Main Topic Reviews 특발성심실빈맥 차의과학대학교내과학교실성정훈 Jung-Hoon Sung, MD, PhD Division of Cardiology, Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Gyeonggi-do, Korea Idiopathic ventricular tachycardia Abstract Ventricular arrhythmias (VAs) in structurally normal hearts can be broadly considered under non-lifethreatening monomorphic and life-threatening polymorphic rhythms. VAs are commonly seen in young patients and typically have a benign course. Monomorphic VAs are classified on the basis of the site of origin in the heart, and the most common areas are the ventricular outflow tracts and left ventricular fascicles. The morphology of the QRS complexes on an electrocardiogram is an excellent tool to identify the site of origin of the rhythm. Treatment options include reassurance, medical therapy, and catheter ablation. Very frequent ventricular ectopy may result in cardiomyopathy in a minority of patients. Key words: ablation electrocardiogram idiopathic ventricular tachycardia normal hearts 서론 유출로심실빈맥 특발성심실빈맥 (idiopathic ventricular tachycardia) 은심실빈맥 (ventricular tachycardia, VT) 이구조적으로정상이며반흔이없는심장에서발생하는것이다. 유출로심실빈맥 (outflow tract VT, OT-VT), 섬유속심실빈맥 (fascicular VT), 유두근심실빈맥 (papillary muscle VT), 윤상심실빈맥 (annular VT), 기타 (miscellaneous) 로분류할수있다. 1 1. 유출로심실빈맥 1) 메카니즘유출로심실빈맥은 catecholamine에의한 delayed afterdepolarization에의해이루어진다. 이메카니즘에의한 tachycardia는 adenosine, 베타차단제, 칼슘차단제로종료시킬수있다. 2 Received: June 21, 2013 Revision Received: September 2, 2013 Accepted: September 28, 2013 Correspondence: Jung-Hoon Sung, MD, PhD, Division of Cardiology, Department of Internal Medicine, CHA Bundang Medical Center, CHA University, 351 Yatap-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-712, Korea Tel: 82-31-780-4864, Fax : 82-31-780-5584 E-mail: atropin5@cha.ac.kr 2) 유출로의해부학적특징우심실유출로 (right ventricular outflow tract, RVOT) 는좌심실유출로 (left ventricular outflow tract, LVOT) 에비해좌측및앞쪽방향으로위치한다. 그리고 pulmonic valve는 aortic valve의위쪽에위치한다. 10 The Official Journal of Korean Heart Rhythm Society
L A P R RAA LMCA RVOT RV Free wall RV Septum Main Topic Reviews A RA L N R P RCA LA Figure 1. Anatomy of the outflow tract. Anatomy of the typical right ventricular outflow tract (RVOT) of the heart. RVOT는 muscular infundibulum으로둘러싸여있고, LVOT는근육과섬유 (fibrous) 로이루어져있다. Aortic sinuses of Valsalva의오른쪽대부분과외쪽의일부분은 LVOT를덮고있고, AV node, His bundle에가까이있다. 1 임상적으로 septal RVOT와자유벽 (free wall) RVOT는전방, 중앙, 후방으로구분할수있다 (Figure 1). 2 전중격 (anteroseptal) RVOT는 LV epicardium 근처 interventricular vein 앞쪽에있다. Posteroseptal RVOT는 right coronary cusp 근처에있으며, RVOT- VT는주로 anteroseptal RVOT에서발생한다. 5 우심실유출로빈맥은좌각차단패턴 QRS에하향축을나타낸다. Precordial transition은주로 V4 또는그뒤에서이루어지고, V3보다일찍나타나지않으며, avl 과 avr은음성이다. Septal origin의심실빈맥은 QRS 기간이짧다. 6 폐동맥 (pulmonary artery, PA) 기원의 RVOT-VT에대한심전도기준은거의없다. 다만심전도상 PA origin 은하위유도 (inferior lead) 에서좀더 R 파가크고, avl/ avr에서 q파가큰비율을차지하여, V2에서 R/S 비율이크다. 2 2. 우심실유출로빈맥 3. LVOT/Aortic cusp tachycardia RVOT-VT는특발성심실빈맥 (idiopathic VT) 중가장흔하며심실빈맥의 70% 가량된다. 이것은좌각차단 (left bundle branch block, LBBB) 패턴의하향축 (inferior axis) 을가진다. 7 1) 심전도특징 1) 해부학 (anatomy) 후방 RVOT는 LVOT와대동맥근부 (aortic root) 의앞쪽에있다. 대동맥근부는심장의가운데에위치하고좌, 우, 비관상판첨으로되어있다. 비관상판첨 (noncoronary cusp) 은심실과바로연결이되지않아심실빈 Vol.14 No.3 11
