·á
i) hypotensionÀÌ ¾ø´Ù¸é ¸ÕÀú vagal maneuver : carotid sinus massage - 80%¿¡¼ Á¾°á
ii) hypotensionÀÌ ÀÖ´Ù¸é IV phenylephrine 0.1mg IV + carotid sinus massage
iii) À§ÀÇ ¹æ¹ýÀÌ ¼º°øÇÏÁö ¸øÇϸé IV verapamil(2.5-10mg) or IV adenosine(6-12mg)ÀÌ choice
: adenosineÀº ¹Ý°¨±â°¡ ª°í ºÎÀÛ¿ëÀÌ ÀûÀ¸¹Ç·Î ´õ ¼±È£µÈ´Ù.
iv) ¥â-blocker : 2nd choice
¡ÚÁÖÀÇ : Digitalis´Â ÀÛ¿ë½Ã°£ÀÌ ´À·Á¼ acute tx·Î´Â »ç¿ëÇÏÁö ¸»°Í.
v) ¾à¹°Ä¡·á¿¡ ½ÇÆÐÇϰųª Àç¹ßÇÒ¶§
: temporary pacemaker¸¦ ÀÌ¿ëÇÑ atrial or ventricular pacing
vi) DC cardioversion
tachycardia¿¡ ÀÇÇØ severe ischemia and/or hypotension¹ß»ý½Ã °í·Á
vii) Àç¹ß¹æÁö
ÀÏÂ÷ÀûÀ¸·Î antegrade slow pathway¿¡ ÀÛ¿ëÇÏ´Â ¾à¹°(digitalis,¥â-blocker, CCB) or
fast pathway¿¡ ÀÛ¿ëÇÏ´Â ¾à¹°(class IA, IC)»ç¿ë.
: ¥â-blocker, CCB or digoxinÀÌ ´õ ³ªÀºµ¥ risk-benefit¸é¿¡¼ IA, ICº¸´Ù ³´±â ¶§¹®.
viii) radiofrequency catheter modification
chronic tx¸¦ ÇÊ¿ä·Î ÇÏ´Â symptomatic pt¿¡¼ °í·Á, 90%À̻󿡼 ¼º°øÀû
permanent pacemaker¸¦ ÇÊ¿ä·Î ÇÒ´Â heart blockÀÇ risk : 1-2%
6) AVRT
- concealed AV bypass tractÀ» ÅëÇÑ reentry
- bypass tractÀº ´ëºÎºÐ ¿ÞÂÊ¿¡ ÀÖÀ¸¹Ç·Î ventricular pacingµ¿¾È earlist activation
sequence´Â LA(coronary sinus¿¡ ÀÖ´Â catheter)¿¡¼ ±â·ÏµÈ´Ù.
- sinus rhythmÀ̳ª ´Ù¸¥ atrial tachyarrhythmiaµ¿¾È antegrade directionÀ¸·Î conduction
ÇÒ¼ø ¾ø´Ù.
- APCs³ª VPCs·Î ½ÃÀÛÇϰųª Á¾·áµÉ¼ö ÀÖÀ¸¸ç VPCs·Î PSVT°¡ ½ÃÀÛÇÒ¶§´Â AVRT·Î Áø´Ü
ÇÒ¼ö ÀÖ´Ù.
- AV reentry¶§ ventricular activationÈÄ¿¡ atrial activationÀÌ ÀϾ¹Ç·Î P wave´Â QRS
complexÈÄ¿¡ ³ªÅ¸³´Ù.
- Ä¡·á´Â AVNRT¿Í µ¿ÀÏÇÏ´Ù.
7) Sinus node reentry & other atrial tachycardia
- APCs¿¡ ÀÇÇØ ½ÃÀ۵ǰí, underlying cardiac ds¿Í °ü·ÃÀÖ´Ù.
- sinus node reentryµ¿¾È¿¡ P wave´Â sinus rhythm¶§¿Í µ¿ÀÏÇÏÁö¸¸ sinus tachycardia¿Í´Â
¹Ý´ë·Î(=PR intervel shortening) PR intervalÀÌ ¿¬ÀåµÈ´Ù.
intraatral reentry¿¡¼ P wave´Â sinus rhythm¶§¿Í ´Ù¸£¸ç PR intervalÀº ¿¬ÀåµÈ´Ù.
- Ä¡·á ; reentrant PSVTó·³ ÇÑ´Ù.
