Asystole on loop recorder in patients with unexplained syncope and negative tilt testing: age distribution and clinical predictors.

BACKGROUND: Approximately 50% of patients with unexplained syncope and negative head-up tilt test (HUTT) who have an electrocardiogram (ECG) documentation of spontaneous syncope during implantable loop recorder (ILR) show an asystolic pause at the time of the event. OBJECTIVE: The aim of the study was to evaluate the age distribution and clinical predictors of asystolic syncope detected by ILR in patients with unexplained syncope and negative HUTT. METHODS: This research employed a retrospective, single-center study of consecutive patients. The ILR-documented spontaneous syncope was classified according to the International Study on Syncope of Uncertain Etiology (ISSUE) classification. RESULTS: Among 113 patients (54.0 ± 19.6 years; 46% male), 49 had an ECG-documented recurrence of syncope during the observation period and 28 of these later (24.8%, corresponding to 57.1% of the patients with a diagnostic event) had a diagnosis of asystolic syncope at ILR: type 1A was present in 24 (85.7%), type 1B in 1 (3.6%), and type 1C in 3 (10.7%) patients. The age distribution of asystolic syncope was bimodal, with a peak at age < 19 years and a second peak at the age of 60-79 years. At Cox multivariable analysis, syncope without prodromes (OR 3.7; p = 0.0008) and use of beta blockers (OR 3.2; p = 0.002) were independently associated to ILR-detected asystole. CONCLUSIONS: In patients with unexplained syncope and negative HUTT, the age distribution of asystolic syncope detected by ILR is bimodal, suggesting a different mechanism responsible for asystole in both younger and older patients. The absence of prodromes and the use of beta blockers are independent predictors of ILR-detected asystole.

Noninvasive electrocardiographic risk factors for sudden cardiac death in dilated ca rdiomyopathy: is ambulatory electrocardiography still relevant?

Risk stratification for sudden cardiac death in dilated cardiomyopathy is a field of constant debate, and the currently proposed criteria have been widely questioned due to their low positive and negative predictive value. In this study, we conducted a systematic review of the literature utilizing the PubMed and Cochrane library platforms, in order to gain insight about dilated cardiomyopathy and its arrhythmic risk stratification utilizing noninvasive risk markers derived mainly from 24 h electrocardiographic monitoring. The obtained articles were reviewed in order to register the various electrocardiographic noninvasive risk factors used, their prevalence, and their prognostic significance in dilated cardiomyopathy. Premature ventricular complexes, nonsustained ventricular tachycardia, late potentials on Signal averaged electrocardiography, T wave alternans, heart rate variability and deceleration capacity of the heart rate, all have both some positive and negative predictive value to identify patients in higher likelihood for ventricular arrhythmias and sudden cardiac death. Corrected QT, QT dispersion, and turbulence slope-turbulence onset of heart rate have yet to establish a predictive correlation in the literature. Although ambulatory electrocardiographic monitoring is frequently used in clinical practice in DCM patients, no single risk marker can be used for the selection of patients at high-risk for malignant ventricular arrhythmic events and sudden cardiac death who could benefit from the implantation of a defibrillator. More studies are needed in order to establish a risk score or a combination of risk factors with the purpose of selecting high-risk patients for ICD implantation in the context of primary prevention.

Cryptogenic stroke as a working diagnosis: the need for an early and comprehensive diagnostic work-up.

In the Nordic Atrial Fibrillation and Stroke (NOR-FIB) study, the causes of ischemic stroke were identified in 43% of cryptogenic stroke patients monitored with implantable cardiac monitor (ICM), but one-third of these patients had non-cardioembolic causes. These results suggest the need for an early and comprehensive diagnostic work-up before inserting an ICM.

Underlying causes of cryptogenic stroke and TIA in the nordic atrial fibrillation and stroke (NOR-FIB) study - the importance of comprehensive clinical evaluation.

