Periodic repolarization dynamics: Different methods for quantifying low-frequency oscillations of repolarization.

BACKGROUND: Periodic repolarization dynamics (PRD) is an electrocardiographic biomarker that quantifies low-frequency (LF) instabilities of repolarization. PRD is a strong predictor of mortality in patients with ischaemic and non-ischaemic cardiomyopathy. Until recently, two methods for calculating PRD have been proposed. The wavelet analysis has been widely tested and quantifies PRD in deg2 units by application of continuous wavelet transformation (PRDwavelet). The phase rectified signal averaging method (PRDPRSA) is an algebraic method, which quantifies PRD in deg. units. The correlation, as well as a conversion formula between the two methods remain unknown. METHOD: The first step for quantifying PRD is to calculate the beat-to-beat change in the direction of repolarization, called dT°. PRD is subsequently quantified by means of either wavelet or PRSA-analysis. We simulated 1.000.000 dT°-signals. For each simulated signal we calculated PRD using the wavelet and PRSA-method. We calculated the ratio between PRDwavelet and PRDPRSA for different values of dT° and RR-intervals and applied this ratio in a real-ECG validation cohort of 455 patients after myocardial infarction (MI). We finally calculated the correlation coefficient between real and calculated PRDwavelet. PRDwavelet was dichotomized at the established cut-off value of ≥5.75 deg2. RESULTS: The ratio between PRDwavelet and PRDPRSA increased with increasing heart-rate and mean dT°-values (p < 0.001 for both). The correlation coefficient between PRDwavelet and PRDPRSA in the validation cohort was 0.908 (95% CI 0.891-0.923), which significantly (p < 0.001) improved to 0.945 (95% CI 0.935-0.955) after applying the formula considering the ratio between PRDwavelet and PRDPRSA obtained from the simulation cohort. The calculated PRDwavelet correctly classified 98% of the patients as low-risk and 87% of the patients as high-risk and correctly identified 97% of high-risk patients, who died within the follow-up period. CONCLUSION: This is the first analytical investigation of the different methods used to calculate PRD using simulated and clinical data. In this article we propose a novel algorithm for converting PRDPRSA to the widely validated PRDwavelet, which could unify the calculation methods and cut-offs for PRD.

Dual antiplatelet therapy de-escalation in acute coronary syndrome: an individual patient meta-analysis.

AIMS: Dual-antiplatelet therapy (DAPT) with aspirin and a potent P2Y12 inhibitor is the standard treatment for patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). De-escalation of the potent P2Y12 inhibtor is an appealing concept to balance the ischaemic and bleeding risks after PCI. An individual patient data meta-analysis was performed to compare de-escalation versus standard DAPT in patients with ACS. METHODS AND RESULTS: Electronic databases, including PubMed, Embase, and the Cochrane database, were searched to identify randomised clinical trials (RCTs) comparing the de-escalation strategy with the standard DAPT after PCI in patients with ACS. Individual patient-level data were collected from the relevant trials. The co-primary endpoints of interest were the ischaemic composite endpoint (a composite of cardiac death, myocardial infarction, and cerebrovascular events) and bleeding endpoint (any bleeding) at 1-year post-PCI. Four RCTs (the TROPICAL-ACS, POPular Genetics, HOST-REDUCE-POLYTECH-ACS, and TALOS-AMI trials) including 10 133 patients were analysed. The ischaemic endpoint was significantly lower in the patients assigned to the de-escalation strategy than in those assigned to the standard strategy (2.3% vs. 3.0%, hazard ratio [HR] 0.761, 95% confidence interval [CI] 0.597-0.972, log rank P = 0.029). Bleeding was also significantly lower in the de-escalation strategy group (6.5% vs. 9.1%, HR 0.701, 95% CI 0.606-0.811, log rank P < 0.001). No significant intergroup differences were observed in terms of all-cause death and major bleeding events. Subgroup analyses revealed that compared to guided de-escalation, unguided de-escalation had a significantly larger impact on bleeding endpoint reduction (P for interaction = 0.007); no intergroup differences were observed for the ischaemic endpoints. CONCLUSION: In this individual patient data meta-analysis, DAPT-based de-escalation was associated with both decreased ischaemic and bleeding endpoints. Reduction in bleeding endpoints was more prominent for the unguided than the guided de-escalation strategy. STUDY REGISTRATION NUMBER: This study was registered in the PROSPERO (ID: CRD42021245477).