´Ù¸¸, multiple foci°¡ Á¸ÀçÇϹǷΠcatheter ablationÀº ¼º°øÀûÀÌÁö ¸øÇÏ´Ù.
8) Nonreentrant atrial tachycardia
¨ç ¿øÀÎ i) digitalis intoxication
ii) severe pul. or cardiac disease
iii) hypokalemia
iv) theophylline or adrenergic drugÅõ¿©
¨è MAT(multifocal atrial tachycardia) Fig 230-9
Á¤ÀÇ : ¼·Î ´Ù¸¥ ¸ð¾çÀÇ P wave°¡ 3°³ ÀÌ»ó ¿¬¼ÓÇØ¼ ³ª¿Ã¶§(rate>100ȸ/min)
theophylline Åõ¿© ÈÄ¿¡ ƯÈ÷ ÈçÇÏ´Ù.
´Ù¾çÇÑ AV conduction ¶§¹®¿¡ ventricular rate´Â ºÒ±ÔÄ¢ÀûÀÌ´Ù.
AF¹ß»ýºóµµ°¡ ³ô´Ù: 50-70%
Ä¡·á ; underlying disorderÄ¡·á
digitalis-induced arrhythmia´Â triggered activity¿¡ ÀÇÇØ ¹ß»ýÇϸç, Ä¡·á´Â ¾à Áß´ÜÀÌ´Ù.
¨é Automatic atrial tachycardia
dititalis¿¡ ÀÇÇØ ¹ß»ýÇÏÁö ¾Ê´Â autonomic atrial tachycardia´Â terminationÀÌ ¾î·Æ´Ù.
Ä¡·á¸ñÇ¥´Â ventricular rate control
i) drug : AV node¿¡ ÀÛ¿ëÇÏ´Â ¾à - digitalis, ¥â-blocker, calcium-channel blocker
ii) ablation technique
catheter ablation & surgery : arrhythmia focus¸¦ ¾ø¾Ö°Å³ª rate control¸ñÀûÀ¸·Î heart
block Çϱâ À§ÇØ »ç¿ëÇÒ¼ö ÀÖ´Ù.
9) Preexcitation(WPW) syndrome
- AV bypass tractÀ» ÅëÇÑ antegrade conduction
- congenital abnormaltiy¿Í °ü·ÃÀÖ´Ù: most important = Ebstein's anomaly
- triad : short PR interval(<0.12sec)
a slurred upstroke of the QRS complex(¥ä wave)
wide QRS complex
- PSVT in WPW
: ´ëºÎºÐ AV systemÀ¸·Î antegrade conduction, bypass tractÀ¸·Î retrograde
conduction
µå¹°°Ô(5%) bypass tractÀ¸·Î antegrade conduction, AV systemÀ¸·Î retrograde
conduction
- AF, atrial flutter in WPW : ÈçÇϸç ventricular fibrillationÀ» ÀÏÀ¸Å³¼ö ÀÖ´Ù.
* Ä¡·á
¨ç pharmacologic tx -> Fig 230-11
¨è PSVT with WPW : PSVT with concealed bypass tract°ú À¯»ç
¨é WPW & AF
i) life-threatening, rapid ventricular response : DC cardioversion
ii) non-life-threatening situation : lidocaine(3-5 mg/kg)
or procainamide(15 mg/kg) IV over 15-20min
ÃÖ±Ù ibutilide°¡ alternative tx
¡ÚÁÖÀÇ : digitalis or IV verapamilÀº accessory pathwayÀÇ ºÒÀÀ±â¸¦ ª°Ô ÇÏ¿©
ventricular rate¸¦ Áõ°¡½ÃÄÑ VF risk¸¦ Áõ°¡½Ãų¼ö ÀÖ´Ù.
chronic oral tx with verapamilÀº ÀÌ·¯ÇÑ riskÁõ°¡¿Í °ü°è¾ø´Ù.
¥â-blocker : È¿°ú°¡ ¾øÀ¸¸ç »ç¿ëÇÏÁö ¾Ê´Â´Ù.
¨ê atrial ventricular pacingÀÌ PSVT with WPWȯÀÚ¿¡¼ PSVT¸¦ Á¾°á½Ãų¼ö´Â ÀÖÀ¸³ª
AF¸¦ À¯¹ß½Ãų¼ö ÀÖ´Ù.
¨ë radiofrequency catheter ablation : permanent cure, 90%ÀÌ»ó ¼º°ø·ü
most cost-effective
-> catheter ablation½ÇÆÐ½Ã surgical ablationÀÌ ÇÊ¿äÇÒ¼ö ÀÖ´Ù.