Main Topic Reviews 맥의발생은거의없다. 좌우의판첨이심실과바로닿아있고좌심실근섬유 (muscle fiber) 는대동맥근부로뻗어있어심실조기수축 (premature ventricular contraction, PVC) 을만들수있다. 1 대동맥판첨에서발생하는빈맥은좌판첨이가장많고그다음이우판첨그리고좌우의판첨의접합부 (junction) 에서많이발생한다. 2) 심전도특징 LVOT 또는대동맥판첨에서발생하는심실빈맥은좌각차단패턴 QRS에하향축을갖지만, RVOT 위치보다 precordial transition이좀더빠르다. precordial의 R파는 V3 또는이보다먼저 transition된다. 좌판첨의 VT는 V1/V2에서 transition이있고우판첨은 V2/3에서나타난다. 대동맥판첨에서발생하는심실빈맥은 R 파가 0.5 ms로좀더넓고 V1, V2에서 R/S파가좀더크게나타난다. LVOT-VT는또한 aortic valve 아래쪽의 LV endocardium에서도나타날수있다. 빈도가낮은 LVOT-VT는 aortomitral continuity에서나타난다 (Table 1). 2 4. 심외막유출로심실빈맥심실빈맥은심외막 (epicardial) 에서거의발생하지않는다. MDI (maximum deflection index, 최초의 QRS 시작에서흉부유도에서최대편향까지의시간을총 QRS 기간으로나눈값 ) 로정량화해서 delayed initial precordial QRS activation이 0.55보다크면심외막심실빈맥을제안한다. 2 Lead I의하향축인 QS도심외막임을가리킨다. Transition 또는 pattern break라해서 V1 to V2의 R파가없어지는것 (QS 또는 rs) 이보이고 V3의 R파가잘보이는것은 aortic root의앞쪽의 anterior LV를가리킨다. 이것이 lead I의 QS와같이보이면심실간정맥 (interventricular vein) 근처의심외막 (epicardial origin) 을가리킨다. 5. 예후 Outflow tract의 VT는주로양성이며대부분은예후가좋다. 하지만두가지예외가있다. Short coupled PVC가 polymorphic VT를유발하거나죄심실기능장애 (LV dysfunction) 가빈맥에의해일어나는경우이다. 이런환자들은전기생리학검사가필요하다. 3 6. 검사및치료환자가전형적인 monomorphic outflow tract PVC를보이면홀터와심초음파로진단이충분하다. 만약 multiple PVC가있거나위치가특이하면 (free wall) MRI 같은검사를통해구조적인심장문제인 arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) 등이있는지고려해야한다. RVOT는 benign이나 ARVD/C가있는경우는돌연심장사 (sudden cardiac death) 의위험도및가족력을살펴봐야한다. 4,5 Table 1. Electrocardiographic classification of right ventricular outflow tract ventricular tachycardia (RVOT-VT) versus left ventricular outflow tract (LVOT)/aortic cusp ventricular tachycardia (VT) RVOT-VT LVOT/Aortic Cusp VT Later precordial transition (V3 or later) With V3 transition: VT transition later than sinus rhythm V2 transition ratio < 0.60 Narrower R-wave duration and greater R/S-wave amplitude ratio in V1 and V2 Earlier precordial transition (by V3) With V3 transition: VT transition earlier than sinus V2 transition ratio 0.60 Broader R-wave duration and greater R/S-wave amplitude ratio in V1 and V2 Notch (qrs) in V1 or V2 12 The Official Journal of Korean Heart Rhythm Society
1) 약물요법증상이있는 outflow tract VT에는베타차단제를일차적으로쓴다. 베타차단제를못쓰면 non-dihydropyridine 칼슘차단제 (verapamil 또는 diltiazem) 를쓸수있다. 2) 전극도자절제술전극도자절제술 (catheter ablation) 은비교적안전하고믿을만한치료방법이다. 심전도 localization이절제술을시행하는데도움이되나, 환자에게는위험도와치료효과를설명해야한다. 수면치료는심실빈맥을줄일수있어서삼가야한다. Isoproterenol을이용한 pacing 은심실빈맥을유발하는데도움이된다. 3D mapping 이절제술에도움이된다. Activation mapping은환자에서 PVC나 VT가잘나오면사용할수있고, bipolar electrogram의 earliest activation이 surface QRS보다 20-40 ms 앞설때성공적인절제부위로고려할수있다. Bipolar electrogram으로는일반적으로날카로운신속한초기편향을가지고있으며, sinus rhythm 동안후반편향의역전 (reversal of a late component present) 을보일수있다. Unipolar electrogram은주로 QS 패턴이뾰족하고아래로향하면서 surface QRS 앞에위치하면고려할수있다. 6 Pace mapping은 PVC/VT가잘나오지않을때시도할수있다. 빈맥의속도와비슷하게 mapping catheter 를 pacing한다. Pace mapping의 surface 12 심전도를임상의 VT/PVC와비교하는것이중요하다. 6 LVOT에서는 intracardiac echocardiography (ICE) 가도움이된다. 1 전극도자절제술의부작용은다른부위의절제술과비슷하다. 