Skin Sympathetic Nerve Activity and the Short-Term QT Interval Variability in Patients With Electrical Storm

Background: Skin sympathetic nerve activity (SKNA) and QT interval variability are known to be associated with ventricular arrhythmias. However, the relationship between the two remains unclear.Objective: The aim was to test the hypothesis that SKNA bursts are associated with greater short-term variability of the QT interval (STVQT) in patients with electrical storm (ES) or coronary heart disease without arrhythmias (CHD) than in healthy volunteers (HV).Methods: We simultaneously recorded the ECG and SKNA during sinus rhythm in patients with ES (N = 10) and CHD (N = 8) and during cold-water pressor test in HV (N = 12). The QT and QTc intervals were manually marked and calculated within the ECG. The STVQT was calculated and compared to episodes of SKNA burst and non-bursting activity.Results: The SKNA burst threshold for ES and HV was 1.06 ± 1.07 and 1.88 ± 1.09 μV, respectively (p = 0.011). During SKNA baseline and burst, the QT/QTc intervals and STVQT for ES and CHD were significantly higher than those of the HV. In all subjects, SKNA bursts were associated with an increased STVQT (from 6.43 ± 2.99 to 9.40 ± 5.12 ms, p = 0.002 for ES; from 9.48 ± 4.40 to 12.8 ± 5.26 ms, p = 0.016 for CHD; and from 3.81 ± 0.73 to 4.49 ± 1.24 ms, p = 0.016 for HV). The magnitude of increased STVQT in ES (3.33 ± 3.06 ms) and CHD (3.34 ± 2.34 ms) was both higher than that of the HV (0.68 ± 0.84 ms, p = 0.047 and p = 0.020).Conclusion: Compared to non-bursting activity, SKNA bursts were associated with a larger increase in the QTc interval and STVQT in patients with heart disease than in HV.

ECMO-Supported Ablation and Percutaneous Repair of Severe Valvulopathy: A Winning Combination in a Complex Clinical Case

In this case report, we describe a complex case of a 67-year-old patient who was suffering from acute heart failure with electrical storm. Clinical case management was based on an integrated approach comprising two different procedures that were complementary and synergistic, and that allowed the patient to reach acute stabilization and to demonstrate mid-term clinical improvement. Complex clinical settings, such as electrical and hemodynamic instability, require complex solutions. The use of an integrated approach that allows physiopathological mechanisms to work together may be beneficial for these patients.

An unusual cause of electrical storm in a young woman

A 35-year-old woman was admitted for recurrent syncope. At admission multiples episodes of non-sustained polymorphic ventricular tachycardia were recorded. After exclusion of all possible aetiologies a carefully electrocardiogram analysis reveals the key for the diagnosis.

671 First-in-man mapping and ablation of ventricular tachycardia using a novel ablation catheter with microelectrodes and thermocouples

Aims Catheter ablation (CA) is an important therapeutic option for patients with recurrent ventricular tachycardia (VT). Recently, a novel contact-force sensing catheter (QDOT, Biosense Webster) allowing radiofrequency ablation in a temperature-controlled fashion, equipped with microelectrodes and thermocouples has been developed and tested in very-high power short duration CA of atrial fibrillation. As of today, this catheter has never been used for VT ablation. To describe the safety and short-term clinical performance of the novel QDOT catheter for the ablation of recurrent VT/electrical storm. Methods and results Case 1: a 43-year-old male patient with prior anterior myocardial infarction (MI), left ventricular (LV) dysfunction with an apical aneurysm, and recurrent VT episodes was admitted to our hospital for CA of VT. The patient underwent high-density electroanatomical mapping of the left ventricle using a multipolar catheter (PentaRay, Biosense Webster), which showed an extensive apical dense scar region, corresponding to the ventricular aneurysm. When the QDOT catheter was advanced in that region, late/fragmented potentials were detected by microelectrodes as well as by conventional electrodes. During the procedure, a sustained VT with right bundle branch block (RBBB)-inferior axis morphology and transition in V2 could be induced. We recorder diastolic fragmented potentials inside the aneurysm, where the novel catheter previously showed late/fragmented potentials; radiofrequency energy delivery with conventional settings (40 W) in that area led to rapid arrhythmia termination (Figure A). At the end of the procedure, VTs were no more inducible. Case 2: a 79-year-old male patient with prior inferior MI, mild LV dysfunction with a 5 cm × 5 cm × 3 cm aneurysm of the basal-mid inferior wall, and two previous CAs for recurrent VT presented to our hospital for electrical storm due to multiple episodes of slow VT (cycle, 470 ms, RBBB morphology, inferior axis, transition in V6), which were refractory to antiarrhythmic drug treatment. We decided to perform redo CA using the QDOT catheter, which revealed long and fragmented low-amplitude diastolic potentials inside the LV aneurysm (Figure B). VT was rapidly terminated by means of radiofrequency energy delivery with usual settings (40 W) in this region, and was no more inducible afterwards. Conclusions The novel ablation catheter showed favourable manoeuverability in the ventricle, while also allowing a precise characterization of the tachycardia circuitry and of the arrhythmogenic myocardial substrate, which was enhanced by the availability of microelectrodes. We believe that this preliminary experience may pave the way for further assessments of this new technology in the so far unexplored ventricular milieu.

555 Torsade-de-pointes electrical storm late after treatment with hydroxychloroquine and azithromycin for COVID-19

A 78-year-old woman was admitted to our hospital due to multiple brief episodes of transient loss of consciousness. She was recently hospitalized elsewhere for SARS-CoV-2 infection and she had been discharged two days before. During the previous hospitalization she had been treated with hydroxychloroquine 400 mg twice daily on Day 1, followed by Hydroxychloroquine 400 mg daily together with azithromycin 500 mg daily for 7 days, leading to symptomatic resolution and two consecutive negative RT-PCR tests at discharge. Her medical history included dilated cardiomyopathy and in 2017 she underwent CRT-D implantation for primary prevention; over the past 3 years, she did not experience any ICD intervention. Her home therapy included amiodarone, bisoprolol, warfarin, and trazodone. Baseline ECG obtained 6 month before admission is shown in Figure 1, Panel A. On admission, her ECG showed sinus bradycardia with biventricular pacing and significant QT prolongation (i.e. 640 ms, Figure 1 B). On day 2 of hospitalization, she reported multiple brief episodes of transient loss of consciousness. An interrogation of her device revealed 27 torsade-de-pointes episodes in a 48-hour period, treated with 11 shocks. All episodes were preceded by a variable period of bigeminal rhythm due to one or two premature ventricular beats coupled to the prolonged QT segment of the preceding basic beat in a ‘short-long-short’ sequence (Figure 2). The patient experienced a torsade-de-pointes TdP during COVID-19 disease. She had multiple concomitant factors for QT prolongation (TISDALE SCORE 13): mainly, female sex, cardiac disease, inflammation, electrolyte imbalances and multiple QT-prolonging drugs. Amiodarone and bisoprolol were subsequently stopped and potassium and magnesium were supplemented, with rapid resolution of torsade-de-pointes. No more episodes of TdP were detected after two weeks of hospitalization. The remote monitoring assessment of her device did not show any further episodes during subsequent follow-up. To our best knowledge, this is the first ICD-documented report of a TdP electrical storm in a COVID-19 patient, treated with HCQ/AZT, who had multiple concomitant factors for QT prolongation. 555 Figure 1