What Do We Really Know About the Effect of Prolonged Heart Rhythm Monitoring After Stroke?

The bulk of the current knowledge on atrial fibrillation (AF)-associated stroke risk and benefit of oral anticoagulation derives from studies on patients with clinically diagnosed AF. Subclinical AF (SCAF), defined as AF discovered during the interrogation of prolonged heart monitoring, is often asymptomatic and short-lasting, is associated with increased stroke risk compared with sinus rhythm, and may progress to clinical AF. Despite the extensive screening for and treatment of SCAF, especially in secondary stroke prevention, the net benefit of this practice is not established. Recent studies of SCAF have provided new insights: (1) SCAF is extremely common and may sometimes indicate physiological findings, (2) the stroke risk associated with SCAF is lower than that of clinically detected AF, and (3) any benefit on stroke risk may be countered by increased bleeding risk (no net benefit). How should we interpret the latest knowledge in the setting of poststroke AF screening and prevention?

Cost-Effectiveness of AF Screening With 2-Week Patch Monitors: The mSToPS Study.

BACKGROUND: The mSToPS study (mHealth Screening to Prevent Strokes) reported screening older Americans at risk for atrial fibrillation (AF) and stroke using 2-week patch monitors was associated with increased rates of AF diagnosis and anticoagulant prescription within 1 year and improved clinical outcomes at 3 years relative to matched controls. Cost-effectiveness of this AF screening approach has not been explored. METHODS: We conducted a US-based health economic analysis of AF screening using patient-level data from mSToPS. Clinical outcomes, resource use, and costs were obtained through 3 years using claims data. Individual costs, survival, and quality-adjusted life years (QALYs) were projected over a lifetime horizon using regression modeling, US life tables, and external data where needed. Adjustment between groups was performed using propensity score bin bootstrapping. RESULTS: Screening participants (mean age, 74 years, 41% female, median CHA2DS2-VASC score 3) wore on average 1.7 two-week monitors at a mean cost of $614/person. Over 3 years, outpatient visits were more frequent for monitored than unmonitored individuals (difference 190 per 100 patient-years [95% CI, 82-298]), but emergency department visits (-8.3 [95% CI, -12.6 to -4.1]) and hospitalizations (-15.2 [CI, -22 to -8.6]) were less frequent. Total adjusted 3-year costs were slightly higher (mean difference, $1551 [95% CI, -$1047 to $4038]) in the monitoring group. In patient-level projections, the monitoring group had slightly greater quality-adjusted survival (8.81 versus 8.71 QALYs, difference, 0.09 [95% CI, -0.05 to 0.24]) and slightly higher lifetime costs, resulting in an incremental cost-effectiveness ratio of $36 100/QALY gained. With bootstrap resampling, the incremental cost-effectiveness ratio for monitoring was <$50 000/QALY in 64% of study replicates, and <$150 000/QALY in 91%. CONCLUSIONS: Using lifetime projections derived from the mSToPS study, we found that AF screening using 2-week patch monitors in older Americans was associated with high economic value. Confirmation of these uncertain findings in a randomized trial is warranted. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02506244.

Long-term safety and efficacy of renal sympathetic denervation in atrial fibrillation: 3-year results of the AFFORD study.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia which has been associated with increased sympathetic nervous system activity and hypertension. Recent evidence indicated that renal sympathetic denervation (RDN) could safely contribute to an improvement in AF burden. OBJECTIVE: To investigate the long-term safety and efficacy of radiofrequency RDN in hypertensive patients with symptomatic AF. METHODS: This pilot study included patients with symptomatic paroxysmal or persistent AF (European Hearth Rhythm Association class ≥ II) despite optimal medical therapy, office systolic blood pressure (BP) ≥ 140 mmHg and ≥ 2 antihypertensive drugs. AF burden was measured using an implantable cardiac monitor (ICM), implanted 3 months prior to RDN. ICM interrogation and 24-h ambulatory BP monitoring were performed at baseline and at 3/6/12/24/36 months post RDN. The primary efficacy outcome was daily AF burden. Statistical analyses were performed using Poisson and negative binomial models. RESULTS: A total of 20 patients with a median age [25th-75th percentiles] of 66.2 [61.2-70.8] years (55% female) were included. At baseline, office BP ± standard deviation (SD) was 153.8/87.5 ± 15.2/10.4 mmHg, while mean 24-h ambulatory BP was 129.5/77.3 ± 15.5/9.3 mmHg. Baseline daily AF burden was 1.4 [0.0-10.9] minutes/day and throughout a 3-year follow-up period, no significant change was observed (- 15.4%/year; 95% confidence interval (CI) - 50.2%, + 43.7%; p = 0.54). The number of defined daily doses of antiarrhythmic drugs and antihypertensive drugs remained stable over time, while mean 24-h ambulatory systolic BP decreased with - 2.2 (95% CI - 3.9, - 0.6; p = 0.01) mmHg/year. CONCLUSIONS: In patients with hypertension and symptomatic AF, stand-alone RDN reduced BP but did not significantly reduce AF burden up until 3 years of follow-up.