혈관으로접근하면서발생할수있는합병증, 심장천공 (cardiac perforation), 심낭압전 (cardiac tamponade), 뇌졸중, 심근경색등이있다. 섬유속심실빈맥 특발성좌심실빈맥 (idiopathic left VT) 또는섬유속심실빈맥은좌각 (left bundle branch) 의섬유속 (fascicles) 에서주로발생한다. 이것은심전도모양및해당되는섬유속 (corresponding fascicles) 에따라 left posterior fascicular VT, left anterior fascicular VT, left upper septal VT로나눈다. Left posterior fascicular VT가가장흔하고그다음이 left anterior, left upper septal 순이다. 1. 메카니즘 Verapamil sensitive left VT는 reentry에의한것으로이는심실또는심방자극에의해유도, 종결된다. 2. 심전도특징 Fascicular VT는우각차단 (right bundle branch block, RBBB) 패턴 QRS에 left superior axis를보인다. 이것은상대적으로좁아져 SVT가 BBB 패턴 QRS와같이있을때와혼돈될수있다. Left posterior fascicular VT는우각차단패턴 QRS에좌향편위 (left axis deviation, LAD) 가관찰되며, left anterior fascicular VT 의경우는우각차단패턴 QRS에우향편위 (right axis deviation, RAD) 가관찰된다. 중격 (septal) 심실빈맥은불완전한우각차단패턴 QRS에 normal axis를보인다. 3. 약물치료 Verapamil이빨리종결시키는데효과적이다. 만성적인 verapamil 치료는전극도자절제술을원하지않을때사용하며, 베타차단제또한효과적이다. 4. 전극도자절제술전극도자절제술은성공률이높아 90% 이상효과가있다. Fascicular potential이 PVC/VT with F-F (fascicular potential-fascicular potential) 보다앞서는것이중요하다. Earliest Purkinje potential이심실빈맥동안 QRS 앞에나오면성공적인절제부위로고려할수있다. Main Topic Reviews Vol.14 No.3 13
Main Topic Reviews 유두근심실빈맥 유두근심실빈맥은주로운동에의해서일어나고, catecholamine에민감해 isoproterenol 또는 epinephrine에의해유도된다. 발생기전은국소성이며회귀하지는않는다. 종종 multiple QRS를보이고자연히바뀌거나절제를통해바뀐다. 3 윤상심실빈맥 승모판과삼첨판륜 (tricuspid annulus) 에서도심실빈맥이발생한다. 각각의발생률은비슷하여삼첨판은 5-8%, 승모판은약 5% 이다. 승모판륜 (mitral annular) 심실빈맥 승모판륜심실빈맥은해부학적으로구분된다. 주로 Table 2. Specific locations and electrocardiographic features 2 Left cusp M or W pattern in V1 Monophasic R by V1/2 Tall R-wave amplitude in inferior leads Greater R-wave II/III ratio or III/II Lead I QS or rs Right cusp Monophasic R by V2/3 Larger R-wave amplitude in lead I R/L cusp junction Aortomitral continuity qrs in lead V1-V2 (notched downstroke), QS in lead V1 (notched downstroke) qr in lead V1 Rs/rs complex in lead I R-wave ratio < 1 in II/IIIqR in lead V1 Rs/rs complex in lead I R-wave ratio < 1 in II/III Epicardial MDI > 55% QS in lead I QS in II, III, avf (MCV) A Q-wave ratio in avl/avr >1.4 or an S-wave amplitude >1.2 mv A transition break, specifically a loss of R from leads V1 to V2 (QS or rs) with prominent R by V3 (AIV); MDI >55% QS in lead I QS in II, III, avf (MCV) A Q-wave ratio in avl/avr >1.4 or an S-wave amplitude >1.2 mv A transition or pattern break, specifically a loss of R from leads V1 to V2 S or rs) with prominent R by V3 (AIV) Pulmonary artery Tall R-wave in the inferior leads Larger Q-wave ratio in avl/avr Larger R/S amplitude in lead V2, larger R-wave amplitude in the inferior leads Larger Q-wave ratio in avl/avr Larger R/S amplitude in lead V2 Tricuspid annular Tricuspid inflow or para-hisian R- or r-wave lead I R or r with overall positive polarity in avl or r-wave I R or r with overall positive polarity in avl Large R-wave in I, R-wave or flat in avl, large R-wave in I, R-wave or flat in avl MDI (maximum deflection index): measured as the time from the earliest QRS onset to the maximum deflection in precordial leads, divided by the total QRS duration.qrs duration. 14 The Official Journal of Korean Heart Rhythm Society