10) Nonparoxysmal junctional tachycardia
- AV junctionÀÇ autonomicity Áõ°¡ ¶Ç´Â triggered activity·Î ¹ß»ý
- most commonly : digitalis intoxication
inf. wall MI, myocarditis, endogenous or exogenous
catecholamine excess, acute rheumatic fever, valve surgeryÈÄ¿¡ ¹ß»ý
- onset : gradual, rate stabilization Àü¿¡ "warm-up" period
- rate : 70-150ȸ, faster rate´Â digitalis intoxication°ú °ü·ÃÀÖ´Ù.
- QRS complex : sinus rhythm°ú µ¿ÀÏ
* Ä¡·á i) underlying etiologyÁ¦°Å
ii) digitalis°¡ °¡Àå ÈçÇÑ ¿øÀÎÀ̹ǷΠdigitalisÁß´Ü
iii) atrial & ventricular irritability°¡ ÀÖ´Ù¸é active intervention with lidocaine or
¥â-blocker
ÀϺο¡¼ digitalis Ab(Fab fragment) °í·Á
iv) cardioversionÀº ½ÃÇàÇÏ¸é ¾ÈµÊ. ƯÈ÷ digitalis intoxication¶§
v) AV conductionÀÌ intactÇÒ¶§ atrial pacingÀº junctional focus¸¦ capture & override
ÇÒ¼ö ÀÖ°í, C.OÀ» ÃÖ´ëÈÇϴµ¥ ÇÊ¿äÇÑ AV synchrony¸¦ Á¦°øÇÒ¼ö ÀÖ´Ù.
11) VT
¨ç Á¤ÀÇ ¹× ¿øÀÎ
sustained VT : 30ÃÊ ÀÌ»ó Áö¼ÓÇϰųª hemodynamic collapse¶§¹®¿¡ terminationÀÌ
ÇÊ¿äÇÑ °æ¿ì
i) ÀϹÝÀûÀ¸·Î structural heart ds¸¦ µ¿¹ÝÇÑ´Ù
(°¡Àå ÈçÈ÷ chronic ischemic heart ds associated with a prior MI)
ii) nonischemic cardiomyopathy
iii) metabolic disorders
iv) drug toxicity
v) prolonged QT syndrome
vi) heart ds³ª predisposing factor¾øÀÌ ¹ß»ýÇÒ¼öµµ ÀÖ´Ù.
nonsustained VT : 3 beats - 30ÃÊ
cardiac disease¿Í °ü·ÃÀÖÀ»¼öµµ ÀÖÁö¸¸ º¸ÅëÀº µ¿¹ÝµÇÁö ¾Ê´Â´Ù.
- stable VT°¡ VF³ª polymorphic VT·Î ÁøÇàÇÏ¸ç ´ëºÎºÐÀÇ VF´Â VT·Î ½ÃÀÛÇÑ´Ù.
¨è ECG diagnosis of VT
: wide-complex QRS tachycardia, rate>100 bpm
¸ð¾çÀº uniform(monomorphic) or polymorphic
cf. bidirectional tachycardia : QRS amplitude & axis alterationÀ» º¸ÀÌ´Â VT
ÀüÇüÀûÀ¸·Î sup(leftward) & inf(rightward) axis
- tachycardia onsetÀº ÀϹÝÀûÀ¸·Î abrupt, ±×·¯³ª nonparoxysmal tachycardia¿¡¼±
gradualÇÒ¼öµµ ÀÖ´Ù.
- paroxysmal VT´Â ÈçÈ÷ VPC·Î ½ÃÀ۵ȴÙ.
¨é SVT¿Í VTÀÇ °¨º°
- SVT c aberration°ú VTÀÇ intraventricular conductionÀ» ±¸º°ÇÏ´Â °ÍÀÌ Áß¿äÇÏ´Ù.
- VTÀÇ °¡Àå Áß¿äÇÑ clinical predictor´Â structural heart diseaseÀÇ Á¸ÀçÀÌ´Ù.
- intermittent cannon a wave & varying S1 soundµµ AV dissociationÀ» ÀǽÉÄÉ Çϰí
VT¸¦ Áø´ÜÇÏ°Ô ÇÏ´Â ¼Ò°ßÀÌ´Ù.
- ´ëºÎºÐ 12-lead ECG¸¦ close examinationÇÔÀ¸·Î½á Áø´ÜÇÒ¼ö ÀÖ´Ù.
