Ventricular Preexcitation (Wolff-Parkinson-White Syndrome and Its Variants) 柯文欽醫師 國泰綜合醫院心臟內科主治醫師 臺北醫學大學講師

Transcription

1 Ventricular Preexcitation (Wolff-Parkinson-White Syndrome and Its Variants) 柯文欽醫師 國泰綜合醫院心臟內科主治醫師 臺北醫學大學講師

2 The Nobel Prize in Physiology or Medicine 1924 "for his discovery of the mechanism of the electrocardiogram" Willem Einthoven the Netherlands Leiden University Leiden, the Netherlands b (in Semarang, Java, then Dutch East Indies) d. 1927

3 Definition Pre-excitation Activation of part of the ventricle by an anomalous connection before it is depolarized by the normal atrioventricular (AV) conducting system.

4 History The heart beat was myogenic or neurogenic? th century. Connection between atria and ventricles?

5 History of Wolff-Parkinson- White Syndrome Louis Wolff ( ) John Parkinson ( ) Paul Dudley White ( ) On April 2,1928, a 35-year-old male patient suffering from racing heart for 10 years came to Dr. White s office. His physical exam and heart X-ray were normal. White turned the patient over to his assistant Louis Wolff and an ECG was recorded.

6 White solicited the opinions of other cardiologists on a previously planned trip to Europe. At that time, London and Vienna were top centers for ECG, but Thomas Lewis (White s teacher in ECG) and Scherf were initially disinterested in the publication of White's unusual Endings. It was only John Parkinson a pupil of Lewis who expressed interest in publication, since he had found similar ECG strips among his own patient records. White and Parkinson coauthored an article in 1930 on the WPW syndrome based on their finding with 11 patients. L. Wolff, J. Parkinson, P. D. White: Bundle-branch block with short P-R interval in healthy young people prone to paroxysmal tachycardia. American Heart Journal, St. Louis, 1930, 5: 685.

7 WPW ECG Pattern 1.PR interval < 0.12 sec. 2.Abnormally wide QRS 0.11 sec. 3.Presence of an initial slurring of the QRS (delta wave). 4.Secondary ST-T changes.

8 WPW Syndrome

9 Orthodromic AV Reentrant Tachycardia (AVRT)

10 Antidromic AV Reentrant Tachycardia (AVRT)

11 Atrial Fibrillation with WPW Syndrome

12 Tachycardia in WPW Syndrome 1.Orthodromic Atrioventricular Reciprocating Tachycardia 2.The Syndrome of Permanent Form of Junctional Reciprocating Tachycardia 3.Antidromic Atrioventricular Reciprocating Tachycardia 4.Reciprocating Tachycardia Using Multiple Accessory Pathways 5.Atrioventricular Nodal Reentrant Tachycardia 6.Atrial Fibrillation and Flutter 7.Ventricular Tachycardia 8.Aborted Sudden Death

13 Epidemiology The prevalence has been estimate to be 0.15~0.20 percent of the general population. The incidence may be higher if concealed form are count. 1.5~2 times as common in males as in females. Most (2/3) subjects have no organic heart disease.

14 Epidemiology A higher incidence in patients with dilated cardiomyopathy and obstructive cardiomyopathy (4 %). Hyperthyroidism, pregnancy, mitral valve prolapse. 15 % of patients with Ebstein s anomaly have an accessory pathway (AP), nearly always right-sided AP. Multiple AP are common in Ebstein s anomaly.

15 Genetics of Preexcitation 3.4% prevalence of preexcitation in first-degree relatives of patients. No genetic linkage has been established for isolated WPW. PRKAG2 cardiac syndrome: g-2 regulatory subunit of the AMP-activated protein kinase on chromosome 7, ventricular preexcitation with supraventricular tachycardia, paradoxical progressive conduction system disease required pacemaker implantation.

16 Anatomy and Pathophysiology At early stage of development of heart, the atrium and the ventricle are continous. The development of AV sulcus and central fibrous body separates the atrium and ventricle into tho syncytia connected only by the AV node and the bundle of His. Falure of this proccess could be considered to resulted in an accessory connection.

17 Anatomy and Pathophysiology Some posterior accessory pathways are related to diverticula of the coronary sinus that invaginate the ventricular muscle. This association suggests that excess predominance of accessory AV connection in the left AV annulus may related to the development of the branches of the coronary sinus that pass from the sinus into the left ventricle.