BACKGROUND: Cryptogenic stroke is a heterogeneous condition, with a wide spectrum of possible underlying causes for which the optimal secondary prevention may differ substantially. Attempting a correct etiological diagnosis to reduce the stroke recurrence should be the fundamental goal of modern stroke management. METHODS: Prospective observational international multicenter study of cryptogenic stroke and cryptogenic transient ischemic attack (TIA) patients clinically monitored for 12 months to assign the underlying etiology. For atrial fibrillation (AF) detection continuous cardiac rhythm monitoring with insertable cardiac monitor (Reveal LINQ, Medtronic) was performed. The 12-month follow-up data for 250 of 259 initially included NOR-FIB patients were available for analysis. RESULTS: After 12 months follow-up probable stroke causes were revealed in 43% patients, while 57% still remained cryptogenic. AF and atrial flutter was most prevalent (29%). In 14% patients other possible causes were revealed (small vessel disease, large-artery atherosclerosis, hypercoagulable states, other cardioembolism). Patients remaining cryptogenic were younger (p < 0.001), had lower CHA2DS2-VASc score (p < 0.001) on admission, and lower NIHSS score (p = 0.031) and mRS (p = 0.016) at discharge. Smoking was more prevalent in patients that were still cryptogenic (p = 0.014), while dyslipidaemia was less prevalent (p = 0.044). Stroke recurrence rate was higher in the cryptogenic group compared to the group where the etiology was revealed, 7.7% vs. 2.8%, (p = 0.091). CONCLUSION: Cryptogenic stroke often indicates the inability to identify the cause in the acute phase and should be considered as a working diagnosis until efforts of diagnostic work up succeed in identifying a specific underlying etiology. Timeframe of 6-12-month follow-up may be considered as optimal. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02937077, EudraCT 2018-002298-23.

The evidence for the implantable loop recorder in patients with inherited arrhythmia syndromes: a review of the literature.

Risk stratification of patients with inherited arrhythmia syndromes (IASs) can be challenging. Recent guidelines acknowledge a place for considering the implantable loop recorder (ILR) to outrule malignant arrhythmia as a cause of syncope in certain inherited arrhythmia patients who are at low risk of sudden cardiac death. In this comprehensive literature review, we evaluate the available evidence for the use of the ILR in the IASs and in relatives of victims of sudden arrhythmic death syndrome.

A Study of Spectrum of Cardiac Rhythm Disturbance after Acute Ischemic Stroke Using 24 Hours Holter Monitoring.

Studies have reported that acute stroke leads to imbalance of central autonomic control; stroke can cause over activity of sympathetic or parasympathetic control, myocardial injury, ECG abnormalities, cardiac arrhythmias and even sudden death. Studies support the notion that patients with acute cerebrovascular events are susceptible to cardiac arrhythmias. MATERIAL: This cross Sectional Study was conducted in over a period of One and half year duration and included subjects of acute ischemic stroke confirmed by brain imaging. After performing a 12 lead ECG in emergency ward, all eligible stroke patients were subjected to 24 hour Holter monitoring. OBSERVATION: Out of 92 stroke patients, 35.28% had abnormal ECG. Changes included LVH in 10.87%, T wave inversion in 9.78%, ST segment depression in4.35%% followed by QTc prolongation 3.26% .24 hours Holter monitoring revealed that common cardiac rhythm disturbances were ventricular ectopics (44.57%) supraventricular ectopics (30.43%), supraventricular tachycardia (11.96%), atrial fibrillation (7.60%). Amongst brady-arrhythmias sinus pause was detected in 1.09%. CONCLUSION: ECG changes occur commonly in case of acute ischemic stroke, even in those having no history of coronary heart disease as suggested clinically. Identification of paroxysmal Atrial Fibrilation episodes is important due to its relevance for planning of long-term treatment.

Effect of Long-term Continuous Cardiac Monitoring vs Usual Care on Detection of Atrial Fibrillation in Patients With Stroke Attributed to Large- or Small-Vessel Disease: The STROKE-AF Randomized Clinical Trial.

