Arrhythmic syncope: From diagnosis to management

Arrhythmia; Electrophysiological study; MyocardiopathyArítmia; Estudi electrofisiològic; MiocardiopatiaArritmia; Estudio electrofisiológico; MiocardiopatíaSyncope is a concerning symptom that affects a large proportion of patients. It can be related to a heterogeneous group of pathologies ranging from trivial causes to diseases with a high risk of sudden death. However, benign causes are the most frequent, and identifying high-risk patients with potentially severe etiologies is crucial to establish an accurate diagnosis, initiate effective therapy, and alter the prognosis. The term cardiac syncope refers to those episodes where the cause of the cerebral hypoperfusion is directly related to a cardiac disorder, while arrhythmic syncope is cardiac syncope specifically due to rhythm disorders. Indeed, arrhythmias are the most common cause of cardiac syncope. Both bradyarrhythmia and tachyarrhythmia can cause a sudden decrease in cardiac output and produce syncope. In this review, we summarized the main guidelines in the management of patients with syncope of presumed arrhythmic origin. Therefore, we presented a thorough approach to syncope work-up through different tests depending on the clinical characteristics of the patients, risk stratification, and the management of syncope in different scenarios such as structural heart disease and channelopathies

Clinical Indications for Therapeutic Cardiac Devices

Both technology and clinical indications have changed since the first cardiac devices. Choosing the right therapy, or abstaining from it, is the key to good clinical management. Pacemakers effectively reduce symptoms of bradycardia, prevent syncope in patients with sick sinus syndrome, and reduce mortality in high-degree atrioventricular block. Cardiac resynchronization therapy improves symptoms and survival in heart failure patients with reduced ejection fraction and ventricular dyssynchrony. Implantable cardioverter defibrillators terminate life-threatening ventricular arrhythmias and are indicated for the prevention of sudden cardiac death, either as secondary prevention in survivors of ventricular fibrillation or ventricular tachycardia with hemodynamic compromise or as primary prevention due to heart failure with reduced ejection fraction or other miscellaneous diseases. More recently, leadless pacemakers and subcutaneous implantable cardioverter defibrillators have been developed as alternatives in specific conditions

