Sudden Cardiac Death; Invasive Evaluation Alpay Çeliker MD Hacettepe University Department of Pediatric Cardiology Ankara, Türkiye

Case 1 11 years old boy suddenly collapsed with a ventricular tachycardia

DC cardioversion by paramedics Restoration of normal sinus rhythm History: Total correction for FT at 1 month old ECG: RBBB, QRS= 130 msn ECHO: Mild PR, normal LV function MRI: Normal RV EF, mild PR

Cardiac Cath and Electrophysiologic Study Normal hemodynamic findings Mild PR Normal AV and sinus node function No inducible SVT Ventricular stimulation: VT induction with two PES Monomorphic VT with LBBB Rate 270 beats/min

Oral amiodarone 10 mg/kg, propranolol 1 mg/kg started EPS after ten days  VT  ICD How we can know the risk before?? Noninvasive methods Invasive methods

Case 2 23 year old male student suddenly collapsed Ventricular fibrillation  Defibrillated several times Brain edema resolved in the following days History: Total correction for FT at 3 years old Transannular patch, previous shunt QRS 180 ms

Cardiac cath & Electrophysiology It was performed 5 years ago No RVOT gradient PA pressure 41/3 mean 20 mmHg Aneursymal dilation at RVOT Severe PR Moderate TR Enlarged RV Stimulation: NS Atrial Flutter, NO NSVT OR SMVT

SCD in Operated CHD When is an invasive evaluation needed? What is the methodology? How we can interprete the results? Can it be used for determine the prognosis?

Indications for Invasive Evaluation Syncope of unknown origin Resusciated sudden cardiac arrest Ventricular tachycardia on Holter ECG Exercise induced/aggrevated ventricular tachycardia/arrhythmia During invasive cardiac catheterisation Drug-electrophysiologic study

Methodology Two venous, one arterial line Hemodynamic and angiographic analysis Electrophysiologic Study Measurement of basal intervals AV conduction (Wenckebach) Sinus node functions Supraventricular tachycardia induction Ventricular tachycardia induction

Supraventricular Tachycardia Induction Programmed atrial stimulation up two three beats basal and during isoproterenol infusion until the atrial refractory period occurs Burst stimulation up to 150 msn pacing cycle lenght Observe the atrial flutter or IART Sustained or non sustained Reinducibility Atrial rate Hemodymanic status during tachycardia AV conduction

Ventricular stimulation Programmed ventricular stimulation from right ventricle apex and RVOT PES up to three beats basal and during isoproterenol infusion at three basic cycle lenghts until the ventricular refractory period occurs Burst stimulation up to 250 msn pacing cycle lenght Observe the ventricular tachycardia Sustained or non sustained Reinducibility Ventricular rate Hemodymanic status during tachycardia

Programmed Ventricular Stimulation after Tetralogy Repair 252 patients at 16±12,3 years (3,3-55,6 years) FU after surgery 18,5 ±9,6 years Median age at surgery 4,5 years Transannular patch repair in 57,2% Surgical palliation in 46,3% QRS duration 146 ±36 ms, ≥ 180 ms in 19,4% and LAH in 22,6% Moderate PR in 74,2% Syncope in 23,6%, documented VT in 16,7%, resusiated cardiac arrest in 1,2% Khairy P et al. Circulation 2004; 109, 1994.

Patient Characteristics No Inducible Monomorphic Polymorphic VT (N=165) VT (n=76)VT (n=11) Age at EP study,y Clinical presentation, % Syncope Documented SVT Cardiac arrest Surgical history Age at surgery, y ,2 Transannular patch, % Palliative surgery,% Electrocardiogram QRS duration, ms QRS ≥180 ms, % Lown ≥2 by Holter, % Hemodynamics ≥Moderate PR, % Follow-up FU after surgery, y ICD, % Clinical VT, % SCD, %

PVS after Tetralogy Repair Sustained monomorphic VT was induced in 30,2% (n=76), sustained polymorphic VT was induced in 4,4% (n=11) and 65,5 % (n=165) were noninducible. 2,7±0,6 PES and isuprel infusion in 23,5% Event occurred in 62 (24,6 %) patients after 6,5±4,5 years; VT 45 VT and SCD 14 SCD 3 Khairy P et al. Circulation 2004; 109, 1994.

Inducible VT and Clinical VT and SCD Results of PVSClinical VT or SCD (n,%)Total Number Sustained monomorphic VT41 (53 %)76 No inducible monomorphic VT 21 (12%)176 Sustained monomorphic or polymorphic VT 48 (55%)87 No inducible VT14 (8,4%)165 Total62 (24,6%)252

Predictors of Inducible Sustained VT VariableOR Age ≥ 18 y 6.0 Operation Age ≥ 7y 3.3 Syncope 4.9 Prior palliative surgery 2.9 QRS ≥ 180 ms 7.3 Modified Lown ≥ Cardiothoracic ratio ≥

PVS has diagnostic value and prognostic significance. Inducible sustained polymorphic VT enhanced the diagnostic yield and predictive ability.EPS should be used in risk stratification in postoperative Fallot patients

significant PR, TR right ventricular dysfunction residuel lesions MRI Hemodynamic study Electrophysiological study Postop FT History Resuscitation in one Syncope&presyncope in five Palpitation in 12 Hacettepe Serie: 46 patients Study Design

Moderate/severe PR in 26 patients (60% ) Moderate/severe PR in 26 patients (60% ) 2 Sustained Monomorphic VT 4 NS-VT 1 PVR: Sustained atrial flutter and VT Residual VSD in 6 patients Residual VSD in 6 patients One NS-VT Three with atrial Flutter

Patient Number% Normal 1535 Sustained AF+fibroflutter 8 18,6 Non-sustained AF 3 6,9 SSS and AV conduction problem 8 18,6 Non-sustained VT 5 11,6 Sustained VT * 4 9,3 Total Electrophysiological Findings

Conclusions Electrophysiological study should be used in the risk stratification in patients with tetralogy surgery. In patients with inducible VT should be treated appropriately to prevent sudden cardiac death. In patients with negative study noninvasive methods may help in follow-up. In patients with residual lesions need corrections to prevent ventricular arhhymias and SCD.