Importance: Patients with ischemic stroke attributed to large- or small-vessel disease are not considered at high risk for atrial fibrillation (AF), and the AF incidence rate in this population is unknown. Objectives: To determine whether long-term cardiac monitoring is more effective than usual care for AF detection in patients with stroke attributed to large- or small-vessel disease through 12 months of follow-up. Design, Setting, and Participants: The STROKE-AF trial was a randomized (1:1), multicenter (33 sites in the US) clinical trial that enrolled 496 patients between April 2016 and July 2019, with primary end point follow-up through August 2020. Eligible patients were aged 60 years or older or aged 50 to 59 years with at least 1 additional stroke risk factor and had an index stroke attributed to large- or small-vessel disease within 10 days prior to insertable cardiac monitor (ICM) insertion. Interventions: Patients randomized to the intervention group (n = 242) received ICM insertion within 10 days of the index stroke; patients in the control group (n = 250) received site-specific usual care consisting of external cardiac monitoring, such as 12-lead electrocardiograms, Holter monitoring, telemetry, or event recorders. Main Outcomes and Measures: Incident AF lasting more than 30 seconds through 12 months. Results: Among 492 patients who were randomized (mean [SD] age, 67.1 [9.4] years; 185 [37.6%] women), 417 (84.8%) completed 12 months of follow-up. The median (interquartile range) CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke or transient ischemic attack, vascular disease, age 65 to 74 years, sex category) score was 5 (4-6). AF detection at 12 months was significantly higher in the ICM group vs the control group (27 patients [12.1%] vs 4 patients [1.8%]; hazard ratio, 7.4 [95% CI, 2.6-21.3]; P < .001). Among the 221 patients in the ICM group who received an ICM, 4 (1.8%) had ICM procedure-related adverse events (1 site infection, 2 incision site hemorrhages, and 1 implant site pain). Conclusions and Relevance: Among patients with stroke attributed to large- or small-vessel disease, monitoring with an ICM compared with usual care detected significantly more AF over 12 months. However, further research is needed to understand whether identifying AF in these patients is of clinical importance. Trial Registration: ClinicalTrials.gov Identifier: NCT02700945.

Effect of Implantable vs Prolonged External Electrocardiographic Monitoring on Atrial Fibrillation Detection in Patients With Ischemic Stroke: The PER DIEM Randomized Clinical Trial.

Importance: The relative rates of detection of atrial fibrillation (AF) or atrial flutter from evaluating patients with prolonged electrocardiographic monitoring with an external loop recorder or implantable loop recorder after an ischemic stroke are unknown. Objective: To determine, in patients with a recent ischemic stroke, whether 12 months of implantable loop recorder monitoring detects more occurrences of AF compared with conventional external loop recorder monitoring for 30 days. Design, Setting, and Participants: Investigator-initiated, open-label, randomized clinical trial conducted at 2 university hospitals and 1 community hospital in Alberta, Canada, including 300 patients within 6 months of ischemic stroke and without known AF from May 2015 through November 2017; final follow-up was in December 2018. Interventions: Participants were randomly assigned 1:1 to prolonged electrocardiographic monitoring with either an implantable loop recorder (n = 150) or an external loop recorder (n = 150) with follow-up visits at 30 days, 6 months, and 12 months. Main Outcomes and Measures: The primary outcome was the development of definite AF or highly probable AF (adjudicated new AF lasting ≥2 minutes within 12 months of randomization). There were 8 prespecified secondary outcomes including time to event analysis of new AF, recurrent ischemic stroke, intracerebral hemorrhage, death, and device-related serious adverse events within 12 months. Results: Among the 300 patients who were randomized (median age, 64.1 years [interquartile range, 56.1 to 73.7 years]; 121 were women [40.3%]; and 66.3% had a stroke of undetermined etiology with a median CHA2DS2-VASc [congestive heart failure, hypertension, age ≥75 years, diabetes, stroke or transient ischemic attack, vascular disease, age 65 to 74 years, sex category] score of 4 [interquartile range, 3 to 5]), 273 (91.0%) completed cardiac monitoring lasting 24 hours or longer and 259 (86.3%) completed both the assigned monitoring and 12-month follow-up visit. The primary outcome was observed in 15.3% (23/150) of patients in the implantable loop recorder group and 4.7% (7/150) of patients in the external loop recorder group (between-group difference, 10.7% [95% CI, 4.0% to 17.3%]; risk ratio, 3.29 [95% CI, 1.45 to 7.42]; P = .003). Of the 8 specified secondary outcomes, 6 were not significantly different. There were 5 patients (3.3%) in the implantable loop recorder group who had recurrent ischemic stroke vs 8 patients (5.3%) in the external loop recorder group (between-group difference, -2.0% [95% CI, -6.6% to 2.6%]), 1 (0.7%) vs 1 (0.7%), respectively, who had intracerebral hemorrhage (between-group difference, 0% [95% CI, -1.8% to 1.8%]), 3 (2.0%) vs 3 (2.0%) who died (between-group difference, 0% [95% CI, -3.2% to 3.2%]), and 1 (0.7%) vs 0 (0%) who had device-related serious adverse events. Conclusions and Relevance: Among patients with ischemic stroke and no prior evidence of AF, implantable electrocardiographic monitoring for 12 months, compared with prolonged external monitoring for 30 days, resulted in a significantly greater proportion of patients with AF detected over 12 months. Further research is needed to compare clinical outcomes associated with these monitoring strategies and relative cost-effectiveness. Trial Registration: ClinicalTrials.gov Identifier: NCT02428140.