anterior mitral annulus에서나오며 posterior or posteroseptal annulus는드물다. 심전도는우각전도차단패턴의 monophasic R 또는 Rs in lead V2-V6가보인다. 전극도자절제술은매우성공적이고이는 earliest ventricular activation 또는 12/12 pace map match를통해된다. 심실빈맥의기전을이해하고약물치료를하거나전극 도자절제술을시행하는것이도움이된다. References Main Topic Reviews 삼첨판륜심실빈맥 삼첨판륜심실빈맥은 8% 에서나타나며우측심실빈맥의 5% 에서보인다. Septal site는자유벽보다더많다고보고되었지만, 다른결과를보인연구도있다. 기타 1. 우심실에서발생하는부정맥 ARVD/C는다른심실빈맥과감별이중요하다. 2. Crux of the Heart 이곳은중간심장정맥 (middle cardiac vein) 과관상부비동 (coronary sinus) 의교차점에가깝게위치한심외막지점이다. 심전도는 left superior axis 및 early precordial transition과 delayed deflection을보인다 (Table 2). 2 결론 특발성심실빈맥은심실빈맥이구조적으로정상이며반흔이없는심장에서발생하는경우이다. 분류하면유출로심실빈맥, 다발성심실빈맥, 유두근심실빈맥, 윤상심실빈맥, 기타등으로구분된다. 이런심실빈맥은주로젊은환자에서비교적좋은예후를보인다. 12-lead 심전도로일반적인발생위치를확인할수있고, 특이한유형의경우결정적으로구별하는데에도도움이된다. 2 1. Prystowsky EN, Padanilam BJ, Joshi S, Fogel RI. Ventricular arrhythmias in the absence of structural heart disease. J Am Col Cardiol. 2012;59:1733 1744. 2. Hoffmayer KS, Gerstenfeld EP. Diagnosis and management of idiopathic ventricular tachycardia. Curr Probl Cardiol. 2013;38: 131-158. 3. European Heart Rhythm Association; Heart Rhythm Society, Zipes DP, Camm AJ, Borggrefe M, Buxton AE, Chaitman B, Fromer M, Gregoratos G, Klein G, Moss AJ, Myerburg RJ, Priori SG, Quinones MA, Roden DM, Silka MJ, Tracy C, Smith SC Jr, Jacobs AK, Adams CD, Antman EM, Anderson JL, Hunt SA, Halperin JL, Nishimura R, Ornato JP, Page RL, Riegel B, Priori SG, Blanc JJ, Budaj A, Camm AJ, Dean V, Deckers JW, Despres C, Dickstein K, Lekakis J, McGregor K, Metra M, Morais J, Osterspey A, Tamargo JL, Zamorano JL; American College of Cardiology; American Heart Association Task Force; European Society of Cardiology Committee for Practice Guidelines. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guide lines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death). J Am Coll Cardiol. 2006;48:e247-346. 4. Kiès P, Bootsma M, Bax JJ, Zeppenfeld K, van Erven L, Wijffels MC, van der Wall EE, Schalij MJ. Serial reevaluation for ARVD/C is indicated in patients presenting with left bundle branch block ven tricular tachycardia and minor ECG abnormalities. J Cardiovasc Electrophysiol. 2006;17:586-593. 5. Lee HW, Kim JB, Joung B, Lee MH, Kim SS. Successful catheter ablation of focal automatic left ventricular tachycardia presented with tachycardia-mediated cardiomyopathy. Yonsei Med J.2011; 52:1022-1024. 6. Takemoto M, Yoshimura H, Ohba Y, et al. Radiofrequency catheter ablation of premature ventricular complexes from right ventricular outflow tract improves left ventricular dilation and clinical status in patients without structural heart disease. J Am Coll Cardiol. 2005;45:1259-1265. 7. Hasdemir C, Ulucan C, Yavuzgil O, Yuksel A, Kartal Y, Simsek E, Musayev O, Kayikcioglu M, Payzin S, Kultursay H, Aydin M, Can LH. Tachycardia-induced cardiomyopathy in patients with idiopathic ventricular arrhythmias: the incidence, clinical and electrophysi ologic characteristics, and the predictors. J Cardiovasc Electro physiol. 2011;22:663-668. Vol.14 No.3 15