Periodic Repolarization Dynamics Identifies ICD Responders in Nonischemic Cardiomyopathy: A DANISH Substudy.

BACKGROUND: Identification of patients with nonischemic cardiomyopathy who may benefit from prophylactic implantation of a cardioverter-defibrillator. We hypothesized that periodic repolarization dynamics (PRD), a marker of repolarization instability associated with sympathetic activity, could be used to identify patients who will benefit from prophylactic implantable cardioverter defibrillator (ICD) implantation. METHODS: We performed a post hoc analysis of DANISH (Danish ICD Study in Patients With Dilated Cardiomyopathy), in which patients with nonischemic cardiomyopathy, left ventricular ejection fraction (LVEF) ≤35%, and elevated NT-proBNP (N-terminal probrain natriuretic peptides) were randomized to ICD implantation or control group. Patients were included in the PRD substudy if they had a 24-hour Holter monitor recording at baseline with technically acceptable ECG signals during the night hours (00:00-06:00). PRD was assessed using wavelet analysis according to previously validated methods. The primary end point was all-cause mortality. Cox regression models were adjusted for age, sex, NT-proBNP, estimated glomerular filtration rate, LVEF, atrial fibrillation, ventricular pacing, diabetes, cardiac resynchronization therapy, and mean heart rate. We proposed PRD ≥10 deg2 as an exploratory cut-off value for ICD implantation. RESULTS: A total of 748 of the 1116 patients in DANISH qualified for the PRD substudy. During a mean follow-up period of 5.1±2.0 years, 82 of 385 patients died in the ICD group and 85 of 363 patients died in the control group (P=0.40). In Cox regression analysis, PRD was independently associated with mortality (hazard ratio [HR], 1.28 [95% CI, 1.09-1.50] per SD increase; P=0.003). PRD was significantly associated with mortality in the control group (HR, 1.51 [95% CI, 1.25-1.81]; P<0.001) but not in the ICD group (HR, 1.04 [95% CI, 0.83-1.54]; P=0.71). There was a significant interaction between PRD and the effect of ICD implantation on mortality (P=0.008), with patients with higher PRD having greater benefit in terms of mortality reduction. ICD implantation was associated with an absolute mortality reduction of 17.5% in the 280 patients with PRD ≥10 deg2 (HR, 0.54 [95% CI, 0.34-0.84]; P=0.006; number needed to treat=6), but not in the 468 patients with PRD <10 deg2 (HR, 1.17 [95% CI, 0.77-1.78]; P=0.46; P for interaction=0.01). CONCLUSIONS: Increased PRD identified patients with nonischemic cardiomyopathy in whom prophylactic ICD implantation led to significant mortality reduction.

Comparing efficacy and safety in catheter ablation strategies for atrial fibrillation: a network meta-analysis.

BACKGROUND: There is no consensus on the most efficient catheter ablation (CA) strategy for patients with atrial fibrillation (AF). The objective of this study was to compare the efficacy and safety of different CA strategies for AF ablation through network meta-analysis (NMA). METHODS: A systematic search of PubMed, Web of Science, and CENTRAL was performed up to October 5th, 2020. Randomized controlled trials (RCT) comparing different CA approaches were included. Efficacy was defined as arrhythmia recurrence after CA and safety as any reported complication related to the procedure during a minimum follow-up time of 6 months. RESULTS: In total, 67 RCTs (n = 9871) comparing 19 different CA strategies were included. The risk of recurrence was significantly decreased compared to pulmonary vein isolation (PVI) alone for PVI with renal denervation (RR: 0.60, CI: 0.38-0.94), PVI with ganglia-plexi ablation (RR: 0.62, CI: 0.41-0.94), PVI with additional ablation lines (RR: 0.8, CI: 0.68-0.95) and PVI in combination with bi-atrial modification (RR: 0.32, CI: 0.11-0.88). Strategies including PVI appeared superior to non-PVI strategies such as electrogram-based approaches. No significant differences in safety were observed. CONCLUSIONS: This NMA showed that PVI in combination with additional CA strategies, such as autonomic modulation and additional lines, seem to increase the efficacy of PVI alone. These strategies can be considered in treating patients with AF, since, additionally, no differences in safety were observed. This study provides decision-makers with comprehensive and comparative evidence about the efficacy and safety of different CA strategies. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registry number: CRD42020169494 .