Role of insertable cardiac monitors in anticoagulation therapy in patients with atrial fibrillation at high risk of bleeding.

AIMS: We aimed to ascertain whether an insertable cardiac monitor (ICM)-guided rhythm-control strategy and assessment of atrial fibrillation (AF) burden may allow safe withdrawal and obviate long-term use of oral anticoagulants (OACs) in AF patients at high bleeding risk. METHODS AND RESULTS: We implanted ICMs in 70 patients with AF with high risk of stroke (CHADS2 ≥2, CHA2DS2-VASc score ≥2) and bleeding (HAS-BLED score ≥3) after restoration of normal sinus rhythm (NSR) for continuous rhythm monitoring and optimization of antiarrhythmic drugs (AADs) when necessary. Patients were categorized into: (i) Group A (NSR/low AF burden, <1%), (ii) Group B (moderate/variable AF burden), and (iii) Group C (high AF burden, always AF). At patients' insistence, OACs were discontinued after proper counselling only if they maintained NSR/low AF burden for ≥3 consecutive months. All patients (age 73.3 ± 11.7 years; 53% male) were followed clinically and with ICM monitoring for 23.5 ± 10.5 months for outcomes including stroke, bleeding, death, device malfunction or infection, and AADs' adverse effects. Patients in Group A (n = 43), Group B (n = 20), and Group C (n = 7) had similar CHADS2 (2.09 ± 0.65, 2.05 ± 0.51, and 2.14 ± 0.38, respectively), CHA2DS2-VASc (3.05 ± 1.05, 2.85 ± 0.99, and 2.42 ± 0.53, respectively), and HAS-BLED (3.02 ± 1.01, 3.40 ± 0.68, and 3.00 ± 0.58, respectively) scores (P > 0.05). In 53 (76%) patients (Group A = 41 and Group B = 12) who maintained NSR/low AF burden, OACs were discontinued without adverse events. Severe bleeding occurred in 4 of 17 (24%) patients who remained on OACs. CONCLUSION: In AF patients with high bleeding risk, ICM-guided rhythm control with AADs and assessment of AF burden may allow safe discontinuation of OACs.

Bradycardia risk stratification with implantable loop recorder after unexplained syncope.