Clinical analysis of 24-hour dynamic electrocardiographic changes in 323 middle-aged and older adult patients with cardiovascular disease / 中国基层医药

Objective:To analyze the 24-hour dynamic electrocardiographic changes in middle-aged and older adult patients with cardiovascular disease, providing effective guidance for clinical targeted intervention.Methods:The clinical data of 232 middle-aged and older adult patients who received treatment in Shanxi Coal Central Hospital from April 2019 to April 2021 were retrospectively analyzed. Among these patients, 166 patients with cardiovascular disease aged ≥ 60 years were included in the observation group, and 157 patients with cardiovascular disease aged < 60 years were included in the control group. The 24-hour dynamic electrocardiographic changes were compared between the two groups.Results:The detection rates of atrial arrhythmias, ventricular arrhythmias, sinus arrhythmias, complex ventricular arrhythmias, and complex atrial arrhythmias in the observation group were 96.99%, 88.55%, 28.31%, 39.76%, and 52.41% respectively, which were significantly higher than 50.32%, 50.96%, 8.28%, 9.55%, 8.92% in the control group ( χ2 = 19.21, 28.75, 23.45, 6.90, 8.06, all P < 0.001). The time of myocardial ischemia attack in the observation group [(1.5 ± 0.5) minutes] was significantly shorter than that in the control group [(2.5 ± 0.5) minutes, t = 23.09, P < 0.001)]. The time of myocardial ischemia attack in the observation group was mostly from 0:00 a.m. to 8:00 a.m. Conclusion:Patients aged ≥ 60 years are more likely to develop cardiovascular disease. The risk of cardiovascular diseases increase with increasing age. In particular at 0:00 a.m. to 8:00 a.m., 24-hour dynamic electrocardiographic changes should be monitored to further understand the actual situation of patients and guide clinical effective prevention and treatment of myocardial ischemia.

Predictive value of dynamic electrocardiography for myocardial ischemia and arrhythmia in patients with coronary heart disease / 中国基层医药

Objective:To investigate the predictive value of dynamic electrocardiography (ECG) for myocardial ischemia and arrhythmia in patients with coronary heart disease.Methods:A total of 87 patients with coronary heart disease who received treatment in Wenling Hospital of Traditional Chinese Medicine from January 2020 to January 2022 were included in this study. These patients were divided into a conventional ECG group (group A, n = 40) and a dynamic ECG group (group B, n = 47) according to different examination methods. The detection rate of myocardial ischemia in the two groups was determined. The diagnostic efficacy of routine ECG and dynamic ECG for myocardial ischemia was analyzed according to the results of coronary angiography. The detection rate of arrhythmia was determined in each group. Patient satisfaction was compared between the two groups. Results:There was no significant difference in the total detection rate of myocardial ischemia between the two groups ( P = 0.154). The detection rate of asymptomatic myocardial ischemia in group B [25% (25/47)] was significantly higher than that in group A [10% (10/40), χ2 = 5.24, P = 0.020). According to the results of coronary angiography, the detection rates of myocardial ischemia in group A and group B were 68% (27/40) and 87% (41/47), respectively. The sensitivity, specificity, and accuracy of group B in diagnosing myocardial ischemia were 80% (33/41), [67% (4/6), and 74% (35/47), respectively, all of which were significantly higher than 74% (20/27), [46% (6/13), 68% (27/40) in group A ( χ2 = 8.03, 5.89, 5.03, P = 0.003, 0.012, 0.005). The detection rates of premature ventricular contraction in bi-triplet rhythm, frequent paired premature atrial contraction in bi-triplet rhythm, right bundle-branch block, atrioventricular block, supraventricular tachycardia in group B were significantly higher compared with group A ( χ2 = 10.78, P = 0.001). According to the results of coronary angiography, the detection rates of arrhythmia in groups A and B were 65% (26/40) and 79% (37/47), respectively. The sensitivity, specificity, and accuracy of diagnosing arrhythmia in coronary heart disease in group B were 86% (32/37), 40% (4/10), and 81% (38/47), respectively. The sensitivity and accuracy of diagnosing arrhythmia in coronary heart disease in group B were significantly higher than those in group A [58% (15/26), 55% (22/40), χ2 = 7.30, 4.90, P = 0.005, 0.010). Patient satisfaction in group B [87% (41/47)] was significantly higher than that in group A [65% (26/40), χ2 = 6.24, P = 0.044]. Conclusion:Compared with conventional ECG detection, dynamic ECG has substantially higher detection and diagnosis rates of myocardial ischemia and arrhythmia, as well as a higher patient satisfaction rate, in patients with coronary heart disease, in particular in those with asymptomatic myocardial ischemia.

Continuous Arrhythmia Monitoring in Pediatric and Adult Patients With Left Ventricular Noncompaction.

Patients with left ventricular noncompaction (LVNC) are at risk of clinically significant arrhythmias and sudden death. We evaluated whether implantable loop recorders could detect significant arrhythmias that might be missed in these patients during annual Holter monitoring. Selected pediatric and adult patients with LVNC who consented to implantable loop recorder placement were monitored for 3 years (study duration, 10 April 2014-9 December 2019). Fourteen subjects were included (age range, 6.5-36.4 yr; 8 males). Of 13 patients who remained after one device extrusion, one underwent implantable cardioverter-defibrillator placement. Four patients (31%) had significant arrhythmias: atrial tachycardia (n=2), nonsustained ventricular tachycardia (n=1), and atrial fibrillation (n=1). All 4 events were clinically asymptomatic and not associated with left ventricular ejection fraction. In addition, a high frequency of benign arrhythmic patterns was detected. Implantable loop recorders enable continuous, long-term detection of important subclinical arrhythmias in selected patients who have LVNC. These devices may prove to be most valuable in patients who have LVNC and moderate or greater ventricular dysfunction.

Left Ventricular Dysfunction in Outpatients with Frequent Ventricular Premature Complexes.

