Predictor Of Arrhythmic Events Research Articles

Progression of myocardial dysfunction and prediction of arrhythmic events in patients with exercise-induced arrhythmogenic cardiomyopathy

Progression of myocardial dysfunction and prediction of arrhythmic events in patients with exercise-induced arrhythmogenic cardiomyopathy

Association of Late Potentials With Fatal Arrhythmic Events in Patients With Brugada Syndrome-A Meta-analysis.

Risk stratification of patients with Brugada syndrome (BrS) remains challenging. Signal-averaged electrocardiogram (SAECG) is a noninvasive tool that can be used to identify the electrophysiologic substrate potentially underlying fatal ventricular arrhythmias. The aim of this meta-analysis is to summarize the existing evidence about the role of late potentials (LP) as a predictor for arrhythmic events in patients with BrS. A systematic search in the MedLine database through to June 2022 without any limitations was performed. Ten studies were included in the quantitative synthesis (1431 patients with BrS, mean age 47.4 years, males 86%). Of these, 1220 patients underwent SAECG evaluation (53.2% had positive LP, and 20.6% had a fatal arrhythmic event). There was a nonsignificant association between positive LPs and fatal arrhythmic events [RR: 2.06 (0.98-4.36), P = 0.06, I 2 = 82%]. By including only studies with patients without a history of fatal arrhythmia, the association between LP with arrhythmic events remained nonsignificant [RR: 1.29 (0.67-2.48), P = 0.44, I 2 = 54%]. In conclusion, there is a possible association between LP and fatal arrhythmic events in patients with BrS, but the literature remains inconclusive. Large cohort studies using a multiparametric approach for risk stratification purposes are needed to improve the risk stratification of BrS and to optimize the selection of BrS patients that should be referred for implantable cardioverter-defibrillator.

Protective role of chronic beta-blocker intake against the appearance of complex ventricular arrhythmias in acute coronary syndrome

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Although the presence of ventricular arrhythmias (ventricular tachycardia and ventricular fibrillation) in the context of acute coronary syndromes (ACS) has decreased in the era of early reperfusion, their occurrence may lead to fatal consequences. However, clear predisposing or protective factors have not been identified yet. Purpose Our purpose is to describe the prevalence of ventricular arrhythmias before reperfusion treatment in a population of patients hospitalized due to ACS, as well as the possible protective role of chronic intake of beta-blockers, among other factors. Material and methods Retrospective, single-center and observational registry of patients admitted to a Coronary Care Unit from July 2011 to September 2022 with a diagnosis of ACS. The baseline characteristics were described, as well as factors related to diagnosis and treatment. A multivariate analysis was performed to study possible predictors of arrhythmic events. Results A total of 3123 patients diagnosed with ACS were included. 682 patients (21.8%) had beta- blockers as a chronic treatment and 201 patients (7.1%) presented ventricular arrhythmias. In Table 1 we can see the baseline characteristics of both groups, as well as the differences between them. Previous intake of beta-blockers was associated with a lower incidence of ventricular arrhythmias in patients with ST-segment elevation myocardial infarction (STEMI) (11% vs 6%, p 0.002), while no differences were observed between patients without ST-segment elevation myocardial infarction (NSTEMI) (2.3% vs 1.6%, p = 0.435). As shown in the multivariate analysis (Table 2), prior intake of beta-blockers turned out to be a protective factor against the development of ventricular arrhythmias, while ST elevation and worse initial Killip were risk factors. Conclusion Chronic intake of beta-blockers could be a protective factor against the development of ventricular arrhythmias before revascularization in patients diagnosed with acute coronary syndrome, specially those with STEMI.

Additional features in Brugada Syndrome stratification: frequent PVC and QRS duration