Rationale and design of a digital trial using smartphones to detect subclinical atrial fibrillation in a population at risk: The eHealth-based bavarian alternative detection of Atrial Fibrillation (eBRAVE-AF) trial.

Current guidelines recommend opportunistic screening for subclinical atrial fibrillation (AF) taking advantage of e-health-based technologies. However, the efficacy of a fully scalable e-health-based strategy for AF detection in a head-to-head comparison with routine symptom-based screening is unknown. eBRAVE-AF is an investigator-initiated, digital, prospective, randomized, siteless, open-label, cross-over study to evaluate an e-health-based strategy for detection of AF in a real-world setting. 67,488 policyholders of a large German health insurance company (Versicherungskammer Bayern, Germany) selected by age ≥ 50 years and a CHA2DS2-VASc score ≥ 1 (females ≥2) are invited to participate. Subjects with known AF or on treatment with oral anticoagulation are excluded. After obtaining electronic informed consent, at least 4,400 participants will be randomly assigned to an e-health-based screening strategy or routine symptom-based screening. The e-health-based strategy consists of repetitive one-minute photoplethysmographic (PPG) pulse wave assessments using a certified smartphone app (Preventicus Heartbeats, Preventicus, Jena, Germany), followed by a confirmatory 14-day ECG patch (CardioMem CM 100 XT, Getemed, Teltow, Germany) in case of abnormal findings. After 6 months, participants are crossed over to the other study arm. Primary endpoint is the incidence of newly diagnosed AF leading to oral anticoagulation indicated by an independent physician. Clinical follow-up will be at least 12 months. In both groups, follow-up is performed by 4-week app-based questionnaires, personal contact in case of abnormal findings, and matching with claim-based insurance data and medical reports. At time of writing enrollment is completed. First results are expected to be available in mid-2021.

Prediction of mortality benefit based on periodic repolarisation dynamics in patients undergoing prophylactic implantation of a defibrillator: a prospective, controlled, multicentre cohort study.

BACKGROUND: A small proportion of patients undergoing primary prophylactic implantation of implantable cardioverter defibrillators (ICDs) experiences malignant arrhythmias. We postulated that periodic repolarisation dynamics, a novel marker of sympathetic-activity-associated repolarisation instability, could be used to identify electrically vulnerable patients who would benefit from prophylactic implantation of ICDs by way of a reduction in mortality. METHODS: We did a prespecified substudy of EUropean Comparative Effectiveness Research to Assess the Use of Primary ProphylacTic Implantable Cardioverter Defibrillators (EU-CERT-ICD), a prospective, investigator-initiated, non-randomised, controlled cohort study done at 44 centres in 15 EU countries. Patients aged 18 years or older with ischaemic or non-ischaemic cardiomyopathy and reduced left ventricular ejection fraction (≤35%) were eligible for inclusion if they met guideline-based criteria for primary prophylactic implantation of ICDs. Periodic repolarisation dynamics from 24-h Holter recordings were assessed blindly in patients the day before ICD implantation or on the day of study enrolment in patients who were conservatively managed. The primary endpoint was all-cause mortality. Propensity scoring and multivariable models were used to assess the interaction between periodic repolarisation dynamics and the treatment effect of ICDs on mortality. FINDINGS: Between May 12, 2014, and Sept 7, 2018, 1371 patients were enrolled in our study. 968 of these patients underwent ICD implantation, and 403 were treated conservatively. During follow-up (median 2·7 years [IQR 2·0-3·3] in the ICD group and 1·2 years [0·8-2·7] in the control group), 138 (14%) patients died in the ICD group and 64 (16%) patients died in the control group. We noted a 43% reduction in mortality in the ICD group compared with the control group (adjusted hazard ratio [HR] 0·57 [95% CI 0·41-0·79]; p=0·0008). Periodic repolarisation dynamics significantly predicted the treatment effect of ICDs on mortality (adjusted p=0·0307). The mortality benefits associated with ICD implantation were greater in patients with periodic repolarisation dynamics of 7·5 deg or higher (n=199; adjusted HR 0·25 [95% CI 0·13-0·47] for the ICD group vs the control group; p<0·0001) than in those with periodic repolarisation dynamics less than 7·5 deg (n=1166; adjusted HR 0·69 [95% CI 0·47-1·00]; p=0·0492; pinteraction=0·0056). The number needed to treat was 18·3 (95% CI 10·6-4895·3) in patients with periodic repolarisation dynamics less than 7·5 deg and 3·1 (2·6-4·8) in those with periodic repolarisation dynamics of 7·5 deg or higher. INTERPRETATION: Periodic repolarisation dynamics predict mortality reductions associated with prophylactic implantation of ICDs in contemporarily treated patients with ischaemic or non-ischaemic cardiomyopathy. Periodic repolarisation dynamics could help to guide treatment decisions about prophylactic ICD implantation. FUNDING: The European Community's 7th Framework Programme.