Frequent ventricular premature complexes (VPCs) and VPC QRS duration are risk factors for left ventricular (LV) dysfunction. To determine which clinical characteristics and electrocardiographic features are associated with LV dysfunction (ejection fraction, <50%) and frequent VPCs, we retrospectively reviewed data from a single-center registry of all patients diagnosed with frequent VPCs at a Korean outpatient clinic. We identified 412 consecutive outpatients (mean age, 54.7 ± 16.8 yr; 227 women [55.1%]) who were diagnosed with frequent VPCs and had no structural heart disease from January 2010 through December 2017. Available transthoracic echocardiograms and 24-hour Holter monitoring data were evaluated to correlate the occurrence of VPCs and symptoms. Typical VPC-related symptoms (palpitations or dropped beats) were observed in 251 patients (61.1%). Electrocardiograms revealed VPCs with a left bundle branch block-like morphology in 327 patients (79.5%) and VPCs with an inferior axis in 353 (85.8%). Twenty-six patients (6.3%) were diagnosed with VPC-related LV dysfunction. The mean VPC burden did not differ significantly by LV functional status (11.06% ± 10.13% [normal] vs 14.41% ± 13.30% [impaired]; P=0.211). Patients with impaired LV function were more often men (P=0.027), had no typical VPC-related symptoms (P=0.006), and had significantly longer VPC QRS durations (mean, 157 ms vs 139 ms; P <0.01). Our findings suggest that male sex, absence of typical VPC-related symptoms, and a VPC QRS duration >157 ms are associated with LV dysfunction in patients with frequent VPCs, findings that may be useful in predicting such dysfunction.

Scanning of paroxysmal atrial fibrillation as an etiological risk factor in patients with acute ischemic stroke: prospective study

Abstract BACKGROUND: Prevention of recurrence of stroke depends on recognition of the underlying mechanism of ischemia. OBJECTIVE: To screen patients who were hospitalized with diagnosis of acute ischemic stroke in terms of atrial fibrillation (AF) with repeated Holter electrocardiography recordings. DESIGN AND SETTING: Prospective study conducted at Konya Education and Research Hospital, Turkey. METHODS: Patients with a diagnosis of acute ischemic stroke, without atrial fibrillation on electrocardiography (ECG), were evaluated. Their age, gender, histories of previous ischemic attack, occurrences of paroxysmal atrial fibrillation (PAF) and other risks were assessed during the first week after acute ischemic stroke and one month thereafter. ECG recordings were obtained from 130 patients through 24-hour ambulatory Holter. Patients without PAF attack during the first Holter were re-evaluated. RESULTS: PAF was detected through the first Holter in 33 (25.4%) out of 130 acute ischemic stroke patients. A second Holter was planned for 97 patients: 53 (54.6%) of them could not attend due to COVID-19 pandemic; while 44 (45.3%) patients had the second Holter and, among these, 4 (9.1%) had PAF. The only parameter associated with PAF was older age. Four (10.8%) of the 37 patients with PAF had also symptomatic carotid stenosis. CONCLUSIONS: Detecting the presence of PAF by screening patients with no AF in the ECG through Holter ECG examinations is valuable in terms of changing the course of the treatment. It should be kept in mind that the possibility of accompanying PAF cannot be ruled out in the presence of other factors that pose a risk of stroke.

Nonsustained Ventricular Tachycardia Is Independently Associated With Sustained Ventricular Arrhythmias in Nonischemic Dilated Cardiomyopathy.

BACKGROUND: Spontaneous nonsustained ventricular tachycardia (NSVT) on Holter, VT inducibility during electrophysiology study, and late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) have been associated with sustained ventricular arrhythmias (SVAs) in nonischemic dilated cardiomyopathy (DCM). This study aimed to analyze whether these parameters carry independent prognostic value for spontaneous SVA in DCM. METHODS: Between 2011 and 2018, patients with the DCM clinical spectrum and documented SVA, suspected SVA, or considered to be at intermediate or high risk for SVA were enrolled in the prospective Leiden Nonischemic Cardiomyopathy Study. Patients underwent a comprehensive evaluation including 24-hour Holter, LGE-CMR, and electrophysiology study. Holters were assessed for the presence of NSVT (≥3 beats; rate, ≥120 bpm; lasting <30 s) and NSVT characteristics (coupling interval, duration, cycle length, morphology, regularity). Patients were followed at 6 to 12 monthly intervals. RESULTS: Of all 115 patients (age, 59±12 years; 77% men; left ventricular ejection fraction, 33±13%; history of SVA, 36%; LGE in 63%; median LGE mass, 13 g; interquartile range, 8-23 g), 62 (54%) had NSVT on Holter, and sustained monomorphic VT was inducible in 34 of 114 patients (30%). NSVT was not associated with LGE on CMR or VT inducibility during electrophysiology study nor were its features (all P>0.05). During 4.0±1.8 years of follow-up, SVA occurred in 39 patients (34%). NSVT (HR, 4.47 [95% CI, 1.87-10.72]; P=0.001) and VT inducibility (HR, 3.08 [95% CI, 1.08-8.81]; P=0.036) were independently associated with SVA during follow-up. A bivariable model including only noninvasively acquired parameters also allowed identification of a high-risk subgroup (ie, those with both NSVT and LGE on CMR). The findings remained similar when only patients without prior SVA were included. CONCLUSIONS: In patients with DCM, NSVT on Holter and VT inducibility during electrophysiology study predict SVA during follow-up independent of LGE on CMR. NSVTs may serve as an initiator, and sustained VT inducibility indicates the presence of the substrate for SVA in DCM. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01940081.

