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APPLICAZIONE DI METODI BIOSTATISTICI AVANZATI NELLA RICERCA SULLA GESTIONE DEL RITMO CARDIACO
No full textCardiac rhythm management (CRM) is a field in cardiology dedicated to the treatment of cardiac arrhythmia-related diseases. Specifically, the implantable cardioverter defibrillator (ICD) is a device implanted in patients at high risk of ventricular arrhythmias for preventing sudden cardiac death. Despite the numerous observational and randomized clinical trials conducted over recent decades, a persistent need exists for enhancing stratification models aimed at preventing and managing arrhythmias. The availability of new statistical and data science techniques has the potential to improve clinical knowledge in this field, yet their application and awareness remain limited. The primary objective of this dissertation is to implement advanced statistical methodologies to address unanswered questions in CRM and to provide clinicians with evidence-based statistical models applicable in clinical practice.
In the first part, we address the safety of ICDs by establishing evidence-based standards for estimating the reliability of ICD leads. The endocardial lead, which connects to the device and is used to deliver electrical therapies, remains a vulnerable component. We conduct a systematic review of observational studies and employ an innovative iterative method to perform a meta-analysis of survival data, effectively reconstructing individual patient data from published Kaplan-Meier curves.
Subsequently, we delve into the practice of catheter ablation for ventricular arrhythmias in patients subjected to multiple ICD shocks. The contribution focuses on the prognostic effect of early ablation after the first shock. By implementing a Bayesian adaptive design, the first planned interim analysis enables an anticipated confirmation of success for a randomized trial by demonstrating the superiority of the experimental treatment (early ablation) over standard therapy.
We further investigate potential sex-related differences in ICD effectiveness. Addressing this question through randomized trials presents ethical and practical challenges. Propensity-score matching is employed to control pre-specified confounding variables, thereby producing unbiased estimates from observational data of arrhythmic risk for both women and men.
The last part of the thesis explores machine learning techniques, with a particular emphasis on Classification and Regression Tree algorithms. The practical application demonstrated the effectiveness of this approach in predicting ICD shock based on various patient characteristics. The resulting model is interpretable and exhibits promising applicability for risk stratification in clinical practice
Subclinical Atrial Tachyarrhythmias:Implantable Devices and Remote Monitoring
No full textAtrial fibrillation (AF) and Atrial Tachyarrhythmias (AT) are the most common clinical arrhythmias and their worst issue is a well-recognized correlation with ischemic stroke. High incidence of "subclinical" AF/ATs has been demonstrated in several trials (TRENDS, ASSERT, CRYSTAL AF, EMBRACE) in patients with both cardiac implantable electronic devices (CIEDS) and external loop recorders. Moreover, a relationship between device-detected AF/ATs and stroke risk has been observed in the same studies. However, while the net clinical benefit of the antithrombotic treatment is well established in patients with "clinical" atrial fibrillation, there may be a lower benefit in patients with device-detected arrhythmias. Subclinical AF/ATs may be considered as a marker of stroke risk rather than the proximate cause and their burden may be used in combination with CHA2DS2-VASC and HAS-BLED scores to identify high-risk population who deserves anticoagulation. Today the remote monitoring associated with the CIEDs is effective in the early detecting of AF/ATs by avoiding delays in the therapy evaluation, as demonstrated by several trials (TRUST, CONNECT, COMPAS). However clinical evidence for stroke risk reduction by remote monitoring is still awaited; the recent trial IMPACT failed to demonstrate that the handling of the anticoagulation therapy guided by device-detected ATs and remote monitoring improves the patients' outcome. The challenges for clinicians are to deal with the huge data entry, to define new organizational models, to improve device patient management and to continuously update AF guidelines in according to the great amount of data offered by the new technology
Closed loop stimulation with His bundle lead placement
No full textClosed-loop stimulation (CLS; BIOTRONIK SE & Co. KG, Berlin, Germany) is a rate-responsive algorithm that analyzes intracardiac impedance trends using a standard lead placed in the right ventricle. It is unknown whether CLS could perform adequately with His bundle (HB) lead placement, as contractility dynamics may be attenuated in this region compared to the right ventricle apex. We performed hand-grip, mental, and bicycle exercise tests in a patient with brady atrial fibrillation and permanent HB pacing. The CLS algorithm responded with an appropriate heart rate to mental and physical tests. LEARNING OBJECTIVE: A combination of permanent His bundle and closed-loop stimulation-driven pacing may be a valid and physiological option for atrial fibrillation patients with chronotropic incompetence
