ICD in a young patient with syncope

Transcription

1 ICD in a young patient with syncope Konstantinos P. Letsas, MD, FESC Second Department of Cardiology Evangelismos General Hospital of Athens Athens, Greece

2 Case presentation A 17-year-old apparently healthy young man with recurrent syncopal episodes during walking was referred to our institution for further evaluation. There was no family history of sudden cardiac death. Transthoracic echocardiography revealed a structurally normal heart. Exercise treadmill test failed to induce any arrhythmic or ischemic events. A drug-free tilt table test was negative for neurocardiogenic syncope.

3 Baseline ECG

4 Baseline ECG Brugada pattern? Early repolarization? Short QT interval?

5 Holter monitoring

6 Abrupt AV block Autonomic nervous system dysfunction (enhanced vagal tone)? AV nodal blocking agents? Distal conduction disease? Concealed His bundle extrasystoles?

7 SAECG and Brugada test Late potentials (RMS-40, LAS-40) as detected and calculated by signalaveraged ECG were positive. Sodium channel blocking test with procainamide (10 mg/kg) failed to induce the diagnostic type 1 ECG of Brugada syndrome.

8 Electrophysiological study EPS demonstrated normal AH (110 ms) and HV (49 ms) intervals. Right ventricular programmed stimulation at three basic cycle lengths (600, 500 and 430 m) with up to three extra stimuli failed to induce any ventricular arrhythmias. The atrial and ventricular refractory periods were 190 and 200 ms, respectively No atrial arrhythmias were induced and no episodes of AV block were documented during EPS.

9 ICD implantation A dual-chamber cardioverter defibrillator (ICD) was implanted. The patient was asymptomatic after a 12-month follow-up period. Careful programming of the defibrillator function and adaptation of sensing levels and decay delays are essential in SQTS to reduce inappropriate shocks related to atrial tachyarrhythmias or T-wave oversensing.

10 Genetic test Genomic DNA was prepared from peripheral blood lymphocytes using standard methods. The entire open reading frame of the KCNQ1, KCNH2 and SCN5A genes was analyzed. The following non-coding genetic variants were identified: KCNQ1 (1638 G[A S546S), KCNH2 (G3152? 22 G[A) and SCN5A (5457 C[T D1819D, 3183 G[A E1061E). The KCNJ2, CACNA1C and CAC-NB2 genes were not screened for mutations.

11 Short QT syndrome HOW SHORT IS SHORT???? QTc <330 msec (none in 12,012 apparently healthy subjects, Gallagher et al. Am J Cardiol; 2006) A QTc value < msec needs further validation. Hyperkalemia, hypercalcemia, acidosis, digoxin overdose, fever, tachycardia, vagal or sympathetic hypertonia, and acute ischemia, early repolarization.

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13 J Am Coll Cardiol 2011;57:802 12

14 Diagnostic Criteria for SQTS: >4 points J Am Coll Cardiol 2011;57:802 12

15 SQTS: diagnosis ESC guidelines 2015 SQTS is diagnosed in the presence of a QTc 340 ms. SQTS should be considered in the presence of a QTc 360 ms and one or more of the following: A confirmed pathogenic mutation A family history of SQTS A family history of sudden death at <40 years Survival from a VT/VF episode in the absence of heart disease.

16 Genes implicated in SQTS Cardiol J 2013; 20, 5:

17 Other ECG findings in SQTS Absent or minimal ST segments Interval from J point to T wave peak (Jp-Tp) measured in the precordial lead with the T wave of greatest amplitude < 120 ms Possible tall T waves with narrow base similar to the T wave of moderate hyperkalemia ( desert tent T waves ) Frequent early repolarization pattern Prolongation of Tpeak-Tend interval Possible presence of prominent U waves Very frequent paroxysmal AF Cardiol J 2013; 20, 5:

18 The minus-plus T-wave signal Cardiol J 2013; 20, 5:

19 PQ segment depression in patients with SQTS Heart Rhythm2014;11:

20 SQTS ECG Courtesy of S. Priori

21 SQTS ECG Courtesy of S. Priori

22 EPS in SQTS Extremely short atrial refractory period (<140 ms) and ventricular refractory period (<150 ms) Atrial refractory periods of < 140 ms and ventricular effective refractory periods of <150 ms are highly suspicious of SQTS. Increased inducibility of AF and ventricular fibrillation (VF). Cardiol J 2013; 20, 5:

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24 VF three years later

25 Thank you very much for your attention