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Brugada syndrome (BrS) is a channelopathy with high prevalence of malignant arrhythmic events. The risk stratification in patients (pts) with Brugada electrocardiographic (ECG) pattern is of major importance, to prevent sudden cardiac death (SCD). A higher risk is evidenced in spontaneous type 1 pattern when compared with induced type-1 pattern, as so other electrocardiographic features have been explored aiming to detect additional prognostic factors. Purpose To evaluate the association of QRS duration and frequent premature ventricular contractions (PVC) with malignant arrhythmic events. Methods Prospective single-center study of consecutive pts with BrS, with spontaneous or induced type 1 pattern included from 2003 to 2021. All pts were enrolled in a protocol including annual non-invasive assessment with ECG and 24-hours Holter monitoring. Primary endpoints were defined as SCD or appropriate shocks in the context of ventricular tachycardia or fibrillation (VT/FV) during follow-up. Cox regression and Kaplan-Meier survival analyses were used to determine the association between the baseline ECG and Holter characteristics and the long-term risk of arrhythmic events. Results A total of 117 pts was included, 75 (65%) with a spontaneous type 1 pattern and 44 (33%) with an induced type 1 pattern. The mean age was 47±13years and 38 (32.5%) were male. During a median follow-up of 4.1±0.3 years, the primary endpoint occurred in 8 (6.8%) pts, with sudden cardiac death in 3 (2.6%) and appropriate shocks due to VT/FV in 5 (4.3%). Pts who suffered arrhythmic events had presented at the study inclusion higher QRS duration (124±18 vs. 108±16ms, p= 0.014) and more frequent PVCs on 24-hour Holter (169±297 vs. 29±198; p = 0.001) - Figure 1. Indeed, the presence of QRS ≥119ms was associated with a 7-fold higher risk (HR: 7.250, 95% CI 1.619-32.461, p = 0.010) and the presence of more than 6 PVC on 24-hour Holter was also associated with a 5-fold higher risk of malignant arrhythmic events (HR 5.376, 95% 1.186-24.260, p = 0.029). Conclusion QRS duration and frequent PVC may established themselves as additional risk factors. In our cohort, they were both predictors of arrhythmic events during follow-up and thus can further complement BrS risk stratification.

Growth/differentiation factor-15 (GDF-15) as a predictor of serious arrhythmic events in patients with nonischemic dilated cardiomyopathy

IntroductionCardiac biomarkers have been proposed as a new tool to improve risk stratification of serious arrhythmic events in patients with heart failure (HF) beyond estimates of left ventricular ejection fraction. Growth differentiation factor (GDF)-15, a stress-induced cytokine, has been found to correlate with markers of myocardial fibrosis and adverse clinical outcomes, but its role as a predictor of arrhythmic events in patients with nonischemic HF is uncertain. Methods and resultsA prospective observational study was conducted in 148 nonischemic patients with HF who underwent comprehensive clinical and laboratory evaluation, including measurement of serum GDF-15. The study endpoints were serious arrhythmic events (which included appropriate implantable cardioverter-defibrillator therapy and sudden cardiac death) and all-cause mortality. Mean age of the cohort was 54.8 ± 12.7 years, and mean left ventricular ejection fraction (LVEF) was 27.4% ± 7.5%. During a mean follow-up time of 42 months, arrhythmic events occurred in 28 patients (19%), and 40 patients (27%) died. An increase in serum GDF-15 (log-transformed) correlated linearly with a higher risk of serious arrhythmic events (HR 1.14, 95% CI 1.01–1.28, p = 0.03) even after adjustment for other potential clinical predictors (HR 1.16, 95% CI 1.02–1.32, p = 0.02). GDF-15 was also strongly and independently associated with all-cause mortality (HR 1.17, 1.05–1.31, p = 0.004). ConclusionIn this cohort of nonischemic HF patients on optimized medical treatment, serum GDF-15 levels were independently associated with major arrhythmic events and overall mortality. This biomarker may add prognostic information to better stratify the risk of sudden death in this particular population.

Fragmented QRS on far-field intracardiac electrograms as a predictor of arrhythmic events.

