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BackgroundPopulation-based studies have reported the association between prolonged corrected QT (QTc) intervals and an increased risk of adverse cardiovascular events. Data regarding the association between longer QTc intervals and incident cardiovascular outcomes in patients with lower extremity arterial disease (LEAD) are scarce.ObjectiveTo examine the impact of QTc interval on long-term cardiovascular outcomes in elderly patients with symptomatic LEAD.MethodsThis cohort study extracted data from the Tzu-chi Registry of ENDovascular Intervention for Peripheral Artery Disease (TRENDPAD) and enrolled 504 patients aged ≥ 70 treated with endovascular therapy for atherosclerotic LEAD from July 1, 2005, to December 31, 2019. The main outcomes of interest were all-cause mortality and major adverse cardiovascular events (MACE). Multivariate analysis was conducted using the Cox proportional hazard model to determine independent variables. We performed interaction analysis between corrected QT and other covariates and Kaplan-Meier analysis to compare the outcome of interest among the groups stratified by the tercile of QTc intervals.ResultsA total of 504 patients [235 men (46.6%); mean age, 79.9 ± 6.2 years; mean QTc interval, 459 ± 33 msec] entered the final data analysis. We categorized the baseline patient characteristics according to terciles of QTc intervals. During the median follow-up time of 3.15 (interquartile ranges, 1.65–5.42) years, we noted 264 deaths and 145 MACEs. The 5-year rates of freedom from all-cause mortality (71% vs. 57% vs. 31%, P

To reduce the error induced by overfitting or underfitting in predicting non-invasive fasting blood glucose (NIBG) levels using photoplethysmography (PPG) data alone, we previously demonstrated that incorporating HbA1c led to a notable 10% improvement in NIBG prediction accuracy (the ratio in zone A of Clarke’s error grid). However, this enhancement came at the cost of requiring an additional HbA1c measurement, thus being unfriendly to users. In this study, the enhanced HbA1c NIBG deep learning model (blood glucose level predicted from PPG and HbA1c) was trained with 1494 measurements, and we replaced the HbA1c measurement (explicit HbA1c) with “implicit HbA1c” which is reversely derived from pretested PPG and finger-pricked blood glucose levels. The implicit HbA1c is then evaluated across intervals up to 90 days since the pretest, achieving an impressive 87% accuracy, while the remaining 13% falls near the CEG zone A boundary. The implicit HbA1c approach exhibits a remarkable 16% improvement over the explicit HbA1c method by covering personal correction items automatically. This improvement not only refines the accuracy of the model but also enhances the practicality of the previously proposed model that relied on an HbA1c input. The nonparametric Wilcoxon paired test conducted on the percentage error of implicit and explicit HbA1c prediction results reveals a substantial difference, with a p-value of 2.75 × 10–7.

Atrial fibrillation (AFib) is a common type of arrhythmia that is often clinically asymptomatic, which increases the risk of stroke significantly but can be prevented with anticoagulation. The photoplethysmogram (PPG) has recently attracted a lot of attention as a surrogate for electrocardiography (ECG) on atrial fibrillation (AFib) detection, with its out-of-hospital usability for rapid screening or long-term monitoring. Previous studies on AFib detection via PPG signals have achieved good results, but were short of intuitive criteria like ECG p-wave absence or not, especially while using interval randomness to detect AFib suffering from conjunction with premature contractions (PAC/PVC). In this study, we newly developed a PPG flux (pulse amplitude) and interval plots-based methodology, simply comprising an irregularity index threshold of 20 and regression error threshold of 0.06 for the precise automatic detection of AFib. The proposed method with automated detection on AFib shows a combined sensitivity, specificity, accuracy, and precision of 1, 0.995, 0.995, and 0.952 across the 460 samples. Furthermore, the flux-interval plot configuration also acts as a very intuitive tool for visual reassessment to confirm the automatic detection of AFib by its distinctive plot pattern compared to other cardiac rhythms. The study demonstrated that exclusive 2 false-positive cases could be corrected after the reassessment. With the methodology’s background theory well established, the detection process automated and visualized, and the PPG sensors already extensively used, this technology is very user-friendly and convincing for promoted to in-house AFib diagnostics.