Clinical aspects of device-detected arrhythmias

INTRODUCTION Cardiac implantable electronic devices (CIEDs) enable continuous monitoring of the heart rhythm. CIEDs constitute a unique opportunity for detecting arrhythmias, as the duration of cardiac monitoring is of the utmost importance for the detection rate. The CIED population consists mostly of patients from older age categories where risk factors for atrial fibrillation (AF) are common. A dual-chamber device can detect and store episodes with a high atrial rate, i.e. atrial high-rate episodes (AHREs). AHREs confirmed to be AF, atrial flutter or focal atrial tachycardia are termed subclinical AF. Both terms refer to patients with no symptoms attributed to AF, with no previous diagnosis of clinical AF. These episodes of device-detected AF are associated with increased risk of ischaemic stroke, although the risk seems to be lower than in patients with documented clinical AF, and the benefit of oral anticoagulation (OAC) treatment in this population has not been established. Patients presenting with syncope represent a diagnostic challenge. Initial evaluation can provide the underlying mechanism in up to half of the patients. However, the mechanism remains unexplained in many patients, and long-term electrocardiogram (ECG) monitoring with an implantable loop recorder (ILR) enables ECG recording at the time of syncope recurrence, which can reveal the underlying mechanism. The aim of this thesis is to highlight different aspects of arrhythmias diagnosed with CIEDs, both from a diagnostic and a therapeutic point of view. More specifically, it aims to describe the incidence of subclinical AF/AHREs in a pacemaker population, along with its OAC treatment, and the incidence of ischaemic stroke and vascular dementia. In addition, it will explore the role of the baseline 12-lead ECG in predicting the syncope mechanism during ILR monitoring, and whether age and gender impact the evaluation before the implantation and subsequent diagnostic yield of the ILR. Finally, the thesis will test the hypothesis that patients with incident AF during inpatient care after coronary artery bypass graft (CABG) surgery often experience a relapse of AF within a year, with little chance of detection. METHODS AND RESULTS In study I, consecutive patients were enrolled who had been implanted with a dual-chamber device for the indication of sinus node disease or atrioventricular block/ bundle branch block between 2010 and 2014 in Halland County in Sweden. The incidence of subclinical AF/AHREs, ischaemic stroke, or vascular dementia, and the initiation of and/or any change of OAC treatment were recorded during follow-up. At inclusion, 271 patients had clinical/known AF, of which 80% (216/271) were on OAC treatment. Four hundred eleven patients had no history of AF, and of these 30% (125/411) were diagnosed with subclinical AF/AHREs during a mean follow-up of 38 months. 62% of these were prescribed OAC treatment. Patients with congestive heart failure (p= .03) and age >75 years (p= .0002) were more often diagnosed with subclinical AF/AHREs. The annual stroke incidence was 2.1% in patients with clinical/known AF, 1.9% in patients with subclinical AF/AHREs, and 1.4% in patients with no AF. Corresponding values for a diagnosis of vascular dementia was 11.2%, 5.6% (p= .09), and 6.2% (p= .048). The study population in studies II and III consisted of consecutive patients with unexplained syncope in Halland County in Sweden, who had been selected to be implanted with an ILR after an initial non-diagnostic evaluation between 2007 and 2016. In study II, baseline 12- lead ECG was compared with clinically adjudicated cause of syncope. In study III the role of age and gender in the evaluation before implantation, and in the diagnostic yield of the ILR, was reported. There is a notable difference between the two terms ILR-guided diagnosis (study II) and ECG-based diagnosis (study III). ILR-guided diagnosis refers to all patients where the ILR has informed the clinical diagnosis, i.e. where captured ECG recordings both during syncope recurrence or other times have enabled a clinical diagnosis to be made, while ECG-based diagnosis only includes patients with syncope recurrence. In total, 300 (147 women) patients were included. The mean age was 66±16 years. In study II, 49% (146/300) received an ILR-guided diagnosis. Bifascicular block was the second most common pathological baseline 12-lead ECG finding (n=33). It was most common in patients ≥60 years of age (31/33), and more common in patients who received an ILR-guided diagnosis (bifascicular block: 25/33, 76%; normal baseline 12-lead ECG: 90/205, 44%, p< .001). Among patients with bifascicular block, 96% (24/25) were clinically adjudicated to have an arrhythmia-caused syncope, and of these, 23 had ECG recordings of a bradyarrhythmia. Bifascicular block was a strong predictor of a clinically adjudicated arrhythmia-caused syncope, with an adjusted odds ratio of 5.5 (95%CI (confidence interval) 2.3-13.2), p< .001, and a positive predictive value of 73%. In the total population, bifascicular block predicted a clinically adjudicated arrhythmia-caused syncope due to bradyarrhythmia, with an adjusted odds ratio of 11.4 (95%CI 5.0-26.2), p< .001. In study III, women experienced syncope recurrence and received an ECG-based diagnosis more often than men (women: 56/147, 38%; men: 33/153, 22%; p= .001), mainly because of a higher incidence of non-arrhythmic syncope recurrence, i.e. syncope with a normal ECG recording (women: 27/147, 18%; men: 15/153, 10%; p= .045). Patients ≥60 years of age had the lowest rate of pre-implant tests (<40 years: 6.5±1.2; 40-59 years: 5.75±1.0; and ≥60 years: 5.1±1.9; p= .002) but the highest rate of arrhythmic syncope (<40 years: 3/11, 27%; 41-59 years: 7/18, 39%; and ≥60 years: 37/60, 62%; p= .045). Fifty patients with no recurrent syncope had ECG findings potentially indicative of recurrent syncope. Study IV was a sub-study of the prospective AFAF study (Atrial Fibrillation AFter CABG and percutaneous coronary intervention). In short, the AFAF study investigates the incidence of AF after percutaneous coronary intervention or CABG surgery by non-invasive handheld ECG recordings. It is investigated three times daily during the first postoperative month, and thereafter for two weeks at three, 12 and 24 months in addition to routine care. This sub-study added continuous ECG monitoring with an ILR. The primary endpoint was the proportion of patients with incident or recurrent AF during the 12-month monitoring period. The secondary endpoints were the proportion of patients who developed persistent AF and calculated AF burden. In total, 27/40 (68%) patients were diagnosed with incident AF, 21 in hospital and six later. Eighteen of these 27 (67%) also experienced AF recurrence, and three patients progressed into persistent AF. The incidence of AF episodes was highest during the first 30 postoperative days, as 17/40 patients had episodes of AF after discharge within this period. The rate of incident and recurrent AF after the first 30 days was low: three patients had incident AF and 10 patients recurrent AF. The CHA2DS2-VASc (Congestive heart failure, Hypertension, Age >75 years (2 points), Diabetes, Stroke (2 points), Vascular disease, Age 65-74 and Sex (female)) score was higher in patients with AF than in patients who remained in sinus rhythm: median 4 (IQR (interquartile range) 1) and median 3 (IQR 2) respectively, p= .006. In patients with paroxysmal AF, the AF burden was low: 0.1% (IQR 0.28). Handheld ECG identified fewer patients with AF after discharge than the ILR (handheld ECG: 9/20, 45%; ILR: 20/20, 100%; p= .001). CONCLUSIONS CIEDs are a valuable asset in arrhythmia diagnostics, and can inform clinical decisions. Subclinical AF/AHREs were common, and were associated with older age and congestive heart failure. The stroke incidence was low, but clinical/known AF was associated with an increased risk of vascular dementia. In syncope patients bifascicular block at baseline 12-lead ECG predicted a clinically adjudicated arrhythmia-caused syncope, commonly due to intermittent complete heart block. Women experienced syncope recurrence more often than men, especially for non-arrhythmic reasons. The highest rate of arrhythmic syncope and the lowest rate of pre-implant tests were found in patients ≥60 years of age. In patients treated with CABG surgery, the recurrence rate of AF was high in patients with incident AF during hospitalisation, especially during the first postoperative month. After the first month, the rate of incident and recurrent AF was low. The ILR was more effective in detecting patients with AF than handheld ECG

