Sudden cardiac death while waiting: do we need the wearable cardioverter-defibrillator?

Sudden cardiac death (SCD) is the most frequent cause of cardiovascular death in industrialized nations. Patients with cardiomyopathy are at increased risk for SCD and may benefit from an implantable cardioverter-defibrillator (ICD). The risk of SCD is highest in the first months after myocardial infarction or first diagnosis of severe non-ischemic cardiomyopathy. On the other hand, left ventricular function may improve in a subset of patients to such an extent that an ICD might no longer be needed. To offer protection from a transient risk of SCD, the wearable cardioverter-defibrillator (WCD) is available. Results of the first randomized clinical trial investigating the role of the WCD after myocardial infarction were recently published. This review is intended to provide insight into data from the VEST trial, and to put these into perspective with studies and clinical experience. As a non-invasive, temporary therapy, the WCD may offer advantages over early ICD implantation. However, recent data demonstrate that patient compliance and education play a crucial role in this new concept of preventing SCD

Fully digital data processing during cardiovascular implantable electronic device follow-up in a high-volume tertiary center

Background Increasing numbers of patients with cardiovascular implantable electronic devices (CIEDs) and limited follow-up capacities highlight unmet challenges in clinical electrophysiology. Integrated software (MediConnect®) enabling fully digital processing of device interrogation data has been commercially developed to facilitate follow-up visits. We sought to assess feasibility of fully digital data processing (FDDP) during ambulatory device follow-up in a high-volume tertiary hospital to provide guidance for future users of FDDP software. Methods A total of 391 patients (mean age, 70 years) presenting to the outpatient department for routine device follow-up were analyzed (pacemaker, 44%; implantable cardioverter defibrillator, 39%; cardiac resynchronization therapy device, 16%). Results Quality of data transfer and follow-up duration were compared between digital (n = 265) and manual processing of device data (n = 126). Digital data import was successful, complete and correct in 82% of cases when early software versions were used. When using the most recent software version the rate of successful digital data import increased to 100%. Software-based import of interrogation data was complete and without failure in 97% of cases. The mean duration of a follow-up visit did not differ between the two groups (digital 18.7 min vs. manual data transfer 18.2 min). Conclusions FDDP software was successfully implemented into the ambulatory follow-up of patients with implanted pacemakers and defibrillators. Digital data import into electronic patient management software was feasible and supported the physician’s workflow. The total duration of follow-up visits comprising technical device interrogation and clinical actions was not affected in the present tertiary center outpatient cohort

Length of hospital stay for elective electrophysiological procedures: a survey from the European Heart Rhythm Association

Aims Electrophysiological (EP) operations that have traditionally involved long hospital lengths of stay (LOS) are now being undertaken as day case procedures. The coronavirus disease-19 pandemic served as an impetus for many centres to shorten LOS for EP procedures. This survey explores LOS for elective EP procedures in the modern era. Methods and results An online survey consisting of 27 multiple-choice questions was completed by 245 respondents from 35 countries. With respect to de novo cardiac implantable electronic device (CIED) implantations, day case procedures were reported for 79.5% of implantable loop recorders, 13.3% of pacemakers (PMs), 10.4% of implantable cardioverter defibrillators (ICDs), and 10.2% of cardiac resynchronization therapy (CRT) devices. With respect to CIED generator replacements, day case procedures were reported for 61.7% of PMs, 49.2% of ICDs, and 48.2% of CRT devices. With regard to ablations, day case procedures were reported for 5.7% of atrial fibrillation (AF) ablations, 10.7% of left-sided ablations, and 17.5% of right-sided ablations. A LOS ≥ 2 days for CIED implantation was reported for 47.7% of PM, 54.5% of ICDs, and 56.9% of CRT devices and for 54.5% of AF ablations, 42.2% of right-sided ablations, and 46.1% of left-sided ablations. Reimbursement (43–56%) and bed availability (20–47%) were reported to have no consistent impact on the organization of elective procedures. Conclusion There is a wide variation in the LOS for elective EP procedures. The LOS for some procedures appears disproportionate to their complexity. Neither reimbursement nor bed availability consistently influenced LOS

Predictors and Prognostic Implications of Cardiac Arrhythmias in Patients Hospitalized for COVID-19