BACKGROUND: An implantable loop recorder is an effective tool for diagnosing unexplained syncope. However, after a first episode in non-high-risk patients, the usefulness of implantable loop recorder implantation remains unclear. AIMS: To analyse relevant risk factors for significant bradycardia in order to identify patients who do or do not benefit from implantable loop recorder implantation. Also, to study whether implantable loop recorder implantation with remote monitoring is associated with less recurrence of traumatic syncope. METHODS: This was a retrospective monocentric study including patients with implantable loop recorder implantation after unexplained syncope, using remote monitoring and iterative consultations. RESULTS: Two hundred and thirty-seven patients were implanted for unexplained syncope. Significant bradycardia occurred in 53 patients (22.4%): 23 (43.4%) caused by paroxysmal atrioventricular block and 30 (56.6%) caused by sinus node dysfunction, leading to permanent pacemaker implantation in 48 patients. Compared with younger patients, there was a 3.46-fold increase (95% confidence interval 1.92-6.23; P<0.0001) in the risk of significant bradycardia in patients aged≥60 years. Based on multivariable analysis, only "typical syncope" was associated with significant bradycardia occurrence (hazard ratio 3.14, 95% confidence interval 1.75-5.65; P=0.0001). There was no recurrence of significant bradycardia with traumatic complications among patients implanted for traumatic syncope. CONCLUSIONS: This study shows that: (1) implantable loop recorders identify more significant bradycardia in patients aged≥60 presenting with a first non-high-risk typical syncope, suggesting that an implantable loop recorder should be implanted after a first episode of unexplained syncope in such conditions; and (2) after traumatic syncope, implantable loop recorder implantation is safe, and is associated with little or no recurrence of traumatic syncope.

ICD function and dysfunction in patients with arrhythmogenic cardiac diseases: the role of home monitoring.

BACKGROUND: Since their implementation in clinical practice, remote home monitoring systems (HM) have undoubtedly become an added value in patients with implantable devices for cardiac rhythm management. The aim of this study was to investigate the impact of HM on clinical management and outcome in patients with channelopathies and other arrhythmogenic diseases who received an implantable cardioverter defibrillator (ICD). METHODS: Fifty-four patients (age 6 months--74 years) were followed by means of HM in our ICD clinic. Alerts and/or device-related clinical events were analysed in all patients and subsequent clinical decisions were made if indicated. RESULTS: During an average observation time of 27 months, 46 alerts were received from 32 different patients. Five patients (9%) received appropriate therapies for life-threatening arrhythmias and four patients (8%) inappropriate therapies because ofT wave oversensing or supraventricular tachycardias. Three patients had alerts due to electrical noise (two on the atrial, one on the ventricular channel). Overall, 18 alerts (39%) required a modification of the pharmacological therapy or the programming of the device. Mean anticipation of clinical visits based on the alerts was 92.6 +/- 56 days (median 97, interquartile range 50-150). CONCLUSION: HM substantially improves the clinical management of patients with cardiac arrhythmogenic disease by early recognition of device-related inappropriate therapies and subsequent anticipation of treatment adaptation.

Obstetric and fetal/neonatal outcomes in pregnant women with frequent premature ventricular complexes and structurally normal heart.

BACKGROUND: High premature ventricular complex (PVC) burden may increase the risk of left ventricular dysfunction and all-cause mortality. We aimed to evaluate maternal and neonatal outcomes of pregnant women with structurally normal heart having PVC burden ≥1%. METHODS: This retrospective cohort study used data from Chang Gung Research Database. Pregnancies from January 1, 2005, through June 30, 2020, with documented maternal PVC burden ≥1% by 24-h Holter monitor were identified. Pregnant women with a diagnosis of structural heart disease or arrhythmias other than PVC were excluded. We used propensity score matching (PSM) to balance the covariates between the PVC group and normal control group. The PVC group was classified into low-PVC (<10%) and high-PVC burden subgroups. The maternal and neonatal outcomes were assessed through 6 months after delivery or termination. RESULTS: After PSM, there were 214, 61, and 46 pregnant women enrolled in the normal control group, low-PVC burden, and high-PVC burden subgroups, respectively. The high-PVC and low-PVC burden subgroups had composite adverse maternal and neonatal events similar to the control group without use of antiarrhythmic drugs (AADs), but a higher proportion of placental abruption was observed in the high-PVC burden subgroup. Maternal age, diabetes, and overweight were significant predictors of composite adverse maternal events, whereas only maternal age was a significant predictor of composite adverse neonatal events. CONCLUSIONS: High PVC burden was not associated with poor composite adverse maternal and neonatal outcomes with no need of AADs therapy in pregnant women with structurally normal heart.