BackgroundStudies suggest that fragmented QRS (fQRS) can predict arrhythmic events in various cardiac diseases. However, the association between fQRS recordings on intracardiac electrogram (EGM) and ventricular arrhythmic events remains unknown.MethodsWe enrolled 51 patients (age, 62 ± 12 years; 40 men) with an implantable cardioverter‐defibrillator (ICD) and structural heart disease and evaluated surface electrocardiogram (ECG) and EGM measurement of fQRS and the association between fQRS and arrhythmic events.ResultsfQRS was detected on surface ECG and ICD‐EGM in 12 (23.5%) and 15 (29.4%) patients, respectively. fQRS was detected more frequently on ICD‐EGM in patients with fQRS on surface ECG than in patients without fQRS (7/12 [58.3%] vs 8/39 patients [20.5%], P = .01). Appropriate ICD therapies were documented in 16 patients. Among these patients, fQRS was detected more frequently on surface ECG and ICD‐EGM in patients with appropriate ICD therapies (8/16, 50.0%; P = .001 and 11/16, 68.9%; P < .001). Nonsustained ventricular tachycardia was significantly more frequent in patients with appropriate ICD therapies (15/16, 93.8%; P = .04). Multiple logistic regression analysis showed that fQRS on ICD‐EGM was a predictor of arrhythmic events (P = .03). Kaplan‐Meier survival analysis revealed that ICD therapies were significantly more frequent among patients with fQRS on both surface ECG and ICD‐EGM than among those without fQRS (66.7% vs 6.6%, P < .001).ConclusionThe presence of fQRS on ICD‐EGM can be a predictor of arrhythmic events in ICD patients. Surface ECG and ICD‐EGM measurement may help predict ventricular arrhythmic events.

Cardiac Sympathetic Innervation Imaging with PET Radiotracers.

The present article reviews the pathophysiology of cardiac sympathetic denervation, the principles of positron emission tomography (PET) imaging of the sympathetic innervation of the heart and its potential clinical role, based on current and expected future evidence. Imaging of cardiac sympathetic denervation can be performed with radiolabeled noradrenaline analogues, e.g., 11C-hydroxyephedrine. A greater burden of sympathetic denervation carries prognostic significance, e.g., in patients with ischemic cardiomyopathy and a left ventricular ejection fraction ≤ 35%, who are more likely to experience sudden cardiac death. Abnormalities of sympathetic cardiac innervation have been demonstrated in hypertrophic, dilated, and arrhythmic right ventricular cardiomyopathies, and may be helpful in better phenotyping patients who will benefit from device therapy, e.g., cardiac resynchronization and implantable cardioverter-defibrillator implantation. The results of future trials, e.g., the Prediction of Arrhythmic Events with Positron Emission Tomography (PAREPET) II study, are awaited to inform on the role of PET cardiac sympathetic imaging in the selection of device therapy. PET cardiac sympathetic innervation imaging allows visualization and quantification of autonomic denervation secondary to various cardiac diseases, and has significant potential to influence clinical decision-making, e.g., the titration of pharmacotherapy and more directed selection of candidates for device implantation.

Correlation between septal midwall late gadolinium enhancement on CMR and conduction delay on ECG in patients with nonischemic dilated cardiomyopathy

BackgroundSeptal midwall late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) is a characteristic finding in nonischemic dilated cardiomyopathy (DCM) and is associated with adverse cardiac events. QRS-prolongation in DCM is also frequently present and a predictor of arrhythmic events and mortality. Since the His-Purkinje fibres are located in the interventricular septum, QRS-prolongation may directly result from septal fibrosis, visualized by LGE. Our aim was to study the correlation of the presence and extent of septal midwall LGE and QRS-duration. MethodsDCM-patients with left ventricular (LV) dysfunction (LVEF < 50%) were included. LV volumes, systolic function and nonischemic septal midwall LGE, defined as patchy or stripe-like LGE in the septal segments, were quantified. QRS-duration on standard 12-lead ECG was measured. Results165 DCM-patients were included (62% male, mean age 59 ± 15 years) with a median LVEF of 36% [24–44]. Fifty-one patients (31%) demonstrated septal midwall LGE with a median extent of 8.1 gram [4.3–16.8]. Patients with midwall LGE had increased LV end-diastolic volumes (EDV) 248 mL [193–301] vs. 193 mL [160–239], p < 0.001) and lower LVEF (26% [18–35] vs. 40% [32–45], p < 0.001). Median QRS-duration was 110 ms [95–146] without a correlation to the presence nor extent of midwall LGE. QRS-duration was moderately correlated with LV-dilation and mass (respectively r = 0.35, p < 0.001 and r = 0.30, p < 0.001). ConclusionIn DCM-patients, QRS-prolongation and septal midwall LGE are frequently present and often co-exist. However, they are not correlated. This suggests that the assessment of LGE-CMR has complementary value to ECG evaluation in the clinical assessment and risk stratification of DCM-patients.

Association between PR Interval, First-degree atrioventricular block and major arrhythmic events in patients with Brugada syndrome - Systematic review and meta-analysis.