Recording of Brugada electrocardiogram pattern by an implantable cardiac monitor
No full textA 51-year-old man with Brugada syndrome (BrS) electrocardiogram (ECG) type I pattern underwent implantable cardiac monitor (ICM) insertion. After pre-insertion potential mapping, we could observe the patient-specific repolarization abnormalities on the subcutaneous ECG provided by the ICM. A few weeks later, we received remotely a device recording with a higher ST-segment elevation and a longer duration of the interval between the onset of the coved elevation and its termination at the isoelectric line. Our observation supports the conceptual premise that ICM could add information on quantifying the amount of time with abnormal ECG patterns rather than only for the diagnosis of cardiac arrhythmias
Temporal relationship between haemodynamic changes and activation of closed-loop stimulation during a tilt-induced vasovagal syncope
No full textAims A dual-chamber pacemaker with closed-loop stimulation (CLS) mode is effective in reducing syncopal recurrences in patients with asystolic vasovagal syncope (VVS). In this study, we explored the haemodynamic and temporal relationship of CLS during a tilt-induced vasovagal reflex.Methods and results Twenty patients underwent a tilt test under video recording 3.9 years after CLS pacemaker implantation. Three patients were excluded from the analysis because of no VVS induced by the tilt test (n = 1) and protocol violation (n = 2). In 14 of the remaining 17 patients, CLS pacing emerged during the pre-syncopal phase of circulatory instability when the mean intrinsic heart rate (HR) was 88 +/- 12 b.p.m. and systolic blood pressure (SBP) was 108 +/- 19 mmHg. The CLS pacing rate thereafter rapidly increased to 105 +/- 14 b.p.m. within a median of 0.1 min [inter-quartile range (IQR), 0.1-0.7 min] when the SBP was 99 +/- 21 mmHg. At the time of maximum vasovagal effect (syncope or pre-syncope), SBP was 63 +/- 17 mmHg and the CLS rate was 95 +/- 13 b.p.m. The onset of CLS pacing was 1.7 min (IQR, 1.5-3.4) before syncope or lowest SBP. The total duration of CLS pacing was 5.0 min (IQR, 3.3-8.3). Closed-loop stimulation pacing was not observed in three patients who had a similar SBP decrease from 142 +/- 22 mmHg at baseline to 69 +/- 4 mmHg at the time of maximum vasovagal effect, but there was no significant increase in HR (59 +/- 1 b.p.m.).Conclusion The reproducibility of a vasovagal reflex was high. High-rate CLS pacing was observed early during the pre-syncopal phase in most patients and persisted, although attenuated, at the time of maximum vasovagal effect.Registration ClinicalTrials.gov identifier: NCT06038708Graphical Abstrac
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Predicting worsening heart failure hospitalizations in patients with implantable cardioverter defibrillators: Is it all about alerts? A pooled analysis of nine trials
Full text linkBackground and aims: To predict worsening heart failure hospitalizations (WHFH) in patients with implantable defibrillators and remote monitoring (RM), the HeartInsight algorithm (Biotronik, Berlin, Germany) calculates a heart failure (HF) score combining seven physiologic parameters: 24-hour heart rate (HR), nocturnal HR, HR variability, atrial tachyarrhythmia, ventricular extrasystoles, patient activity, and thoracic impedance. We compared temporal trends of the HF score and its components 12 weeks before a WHFH with 12-week trends in patients without WHFH, to assess whether trends indicate deteriorating HF regardless of alert status. Methods: Data from nine clinical trials were pooled, including 2,050 patients with a defibrillator capable of atrial sensing, ejection fraction ≤ 35%, NYHA class II/III, no long-standing atrial fibrillation, and 369 WHFH from 259 patients. Results: The mean HF score was higher in the WHFH group than in the no WHFH group (42.3 ± 26.1 versus 30.7 ± 20.6, p < 0.001) already at the beginning of 12 weeks. The mean HF score further increased to 51.6 ± 26.8 until WHFH (+22% versus no WHFH group, p = 0.003). As compared to the no WHFH group, the algorithm components either were already higher 12 weeks before WHFH (24 h HR, HR variability, thoracic impedance) or significantly increased until WHFH (nocturnal HR, atrial tachyarrhythmia, ventricular extrasystoles, patient activity). Conclusion: The HF score was significantly higher at, and further increased during 12 weeks before WHFH, as compared to the no WHFH group, with seven components showing different behavior and contribution. Temporal trends of HF score may serve as a quantitative estimate of HF condition and evolution prior to WHFH
Remote assessment of QT interval: A new perspective for implantable cardiac monitors
No full textThere is an unmet need for simple tools for monitoring QT intervals. The feasibility of measuring the QT interval on the single‐lead subcutaneous electrocardiogram (subECG) recorded and transmitted by implantable cardiac monitors (ICMs) has never been tested
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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