Converging Indicators for Assessing Individual Differences in Adaptation to Extreme Environments: Preliminary Report

This paper describes the development and validation of a new methodology for assessing the deleterious effects of spaceflight on crew health and performance. It is well known that microgravity results in various physiological alterations, e.g., headward fluid shifts which can impede physiological adaptation. Other factors that may affect crew operational efficiency include disruption of sleep-wake cycles, high workload, isolation, confinement, stress and fatigue. From an operational perspective, it is difficult to predict which individuals will be most or least affected in this unique environment given that most astronauts are first-time flyers. During future lunar and Mars missions space crews will include both men and women of multi-national origins, different professional backgrounds, and various states of physical condition. Therefore, new methods or technologies are needed to monitor and predict astronaut performance and health, and to evaluate the effects of various countermeasures on crew during long duration missions. This paper reviews several studies conducted in both laboratory and operational environments with men and women ranging in age between 18 to 50 years. The studies included the following: soldiers performing command and control functions during mobile operations in enclosed armored vehicles; subjects participating in laboratory tests of an anti-motion sickness medication; subjects exposed to chronic hypergravity aboard a centrifuge, and subject responses to 36-hours of sleep deprivation. Physiological measurements, performance metrics, and subjective self-reports were collected in each study. The results demonstrate that multivariate converging indicators provide a significantly more reliable method for assessing environmental effects on performance and health than any single indicator

Digital remote monitoring in adult congenital heart disease patients:Lessons learned and recommendations

In cardiology telemedicine is introduced for care for patients with heart failure and (possible) arrhythmia. mHealth telemonitoring might be a powerful tool for remote diagnosing and managing arrhythmias, heart failure and blood pressure. This thesis focuses on the question whether introducing digital remote patient monitoring (DRPM) by a dedicated mHealth program in the routine care management of adult congenital heart disease (ACHD) patients improves care for these patients.The project was funded with a successful crowdfunding campaign. Critical success factors contributing to this success are described. The crowdfunding campaign could have met the needs of donors, leading to enforcing of the public engagement. Appropriate patient selection for participation in mHealth contributes to an efficient use of mHealth and lower emergency care utilization. Results of a study to evaluate a mHealth telemonitoring program for managing arrhythmia, heart failure and blood pressure in symptomatic ACHD patients are presented. mHealth can be an acceptable alternative for ILR implantation in detecting arrhythmia in symptomatic ACHD patients in respect to diagnostic yield, safety and management decisions, especially in those without syncope.A narrative review is presented of scientific publications published regarding extended arrhythmia screening in ACHD patients. The number of studies found was limited. The studies found demonstrated a higher rate of arrhythmia and bradycardia detection leading to clinical care changes by extending the time of rhythm monitoring to more than 24 hours. Although several non-invasive diagnostic tools are, in symptomatic patients, a good alternative for ILRs, the optimal mode of detection is still unclear. Future directions for DRPM and key points for future DRPM research are given

Digital remote monitoring in adult congenital heart disease patients:Lessons learned and recommendations