Platelet reactivity and clinical outcomes in acute coronary syndrome patients treated with prasugrel and clopidogrel: a pre-specified exploratory analysis from the TROPICAL-ACS trial.

AIMS: The value of platelet function testing (PFT) in predicting clinical outcomes and guiding P2Y12-inhibitor treatment is uncertain. In a pre-specified sub-study of the TROPICAL-ACS trial, we assessed ischaemic and bleeding risks according to high platelet reactivity (HPR) and low platelet reactivity (LPR) to ADP in patients receiving uniform prasugrel vs. PFT-guided clopidogrel or prasugrel. METHODS AND RESULTS: Acute coronary syndrome patients with PFT done 14 days after hospital discharge were included with prior randomization to uniform prasugrel for 12 months (control group, no treatment modification) vs. early de-escalation from prasugrel to clopidogrel and PFT-guided maintenance treatment (HPR: switch-back to prasugrel, non-HPR: clopidogrel). The composite ischaemic endpoint included cardiovascular death, myocardial infarction, or stroke, while key safety outcome was Bleeding Academic Research Consortium (BARC) 2-5 bleeding, from PFT until 12 months. We identified 2527 patients with PFT results available: 1266 were randomized to the guided and 1261 to the control group. Before treatment adjustment, HPR was more prevalent in the guided group (40% vs. 15%), while LPR was more common in control patients (27% vs. 11%). Compared to control patients without HPR on prasugrel (n = 1073), similar outcomes were observed in guided patients kept on clopidogrel [n = 755, hazard ratio (HR): 1.06 (0.57-1.95), P = 0.86] and also in patients with HPR on clopidogrel switched to prasugrel [n = 511, HR: 0.96 (0.47-1.96), P = 0.91]. In contrast, HPR on prasugrel was associated with a higher risk for ischaemic events in control patients [n = 188, HR: 2.16 (1.01-4.65), P = 0.049]. Low platelet reactivity was an independent predictor of bleeding [HR: 1.74 (1.18-2.56), P = 0.005], without interaction (Pint = 0.76) between study groups. CONCLUSION: Based on this substudy of a randomized trial, selecting prasugrel or clopidogrel based on PFT resulted in similar ischaemic outcomes as uniform prasugrel therapy without HPR. Although infrequent, HPR on prasugrel was associated with increased risk of ischaemic events. Low platelet reactivity was a strong and independent predictor of bleeding both on prasugrel and clopidogrel.

Bedside autonomic risk stratification after myocardial infarction by means of short-term deceleration capacity of heart rate.