Abstract Nonischemic cardiomyopathies (NICMs) are composed of variable disease entities, including primary and secondary cardiomyopathies. Determining the etiology of NICM provides pivotal roles of not only the understanding of the individual pathogenesis, but also the clinical management, such as risk stratification, pharmacological treatment, and intervention therapies. Despite the diverse causes of NICM, these cases mostly require clinical attention owing to progressive myocardial injury, resulting in ventricular dysfunction and heart failure. The interaction between the diseased ventricular substrates and systemic/neurophysiological factors contributes to the cornerstones responsible for ventricular arrhythmogenesis and sudden cardiac death (SCD). Prevention of SCD and diminishing ventricular tachyarrhythmias are the important mainstays for the management of NICM patients. Given the understanding of the abnormal ventricular substrates and advancement of navigation systems, radiofrequency catheter ablation (RFCA) has become an adjunctive or alternative strategy for NICM patients who experience drug‐refractory ventricular tachycardias (VTs). Successful ablation can frequently be achieved at the expense of an epicardial intervention. A recent study has proven the survival benefits for NICM patients who are free from recurrent VTs after a successful RFCA, regardless of the New York Heart Association (NYHA) functional class status or left ventricular ejection fraction. Additionally, recent evidence has highlighted the better delineation of a diseased myocardium through the incorporation of cardiovascular magnetic resonance imaging (CMRI) and 3D mapping systems, which can facilitate the identification of critical ventricular arrhythmogenic substrates in NICM patients.

Previously published photoplethysmography-(PPG) based non-invasive blood glucose (NIBG) measurements have not yet been validated over 500 subjects. As illustrated in this work, we increased the number subjects recruited to 2538 and found that the prediction accuracy (the ratio in zone A of Clarke’s error grid) reduced to undesirable 60.6%. We suspect the low prediction accuracy induced by larger sample size might arise from the physiological diversity of subjects, and one possibility is that the diversity might originate from medication. Therefore, we split the subjects into two cohorts for deep learning: with and without medication (1682 and 856 recruited subjects, respectively). In comparison, the cohort training for subjects without any medication had approximately 30% higher prediction accuracy over the cohort training for those with medication. Furthermore, by adding quarterly (every 3 months) measured glycohemoglobin (HbA1c), we were able to significantly boost the prediction accuracy by approximately 10%. For subjects without medication, the best performing model with quarterly measured HbA1c achieved 94.3% prediction accuracy, RMSE of 12.4 mg/dL, MAE of 8.9 mg/dL, and MAPE of 0.08, which demonstrates a very promising solution for NIBG prediction via deep learning. Regarding subjects with medication, a personalized model could be a viable means of further investigation.

BackgroundMyocardial infarction increases the risk of heart failure (HF) and atrial fibrillation. Renal denervation (RDN) might suppress the development of atrial remodeling. This study aimed to elucidate the molecular mechanism of RDN in the suppression of atrial fibrillation in a HF model after myocardial infarction. Methods and ResultsHF rabbits were created 4 weeks after coronary ligation. Rabbits were classified into 3 groups: normal control (n=10), HF (n=10), and HF‐RDN (n=6). Surgical and chemical RDN were approached through midabdominal incisions in HF‐RDN. Left anterior descending coronary artery in HF and HF‐RDN was ligated to create myocardial infarction. After electrophysiological study, the rabbits were euthanized and the left atrial appendage was harvested for real‐time polymerase chain reaction analysis and Trichrome stain. Left atrial dimension and left ventricular mass were smaller in HF‐RDN by echocardiography compared with HF. Attenuated atrial fibrosis and tyrosine hydroxylase levels were observed in HF‐RDN compared with HF. The mRNA expressions of Cav1.2, Nav1.5, Kir2.1, KvLQT1, phosphoinositide 3‐kinase, AKT, and endothelial nitric oxide synthase in HF‐RDN were significantly higher compared with HF. The effective refractory period and action potential duration of HF‐RDN were significantly shorter compared with HF. Decreased atrial fibrillation inducibility was noted in HF‐RDN compared with HF (50% versus 100%, P

INTRODUCTION:The signal characteristics of intracardiac bipolar electrograms at the origin of idiopathic RVOT-VT during sinus rhythm remain unclear. OBJECTIVE:The study sought to develop a novel real-time/online technique, simultaneous amplitude frequency electrogram transformation (SAFE-T), to quantify and localize the diseased ventricular substrate in idiopathic RVOT-VT. METHODS:We retrospectively investigated the intracardiac bipolar recordings in 70 consecutive patients (26% male, mean age 42±12 years) who underwent successful radiofrequency catheter ablation of idiopathic RVOT-VT. We quantified the extent of the frequency fraction of ventricular potentials during sinus rhythm or ventricular pacing using a novel formula, the product of instantaneous amplitude and frequency, and showed that in a 3D geometry as an online SAFE-T map. RESULTS:The characteristics of the HHT spectra of electrograms derived from VT origins demonstrated high frequency components (>70 Hz), which were independent of the rhythm. The density of the abnormal potentials at the VT origins were higher (VT origins, 7.5±2.3 sites/cm2 vs. surrounding myocardium, 1.5±1.3 sites/cm2, p3.0 Hz·mV. CONCLUSION:The online SAFE-T map was feasible for quantifying the diseased ventricular substrate, irrespective of the rhythm of activation, and can be used to identify the optimal ablation targets for idiopathic RVOT-VT. We found a limited region of abnormal potentials where the RVOT-VT origins were successfully ablated.