Background: Cardiac manifestation of COVID-19 has been reported during the COVID pandemic. The role of cardiac arrhythmias in COVID-19 is insufficiently understood. This study assesses the incidence of cardiac arrhythmias and their prognostic implications in hospitalized COVID-19-patients. Methods: A total of 166 patients from eight centers who were hospitalized for COVID-19 from 03/2020–06/2020 were included. Medical records were systematically analyzed for baseline characteristics, biomarkers, cardiac arrhythmias and clinical outcome parameters related to the index hospitalization. Predisposing risk factors for arrhythmias were identified. Furthermore, the influence of arrhythmia on the course of disease and related outcomes was assessed using univariate and multiple regression analyses. Results: Arrhythmias were detected in 20.5% of patients. Atrial fibrillation was the most common arrhythmia. Age and cardiovascular disease were predictors for new-onset arrhythmia. Arrhythmia was associated with a pronounced increase in cardiac biomarkers, prolonged hospitalization, and admission to intensive- or intermediate-care-units, mechanical ventilation and in-hospital mortality. In multiple regression analyses, incident arrhythmia was strongly associated with duration of hospitalization and mechanical ventilation. Cardiovascular disease was associated with increased mortality. Conclusions: Arrhythmia was the most common cardiac event in association with hospitalization for COVID-19. Older age and cardiovascular disease predisposed for arrhythmia during hospitalization. Whereas in-hospital mortality is affected by underlying cardiovascular conditions, arrhythmia during hospitalization for COVID-19 is independently associated with prolonged hospitalization and mechanical ventilation. Thus, incident arrhythmia may indicate a patient subgroup at risk for a severe course of disease

SPW-coupled firing is specifically enhanced after carbachol induced gamma oscillations in both CA1 and CA3.

<p><b>A</b>: Each line represents one unit and the modulation of its SPW-R-related firing rate after carbachol induced gamma oscillations. Red lines illustrate potentiated units, black lines depict suppressed units. Note the dominance of enhanced units in the <i>CCh</i> experiments in contrast to ongoing SPW-R recordings. <b>B</b>: Increase of SPW-R-coupled firing (see Methods section for plasticity coefficient) was significantly stronger in the <i>CCh</i> experiments compared to ongoing SPW-R-recordings and the <i>atropine</i> control, p<0.0001 for CA1, p<0.001 for CA3; ANOVA with post-hoc test between groups). <b>C</b>: Modulation in firing outside SPW-R was calculated as a coefficient (see <i>c2</i> in Methods Section) and compared between groups. In CA1 of <i>CCh</i> experiments firing outside SPW decreased in contrast to ongoing SPW-recordings and <i>atropine</i> control (p<0.001, ANOVA and post-hoc tests). In CA3 firing outside SPWs was slightly increased in all groups. However, groups did not differ statistically (p>0.05, ANOVA).</p

Intermittent carbachol induced gamma oscillations lead to changes in SPW-R-waveforms reflecting modulation of local neuronal assembly structure.

<p><b>A</b>: Example of 2456 (left panel, baseline episode of 1000 s) and 7237 (right panel, post gamma episode of 2000 s) individual SPW-R events from one experiment sorted onto the respective reference SOM. Traces left and right to the SOM depict an enlarged view of the waveforms at the corner positions. Grey lines indicate individual events, yellow lines show mean waveforms which are also shown in the respective map unit. Note the shift in SPW-R-waveforms after intermittent gamma oscillations. <b>B</b>: Differences of reference maps and partial data maps after <i>CCh</i> (red), ongoing <i>SPW-R</i> oscillations (blue), and <i>atropine</i> application (green) are quantified by their mean distance to the reference episode. The shift to more different waveforms was significantly more pronounced after gamma oscillations than in the other two experimental groups (p<0.05; ANOVA with post-hoc test between groups). <b>C</b>: similar to B but baseline SPWs are normalized to the median SPW-amplitude during baseline recording and SPWs from the second recording episode are normalized to the median amplitude during that recording period. Again, gamma-induced modulation in SPW-R waveforms significantly exceeds changes in ongoing SPW-R recordings and <i>atropine</i> control (p<0.05; ANOVA with post-hoc test between groups).</p

Potentiation of unit assemblies is reflected by plastic changes on the network level.