Aims: Twenty-four-hour deceleration capacity (DC24h) of heart rate is a strong predictor of mortality after myocardial infarction (MI). Assessment of DC from short-term recordings (DCst) would be of practical use in everyday clinical practice but its predictive value is unknown. Here, we test the usefulness of DCst for autonomic bedside risk stratification after MI. Methods and results: We included 908 patients after acute MI enrolled in Munich and 478 patients with acute (n = 232) and chronic MI (n = 246) enrolled in Tuebingen, both in Germany. We assessed DCst from high-resolution resting electrocardiogram (ECG) recordings (<30 min) performed under standardized conditions in supine position. In the Munich cohort, we also assessed DC24h from 24-h Holter recordings. Deceleration capacity was dichotomized at the established cut-off value of ≤ 2.5 ms. Primary endpoint was 3-year mortality. Secondary endpoint was 3-year cardiovascular mortality. In addition to DC, multivariable analyses included the Global Registry of Acute Coronary Events score >140 and left ventricular ejection fraction ≤ 35%. During follow-up, 48 (5.3%) and 48 (10.0%) patients died in the Munich and Tuebingen cohorts, respectively. On multivariable analyses, DCst ≤ 2.5 ms was the strongest predictor of mortality, yielding hazard ratios of 5.04 (2.68-9.49; P < 0.001) and 3.19 (1.70-6.02; P < 0.001) in the Munich and Tuebingen cohorts, respectively. Deceleration capacity assessed from short-term recordings ≤ 2.5 ms was also an independent predictor of cardiovascular mortality in both cohorts. Implementation of DCst ≤ 2.5 ms into the multivariable models led to a significant increase of C-statistics and integrated discrimination improvement score. Conclusion: Deceleration capacity assessed from short-term recordings is a strong and independent predictor of mortality and cardiovascular mortality after MI, which is complementary to existing risk stratification strategies.

Prediction of sudden and non-sudden cardiac death in post-infarction patients with reduced left ventricular ejection fraction by periodic repolarization dynamics: MADIT-II substudy.

AIMS: To test the value of Periodic Repolarization Dynamics (PRD), a recently validated electrocardiographic marker of sympathetic activity, as a novel approach to predict sudden cardiac death (SCD) and non-sudden cardiac death (N-SCD) and to improve identification of patients that profit from ICD-implantation. METHODS AND RESULTS: We included 856 post-infarction patients with left-ventricular ejection fraction (LVEF) ≤30% of the MADIT-II trial in sinus rhythm. Of these, 507 and 348 patients were randomized to ICD or conventional treatment. PRD was assessed from multipolar 10-min baseline ECGs. Primary and secondary endpoints were total mortality, SCD and N-SCD. Multivariable analyses included treatment group, QRS-duration, New York Heart Association classification, blood-urea nitrogen, diabetes mellitus, beta-blocker therapy and LVEF. During follow-up of 20.4 months, 119 patients died (53 SCD and 36 N-SCD). On multivariable analyses, increased PRD was a significant predictor of mortality (standardized coefficient 1.37[1.19-1.59]; P < 0.001) and SCD (1.40 [1.13-1.75]; P = 0.003) but also predicted N-SCD (1.41[1.10-1.81]; P = 0.006). While increased PRD predicted SCD in conventionally treated patients (1.61[1.23-2.11]; P < 0.001), it was predictive of N-SCD (1.63[1.28-2.09]; P < 0.001) and adequate ICD-therapies (1.20[1.03-1.39]; P = 0.017) in ICD-treated patients. ICD-treatment substantially reduced mortality in the lowest three PRD-quartiles by 53% (P = 0.001). However, there was no effect in the highest PRD-quartile (mortality increase by 29%; P = 0.412; P < 0.001 for difference) as the reduction of SCD was compensated by an increase of N-SCD. CONCLUSION: In post-infarction patients with impaired LVEF, PRD is a significant predictor of SCD and N-SCD. Assessment of PRD is a promising tool to identify post-MI patients with reduced LVEF who might benefit from intensified treatment.

Implantable cardiac monitors in high-risk post-infarction patients with cardiac autonomic dysfunction and moderately reduced left ventricular ejection fraction: Design and rationale of the SMART-MI trial.