The impact of non-sustained ventricular tachycardia (NSVT) on the risk of thromboembolic event and clinical outcomes in patients without structural heart disease remains undetermined. This study aimed to evaluate the association between NSVT and clinical outcomes.The study population of 5903 patients was culled from the "Registry of 24-hour ECG monitoring at Taipei Veterans General Hospital" (REMOTE database) between January 1, 2002 and December 31, 2004. Of that total, we enrolled 3767 patients without sustained ventricular tachycardia, structural heart disease, and permanent pacemaker. For purposes of this study, NSVT was defined as 3 or more consecutive beats arising below the atrioventricular node with an RR interval of 100 beats/min) and lasting < 30 seconds.There were 776 deaths, 2042 hospitalizations for any reason, 638 cardiovascular (CV)-related hospitalizations, 350 ischemic strokes, 409 transient ischemic accident (TIA), 368 new-onset heart failure (HF), and 260 new-onset atrial fibrillation (AF) with a mean follow-up duration of 10 ± 1 years. In multivariate analysis, the presence of NSVT was independently associated with death (hazard ratio [HR]: 1.362, 95% confidence interval [CI]: 1.071-1.731), CV hospitalization (HR: 1.527, 95% CI: 1.171-1.992), ischemic stroke (HR: 1.436, 95% CI: 1.014-2.032), TIA (HR 1.483, 95% CI: 1.069-2.057), and new-onset HF (HR: 1.716, 95% CI: 1.243-2.368). There was no significant association between the presence of NSVT and all-cause hospitalization or new-onset AF.In patients without structural heart disease, presence of NSVT on 24-hour monitoring was independently associated with death, CV hospitalization, ischemic stroke, TIA, and new onset heart failure.

Aims MicroRNAs (miRNAs) have been implicated in cardiac diseases. This study aimed to characterize the circulating miRNAs in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and correlate the miRNAs with the clinical outcomes of ARVC. Methods and results This study included 62 patients with ventricular arrhythmia (VA): 28 patients (45%) had definite ARVC, 11 (18%) had borderline or possible ARVC, and 23 (37%) had idiopathic ventricular tachycardia (VT). In addition, 33 age- and sex-matched healthy subjects were enrolled as normal control subjects. The expression of selected miRNAs was analysed in all study subjects. The clinical outcomes of patients with definite ARVC after catheter ablation were further investigated. On the basis of the miRNA polymerase chain reaction array, we selected 11 miRNAs for analysis of their expression in the plasma of all subjects. Definite ARVC patients had significantly higher expression of circulating miR-144-3p, 145-5p, 185-5p, and 494 than the three other groups. Out of 25 definite ARVC patients who underwent radiofrequency catheter ablation, recurrent VA occurred in 8 patients (32%) during the follow-up period (45 ± 20 months). Definite ARVC patients with recurrent VA had a higher level of circulating miR-494 than did those without recurrence. Receiver operating characteristic analysis showed miR-494 to be a predictive factor of recurrent VA (area under the curve: 0.832). Conclusion Plasma levels of miR-144-3p, 145-5p, 185-5p, and 494 were significantly elevated in definite ARVC patients with VA. An increased plasma level of miR-494 was associated with the recurrence of VA after ablation in definite ARVC patients. [ABSTRACT FROM AUTHOR]