In cardiology telemedicine is introduced for care for patients with heart failure and (possible) arrhythmia. mHealth telemonitoring might be a powerful tool for remote diagnosing and managing arrhythmias, heart failure and blood pressure. This thesis focuses on the question whether introducing digital remote patient monitoring (DRPM) by a dedicated mHealth program in the routine care management of adult congenital heart disease (ACHD) patients improves care for these patients.The project was funded with a successful crowdfunding campaign. Critical success factors contributing to this success are described. The crowdfunding campaign could have met the needs of donors, leading to enforcing of the public engagement. Appropriate patient selection for participation in mHealth contributes to an efficient use of mHealth and lower emergency care utilization. Results of a study to evaluate a mHealth telemonitoring program for managing arrhythmia, heart failure and blood pressure in symptomatic ACHD patients are presented. mHealth can be an acceptable alternative for ILR implantation in detecting arrhythmia in symptomatic ACHD patients in respect to diagnostic yield, safety and management decisions, especially in those without syncope.A narrative review is presented of scientific publications published regarding extended arrhythmia screening in ACHD patients. The number of studies found was limited. The studies found demonstrated a higher rate of arrhythmia and bradycardia detection leading to clinical care changes by extending the time of rhythm monitoring to more than 24 hours. Although several non-invasive diagnostic tools are, in symptomatic patients, a good alternative for ILRs, the optimal mode of detection is still unclear. Future directions for DRPM and key points for future DRPM research are given

Occupational Therapy Strategies for Postural Orthostatic Tachycardia Syndrome

Effectiveness of occupational therapy strategies with adults with postural orthostatic tachycardia syndrome

Distributed Computing and Monitoring Technologies for Older Patients

This book summarizes various approaches for the automatic detection of health threats to older patients at home living alone. The text begins by briefly describing those who would most benefit from healthcare supervision. The book then summarizes possible scenarios for monitoring an older patient at home, deriving the common functional requirements for monitoring technology. Next, the work identifies the state of the art of technological monitoring approaches that are practically applicable to geriatric patients. A survey is presented on a range of such interdisciplinary fields as smart homes, telemonitoring, ambient intelligence, ambient assisted living, gerontechnology, and aging-in-place technology. The book discusses relevant experimental studies, highlighting the application of sensor fusion, signal processing and machine learning techniques. Finally, the text discusses future challenges, offering a number of suggestions for further research directions

Advanced Signal Processing in Wearable Sensors for Health Monitoring

Smart, wearables devices on a miniature scale are becoming increasingly widely available, typically in the form of smart watches and other connected devices. Consequently, devices to assist in measurements such as electroencephalography (EEG), electrocardiogram (ECG), electromyography (EMG), blood pressure (BP), photoplethysmography (PPG), heart rhythm, respiration rate, apnoea, and motion detection are becoming more available, and play a significant role in healthcare monitoring. The industry is placing great emphasis on making these devices and technologies available on smart devices such as phones and watches. Such measurements are clinically and scientifically useful for real-time monitoring, long-term care, and diagnosis and therapeutic techniques. However, a pertaining issue is that recorded data are usually noisy, contain many artefacts, and are affected by external factors such as movements and physical conditions. In order to obtain accurate and meaningful indicators, the signal has to be processed and conditioned such that the measurements are accurate and free from noise and disturbances. In this context, many researchers have utilized recent technological advances in wearable sensors and signal processing to develop smart and accurate wearable devices for clinical applications. The processing and analysis of physiological signals is a key issue for these smart wearable devices. Consequently, ongoing work in this field of study includes research on filtration, quality checking, signal transformation and decomposition, feature extraction and, most recently, machine learning-based methods

Diagnostic Challenges in Sports Cardiology

The foundations of sports cardiology include promoting physical activity and providing a safe environment for training and competition for all athletes at all levels, from professional to recreational. To combine these two aims, reliable tools to perform preparticipation screenings are needed. Moreover, those at high risk of potentially life-threatening events should be advised to limit their training load, while others should be reassured that there is no exercise-related cardiovascular risk. We are currently witnessing the advent of new portable devices for remote and mobile heart monitoring and several new and promising biochemical markers, which can support athletes’ diagnostic processes. In this Special Issue of the Diagnostics journal entitled “Diagnostic Challenges in Sports Cardiology”, we present a series of 13 manuscripts, including eight original works, three reviews, and two case reports, which give a glimpse into the current research topics in the area of sports cardiology