Correlation between circadian blood pressure pattern and heart rate variability and stroke severity and outcome in patients with acute ischemic stroke / 国际脑血管病杂志

Objective:To investigate the correlation between circadian blood pressure pattern and heart rate variability and stroke severity and outcome in patients with acute ischemic stroke (AIS).Methods:Patients with first-ever AIS admitted to the Affiliated Qingdao Central Hospital of Qingdao University from January 2015 to January 2021 were retrospectively included. Ambulatory blood pressure monitoring (ABPM) and ambulatory electrocardiogram (AECG) were performed after admission. The severity of stroke was assessed according to the National Institutes of Health Stroke Scale. ≤8 were defined as minor stroke, and >8 were defined as moderate to severe stroke. The modified Rankin Scale was used to evaluate the clinical outcome at 3 months after onset. ≤ 2 were defined as good outcomes, and >2 were defined as poor outcomes. Multivariate logistic regression analysis was used to determine the independent influencing factors of stroke severity and outcome. Results:A total of 516 patients with AIS were enrolled, including 328 male (63.57%), aged 59.62±6.67 years old. Among them, 266 patients (51.55%) were in the minor stroke group and 250 (48.45%) were in the moderate to severe stroke group. There were 463 patients (89.73%) were in the good outcome group and 53 (10.27%) were in the poor outcome group. Multivariate logistic regression analysis showed that hypertension (odds ratio [ OR] 5.021, 95% confidence interval [ CI] 2.635-10.923; P<0.001), atrial fibrillation ( OR 3.896, 95% CI 2.574-8.521; P<0.001), circadian blood pressure pattern (non-dipper type: OR 2.436, 95% CI 1.031-4.749, P<0.001; reverse dipper type: OR 2.654, 95% CI 1.642-5.268, P<0.001), SDNN ( OR 0.298, 95% CI 0.114-0.730; P=0.002), SDANN ( OR 0.325, 95% CI 0.200-0.679; P=0.009), rMSSD ( OR 0.437, 95% CI 0.255-0.876; P=0.016) and pNN50 ( OR 0.369, 95% CI 0.291-0.767; P=0.013) were the independent influencing factors of stroke severity. Hypertension ( OR 4.857, 95% CI 1.957-8.552; P<0.001), baseline NIHSS score ( OR 2.189, 95% CI 1.597-3.315; P<0.001), stroke severity ( OR 3.853, 95% CI 2.316-5.958; P<0.001), circadian blood pressure pattern (non-dipper type: OR 2.997, 95% CI 1.128-5.430, P<0.001; reverse dipper type: OR 3.703, 95% CI 1.478-5.902; P<0.001), SDNN ( OR0.369, 95% CI 0.215-0.779; P=0.015), SDANN ( OR 0.372, 95% CI 0.198-0.862; P=0.018), rMSSD ( OR 0.455, 95% CI 0.314-0.896; P=0.026) and pNN50 ( OR 0.448, 95% CI 0.307-0.825; P=0.021) were the independent influencing factors of poor outcomes. Conclusion:The non-dipper and reverse dipper circadian blood pressure patterns and lower heart rate variability are independently associated with stroke severity and poor outcomes in patients with AIS.

The study on the value of synchronized 12-lead Holter in the diagnosis of coronary heart disease myocardial ischemia / 中国医师进修杂志

Objective:To explore the clinical value of synchronized 12-lead Holter in the diagnosis of coronary heart disease myocardial ischemia.Methods:A total of 101 patients with coronary heart disease who came to the Affiliated Hospital of Jining Medical College from May 2019 to May 2020 were selected. They all received conventional electrocardiogram(ECG) and synchronized 12-lead Holter examinations. The value of different examination methods in the diagnosis of myocardial ischemia was compared, and the characteristics of myocardial ischemia in patients with different degrees of coronary artery disease were analyzed.Results:The detection rates of synchronized 12-lead Holter for myocardial ischemia in single-vessel coronary artery disease and multi-vessel coronary artery disease were 28.71% (29/101) and 56.44%(57/101), respectively, which were slightly higher than 17.82%(18/101) and 45.54% (46/101) of conventional ECG, but with no statistically significant difference ( P>0.05), the total myocardial ischemia detection rate of synchronized 12-lead Holter was 85.15%(86/101), which was higher than 63.37%(64/101) of conventional ECG ( P<0.05). The mean frequency of myocardial ischemia in coronary heart disease diagnosed by synchronized 12-lead Holter was higher than that of conventional ECG, and the duration and amplitude of ST-segment depression were higher than those in conventional ECG ( P<0.05). The detection rates of lateral and inferior myocardial ischemia on synchronized 12-lead Holter were 16.28%(14/86) and 22.09%(19/86), respectively, which were higher than 0 of conventional ECG. The detection rate of myocardial ischemia in the anterior septum/anterior wall was 61.62%(53/86), which was lower than 100.00% (64/64)of the conventional ECG ( P<0.01). Synchronized 12-lead Holter in the diagnosis of coronary cardiac myocardial ischemia was highly consistent with that by coronary angiography, the Kappa value was 0.648, and the sensitivity, specificity, accuracy and negative predictive value were 93.33%, 81.82%, 92.08% and 60.00%, respectively, which were higher than 54.44%, 63.64%, 55.45%, 14.58% of conventional ECG ( P<0.05). The number of myocardial ischemic attacks in patients with multi-vessel disease of coronary heart disease was more than that of single vessel disease ( P<0.05), the mean frequency of myocardial ischemia was higher than that of single vessel disease, and the duration and amplitude of ST-terminal depression were higher than those of patients with single-vessel disease ( P<0.05). Conclusions:Synchronized 12-lead Holter is more effective than conventional ECG in the diagnosis of myocardial ischemic attack of coronary heart disease, and it is more consistent with coronary angiography. It can clarify the frequency and extent of myocardial ischemic attacks and help identify the location of myocardial ischemia. It can be used as an important basis for screening myocardial ischemia attacks of coronary heart disease.