- IV verapamil or adenosineÅõ¿©¿Í °°Àº pharmacologic maneuver ´Â ÇØ·Î¿ì¸ç ÇÇÇØ¾ß
ÇÑ´Ù.
- sinus rhythmµ¿¾È¿¡ tachycardia¶§¿Í °°Àº morphologic feature¸¦ °®´Â´Ù¸é PSVT with
aberrationÀ¸·Î Áø´ÜÇÒ¼ö ÀÖ´Ù.
* VT ½Ã»ç¼Ò°ß
i) QRS complex > 0.14sec
ii) AV dissociation c/s fusion or captured beats or variable retrograde conduction
iii) sup. axis + RBBB
iv) precordial lead¿¡¼ QRS concordance
v) typical RBBB or LBBB pattern°ú ÀÏÄ¡ÇÏÁö ¾Ê´Â QRS pattern(prolonged duration)
- SVT c aberrant conduction°ú VT¸¦ °¨º°Çϱâ À§ÇØ verapamilÀ» »ç¿ëÇÏ´Â °ÍÀº cardiac
arrest¸¦ ÀÏÀ¸Å³¼ö Àֱ⠶§¹®¿¡ ±ØÈ÷ À§ÇèÇÏ´Ù.
- sustained uniform VT´Â programmed stimulationÀ̳ª rapid pacingÀ¸·Î Àû¾îµµ 75%¿¡¼
terminationµÉ¼ö ÀÖ´Ù. ³ª¸ÓÁö´Â cardioversionÀÌ ÇÊ¿äÇÏ´Ù.
- ºÒÇàÈ÷µµ °¡Àå È¿°úÀûÀÎ Ä¡·áÀÎ rapid pacingÀº tachycardia¸¦ ¾ÇȽÃų¼ö ÀÖ°í VF¸¦
À¯¹ßÇÒ¼öµµ ÀÖ´Ù. ±×·¯¹Ç·Î antitachycardia pacingÀº pacing device¿¡ backup
defibrillation capability°¡ ÀÖÀ»¶§¿¡¸¸ ½ÃÇà°¡´ÉÇÏ´Ù.
¨ê ÀÓ»óƯ¡
¿¹ÈÄ´Â underying heart ds¿¡ ´Þ·Á ÀÖ´Ù.
AMIÈÄ Ã¹ 6ÁÖ³»¿¡ ¹ß»ýÇÑ sustained VT´Â ¿¹Èİ¡ ºÒ·®ÇÏ´Ù(1³â³» »ç¸Á·ü 75%)
MIÈÄ nonsustained VT ´Â »ç¸ÁÀ§ÇèÀÌ 3¹è ³ô´Ù.
±×·¯³ª nonsustained tachycardia¿Í subsequent sudden death»çÀÌÀÇ cause-and-effect
relationship¿¡ ´ëÇØ¼´Â È®¸³µÈ °ÍÀÌ ¾ø´Ù.
heart disease¾øÀÌ uniform VT´Â ¿¹Èİ¡ ÁÁÀ¸¸ç sudden death risk°¡ ¾ÆÁÖ ³·´Ù.
¨ë Ä¡·á
i) without organic heart ds & asymptomatic, nonsustained VT : benign course
: Ä¡·áÇʿ䡿
¿¹¿Ü) congenital long QT syndromeÀº Ä¡·áÇØ¾ß ÇÑ´Ù.
¡ñ recurrent polymorphic VT·Î sudden deathÇÒ¼ö Àֱ⠶§¹®
ii) sustained VT without heart disease
arrhythmia°¡ Áõ»óÀ» ÀÏÀ¸Å°±â ¶§¹®¿¡ Ä¡·á°¡ ÇÊ¿äÇÏ´Ù.
: ¥â-blocker, verapamil, IA, IC or III agent, or amiodarone
iii) with organic heart disease
hemodynamic compromise ȤÀº ischemia, CHF, CNS hypoperfusion evidence(+)
=> Áï°¢ DC cardioversion
tolerableÇϸé pharmacologic tx ½ÃµµÇÒ¼ö ÀÖ´Ù
=> procainamide : most effective agnet of acute tx
iv) overdrive pacing
¾à¹°·Î terminationµÇÁö ¾Ê´Â stable pt´Â RV apex·Î pacing catheter¸¦ »ðÀÔÇÏ¿©
overdrive pacingÇÔÀ¸·Î½á termination½Ãų¼ö ÀÖ´Ù.
