Long QT Syndrome and WPW Syndrome: A Very Rare Association between Two Causes of Sudden Cardiac Death in a Young Patient

Long QT syndrome (LQT) and WPW syndrome are causes of sudden cardiac death (SCD) in the young, and their association has been rarely reported. A 26-year-old woman presented with recurrent syncope. Her ECG showed a short PR interval, wide QRS (150 ms) due to a delta wave, and QT prolongation (QT 580 ms, QTc 648 ms). ECG monitoring documented recurrent salvos of a self-terminating wide QRS tachycardia, generally slightly polymorphic, sometimes with "torsade des pointes" (TdP) appearance, which were linked to the syncopal/presyncope episodes. Electrophysiologic monitoring diagnosed a right para-hisian accessory pathway with a very short ERP (240 ms baseline, <200 ms after isoproterenol). The pathway was ablated successfully. Despite QRS narrowing (80 ms), QT prolongation persisted after ablation (QT 620 ms, QTc 654 ms), with short runs of TdP, despite beta-blocker treatment, which was increased to the maximal dosage. A dual-chamber implantable cardioverter defibrillator (ICD) was implanted. To our knowledge, this is the first case report of an association between LQT and WPW syndrome in which both conditions are associated with an increased risk of SCD.

P355Complete non-inducibility after radiofrequency ablation for electrical storm improves survival rates

Background

Electric storm is a life threatening condition, that can complicate multiple cardiac pathologies and is associated with high mortality.  Catheter ablation has been shown to reduce ventricular tachycardia (VT) burden in patients with electrical storm but the optimal procedural endpoint and the therapeutic particularities required by different etiologies are still under debate.

Purpose

Our objective was to determine if there are any periprocedural factors that influence midterm outcomes.  We also sought if there were any significant differences between the results for ischemic and nonischemic patients.

Methods

The study included 66 consecutive patients, mean age 60 years, 82% males, treated for electrical storm in our center with endocardial/endo-epicardial radiofrequncy catheter ablation (with or without remote magnetic navigation). Acute success was defined as elimination of the clinical tachycardia with complete non-inducibility (including ventricular fibrillation) or non-inducibility for monomorphic VT with programmed ventricular stimulation using up to 4 extrastimuli. Mean follow-up duration was 9.4 months and the type of recurrence was catalogued in 3 categories: initial VT (isolated), electric storm and other sustained VT.

Results

The overall acute success rate was 93%, complete non-inducibility was achieved in 64.5% and non-inducibility for monomorphic VT in 87.5% of the cases. Epicardial approach was used in 44% of the non-ischemic cases vs 10.5% of the ischemic ones (p = 0.005). There were no significant differences between complete noninducibility rates and recurrence/death rates of the ischemic vs nonischemic groups. Among the variables analysed for predicting noninducibility, only two reached statistical significance: mean QRS duration of the clinical tachycardia (160 ± 32 ms vs 240 ± 63.3ms, p = 0.02) and shortest RS complex (124 ± 14.7 ms vs 210 ± 12ms, p = 0.02). Recurrent ventricular arrhythmia occurred in 25% of the patients during follow up, from which: 27.2 % initial VT (isolated), 36.4% electric storm and 36.4% other sustained VT. Death rate was 10.6% (7 patients).  Kaplan Meier plot showed that the lot with complete noninducibility after programmed ventricular stimulation had better survival rates (p = 0.01).

Conclusions

Ablative therapy had a good acute success rate, without significant differences between ischemic and noninschemic patients in our study. Complete noninducibility after programmed ventricular stimulation  after ablation was associated with better survival rates. Unsuccessfull ablation is a predictor of inhospital death of these patients.

P1171Optimal fusion vs. biventricular pacing in cardiac resynchronization therapy: long-term results of 540 consecutive patients

Background

Right ventricular (RV) stimulation induces supplemental dyssynchrony in case of left bundle branch block (LBBB) patients. Isolated left ventricular (LV) pacing has been proven superior to biventricular pacing (BiV) in terms of acute hemodynamic response.

Purpose

We sought to determine whether an optimised isolated LV pacing algorithm called "optimal fusion" (OFu) produces better and sustainable effects when compared to BiV in the long term.

Methods

540/760 (reasonable data collection) consecutive patients implanted with CRT in CEHB were analysed. The follow-up included 7 hospital visits for each patient (between baseline and 3 years). Demographics, risk factors, usual serum levels, pre-procedural planning factors, clinical, ECG, TTE and biochemical markers were recorded. Statistical analysis was performed using software. Data were reported as either p-values from crosstabs (discrete) or mean differences, p-values and confidence intervals from t-tests (continuous). A p-value of .05 was chosen for statistical significance (SS).

Results

The overall group consisted of 51% OFu (275) and the rest BiV patients. Subjects in OFu were younger (-4.379 ys; &lt;.001; (-7.028;-1.729)), more often females (40.9 vs. 24.9%; &lt;.002), more obese (40.1 vs. 29.6%; &lt;0.40) and had more structural disease other than ischaemic scar burden (10.8 vs. 2.7%; &lt;.005). Procedures in OFu were mainly "de novo" (93 vs. 73.4%; &lt;.000), more often CRT-Ds (58.2 vs. 42.9%; &lt;.005) and more frequently in sinus rhythm (99.4 vs. 62.3%; &lt;.000) and with typical LBBB (77.2 vs. 45%; &lt;.000). Baseline PR interval was shorter in OFu (-32.20 msec; &lt;.033; (-61.58;-2.58)). Notably, OFu patients started from a lower EF (-3.29%; &lt;.001; (-5.156;-1.441)), had more dyssynchrony as evaluated by Pitzalis’ index (34.32 msec; &lt;.017; (6.132;62.522)) and poorer initial mechanical performance by dP/dt (-104.83 mm Hg/sec; &lt;.012; (-185.301;-24.366)). There was no SS difference in clinical parameters at 3 years. Mean EF was higher in OFu (38.59 vs. 34.82%; NS; (4.183;-4.755)) while both EDVs (170.40 vs. 161.40 ml; NS; (-82.40;100.40)) and ESVs (115.36 vs. 102.67 ml; NS; (-82.65;108.03)) were lower. When looking at absolute Δs, OFu performed much better in the long term: EF (+15.81 vs. +8.86%; NS; (-17.06877;3.17710)), EDV (-46.07 vs. – 10.1 ml; NS; (-19.88;102.60)) and ESV (-55.91 vs. -17.46 ml; NS; (-39.88;124.71)). The cumulated super-responder/responder (SR/R) percentage at 1 year was much higher in OFu (83.43 vs. 57.75; &lt;.040).

Conclusions

The benefit of OFu is definitely sustainable in the long term. Structural response is constantly superior with OFu when compared to BiV although the current data set did not yield SS when comparing absolute means. However, parameter Δs are clearly in favor of OFu which produced a SS higher cumulated rate of SR/Rs over 3 years of follow-up.