BackgroundRisk stratification in patients with asymptomatic Brugada Syndrome is challenging, and despite recent advances, there is no clear evidence. The first‐degree atrioventricular block was hypothesized to be a predictor of arrhythmic events. Measurement of the PR interval and diagnosing atrioventricular block from surface ECG is easy, noninvasive, and cost‐effective. We aimed to assess the latest evidence on PR interval or first‐degree atrioventricular block and major arrhythmic events related to Brugada Syndrome.MethodsWe performed a comprehensive search in PubMed for “atrioventricular block” OR “PR interval” and “Brugada syndrome.” We included studies that have a component of PR interval and/or first‐degree atrioventricular block and major arrhythmic events related to Brugada Syndrome including syncope/VT/VF/appropriate ICD shocks/ICD implantation.ResultsWe included 1526 subjects from 7 studies. Pooled mean difference of PR interval in 4 studies showed a significant difference [MD 10.77 ms (2.97‐18.57) P = 0.007, moderate‐high heterogeneity I2 = 53% P = 0.08]. On sensitivity analysis by removing a study, it became MD 6.50 ms [1.97‐11.03], P = 0.005, heterogeneity I2 = 0% P = 0.52. Indicating that PR interval was prolonged by small margin. Pooled analysis of the association between a first‐degree atrioventricular block and major arrhythmic events was significant [OR 3.33 (2.02‐5.50) P < 0.001, low heterogeneity I2 = 0% P = 0.57].ConclusionFirst‐degree AV block is associated with more frequent major arrhythmic events in Brugada syndrome patients. PR interval seemed to be prolonged but is yet to be determined whether the PR interval association is still significant if it did not cross the first‐degree AVB threshold.

The role of heart rate variability, heart rate turbulence, and deceleration capacity in predicting cause-specific mortality in chronic heart failure

BackgroundThe volume of regional denervated myocardium (D-M) on positron emission tomography has been recently suggested as a strong independent predictor of cause-specific mortality from sudden cardiac arrest (SCA) in chronic heart failure. We sought to evaluate whether ECG indices of global autonomic function predict risk of SCA to a similar degree as regional D-M. MethodsSubjects enrolled in the Prediction of Arrhythmic Events using Positron Emission Tomography (PAREPET) study were included in this study. Patients completed a 24-hour Holter ECG at enrollment and were followed up at 3-month intervals. SCA events were adjudicated by two board-certified cardiologists. Other cardiovascular death events were classified as nonsudden cardiac death (NSCD). Eight measures of heart rate variability were analyzed: SDNN, RMSSD, low-frequency (LF) and high-frequency (HF) power, heart rate turbulence onset and slope, and acceleration and deceleration capacity. We used competing risk regression to delineate cause-specific mortality from SCA versus NSCD. ResultsOur sample included 127 patients (age 67 ± 12, 92% male). After a median follow-up of 4.1 years, there were 22 (17%) adjudicated SCA and 18 (14%) adjudicated NSCD events. In multivariate Cox-regression, LF power was the only HRV parameter to predict time-to-SCA. However, in competing risk analysis, reduced LF power was preferentially associated with NSCD rather than SCA (HR = 0.92 [0.85–0.98], p = 0.019). ConclusionDepressed LF power might indicate impaired vagal reflex, which suggests that increasing vagal tone in these patients would have a protective effect against NSCD beyond that achieved by the mere slowing of heart rate using β-blockers.

Left Ventricular Entropy Is a Novel Predictor of Arrhythmic Events in Patients With Dilated Cardiomyopathy Receiving Defibrillators for Primary Prevention