18 Anatomy and Pathophysiology Left free wall (45%) Posteroseptal (32%) Right free wall (16%) Anteroseptal (6%) Midseptal (1%)

19 Clinical Presentation and Natural History Highly variable Asymptomatic people usually have a benign prognosis, although they can rarely present with ventricular fibrillation as the first manifestation. Arrhythmic event rate 1.7/100 patient years. No clinical or electrophysiological variables could predict which people to become symptomatic.

20 Clinical Presentation and Natural History Infant < 1 year with preexcitation or AVRT often show spontaneous disappearance or remission. However, once symptomatic tachycardia appeared in adolescence, the course is usually chronic. Palpitation, chest discomfort, dyspnea, lightheadedness or syncope. Incidence of sudden death < 1 per 1000 patient years.

21 Tachycardia in WPW Syndrome Paroxysmal tachycardia recorded in % of patients with WPW pattern. Atrioventricular reentrant (reciprocating) tachycardia (AVRT) (75-80 %) orthodromic / antidromic AVNRT; atrialtachycardia (uncommon) Atrial fibrillation/ flutter (20-35%) Ventricular fibrillation (rare) Ventricular tachycardia (rare)

22 Orthodromic Atrioventricular Reciprocating Tachycardia The tachycardia loop is formed by the atrium, AV node, His-Purkinje system, and ventricular myocardium in the antegrade direction, returning to the atrium via AP in the retrograde direction. Delta wave is not observed during the tachycardia QRS complex is normal (narrow) BEATS/min

23 Orthodromic Atrioventricular Reciprocating Tachycardia 1.PR is longer than RP when the retrograde pathway is fast. 2.P wave is inscribed after the QRS complex. 3.The tachycardia cycle length is prolonged in the presence of functional ipsilateral bundle block. 4.Ocassional electrical alternans

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27 Antidromic Atrioventricular Reciprocating Tachycardia 1.Wide QRS complex identical to the fully preexcited complex 2.Inducible in only 5 % patients 3.1/3 multiple accessory pathways 4.Relatively high incidence of atrial fibrillation 5.Location of the accessory pathway farther form AV node.(5cm) beats/min

28 Incessant Supraventricular Tachycardia 1.PJRT-permanent junctional reciprocating tachycardia 2.Over months and sometimes years 3.Patients may be unaware of palipitation and only present when dilated cardiomyopathy develops beats/min 5.Ablation of the AP resulted in complete resolution of cardiomyopathy 6.Using a concealed decremental AP 7.Inverted P in II III AVF 8.RP> PR

29 Atrial fibrillation Atrial rate impulses/min Antegrade conduction over AV node is limited to beats/min Some APs have a short effective refractory period that permits conduction to > beats/min 15-35% of symptomatic WPW Atrial flutter with 1:1 conduction beats/min

30 Sudden Death Preexcitation accounts for 10% of sudden death in young patients. Atril fibrillation Multiple APs. Inappropriate AV node blocking agent: Calcium channel and digoxin

31 ECG Localization of accessory Pathways

32 Multiple Accessory Pathways Approximately 5~10% Combination patterns of two APS: RFW + PS LFW + PS LFW (anterolateral) + LFW (posterior) LFVV + AS (or MS) RFW+AS APs more than 2are rare, but up to 5 or 6 APs have been reported

33 Concealed WPW Syndrome Presence of AP capable only of retrograde conduction, most commonly located in left free wall and posteroseptum.

34 Intermittent WPW Syndrome

35 ECG Diagnostic Difficulty in the Presence of WPW Syndrome Difficult to make diagnosis of LVH, RVH, LBBB, RBBB, and old Ml Pseudoinfarction pattern in WPW Pseudoischemia (inverted T) post ablation of the AP

36 Pseudoinfarction pattern in WPW

37 RVH in the Presence of WPW Syndrome

38 RVH

39 Mechanism of Radiofrequency Catheter Ablation

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55 Mahaim Fibers Almost all Mahaim fibers are right-sided The proximal end of the fiber is either at the RA, AV node, bundle of His, or in the bundle branch The distal portion ends in the region of the septum or the right bundle branch Atriofascicular, nodoventricular (or nodofascicular), fasciculoventricular connections Most patients do not show delta wave during sinus rhythm Only antegrade with decremental conduction is present During reentrant tachycardia, the QRS shows LBBB pattern with left axis deviation

56 Lown-Ganong-Levine (LGL) syndrome Short PR < 0.12sec Normal QRS Paroxysmal tachycardia (AVNRT, AVRT, A fib/flu, VT) James fiber (Atrio-His AP)? Accelerated Av conduction a small, underdeveloped AV node a preferential rapid conduction in AV node enhanced AV nodal conduction (short AH<60 ms; 1:1 AV conduction with atrial pacing rate > 200 bpm)

57 Pseudodelta wave