v) programmed stimulation
recurrent, sustained VT¸¦ ¿¹¹æÇϱâ À§ÇØ ÀûÀýÇÑ Ç׺ÎÁ¤¸Æ ¾àÁ¦¸¦ ¼±ÅÃÇϱâ À§ÇÑ °¡Àå
ÁÁÀº ¹æ¹ýÀÌ´Ù.
vi) automatic antitachycardia pacing
VT¸¦ ¾ÇȽÃÄÑ severe hemodynamic compromise¸¦ À¯¹ßÇÒ¼ö ÀÖÀ¸¹Ç·Î ´Üµ¶À¸·Î´Â »ç¿ë
ÇÏÁö ¾Ê´Â´Ù. ±×·¯³ª ICD°¡ ³»ÀåµÇ¾î ÀÖ´Â antitachycardia pacingÀº unstable arrhythmia
¸¦ termination ÇÒ¼ö ÀÖ´Â "backup"ÀåÄ¡¸¦ Á¦°øÇÑ´Ù.
¨ì Specific types of VT
©Í TdP (Fig 230-13)
amplitude & cycle length°¡ º¯ÇÏ´Â polymorphic QRS complex
oscillations around the baseline
QT prolongation°ú ¿¬°üÀÖ´Ù.
* QT prolongationÀ» ÀÏÀ¸Å°´Â »óȲ
i) electrolyte disturbance(ƯÈ÷ hypokalemia & hypomagnesemia)
ii) antiarrhythmic drug(ƯÈ÷ quinidine)
iii) phenothiazines & TCA
iv) liquid protein diets
v) intracranial events
vi) bradyarrhythmia(ƯÈ÷ 3rd-degree AV block)
- young age¿¡¼´Â congenital anomaly°¡ TdP·Î ÀÚÁÖ ³ªÅ¸³´Ù.
- ECG hallmark : marked QT prolongation(>0.6sec)ÈÄ¿¡ µû¶ó¿À´Â polymorphic VT
- VF·Î ÁøÇàÇÏ¿© sudden cardiac death¸¦ ÀÏÀ¸Å³¼ö ÀÖ´Ù.
*Ä¡·á : À¯¹ßÀÎÀÚ Á¦°Å
¨ç drug-induced TdP : atrial or ventricular overdrive pacing & MgÅõ¿©°¡ È¿°úÀû
¨è congenital prolonged QT syndrome
i) ¥â-blocker(choice), phenytoin
ii) cervicothoracic sympathectomy : ´Üµ¶À¸·Î´Â È¿°ú°¡ ¾øÀ¸¸ç ¥â-blocker¿Í º´ÇÕ
Horner's syndromeÀ¯¹ß
iii) ICD with dual chambered pacing capability & ¥â-blocker
: ¥â-blocker¿¡µµ ºÒ±¸Çϰí recurrent episode¸¦ º¸À̴ ȯÀÚ¿¡¼ TOC
©Î polymorphic VT associated with normal QT interval
ischemic heart dsȯÀÚ¿¡¼ "R-on-T" VPCs¿¡ ÀÇÇØ ½ÃÀÛ.
ÈçÈ÷ reentry¿¡ ÀÇÇØ ¹ß»ý
TdP¿Í ´Ù¸£´Ù.
Ä¡·á> class I or III agent : most effective, full doseÅõ¿©ÇØ¾ß ÇÑ´Ù.
©Ï Accelerated idioventricular rhythm(=slow VT) 60-120 bpm
AMIÈÄ reperfusionµ¿¾È ÈçÈ÷ ¹ß»ý
±×¿Ü, cardiac opÈÄ, CMP, rheumatic fever, digitalis intoxication
cardiac disease°¡ ¾øÀ̵µ ¹ß»ýÇÒ¼ö ÀÖ´Ù.
´ëºÎºÐ Ä¡·á°¡ ÇÊ¿ä¾øÀ¸¸ç Áõ»óÀÌ »ý±ä´Ù¸é impaired hemodynamics¿¡ ÀÇÇÑ´Ù
(most commonly, AV dissociation)
´ëºÎºÐ atropine¿¡ Àß ¹ÝÀÀÇÑ´Ù.
12) Ventricular flutter & fibrillation
ÈçÈ÷ ischemic heart disease¸¦ °¡Áø ȯÀÚ¿¡¼ »ý±ä´Ù.