[Use of the insertable Holter with remote detection in the etiological diagnosis of cryptogenic stroke: Analysis of 73 patients]. / Utilidad del Holter insertable con detección remota en el diagnóstico etiológico del ictus criptogénico: análisis de 73 pacientes.

INTRODUCTION: Cryptogenic stroke constitutes 25% of all ischemic strokes, of which 20-30% are due to atrial fibrillation (AF). With the aim of increasing the detection rate, implantable long-term monitoring devices have emerged. The study of the profile of the ideal candidate subsidiary to such monitoring would provide a better understanding of the mechanisms underlying this subtype of stroke. OBJECTIVE: To determine which variables are related and can predict the detection of silent AF in patients with cryptogenic stroke. PATIENTS AND METHODS: This is a longitudinal cohort with recruitment from March 2017 to May 2022. They are patients with an implantable monitoring device and cryptogenic stroke with a minimum monitoring of one year. RESULTS: The total number of patients included was 73, with a mean age of 58.8 years, 56.2% were male. AF was detected in 21 patients (28.8%). The most frequent cardiovascular risk factors were hypertension (47.9%) and dyslipidemia (45.2%). The most frequent topography was cortical (52%). Regarding the echocardiographic parameters, 22% had a dilated left atrium, 19% had a patent foramen ovale, and 22% had high-density supraventricular tachycardia (>1%) on Holter monitoring. In the multivariate analysis, the only variable that predicts AF is the presence of high-density supraventricular tachycardia, with an area under the curve of 0.726 (CI 0.57-0.87, p=0.04), sensitivity of 47.6%, specificity of 97.5%, positive predictive value of 90.9%, negative predictive value of 78.8%, and accuracy of 80.9%. CONCLUSIONS: The presence of high-density supraventricular tachycardia can be indicative for predicting silent AF. No other variables have been observed that allow us to predict detection of AF in these patients.

14-day Holter monitoring for atrial fibrillation after ischemic stroke: The yield of guideline-recommended monitoring duration.

Introduction: Current European Stroke Organisation (ESO) guidelines recommend >48 h of continuous electrocardiographic monitoring for atrial fibrillation (AF) in all patients with ischemic stroke or transient ischemic attack (TIA) with undetermined origin. We assessed the yield of the guideline-recommended monitoring for AF, as well as of extending monitoring up to 14 days. Patients and methods: We included consecutive patients with stroke/TIA without AF in an academic hospital in The Netherlands. We reported AF incidence and number needed to screen (NNS) in the overall sample after 48 h and 14 days of Holter monitoring. Results: Among 379 patients with median age 63 years (IQR 55-73), 58% male, Holter monitoring detected 10 cases of incident AF during a median of 13 (IQR 12-14) days of monitoring. Seven AF cases were detected within the first 48 hours (incidence 1.85%, 95% CI 0.74-3.81; NNS 54), and three additional AF cases were recorded among the 362 patients with >48 h of monitoring and without AF ⩽ 48 h (incidence 0.83%, 95% CI: 0.17-2.42; NNS 121). All AF cases were detected within the first 7 days of monitoring. Our sample was subject to sampling bias favoring inclusion of participants with low AF risk. Discussion: Strengths of this work were the broad inclusion criteria as recommended by ESO guidelines, and high Holter adherence among participants. The analysis was limited by inclusion of lower-risk cases and a relatively small sample size. Conclusion: In low-risk patients with recent stroke or TIA, ESO guideline-recommended screening for AF resulted in a low AF yield, with limited additional value of monitoring up to 14 days. Our results underline the need for a personalized approach in determining a patient's optimum duration for post-stroke non-invasive ambulatory monitoring.

Atrial fibrillation in cryptogenic stroke and TIA patients in The Nordic Atrial Fibrillation and Stroke (NOR-FIB) Study: Main results.