BACKGROUND: Most deaths after myocardial infarction (MI) occur in patients with left ventricular ejection fraction (LVEF) >35%, for whom no specific prophylactic strategies exist. Deceleration capacity (DC) of heart rate and periodic repolarization dynamics (PRD) are noninvasive electrophysiological markers depending on the vagal and sympathetic tone. The combination of abnormal DC and/or PRD identifies a new high-risk group among postinfarction patients with LVEF 36%-50%. This new high-risk group has similar characteristics with respect to prognosis and patient numbers to those of the established high-risk group identified by LVEF ≤ 35%. STUDY DESIGN: The SMART-MI trial is an investigator-initiated randomized prospective multicenter trial that tests the efficacy of implantable cardiac monitors (ICM) in this new high-risk group. The study will enroll approximately 1,600 survivors of acute MI with sinus rhythm and an LVEF of 35%-50% in 17 centers in Germany who will be tested for presence of cardiac autonomic dysfunction. Four hundred patients with either abnormal DC (≤2.5 ms) and/or PRD (≥5.75deg2) will be randomized in a 1:1 fashion to intensive follow-up via telemonitoring using an ICM device (experimental arm) or conventional follow-up (control arm). For the ICM arm, specific treatment paths have been developed according to current guidelines. OUTCOMES: The primary end point is time to detection of predefined serious arrhythmic events during follow-up, including atrial fibrillation ≥6minutes, nonsustained ventricular tachycardia (cycle length≤320 ms; ≥40 beats), atrioventricular block ≥IIb, and sustained ventricular tachycardia/ventricular fibrillation. The median follow-up period is 18months with a minimum follow-up of 6months. The effect of remote monitoring on clinical outcomes will be tested as secondary outcome measure (ClinicalTrials.gov NCT02594488).

Periodic repolarization dynamics in patients with moderate to severe aortic stenosis.

BACKGROUND: Periodic repolarization dynamics (PRD) refers to low-frequency oscillations of cardiac repolarization, most likely related to phasic sympathetic activation. Increased PRD is a validated predictor of mortality after myocardial infarction and in ischemic heart disease, but has not been tested in aortic valve stenosis (AS). Here, we assessed PRD in patients with AS and tested its correlation with clinical and hemodynamic parameters as well as markers of heart rate variability (HRV). MATERIALS AND METHODS: We prospectively enrolled 139 consecutive patients with moderate to severe AS in sinus rhythm. In all patients we performed a 24-h Holter ECG in Frank-leads configuration. We assessed PRD according to previously published technologies from the nocturnal hours (0am-6am) and dichotomized PRD at the established cut-off value of ≥5.75deg2. In addition to clinical and hemodynamic markers, we also assessed deceleration capacity (DC) of heart rate, heart rate turbulence and standard HRV parameters. RESULTS: In the patients studied, PRD was 6.55±3.96deg2. Seventy-three patients (52.5%) had increased PRD. Among them, 36 (49.9%) patients were classified as being asymptomatic. There was no association between increased PRD and clinical or hemodynamic markers, including presence of symptoms, NYHA-classification, aortic valve area, and left-ventricular ejection fraction. Thirty-three of the 73 (45.2%) patients with PRD ≥5.75deg2 also suffered from decreased vagal tonic activity by means of abnormal DC (≤2.5ms) indicating severe autonomic dysfunction. CONCLUSION: Prevalence of increased PRD is high among patients with moderate to severe AS. Patients with increased PRD cannot be identified by clinical or hemodynamic markers Future studies should test the prognostic value of PRD in patients with AS.

Autonomic nervous system activity as risk predictor in the medical emergency department: a prospective cohort study.