ObjectivesThe aim of this study was to assess the utility of left ventricular (LV) entropy, a novel measure of myocardial heterogeneity, for predicting cardiovascular events in patients with dilated cardiomyopathy (DCM). BackgroundCurrent risk stratification for ventricular arrhythmia in patients with DCM is imprecise. LV entropy is a measure of myocardial heterogeneity derived from cardiac magnetic resonance imaging that assesses the probability distribution of pixel signal intensities in the LV myocardium. MethodsA registry-based cohort of primary prevention implantable cardioverter-defibrillator patients with DCM had their LV entropy, late gadolinium enhancement (LGE) presence, and LGE mass measured on cardiac magnetic resonance imaging. Patients were followed from implantable cardioverter-defibrillator placement for arrhythmic events (appropriate implantable cardioverter-defibrillator therapy, ventricular arrhythmia, or sudden cardiac death), end-stage heart failure events (cardiac death, transplantation, or ventricular assist device placement), and all-cause mortality. ResultsOne hundred thirty patients (mean age 55 years, 83% men, LV ejection fraction 29%, mean LV entropy 5.58 ± 0.72, LGE present in 57%) were followed for a median of 3.2 years. Eighteen (14.0%) experienced arrhythmic events, 17 (13.1%) experienced end-stage heart failure events, and 7 (5.4%) died. LV entropy provided substantial improvement of predictive ability when added to a model containing clinical variables and LGE mass (hazard ratio: 3.5; 95% confidence interval: 1.42 to 8.82; p = 0.007; net reclassification index = 0.345, p = 0.04). For end-stage heart failure events, LV entropy did not improve the model containing clinical variables and LGE mass (hazard ratio: 2.03; 95% confidence interval: 0.78 to 5.28; p = 0.14). Automated LV entropy measurement has excellent intraobserver (mean difference 0.04) and interobserver (mean difference 0.03) agreement. ConclusionsAutomated LV entropy measurement is a novel marker for risk stratification toward ventricular arrhythmia in patients with DCM.

Phase Relation between Depolarization and Repolarization Alternans in ECG.

T-Wave Alternans (TWA) in the electro cardiogram (ECG) has been widely investigated as a potential predictor of ventricular arrhythmia. However, large clinical trials show that TWA has a high negative predictive value (NPV) but poor positive predictive value (PPV). Therefore, there is need for exploration of approaches to improve PPV of TWA. More recent studies suggest that whether alternans is spatially concordant or discordant affects arrhythmic potential. Results of our previous animal and simulation studies show that the phase relation between depolarization and repolarization alternans has an effect on the transition of concordant to discordant alternans. Towards the eventual goal of developing indexes that complement TWA and improve prediction of arrhythmia, the objectives in this study were to verify the existence of R wave amplitude alternans (RWAA, a surrogate of depolarization alternans) and investigate the phase relationship between RWAA and TWA in clinical grade ECGs. Results show that RWAA does occur in ECGs and that the phase relationship between RWAA and TWA can be labile. These results support further investigation of the co-occurrence of these alternans for prediction of arrhythmic events.

Role of cardiac 123I-mIBG imaging in predicting arrhythmic events in stable chronic heart failure patients with an ICD

BackgroundDespite therapeutic improvement, the prognosis of chronic heart failure (CHF) remains unfavorable partly due to arrhythmia and sudden cardiac death (SCD). This prospective study evaluated myocardial 123I-meta-iodobenzylguanidine (123I-mIBG) scintigraphy as a predictor of arrhythmic events (AE) in CHF patients. Methods170 CHF patients referred for implantable cardioverter-defibrillator (ICD) implantation for both primary and secondary prevention were enrolled. All patients underwent planar and SPECT imaging. Early and late heart-to-mediastinum (H/M) ratio, 123I-mIBG washout (WO), early and late summed SPECT scores were calculated The primary endpoint was an AE: sustained ventricular tachycardia, resuscitated cardiac arrest, appropriate ICD therapy or SCD. The secondary endpoint was appropriate ICD therapy. ResultsDuring a median follow-up of 23.3 months, 69 patients experienced an AE. Early summed score (ESS) was the only independent predictor of AE [HR 1.023 (1.003-1.043)]. Focussing on only patients with an ICD for primary prevention, ESS was the only independent predictor of AE [HR 1.028 (1.007-1.050)]. 123I-mIBG-derived parameters failed to be independent predictors of appropriate ICD therapy. However there was a “bell-shaped” relation between 123I-mIBG scintigraphy-derived parameters and AE and appropriate ICD therapy, i.e., those with intermediate 123I-mIBG abnormalities tended to be at higher risk of events. ConclusionAlthough SPECT 123I-mIBG scintigraphy was associated with AE in CHF patients with ICD implantation for primary and secondary prevention, no association was found between 123I-mIBG scintigraphy-derived parameters and appropriate ICD therapy.