Introduction: Secondary stroke prevention depends on proper identification of the underlying etiology and initiation of optimal treatment after the index event. The aim of the NOR-FIB study was to detect and quantify underlying atrial fibrillation (AF) in patients with cryptogenic stroke (CS) or transient ischaemic attack (TIA) using insertable cardiac monitor (ICM), to optimise secondary prevention, and to test the feasibility of ICM usage for stroke physicians. Patients and methods: Prospective observational international multicenter real-life study of CS and TIA patients monitored for 12 months with ICM (Reveal LINQ) for AF detection. Results: ICM insertion was performed in 91.5% by stroke physicians, within median 9 days after index event. Paroxysmal AF was diagnosed in 74 out of 259 patients (28.6%), detected early after ICM insertion (mean 48 ± 52 days) in 86.5% of patients. AF patients were older (72.6 vs 62.2; p < 0.001), had higher pre-stroke CHA2DS2-VASc score (median 3 vs 2; p < 0.001) and admission NIHSS (median 2 vs 1; p = 0.001); and more often hypertension (p = 0.045) and dyslipidaemia (p = 0.005) than non-AF patients. The arrhythmia was recurrent in 91.9% and asymptomatic in 93.2%. At 12-month follow-up anticoagulants usage was 97.3%. Discussion and conclusions: ICM was an effective tool for diagnosing underlying AF, capturing AF in 29% of the CS and TIA patients. AF was asymptomatic in most cases and would mainly have gone undiagnosed without ICM. The insertion and use of ICM was feasible for stroke physicians in stroke units.

Etiologic reclassification of cryptogenic stroke after implantable cardiac monitoring and computed tomography angiography re-assessment.

INTRODUCTION: Different mechanisms may underlie cryptogenic stroke, including subclinical atrial fibrillation (AF), nonstenotic carotid plaques (NCP), and aortic arch atherosclerosis (AAA). In a cohort of cryptogenic stroke patients, we aimed to: (1) evaluate the prevalence of subclinical AF, NCP, and AAA, and reclassify the etiology accordingly; (2) compare the clinical features of patients with reclassified etiology with those with confirmed cryptogenic stroke. METHODS: Data of patients hospitalized for cryptogenic stroke between January 2018 and February 2021 were retrospectively analyzed. Patients were included if they received implantable cardiac monitoring (ICM) to detect subclinical AF. Baseline computed tomography angiography (CTA) was re-evaluated to assess NCP and AAA. Since aortic plaques with ulceration/intraluminal thrombus were considered pathogenetic during the initial workup, only patients with milder AAA were included. Stroke etiology was reclassified as "cardioembolic", "atherosclerotic", or "mixed" based on the detection of AF and NCP/AAA. Patients with "true cryptogenic" stroke (no AF, ipsilateral NCP, or AAA detected) were compared with those with reclassified etiology. RESULTS: Among 63 patients included, 21 (33%) were diagnosed with AF (median follow-up time of 15 months), 12 (19%) had ipsilateral NCP, and 6 (10%) had AAA. Stroke etiology was reclassified in 30 patients (48%): cardioembolic in 14 (22%), atherosclerotic in 9 (14%), and mixed in 7 (11%). Patients with true cryptogenic stroke were younger compared to those with reclassified etiology (p = 0.001). DISCUSSION: One or more potential covert stroke sources can be recognized in half of the patients with a cryptogenic stroke through long-term cardiac monitoring and focused CTA re-assessment.

Association of non-sustained atrial tachycardia and its duration in 24-h Holter monitoring with embolic stroke of unknown source.