Aims: Whether the distribution of scar in arrhythmogenic right ventricular cardiomyopathy (ARVC) plays a role in predicting different types of ventricular arrhythmias is unknown. This study aimed to investigate the prognostic value of scar distribution in patients with ARVC.Methods and results: We studied 80 consecutive ARVC patients (46 men, mean age 47 ± 15 years) who underwent an electrophysiological study with ablation. Thirty-four patients receive both endocardial and epicardial mapping. Abnormal endocardial substrates and epicardial substrates were characterized. Three groups were defined according to the epicardial and endocardial scar gradient (<10%: transmural, 10-20%: intermediate, >20%: horizontal, as groups 1, 2, and 3, respectively). Sinus rhythm electrograms underwent a Hilbert-Huang spectral analysis and were displayed as 3D Simultaneous Amplitude Frequency Electrogram Transformation (SAFE-T) maps, which represented the arrhythmogenic potentials. The baseline characteristics were similar between the three groups. Group 3 patients had a higher incidence of fatal ventricular arrhythmias requiring defibrillation and cardiac arrest during the initial presentation despite having fewer premature ventricular complexes. A larger area of arrhythmogenic potentials in the epicardium was observed in patients with horizontal scar. The epicardial-endocardial scar gradient was independently associated with the occurrence of fatal ventricular arrhythmias after a multivariate adjustment. The total, ventricular tachycardia, and VF recurrent rates were higher in Group 3 during 38 ± 21 months of follow-up.Conclusion: For ARVC, the epicardial substrate that extended in the horizontal plane rather than transmurally provided the arrhythmogenic substrate for a fatal ventricular arrhythmia circuit. [ABSTRACT FROM AUTHOR]

Aims: The detailed electrophysiological characteristics of patients with both atrioventricular nodal re-entrant tachycardia (AVNRT) and atrial flutter (AFL) have not been clarified. This study investigated the related electrophysiological differences in a large series of patients undergoing radiofrequency catheter ablation of AVNRT.Methods and Results: A total of 1063 clinically documented AVNRT patients underwent catheter ablation were enrolled. Before the slow pathway (SP) ablation, 61 patients (5.7%) had inducible sustained cavotricuspid isthmus (CTI)-dependent AFL (Group 1), and the others (94.3%) without inducible sustained CTI-dependent AFL were defined as Group 2. The electrophysiological characteristics of these two groups and effect of the SP ablation on the inducibility of AFL were assessed. In Group 1, 36 patients (59%) had inducible/sustained AFL after the ablation of AVNRT and required a CTI ablation. The Group 1 patients had more AVNRT with continuous atrioventricular (AV) node function curves (P < 0.001, odds ratio = 7.55 [3.70-16.7], multivariate regression), and a younger age (P = 0.02, odds ratio = 1.02 [1.003-1.03], multivariate regression) than Group 2. The other characteristics were comparable between the two groups. The long-term follow-up (64.9 ± 34.9 months) revealed that the recurrence of AFL/atrial fibrillation was similar between the two groups (P > 0.05).Conclusion: Atrioventricular nodal re-entrant tachycardia patients with concomitant CTI-dependent AFL had more continuous AV node function curves. Forty-one per cent of these patients had non-inducible AFL after the SP ablation, indicating a slow conduction isthmus in the triangle of Koch area. [ABSTRACT FROM AUTHOR]

Background: Radiofrequency ablation of ventricular arrhythmias (VAs) originating from the continuum between the aortic sinus of Valsalva (ASV) and the left ventricular (LV) summit is a challenge.Objectives: The objectives of this study were to investigate the electrocardiographic, electrophysiological, and anatomical characteristics of VAs and to develop an algorithm for predicting the successful ablation site.Methods: We recruited 66 patients (mean age, 47 ± 15 years; 42 male patients) with symptomatic VAs originating from the continuum between the ASV and the LV summit who underwent radiofrequency ablation. Patients were classified into 4 groups (group 1: ASV, n = 20; group 2: subvalvular region, n = 15; group 3: great cardiac vein/anterior interventricular vein [GCV/AIV], n = 16; group 4: epicardium requiring pericardial access, n = 15). The QRS morphological characteristics of VAs were compared between the 4 groups.Results: Electrocardiographic analysis revealed that the aVL/aVR Q-wave ratio is useful in the prediction of successful ablation sites in the ASV, subvalvular area, GCV/AIV, and epicardium requiring pericardial access at cutoff values of ≤1.415, 1.416-1.535, 1.536-1.740, and >1.740, respectively. The aVL/aVR Q-wave ratio was well correlated with the distance between the successful ablation site and the tip of the LV summit. A distance of >18.9 mm and an LV myocardial thickness of >9.1 mm predicted the need for the epicardial or GCV/AIV approaches. There were no major procedural complications. Eight patients (12.1%) developed VA recurrence during a mean follow-up of 15.9 months (interquartile range 9.2-24.2 months).Conclusion: The aVL/aVR Q-wave ratio is a useful parameter for predicting the successful ablation sites of VAs originating from the continuum between the ASV and the LV summit. [ABSTRACT FROM AUTHOR]