<p><b>A</b>: Increase of amplitudes was significantly stronger after an intermittent carbachol induced gamma state than after ongoing SPW-R-oscillations. However, the increase in amplitude was not significantly different from values derived from the <i>atropine</i> control (p<0.05, <i>CCh</i> vs. <i>SPW-R</i>: p<0.01, <i>CCh</i> vs. <i>atropine</i>: p>0.05, ANOVA with post-hoc test between groups). <b>C</b>: Population spike amplitude in CA1 str. pyramidale (upper panel) and the slope of field-EPSPs in CA1 str. radiatum (lower panel) are potentiated after gamma oscillations. Intakes depict representative waveforms before (black) and after gamma (red).</p

Different network states and corresponding unit activity can be analyzed in the in vitro model.

<p><b>A</b>: Schematics of recording conditions. Tetrode recordings are performed in the pyramidal cell layers of CA3 and CA1. During sharp wave-ripple oscillations (SPW-R), field potentials are generated by the recurrent network of CA3 (green) and transmitted via the Schaffer collaterals to selectively activate cell assemblies in CA1 (red). Examples of field potential waveforms are shown in the respective colors. <b>B</b>: Example traces of field potentials recorded in CA1 during SPW-R (left panel) and gamma oscillations (right panel). Raw field potential (upper trace) and the high pass filtered (0.5–10 kHz) potential in the four tetrode channels (lower traces). Filtering reveals high-frequency multiunit activity on SPW-R and gamma cycles. Firing of two individual units extracted by waveform analysis is highlighted in orange and blue. Time points of firing relative to the field potential are visualized by vertical ‘ticks’. The middle panel illustrates the detection criterion for unit events: horizontal histograms of all data points show largely normal distribution around zero. Events are detected if they exceed 4.5 times the standard deviation as indicated by the dashed red line. <b>C</b>: Wavelet spectrograms of the example traces from B. Sharp waves are superimposed by high-frequency ripple oscillations (∼200 Hz, left panel). The carbachol-induced gamma state consists of a continuous oscillation at ∼30 Hz.</p

Hippocampal units maintain coupling precision to the local field potential during alternating network states.

<p><b>A</b>: Local field potential recordings and single unit activity (symbolized by vertical ticks) in CA1 and CA3 during the three experimental steps of the <i>CCh</i> experiments: baseline recording (SPW 1, left panel) followed by carbachol-induced gamma oscillations (Gamma, middle panel) and re-established SPW by wash-in of atropine (SPW 2, right panel). Two representative units are indicated by colored ticks in each region. Note that the individual units could be observed in all three phases of the experiment. <b>B</b>: Event cross-correlograms of field-potentials and firing time points of the units depicted in A. During SPW 1 and SPW 2, unit firing is correlated to the ripple-oscillation troughs in CA1 (peak intervals at ∼5 ms, corresponding to ripple cycle length); during the gamma episode they are correlated to the local gamma oscillation troughs (peak intervals at ∼30 ms). <b>C</b>: Mean firing rates of units remain constant during gamma oscillations. <b>D</b>: Firing phases of units to ripple troughs remain stable after an intermittent episode of gamma oscillations. The ripple cycle is described by a circular scale of 360° and the ripple trough is set to 0°. Each unit's preferred firing phase angle to the ripple contributes as one data point. Mean angle of the sum of all units is represented by the red arrow. The length of the red arrow is proportional to the length of the vector corresponding to the mean angle.</p

Sudden cardiac death while waiting: do we need the wearable cardioverter-defibrillator?

International audienceSudden cardiac death (SCD) is the most frequent cause of cardiovascular death in industrialized nations. Patients with cardiomyopathy are at increased risk for SCD and may benefit from an implantable cardioverter-defibrillator (ICD). The risk of SCD is highest in the first months after myocardial infarction or first diagnosis of severe non-ischemic cardiomyopathy. On the other hand, left ventricular function may improve in a subset of patients to such an extent that an ICD might no longer be needed. To offer protection from a transient risk of SCD, the wearable cardioverter-defibrillator (WCD) is available. Results of the first randomized clinical trial investigating the role of the WCD after myocardial infarction were recently published. This review is intended to provide insight into data from the VEST trial, and to put these into perspective with studies and clinical experience. As a non-invasive, temporary therapy, the WCD may offer advantages over early ICD implantation. However, recent data demonstrate that patient compliance and education play a crucial role in this new concept of preventing SCD