BACKGROUND AND PURPOSE: Although supraventricular ectopic beats (SVE), including premature atrial contractions (PACs) and non-sustained atrial tachycardia (NSAT), are frequent in the general population, some study results indicate that they are pathologic. SVE may predict undiagnosed atrial fibrillation or be associated with the embolic pattern of ischemic stroke. The aim of this study was to identify the indicators most associated with embolic stroke among the parameters that suggest the burden of SVE. METHODS: A total of 1920 consecutive acute ischemic stroke (AIS) patients were enrolled from two university hospitals. We defined embolic stroke of unknown source (ESUS) and small vessel occlusion (SVO) etiologies using stricter criteria than the existing conventional criteria. RESULTS: We enrolled 426 (SVO: 310 vs. ESUS: 116) patients who met the inclusion criteria. In the 24-h Holter monitoring parameters, total number of PACs and PAC-to-total beat ratio were not significantly different between the two groups. However, NSATs were more frequent, and the duration of the longest NSAT was longer in the ESUS group. Multivariate logistic regression revealed that high brain natriuretic peptide levels, presence of NSAT, history of previous stroke, and the longest NSAT duration significantly correlated with the ESUS etiology. CONCLUSION: The presence of NSAT and its duration are more important indicators of embolic stroke than the frequency of PACs is. Therefore, considering secondary prevention in AIS patients with ESUS, 24-h Holter monitoring parameters, such as the presence of NSAT and its duration, could be considered as potential sources of cardio-embolism.

Fatal undersensing of ventricular fibrillation due to intermittent high-amplitude R waves.

A 48-year-old man was admitted after an episode of aborted sudden death with external defibrillation. An implantable cardioverter defibrillator implanted 2 years before for secondary prevention failed to sense properly an episode of ventricular fibrillation. Interrogation of the device showed large oscillatory changes of the amplitude of the local electrogram during ventricular fibrillation, causing undersensing and inappropriate refraining from shock therapy.

Palpitations: Evaluation and management by primary care practitioners.

Palpitations are a common, non-specific presenting complaint in primary healthcare and emergency departments. Palpitations are mostly a symptom of benign underlying disease but a sign of life-threatening conditions. Importantly, palpitations are a symptom and not a diagnosis, and cardiac causes are the most concerning aetiology. Clinicians should seek to identify the underlying cause. History and physical examination are important in the assessment of patients with palpitations, and the use of a 12-lead electrographic (ECG) monitor on presentation is the gold standard of diagnosis. If the aetiology cannot be determined, an ambulatory Holter 24-48-h monitor can be used. Treatment and follow-up of patients presenting with palpitations as the main complaint will depend on the aetiology and investigation findings. Patients with palpitations accompanied by dizziness, excessive fatigue, or chest pains should receive adequate acute care aiming to stabilise their condition before referring to a higher level of care.

Role of the autonomic nervous system and premature atrial contractions in short-term paroxysmal atrial fibrillation forecasting: Insights from machine learning models.

BACKGROUND: Machine learning and deep learning techniques are now used extensively for atrial fibrillation (AF) screening, but their use for AF crisis forecasting has yet to be assessed in a clinical context. AIMS: To assess the value of two machine learning algorithms for the short-term prediction of paroxysmal AF episodes. METHODS: We conducted a retrospective study from an outpatient clinic. We developed a deep neural network model that was trained for a supervised binary classification, differentiating between RR interval variations that precede AF onset and RR interval variations far from any AF. We also developed a random forest model to obtain forecast results using heart rate variability variables, with and without premature atrial complexes. RESULTS: In total, 10,484 Holter electrocardiogram recordings were screened, and 250 analysable AF onsets were labelled. The deep neural network model was able to distinguish if a given RR interval window would lead to AF onset in the next 30 beats with a sensitivity of 80.1% (95% confidence interval 78.7-81.6) at the price of a low specificity of 52.8% (95% confidence interval 51.0-54.6). The random forest model indicated that the main factor that precedes the start of a paroxysmal AF episode is autonomic nervous system activity, and that premature complexes add limited additional information. In addition, the onset of AF episodes is preceded by cyclical fluctuations in the low frequency/high frequency ratio of heart rate variability. Each peak is itself followed by an increase in atrial extrasystoles. CONCLUSIONS: The use of two machine learning algorithms for the short-term prediction of AF episodes allowed us to confirm that the main cause of AF crises lies in an imbalance in the autonomic nervous system, and not premature atrial contractions, which are, however, required as a final firing trigger.