OBJECTIVES: To evaluate heart rate deceleration capacity, an electrocardiogram-based marker of autonomic nervous system activity, as risk predictor in a medical emergency department and to test its incremental predictive value to the modified early warning score. DESIGN: Prospective cohort study. SETTING: Medical emergency department of a large university hospital. PATIENTS: Five thousand seven hundred thirty consecutive patients of either sex in sinus rhythm, who were admitted to the medical emergency department of the University of Tübingen, Germany, between November 2010 and March 2012. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Deceleration capacity of heart rate was calculated within the first minutes after emergency department admission. The modified early warning score was assessed from respiratory rate, heart rate, systolic blood pressure, body temperature, and level of consciousness as previously described. Primary endpoint was intrahospital mortality; secondary endpoints included transfer to the ICU as well as 30-day and 180-day mortality. One hundred forty-two patients (2.5%) reached the primary endpoint. Deceleration capacity was highly significantly lower in nonsurvivors than survivors (2.9 ± 2.1 ms vs 5.6 ± 2.9 ms; p < 0.001) and yielded an area under the receiver-operator characteristic curve of 0.780 (95% CI, 0.745-0.813). The modified early warning score model yielded an area under the receiver-operator characteristic curve of 0.706 (0.667-0.750). Implementing deceleration capacity into the modified early warning score model led to a highly significant increase of the area under the receiver-operator characteristic curve to 0.804 (0.770-0.835; p < 0.001 for difference). Deceleration capacity was also a highly significant predictor of 30-day and 180-day mortality as well as transfer to the ICU. CONCLUSIONS: Deceleration capacity is a strong and independent predictor of short-term mortality among patients admitted to a medical emergency department.

Automated assessment of cardiac autonomic function by means of deceleration capacity from noisy, nonstationary ECG signals: validation study.

BACKGROUND: Assessment of heart rate variability by means of deceleration capacity (DC) provides a noninvasive probe of cardiac autonomic activity. However, clinical use of DC is limited by the need of manual review of the ECG signals to eliminate artifacts, noise, and nonstationarities. OBJECTIVE: To validate a novel approach to fully automatically assess DC from noisy, nonstationary signals METHODS: We analyzed 100 randomly selected ECG tracings recorded for 10 minutes by routine monitor devices (GE DASH 4000, sample size 100 Hz) in a medical emergency department. We used a novel automated R-peak detection algorithm, which is mainly based on a Shannon energy envelope estimator and a Hilbert transformation. We transformed the automatically generated RR interval time series by phase-rectified signal averaging (PRSA) to assess DC of heart rate (DCauto ). DCauto was compared to DCmanual , which was obtained from the same manually preprocessed ECG signals. RESULTS: DCauto and DCmanual showed good correlation and agreement, particularly if a low-pass filter was implemented into the PRSA algorithm. Correlation coefficient between DCauto and DCmanual was 0.983 (P < 0.0001). Average difference between DCauto and DCmanual was -0.23±0.49 ms with limits of agreement ranging from -1.19 to 0.73 ms. Significantly lower correlations were observed when a different R-peak detection algorithm or conventional heart rate variability (HRV) measures were tested. CONCLUSIONS: DC can be fully automatically assessed from noisy, nonstationary ECG signals.

Biomarker Periodic Repolarization Dynamics Indicates Enhanced Risk for Arrhythmias and Sudden Cardiac Death in Myocardial Infarction in Pigs.

BACKGROUND: Periodic repolarization dynamics (PRD) is an electrocardiographic biomarker that captures repolarization instability in the low frequency spectrum and is believed to estimate the sympathetic effect on the ventricular myocardium. High PRD indicates an increased risk for postischemic sudden cardiac death (SCD). However, a direct link between PRD and proarrhythmogenic autonomic remodeling has not yet been shown. METHODS AND RESULTS: We investigated autonomic remodeling in pigs with myocardial infarction (MI)-related ischemic heart failure induced by balloon occlusion of the left anterior descending artery (n=17) compared with pigs without MI (n=11). Thirty days after MI, pigs demonstrated enhanced sympathetic innervation in the infarct area, border zone, and remote left ventricle paralleled by altered expression of autonomic marker genes/proteins. PRD was enhanced 30 days after MI compared with baseline (pre-MI versus post-MI: 1.75±0.30 deg2 versus 3.29±0.79 deg2, P<0.05) reflecting pronounced autonomic alterations on the level of the ventricular myocardium. Pigs with MI-related ventricular fibrillation and SCD had significantly higher pre-MI PRD than pigs without tachyarrhythmias, suggesting a potential role for PRD as a predictive biomarker for ischemia-related arrhythmias (no ventricular fibrillation versus ventricular fibrillation: 1.50±0.39 deg2 versus 3.18±0.53 deg2 [P<0.05]; no SCD versus SCD: 1.67±0.32 deg2 versus 3.91±0.63 deg2 [P<0.01]). CONCLUSIONS: We demonstrate that ischemic heart failure leads to significant proarrhythmogenic autonomic remodeling. The concomitant elevation of PRD levels in pigs with ischemic heart failure and pigs with MI-related ventricular fibrillation/SCD suggests PRD as a biomarker for autonomic remodeling and as a potential predictive biomarker for ventricular arrhythmias/survival in the context of MI.

