Search

Background: Morphology algorithms are currently recommended as a standalone discriminator in single‐chamber implantable cardioverter defibrillators (ICDs). However, these proprietary algorithms differ in both design and nominal programming. Objective: To compare three different algorithms with nominal versus advanced programming in their ability to discriminate between ventricular (VT) and supraventricular tachycardia (SVT). Methods: In nine European centers, VT and SVTs were collected from Abbott, Boston Scientific, and Medtronic dual‐ and triple‐chamber ICDs via their respective remote monitoring portals. Percentage morphology matches were recorded for selected episodes which were classified as VT or SVT by means of atrioventricular comparison. The sensitivity and related specificity of each manufacturer discriminator was determined at various values of template match percentage from receiving operating characteristics (ROC) curve analysis. Results: A total of 534 episodes were retained for the analysis. In ROC analyses, Abbott Far Field MD (area under the curve [AUC]: 0.91; P <.001) and Boston Scientific RhythmID (AUC: 0.95; P <.001) show higher AUC than Medtronic Wavelet (AUC: 0.81; P <.001) when tested for their ability to discriminate VT from SVT. At nominal % match threshold all devices provided high sensitivity in VT identification, (91%, 100%, and 90%, respectively, for Abbott, Boston Scientific, and Medtronic) but contrasted specificities in SVT discrimination (85%, 41%, and 62%, respectively). Abbott and Medtronic's nominal thresholds were similar to the optimal thresholds. Optimization of the % match threshold improved the Boston Scientific specificity to 79% without compromising the sensitivity. Conclusion: Proprietary morphology discriminators show important differences in their ability to discriminate SVT. How much this impact the overall discrimination process remains to be investigated. [ABSTRACT FROM AUTHOR]

Background and Aim: A potential correlation between severe acute respiratory syndrome coronavirus 2 and air pollution has been suggested in some nationwide studies. It is not clear whether air pollution contributes to the spread of SARS-CoV-2 and to increase mortality., Methods: Data on COVID-19 incidence, mortality rate, air pollution, and greenhouse gas element of 33 European countries were extracted from public available databases and analysed with Pearson correlation analysis for the overall population and normalizing for the population over 65 years., Results: Air pollutant agents such as particulate matter <10µm (PM10), particulate matter <2.5µm (PM2.5), ammonia (NH3), sulphur dioxide (SO2), non-methane volatile organic compounds (NMVOCs), nitrogen dioxide (NO2) and greenhouse gas elements recorded showed a remarkable correlation with cumulative positive number of SARS-CoV-2 cases and with cumulative number of COVID-19 deaths. PM2.5 (r = 0.68, p-value = 0.0001 for cumulative positive cases; r = 0.73, p-value <0.0001 for cumulative deaths) and nitrogen oxides (r = 0.85, p-value <0.0001 for cumulative positive cases; r = 0.70, p-value 0.0001 for cumulative deaths) were among the pollutant agents with the strongest correlation for both positive cases and deaths., Conclusions: High levels of pollution in European countries should be considered a potential risk for severe COVID-19 and SARS-CoV-2-related death.

Background: Ventricular tachycardia (VT) with structural heart disease is dependent on reentry within scar regions. We set out to assess the VT circuit in greater detail than has hitherto been possible, using ultra-high-density mapping., Methods: All ultra-high-density mapping guided VT ablation cases from 6 high-volume European centers were assessed. Maps were analyzed offline to generate activation maps of tachycardia circuits. Topography, conduction velocity, and voltage of the VT circuit were analyzed in complete maps., Results: Thirty-six tachycardias in 31 patients were identified, 29 male and 27 ischemic. VT circuits and isthmuses were complex, 11 were single loop and 25 double loop; 3 had 2 entrances, 5 had 2 exits, and 15 had dead ends of activation. Isthmuses were defined by barriers, which included anatomic obstacles, lines of complete block, and slow conduction (in 27/36 isthmuses). Median conduction velocity was 0.08 m/s in entrance zones, 0.29 m/s in isthmus regions ( P<0.001), and 0.11 m/s in exit regions ( P=0.002). Median local voltage in the isthmus was 0.12 mV during tachycardia and 0.06 mV in paced/sinus rhythm. Two circuits were identifiable in 5 patients. The median timing of activation was 16% of diastole in entrances, 47% in the mid isthmus, and 77% in exits., Conclusions: VT circuits identified were complex, some of them having multiple entrances, exits, and dead ends. The barriers to conduction in the isthmus seem to be partly functional in 75% of circuits. Conduction velocity in the VT isthmus slowed at isthmus entrances and exits when compared with the mid isthmus. Isthmus voltage is often higher in VT than in sinus or paced rhythms.