Locais de Reconexão na Técnica de Reablação após Isolamento das Veias Pulmonares com Criobalão em Pacientes com Fibrilação Atrial Paroxística / Reconnection Sites in Redo Ablation after Cryoballoon Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation

Resumo Fundamento Na fibrilação atrial paroxística (FAP), o isolamento das veias pulmonares com criobalão (IVP-CB) tem eficácia semelhante à da ablação por radiofrequência (IVP-RF). Em procedimentos de reablação após IVP-RF, a reconexão das VPs é alta, ao passo que em pacientes com reablação após IVP-CB, as informações são escassas. Objetivo Determinar os locais de reconexão das VPs em pacientes que foram submetidos à reablação após IVP-CB inicial. Métodos Pacientes que foram submetidos a um procedimento de reablação de fibrilação atrial, após um IVP-CB inicial para FAP foram incluídos. O mapeamento eletroanatômico do AE foi utilizado. Um local de reconexão foi definido com a presença de uma voltagem de 0,3mV ou maior nas VPs e condução unidirecional ou bidirecional nas VPs durante o ritmo sinusal. Os locais de reconexão foram identificados por meio de corte paraesternal longitudinal e posteriormente ablacionados com radiofrequência. Resultados Dos 165 pacientes submetidos ao IVP inicial, 27 necessitaram reablações, dos quais 18 (66,6%) eram do sexo masculino, com média de idade de 55+12,3 anos. O tempo de recorrência foi de 8,9+6,4 meses. A reconexão das VPs foi encontrada em 21 (77,8%) pacientes. Houve um total de 132 lacunas de condução, seis por paciente, 3,6 por VP. Um número significativo de lacunas ocorreu na região ântero-superior da VP superior esquerda (VPSE) e nas regiões septal e inferior da VP superior direita (VPSD). Conclusões As VPs superiores apresentaram os locais de maior reconexão, principalmente na região anterior da VPSE e na região septal da VPSD. A razão por trás disso pode ser devido à maior espessura da parede atrial e à dificuldade em alcançar o contato de criobalão adequado.

Abstract Background In paroxysmal atrial fibrillation (PAF), pulmonary vein isolation using cryoballoon (CB-PVI) has similar efficacy as radiofrequency ablation (RF-PVI) has. In redo ablation procedures following RF-PVI, PV reconnection is high, whereas in patients with redo following CB-PVI, information is scarce. Objective To determine the sites of PV reconnection in patients who underwent redo ablation after initial CB-PVI. Methods Patients who underwent an AF redo procedure, following an initial CB-PVI for PAF were included. LA electroanatomic mapping was used. A reconnection site was defined as the presence of a voltage of 0.3mV or greater in the PV and unidirectional or bidirectional conduction in the PV during sinus rhythm. Reconnections sites were identified using a clock-face view description and were ablated with radiofrequency afterwards. Results Out of the 165 patients who underwent initial PVI, 27 required redo ablations, of which 18 (66.6%) were males, with a mean age of 55+12.3 years. The time of recurrence was 8.9+6.4 months. PV reconnection was found in 21 (77.8%) patients. There was a total of 132 conduction gaps, six per patient, 3.6 per PV. A significant number of gaps were in the anterosuperior region of the left superior PV (LSPV), and in the septal and inferior regions of the right superior PV (RSPV). Conclusions The upper PVs had the most reconnection sites, mostly at the anterior region of the LSPV and the septal region of the RSPV. The reason behind this may be due to greater atrial wall thickness, and difficulty in achieving adequate cryoballoon contact.

Radiofrequency Versus Cryoballoon Catheter Ablation for Paroxysmal Atrial Fibrillation: Durability of Pulmonary Vein Isolation and Effect on Atrial Fibrillation Burden: The RACE-AF Randomized Controlled Trial.

[Figure: see text].

Confirmación diagnóstica de la metodología diseñada para evaluar los registros Holter durante 18 horas mediante la entropía proporcional / Diagnostic confirmation of the methodology designed to evaluate the Holter registers for 18 hours through proportional entropy