Risk stratification in Brugada syndrome

Brugada syndrome is an arrhythmogenic disease associated with sudden cardiac death due to ventricular arrhythmias. The risk stratification of patients without previous cardiac arrest remains the most controversial issue, especially for asymptomatic individuals, in Brugada syndrome. We review the recent data of several clinical, electrocardiographic, and electrophysiological parameters proposed for risk stratification. A history of documented fatal ventricular arrhythmias or aborted sudden cardiac death and/or arrhythmogenic syncope is a predictor of arrhythmic events, whereas the prognostic value of a familial history of sudden cardiac death and the presence of an SCN5A mutation are not well defined. On the electrocardiographic features, the spontaneous type 1 electrocardiogram (ECG) is associated with the risk for arrhythmic events in most of the studies, whereas early repolarization and fragmented QRS increases the risk in some studies. Late potentials using signal-averaged ECG and microscopic T-wave alternans indicate some available results in small studies that should be validated. The prognostic value of programmed electrical stimulation during electrophysiological study as a risk marker also remains controversial. A less aggressive protocol of programmed electrical stimulation may be preferable for risk stratification in the Brugada syndrome patients without previous cardiac arrest. Multiparametric approaches evaluating specific clinical factors and ECG may improve risk stratification.

Highlights From the Circulation Family of Journals.

Highlights From the Circulation Family of Journals.

Denervated Myocardium Is Preferentially Associated With Sudden Cardiac Arrest in Ischemic Cardiomyopathy: A Pilot Competing Risks Analysis of Cause-Specific Mortality.

Previous studies have identified multiple risk factors that are associated with total cardiac mortality. Nevertheless, identifying specific factors that distinguish patients at risk of arrhythmic death versus heart failure could better target patients likely to benefit from implantable cardiac defibrillators, which have no impact on nonsudden cardiac death. We performed a pilot competing risks analysis of the National Institutes of Health-sponsored PAREPET trial (Prediction of Arrhythmic Events with Positron Emission Tomography). Death from cardiac causes was ascertained in subjects with ischemic cardiomyopathy (n=204) eligible for an implantable cardiac defibrillator for the primary prevention of sudden cardiac arrest after baseline clinical evaluation and imaging at enrollment (positron emission tomography and 2-dimensional echo). Mean age was 67±11 years with an ejection fraction of 27±9%, and 90% were men. During 4.1 years of follow-up, there were 33 sudden cardiac arrests (arrhythmic death or implantable cardiac defibrillator discharge for ventricular fibrillation or ventricular tachycardia >240 bpm) and 36 nonsudden cardiac deaths. Sudden cardiac arrest was correlated with a greater volume of denervated myocardium (defect of the positron emission tomography norepinephrine analog 11C-hydroxyephedrine), lack of angiotensin inhibition therapy, elevated B-type natriuretic peptide, and larger left ventricular end-diastolic volume index. In contrast, nonsudden cardiac death was associated with a higher resting heart rate, older age, elevated creatinine, larger left atrial volume index, and larger left ventricular end-diastolic volume index. Distinct clinical, laboratory, and imaging variables are associated with cause-specific cardiac mortality in primary-prevention candidates with ischemic cardiomyopathy. If prospectively validated, these multivariable associations may help target specific therapies to those at the greatest risk of sudden and nonsudden cardiac death. URL: https://clinicaltrials.gov. Unique identifier: NCT01400334.

Deceleration and Acceleration Capacities in Risk Stratification for Arrhythmias in Patients With Chronic Obstructive Pulmonary Disease.

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk for both supraventricular and ventricular arrhythmias. Autonomic dysregulation may be responsible for the development of arrhythmias in these patients, and its analysis could be useful for identifying those at high risk for arrhythmias. Our purpose is to analyze the role of acceleration capacity (AC) and deceleration capacity (DC), novel markers of the autonomic balance, as potential arrhythmic risk predictors in patients with COPD. We prospectively included 47 patients diagnosed with COPD, and a control group of 64 age-matched subjects without COPD. AC and DC values were obtained using 24-hour Holter monitoring. The arrhythmias were isolated premature atrial complexes, supraventricular tachycardias, isolated premature ventricular beats (PVC), and combined ventricular arrhythmias consisting in ventricular tachycardias or more than 10 PVC per hour. Supraventricular arrhythmias and isolated PVC were more frequent in the COPD group. The DC was significantly lower (3.10 vs. 5.60, P < 0.0001) and AC higher (-4.60 vs. -6.60, P = 0.002) in patients with COPD. DC was identified as a predictor of arrhythmic events with an area under the curve (AUC) for premature atrial complexes >70/d of 0.72 (0.56-0.87, P = 0.013), for supraventricular tachycardias 0.76 (0.62-0.90, P = 0.002), and for combined ventricular arrhythmias 0.69 (0.54-0.82, P = 0.025). AC was predictor only for combined ventricular arrhythmias with an AUC of 0.74 (0.58-0.85, P = 0.002). Patients with COPD associate a significant autonomic imbalance and a higher incidence of arrhythmias. DC could be a strong predictor for supraventricular and ventricular arrhythmias in patients with COPD with no clinically apparent cardiac disease. AC could be useful alongside with DC regarding the risk for ventricular arrhythmias, but seems to have lesser value as a predictor for supraventricular arrhythmias.