±×¿Ü¿¡ antiarrhythmic drug Åõ¿©(ƯÈ÷ QT intervalÀ» Áõ°¡½ÃŰ´Â ¾àÁ¦)
Torsade de pointes(TdP)
severe hypoxia, ischemia
rapid ventricular response¸¦ °¡Áö´Â AF·Î ¹ßÀüÇÏ´Â WPW
Ä¡·áÇÏÁö ¾ÊÀ¸¸é »ç¸ÁÇÑ´Ù.
late coupled VPC·Î ½ÃÀ۵Ǵ rapid VT·Î ÇÏ¿© VF·Î ÁøÇà
acute infarction 48½Ã°£ ³»¿¡ primary VFÀÇ long-term Px´Â good
¡ñ Àç¹ß or sudden cardiac death¡é, ±×·¯³ª short-term mortality´Â ¾à°£ Áõ°¡.
acute MI¿Í °ü·Ã¾ø´Â VF´Â 20-30%°¡ Àç¹ß
Ventricular flutter´Â 150-300 bpmÀ¸·Î rapid VT¿Í ±¸ºÐÀÌ ºÒ°¡´ÉÇÏ´Ù.
*Ä¡·á
¨ç pharmacologic antiarrhythmic tx
Ä¡·á½ÃÀÛÀü¿¡ potential aggrevating factor¸¦ ±³Á¤ÇØ¾ß ÇÑ´Ù.
: transient metabolic abnormalities, CHF, or acute ischemia
*Ä¡·á¸ñÀû
i) acute arrhythmiaÀÇ terminateion
ii) arrhythmiaÀç¹ß¹æÁö
iii) life-threatening arrhythmia¿¹¹æ
*ÇöÀç ³Î¸® »ç¿ëµÇ´Â antiarrhythmic agent : Tab 230-4, 230-7(toxicity)
: ¸ðµç ¾àÀÌ proarrhythmic effect°¡ ÀÖ¾î underlying arrhythmia¸¦ ¾ÇȽÃų¼ö ÀÖ´Ù.
¨è classification of antiarrhythmic drug
Tab 230-2(Vaughan-Williams classification)
*ºÐ·ù±âÁØ
i) excitatory current(Na+ or Ca2+)
ii) action potential duration
iii) automaticity(phase 4 depolarization)
ÀÌ ºÐ·ù´Â ¸¹Àº ÇѰèÁ¡ÀÌ Àִµ¥, ¸ðµç ¾àÀÌ ÀÌ ºÐ·ù¿¡ ¸Â´Â °ÍÀº ¾Æ´Ï°í, ÀϺξà
(amiodaroneó·³) multiple class property¸¦ º¸ÀδÙ.
¨é electrical tx of tachyarrhythmia
i) pacemaker
ii) cardioversion & defibrillation
12cm Á÷°æÀÇ 2 paddles
1°³- 2nd rib levelÀÇ sternum right
´Ù¸¥ 1°³ - Lt midclavicular lineÀÇ 5th intercostal space
ÀǽÄÀÌ ÀÖÀ»¶§´Â short-acting barbiturate¸¦ Åõ¿©(¸¶Ãë or amnesic drug»ç¿ë,
¿¹=diazepam)
VF, ventricular flutter¸¦ Á¦¿ÜÇϰí´Â QRS complex¿Í synchronousÇÏ°Ô ½ÃÇà
¡ñ asynchronous shock -> VFÀ¯¹ß
* energy
AF¸¦ Á¦¿ÜÇÑ SVT : 25-50J
AF : 100J¡è
VT : 100J¡è
VF : 200J¡è
* Indication
a. hypotension, myocaridal ischemia, Ht failure¸¦ ÃÊ·¡ÇÏ´Â any 'tachycardia'
(sinus tachycardiaÁ¦¿Ü)
b. pharmacologic tx·Î ½ÇÆÐÇÑ arrhythmia
iii) ICD(Implanted cardioverter/defibrillator)
Tab 230-9 ACC/AHA guidelines for ICD implantation
* class I
a. cardiac arrest due to VF or VT(not transient or reversible cause)
b. spontaneous sustained VT
c. syncope of undetermined origin
+ EP¿¡¼ significant sustained VT or VF
d. nonsustained VT with coronary ds, prior MI, LV dysfx
+ EP¿¡¼ inducible VF or sustained VT
iv) Ablative tx for arrhythmia
´ë»ó :WPW, AVNRT, typical atrial flutter
poorly controlled ventricular response to atrial arrhythmia, most commonly AF