Resumen Introducción: Los sistemas dinámicos, la entropía y la probabilidad han contribuido de forma significativa al desarrollo de nuevas metodologías que caracterizan al grado de complejidad de la dinámica cardíaca. Objetivo: Confirmar la aplicabilidad clínica de la metodología fundamentada en la teoría de los sistemas dinámicos, la probabilidad y la entropía para evaluar la dinámica cardíaca durante 18 horas. Material y métodos: Se tomaron 570 registros Holter normales en diferentes enfermedades. Para cada uno se construyó un atractor en un mapa de retardo y se evaluó la probabilidad de ocupación de pares ordenados de frecuencias cardíacas durante 18 horas, así como la entropía y sus proporciones. Se compararon las medidas obtenidas con los valores de normalidad y enfermedad establecidos previamente para obtener el diagnóstico matemático de cada Holter. Las conclusiones del Holter se revelaron luego de aplicar la metodología fisicomatemática para calcular sensibilidad, especificidad y coeficiente kappa respecto de la norma de referencia clínica. Resultados: Con las proporciones de la entropía de los atractores se diferenciaron dinámicas cardíacas agudas, crónicas, normales y la evolución entre estos estados con resultados de sensibilidad y especificidad del 100% con una concordancia entre la norma de referencia y el diagnóstico fisicomatemático evaluado con el coeficiente kappa de 1. Conclusiones: Este estudio confirma que la metodología aplicada logra diagnosticar objetivamente la dinámica cardíaca, ya que establece predicciones de estados de normalidad o del nivel de agravamiento de la dinámica, y evidencia la aplicabilidad de esta metodología, lo cual sugiere su potencial uso en el contexto clínico.

Abstract Introduction: Dynamic systems, entropy and probability have contributed significantly in the development of new methodologies that characterize the degree of complexity of cardiac dynamics. Objective: To confirm the clinical applicability of the methodology based on the theory of dynamic systems, probability and entropy to evaluate cardiac dynamics during 18 hours. Material and methods: 570 normal Holter records with different pathologies were taken. For each one an attractor was built on the delay map and the probability of occupation of ordered pairs of heart rates during 18 hours was evaluated, as well as the entropy and its proportions. The measurements obtained were compared with the values of normality and illness established previously to obtain the mathematical diagnosis of each Holter. The conclusions of the Holter were unblinded after having applied the physical-mathematical methodology to calculate sensitivity, specificity and Kappa coefficient with respect to the Gold-Standard. Results: With the proportions of the entropy of the attractors, acute, chronic, normal, and evolution cardiac dynamics were differentiated between these states. the application of the methodology showed a sensitivity and specificity of 100 %. The agreement between the Gold-Standard and the physical-mathematical diagnosis evaluated with the kappa coefficient was 1. Conclusions: This study confirms that the applied methodology manages to objectively diagnose cardiac dynamics, establishing predictions of normality states or the level of aggravation of the dynamics, evidencing the applicability of this methodology, suggesting its potential use in the clinical context.

Utilidad de un sistema de registro de una derivación electrocardiográfica y transmisión inalámbrica durante la pandemia por COVID-19 / Electrocardiographic Recording System and Wireless Transmission During the COVID-19 Pandemic

RESUMEN Introducción: Se ha comunicado que algunos tratamientos utilizados para la infección por COVID-19 pueden ocasionar alteraciones del intervalo QT y arritmias graves. La medición por electrocardiograma (ECG) convencional requiere personal adicional y riesgo de contagio. Nuevas tecnologías para obtención de un ECG conectados a teléfonos inteligentes (smartphones) proporcionan una alternativa para evaluación del QTc. Objetivo: El objetivo fue evaluar la factibilidad de un dispositivo para registro electrocardiográfico de un canal, para la medición del intervalo QT en pacientes con sospecha o confirmación de infección por COVID-19, antes de recibir drogas que prolongan el intervalo QT. Material y métodos: Se obtuvieron registros de ECG con un dispositivo Kardia Mobile (KM) con trasmisión a un smarthphone. La sección de electrofisiología cardíaca centralizó la recepción por medio electrónico de los ECG en formato de archivo pdf y realizó las mediciones de los intervalos QTm y QTc. Resultados: Se estudiaron 31 pacientes, edad promedio 61 años (rango 20-95 años), sospechosos de presentar infección por COVID-19 enrolados para tratamiento con hidroxicloroquina, azitromicina, ritonavir y lopinavir. Los registros pudieron ser leídos en todos los casos, y debieron repetirse en dos casos. Los valores del intervalo QTc promedio en varones y mujeres fue 423 mseg (rango 380-457 mseg) y 439 mseg (rango 391-540 mseg), respectivamente. El tiempo de respuesta desde el envío del ECG al grupo de análisis fue 11 min (rango 1-155). Conclusiones: Los registros ECG obtenidos con dispositivos KM, para trasmisión a un smartphone a un grupo central de lectura, permitieron la medición del intervalo QTc en todos los pacientes.

ABSTRACT Background: Some therapies used for COVID-19 can prolong the QT interval and produce severe arrhythmias. QT interval measured from a standard electrocardiogram (ECG) requires additional personnel and risk of infection. Novel technologies to obtain an ECG connected to smartphones provide an alternative for the evaluation of corrected QT interval (QTc). Objective: The aim of this study was to evaluate the feasibility of using a single-lead ECG device to measure the QT interval in patients with suspected or confirmed COVID-19 before receiving treatment with drugs that can prolong the QT interval. Methods: The ECG was obtained with a KardiaMobile (KM) device and transmitted to a smartphone. The ECG recordings were saved as pdf files and electronically submitted to the electrophysiology section which centralized the reception and assessed the measured QT and QTc intervals. Results: A total of 31 patients (mean age 61 years, range 20-95 years) with suspected COVID-19 enrolled for treatment with hydroxychloroquine, azithromycin, ritonavir or lopinavir were analyzed. The recordings could be read in all the cases and had to be repeated in two cases. The mean value of the QTc interval was 423 ms (range 380-457 ms) in men and 439 ms (range 391-540 ms) in women. The response time since the ECG recording was submitted for analysis was 11 min (range 1-155). Conclusions: The QTc interval could be measured from ECG recordings obtained with KM devices connected to a smartphone and transmitted to a centralized reading center in all patients.