Atrial Functional Tricuspid Regurgitation in Patients Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: Knowledge about atrial functional tricuspid regurgitation (afTR) in transcatheter aortic valve replacement (TAVR) patients is scarce. OBJECTIVES: The aim of the study was to analyze the association between the entity and the development of tricuspid regurgitation (TR) in patients undergoing TAVR for aortic stenosis and concomitant TR. METHODS: We analyzed patients undergoing TAVR for severe aortic stenosis from January 2013 to December 2020 and concomitant at least moderate TR at baseline. afTR was defined as enlargement of the right atrium in relation to the right ventricle. TR development after TAVR and 3-year all-cause mortality were evaluated. RESULTS: Out of 3,474 TAVR patients, we identified 420 patients with concomitant at least moderate TR. A total of 363 patients were included in the study, with 178 patients stratified in the afTR and 185 in the non-afTR group based on a receiver-operating characteristic curve cutoff of 1.132 of the right atrial/right ventricular area ratio. TR improvement after TAVR was observed in significantly less patients with afTR compared with non-afTR (31.1% vs 60.6%; P < 0.001). Multivariate regression analysis confirmed afTR as independent predictor for TR persistence (adjusted OR: 2.80; 95% CI: 1.66-4.76; P < 0.001). Moreover, afTR was associated with aggravation of TR after TAVR (17.0% vs 6.8%; P = 0.013). Three-year all-cause mortality was significantly higher in patients with persistence compared with patients with improvement of TR (P < 0.001). CONCLUSIONS: In TAVR patients, afTR is an independent predictor for TR persistence. Moreover, TR persistence is associated with increased 3-year all-cause mortality.

Impact of body mass on P2Y12-inhibitor de-escalation in acute coronary syndromes-a substudy of the TROPICAL-ACS trial.

AIMS: Clinical guidelines recommend de-escalation antiplatelet strategies to reduce bleeding risk in acute coronary syndrome (ACS) patients, albeit with a weak recommendation. This substudy of the TROPICAL-ACS trial aimed to determine the impact of body mass on the efficacy of a platelet function testing-guided de-escalation regimen in ACS patients after percutaneous coronary intervention. METHODS AND RESULTS: Patients were randomized to prasugrel (control group) or a platelet function testing-guided regimen with clopidogrel or prasugrel defined after 1-week clopidogrel. The primary endpoint was the net clinical benefit [cardiovascular death, myocardial infarction, stroke, or Bleeding Academic Research Consortium (BARC) 2-5 bleeding] for 12 months. Overweight was defined as a body mass index >25 kg/m2.Patients without overweight showed a significant net clinical benefit from the de-escalation strategy, while in overweight cases de-escalation was comparable to prasugrel treatment [hazard ratio (HR): 0.52; 95% confidence interval (CI): 0.31-0.88; P = 0.013 and HR: 0.95; 95% CI: 0.69-1.31, P = 0.717, P-non-inferiority = 0.03, respectively, P-interaction = 0.053]. The benefit of de-escalation in terms of the risk of bleeding or of the ischaemic events did not reach statistical significance. Bleeding events with de-escalation were less frequent in non-overweight patients but comparable in overweight patients (HR: 0.55; 95% CI: 0.30-1.03; P = 0.057 and HR: 0.95; 95% CI: 0.64-1.41, respectively, P-interaction = 0.147). Non-overweight patients had lower ischaemic event rates with de-escalation, while overweight cases had slightly less (HR: 0.47; 95% CI: 0.18-1.25; P = 0.128 and HR: 0.89; 95% CI: 0.53-1.50, respectively, P-interaction = 0.261). CONCLUSION: The strategy of guided dual antiplatelet therapy de-escalation was associated with a significant net clinical benefit in non-overweight patients, while the two strategies were equivalent in overweight patients.