The Potential of Late Gadolinium Enhancement to Serve as a Predictor of Ventricular Arrhythmias in Hypertrophic Cardio-myopathy Patients

Hypertrophic cardiomyopathy, the most common inherited cardiomyopathy is well known to be the leading cause of sudden cardiac death in young people. However, amongst the population of patients, a small subset bears increased risk of sudden cardiac death and would benefit from implantation of a defibrillator, currently recognized utilizing a series of established risk factors. This risk stratification model is hampered by low positive predictive value. Therefore, novel predictors of sudden death are sought. The advent of cardiac magnetic resonance and late gadolinium enhancement has allowed accurate quantification of regional fibrosis, a key element of hypertrophic cardiomyopathy, pathophysiologically linked to increased arrhythmogenicity. We sought to review currently available data on the utility of late gadolinium enhancement to serve as a novel predictor of arrhythmias and sudden death. In conclusion, significantly diverse methodological approaches and subsequent findings between available studies on the topic have hampered such use, highlighting the need for uniformly designed large scale, prospective studies in order to clarify which aspects of myocardial fibrosis could serve as predictors of arrhythmic events.

Prognostic significance of the extent of septal fibrosis quantified on late gadolium enhanced images in patients with nonischemic cardiomyopathy

Background Midwall septal fibrosis on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging has been shown to be an independent predictor of adverse events in patients with non-ischemic dilated cardiomyopathy (NICM). Recent studies in other cardiomyopathy cohorts, such as Hypertrophic Cardiomyopathy, suggest that LGE extent provides incremental prognostic value over its binary presence or absence. The objective of this study was to investigate the prognostic value of septal LGE quantification for the prediction of arrhythmic events among patients with NICM.

Predictors of Arrhythmic Events Detected by Implantable Loop Recorders in Renal Transplant Candidates.

BackgroundThe recording of arrhythmic events (AE) in renal transplant candidates (RTCs) undergoing dialysis is limited by conventional electrocardiography. However, continuous cardiac rhythm monitoring seems to be more appropriate due to automatic detection of arrhythmia, but this method has not been used.ObjectiveWe aimed to investigate the incidence and predictors of AE in RTCs using an implantable loop recorder (ILR).MethodsA prospective observational study conducted from June 2009 to January 2011 included 100 consecutive ambulatory RTCs who underwent ILR and were followed-up for at least 1 year. Multivariate logistic regression was applied to define predictors of AE.ResultsDuring a mean follow-up of 424 ± 127 days, AE could be detected in 98% of patients, and 92% had more than one type of arrhythmia, with most considered potentially not serious. Sustained atrial tachycardia and atrial fibrillation occurred in 7% and 13% of patients, respectively, and bradyarrhythmia and non-sustained or sustained ventricular tachycardia (VT) occurred in 25% and 57%, respectively. There were 18 deaths, of which 7 were sudden cardiac events: 3 bradyarrhythmias, 1 ventricular fibrillation, 1 myocardial infarction, and 2 undetermined. The presence of a long QTc (odds ratio [OR] = 7.28; 95% confidence interval [CI], 2.01–26.35; p = 0.002), and the duration of the PR interval (OR = 1.05; 95% CI, 1.02–1.08; p < 0.001) were independently associated with bradyarrhythmias. Left ventricular dilatation (LVD) was independently associated with non-sustained VT (OR = 2.83; 95% CI, 1.01–7.96; p = 0.041).ConclusionsIn medium-term follow-up of RTCs, ILR helped detect a high incidence of AE, most of which did not have clinical relevance. The PR interval and presence of long QTc were predictive of bradyarrhythmias, whereas LVD was predictive of non-sustained VT.