Aplicación de la ley de Zipf-Mandelbrot al diagnóstico de la dinámica cardíaca normal y aguda / Application of the law of Zipf-Mandelbrot to the diagnosis of normal and acute cardiac dynamics

Introducción: Es conocida la capacidad de los fractales estadísticos en la evaluación de la complejidad de diferentes sistemas cuya dinámica pueda ser evaluada a partir de las frecuencias de una variable; para esto, se utiliza la medida de la dimensión fractal estadística, la cual puede ser calculada con la ley de Zipf-Mandelbrot. Esta ley matemática ha sido aplicada en cardiología para evaluar el grado de complejidad de la dinámica cardíaca. En el presente trabajo se aplicó la ley de Zipf-Mandelbrot junto con la metodología diagnóstica desarrollada previamente para evaluar dinámicas cardíacas normales y con enfermedad aguda. Materiales y métodos: Se tomaron 15 registros Holter; 10 con diagnóstico normal y 5 con patologías agudas de pacientes de la Unidad de Cuidados Intensivos. Se organizaron jerárquicamente las frecuencias de aparición de las frecuencias cardíacas de cada dinámica en rangos de a 15 lat/min, en busca del comportamiento hiperbólico necesario para la aplicación de la ley de Zipf-Mandelbrot. Posteriormente se realizó una linealización y se obtuvo la dimensión fractal estadística para cada dinámica. Resultados: Los valores de la dimensión fractal estadística para una dinámica cardíaca aguda variaron entre 0.4925 y 0.6061, mientras que para una dinámica normal variaron entre 0.7134 y 0.9749, evidenciando la diferenciación entre ambos grupos. Conclusiones: El comportamiento fractal estadístico de la dinámica cardíaca fue corroborado, de igual forma la pérdida de complejidad para las dinámicas agudas respecto a las dinámicas normales

Background: The capacity of statistical fractals in the evaluation of the complexity of different systems whose dynamics can be evaluated from the frequencies of a variable is known. This is why the measure of the statistical fractal dimension is used, which can be calculated with the Zipf-Mandelbrot law, this mathematical law has been applied in cardiology evaluating the degree of complexity of cardiac dynamics. In the present work, the Zipf-Mandelbrot law was applied together with the diagnostic methodology previously developed to evaluate normal cardiac dynamics and acute disease. Material and methods: 15 Holter records were taken; 10 with normal diagnosis and 5 with acute pathologies of patients of the Intensive Care Unit. The frequencies of occurrence of the heart frequencies of each dynamics were organized hierarchically in ranges of 15 lat/min, in search of the hyperbolic behavior required for the application of the law of Zipf-Mandelbrot. Subsequently, a linearization was performed and the statistical fractal dimension was obtained for each dynamics. Results: The values of the statistical fractal dimension for acute cardiac dynamics varied between 0.4925 and 0.6061, whereas for normal dynamics they varied between 0.7134 and 0.9749, evidencing the differentiation between both groups. Conclusions: The statistical fractal behavior of the cardiac dynamics was corroborated, as well as the loss of complexity for the acute dynamics with respect to the normal dynamics

HIV Infection Is Associated With Variability in Ventricular Repolarization: The Multicenter AIDS Cohort Study (MACS).

BACKGROUND: People living with human immunodeficiency virus (HIV+) have greater risk for sudden arrhythmic death than HIV-uninfected (HIV-) individuals. HIV-associated abnormal cardiac repolarization may contribute to this risk. We investigated whether HIV serostatus is associated with ventricular repolarization lability by using the QT variability index (QTVI), defined as a log measure of QT-interval variance indexed to heart rate variance. METHODS: We studied 1123 men (589 HIV+ and 534 HIV-) from MACS (Multicenter AIDS Cohort Study), using the ZioXT ambulatory electrocardiography patch. Beat-to-beat analysis of up to 4 full days of electrocardiographic data per participant was performed using an automated algorithm (median analyzed duration [quartile 1-quartile 3]: 78.3 [66.3-83.0] hours/person). QTVI was modeled using linear mixed-effects models adjusted for demographics, cardiac risk factors, and HIV-related and inflammatory biomarkers. RESULTS: Mean (SD) age was 60.1 (11.9) years among HIV- and 54.2 (11.2) years among HIV+ participants (P<0.001), 83% of whom had undetectable (<20 copies/mL) HIV-1 viral load (VL). In comparison with HIV- men, HIV+ men had higher QTVI (adjusted difference of +0.077 [95% CI, +0.032 to +0.123]). The magnitude of this association depended on the degree of viremia, such that in HIV+ men with undetectable VL, adjusted QTVI was +0.064 (95% CI, +0.017 to +0.111) higher than in HIV- men, whereas, in HIV+ men with detectable VL, adjusted QTVI was higher by +0.150 (95% CI, 0.072-0.228) than in HIV- referents. Analysis of QTVI subcomponents showed that HIV+ men had: (1) lower heart rate variability irrespective of VL status, and (2) higher QT variability if they had detectable, but not with undetectable, VL, in comparison with HIV- men. Higher levels of C-reactive protein, interleukin-6, intercellular adhesion molecule-1, soluble tumor necrosis factor receptor 2, and soluble cluster of differentiation-163 (borderline), were associated with higher QTVI and partially attenuated the association with HIV serostatus. CONCLUSIONS: HIV+ men have greater beat-to-beat variability in QT interval (QTVI) than HIV- men, especially in the setting of HIV viremia and heightened inflammation. Among HIV+ men, higher QTVI suggests ventricular repolarization lability, which can increase susceptibility to arrhythmias, whereas lower heart rate variability signals a component of autonomic dysfunction.

Holter heart rhythm disorders in patients with acute kidney injury during hemodialysis / Trastornos del ritmo cardiaco por Holter en pacientes con lesión renal aguda durante hemodiálisis

BACKGROUND: The presence of acute renal injury has been associated with increased cardiovascular morbidity and mortality (sudden death and arrhythmias). OBJECTIVE: To know the frequency of heart rhythm disorders documented by Holter in patients in need of intermittent hemodialysis due to acute renal injury. MATERIAL AND METHODS: A prospective observational study was conducted including patients with a diagnosis of acute renal injury who received intermittent hemodialysis; demographic, clinical and laboratory data were collected from 28 patients. Monitoring was carried out through Holter before, during and after the hemodialysis session. Nonparametric statistics were used, with a significant value of p < 0.05. Risks were established with logistic regression. RESULTS: There was a significant difference in supraventricular extra systoles (82.1% vs. 57.1%), ventricular extra systoles (26.7% vs. 3.6%), and supraventricular tachycardia (6.7% vs. 3.6%). The rest of the rhythm alterations without significance. CONCLUSIONS: Intermittent hemodialysis is a factor associated with the appearance of heart rhythm disorders. The death of patients with acute renal injury and substitution was related to ventricular extra systole detected by transhemodialysis Holter.

INTRODUCCIÓN: La presencia de lesión renal aguda se ha asociado a unas mayores morbilidad y mortalidad de causa cardiovascular (muerte súbita y arritmias). OBJETIVO: Conocer la frecuencia de trastornos del ritmo cardiaco documentado por Holter en pacientes con necesidad de hemodiálisis intermitente por lesión renal aguda. MATERIAL Y MÉTODOS: Se realizó un estudio observacional, prospectivo, en pacientes con diagnóstico de lesión renal aguda que recibieron hemodiálisis intermitente; se recabaron datos demográficos, clínicos y de laboratorio de 28 pacientes. Se realizó monitoreo mediante Holter, previo, durante y posterior a la sesión de hemodiálisis. Se utilizó estadística no paramétrica, con un valor significativo de p < 0.05. Se establecieron riesgos con regresión logística. RESULTADOS: Hubo diferencia significativa en extrasístoles supraventriculares (82.1% frente a 57.1%), extrasístoles ventriculares (26.7% frente a 3.6%) y taquicardia supraventricular (6.7% frente a 3.6%). El resto de las alteraciones del ritmo no mostraron significancia. CONCLUSIONES: La hemodiálisis intermitente es un factor asociado a la aparición de trastornos del ritmo cardiaco. La muerte de los pacientes con lesión renal aguda y sustitución estuvo relacionada con la extrasístole ventricular detectada por Holter transhemodiálisis.

Aplicabilidad clínica de software diagnóstico de la dinámica cardíaca basado en la Ley de Zipf-Mandelbrot / Clinical applicability of the diagnostic software of cardiac dynamics based on the Zipf-Mandelbrot law

RESUMEN Introducción: La Ley de Zipf-Mandelbrot permitió el desarrollo de una metodología que realiza distinciones cuantitativas entre dinámicas cardíacas agudas y normales, de forma objetiva y reproducible. Objetivo: Confirmar la capacidad diagnóstica y utilidad clínica de un software que automatiza una metodología basada en la Ley de Zipf-Mandelbrot, que realiza diagnósticos objetivos de la dinámica cardíaca. Material y Métodos: Se realizó un estudio ciego con 80 registros Holter, 20 normales y 60 con hallazgos patológicos. El software organizó de manera jerárquica las frecuencias cardíacas mediante las frecuencias de aparición en rangos de 15 lat/min, linealizó los datos y obtuvo la dimensión fractal estadística, lo cual permitió la realización del análisis de complejidad. Resultados: La dimensión fractal estadística de los registros Holter normales se halló entre 0,720 y 0,913, y exhibió valores entre 0,454 y 0,665 en los registros Holter anormales. Se encontró un coeficiente Kappa de 1, y valores de especificidad y sensibilidad de 100%. Conclusiones: Se confirmó la utilidad clínica del software que automatiza la metodología fundamentada en La ley de Zipf-Mandelbrot, el cual permitió evaluar el comportamiento de los sistemas cardíacos normales y agudos.

ABSTRACT Introduction: The Zipf-Mandelbrot law allowed the development of a methodology that makes quantitative distinctions between acute and normal cardiac dynamics in an objective and reproducible way. Objective: To confirm the diagnostic capacity and clinical utility of the software that automates a methodology based on the Zipf-Mandelbrot law that performs objective diagnoses of the cardiac dynamics. Material and Methods: A blind study was performed with 80 Holter records, 20 normal and 60 with pathological findings. The software organized heart rates in a hierarchical way through their frequencies of occurrence in ranges of 15 beats per min, linearized data, and obtained statistical fractal dimension which allowed the realization of the complexity analysis. Results: The statistical fractal dimension of the normal Holter records was found between 0,720 and 0,913, and exhibited values ​​between 0,454 and 0,665 in the abnormal Holter records. A Kappa coefficient of 1, and specificity and sensitivity values ​​of 100% were found. Conclusions Methods: The clinical utility of the Software that automates the methodology based on the Zipf-Mandelbrot law was confirmed, which allowed to evaluate the behavior of normal and acute cardiac systems.