Alleviation of arrhythmia burden in children with frequent idiopathic premature ventricular contractions by omega-3-fatty acid supplementation.

BACKGROUND: Patients at our pediatric outpatient clinic were offered 24-h Holter electrocardiogram (ECG) before and after 3-month period of dietary supplementation with omega-3 fatty acids to monitor the effect on heart rate variability (HRV) and arrhythmias. METHODS: The study included 17 children (mean age: 11.6 ±â€¯4.9 years) with >1% premature ventricular contractions (PVC) at baseline. 24-h Holter ECG monitoring was performed before and after omega-3 fatty acid supplementation (mean duration: 143 days). RESULTS: Compared with 86 age-matched healthy control children, baseline HRV was significantly reduced and mean heart rate was significantly increased in children with frequent PVC. After omega-3-fatty acid supplementation, the mean heart rate decreased from 92.6 ±â€¯3.4 bpm to 83.9 ±â€¯9.9 bpm (p = 0.001), while global HRV showed a significant increase [standard deviation of all NN intervals (SDNN): 148.1 ±â€¯34.4 ms vs. 126.5 ±â€¯39.3 ms, p = 0.022)]. Enhanced vagal activity was indicated by significantly higher square root of the mean of the sum of the squares of differences between adjacent NN intervals (rMSSD) (42.3 ±â€¯12.6 vs. 33.2 ±â€¯14.8; p = 0.0003). PVC percentage significantly decreased by 45% (6.9 ±â€¯7.0% vs. 12.1 ±â€¯8.2%; p = 0.014). CONCLUSIONS: Omega-3-fatty acid supplementation caused a 45% reduction in frequent PVC in children with structurally healthy hearts. This antiarrhythmic effect was likely attributable to improved autonomic function, which is consistent with previous findings in children with obesity, attention deficit disorder, and short stature.

Wearable devices for cardiac arrhythmia detection: a new contender?

There has been increased consumer uptake of smart devices and wearable technology. They facilitate non-invasive, ambulatory assessment of numerous cardiac indices, including the heart rate and rhythm. Several studies have reported on the utility and deficiencies of these devices in identifying and monitoring cardiac arrhythmias. The rapid uptake of these consumer devices has the potential to generate vast amounts of biometric data. This coupled with gaps in knowledge pertaining to the optimal management of conditions such as sub clinical atrial fibrillation, may result in unnecessary and expensive downstream testing. An improved understanding of this nascent field by the clinician is vital.

Delayed pacemaker requirement after transcatheter aortic valve implantation with a new-generation balloon expandable valve: Should we monitor longer?

OBJECTIVES: To analyze the timing of appearance of conduction abnormalities (CAs) after transcatheter aortic valve implantation (TAVI), to identify predictors of delayed CAs requiring pacemaker (PM) implantation and to provide guidance regarding the duration of telemetry monitoring. BACKGROUND: How long patients remain at risk of development of CAs requiring PM implantation after TAVI and for how long they should be monitored remains unclear but is crucial when considering early discharge. METHODS: Development of CAs was studied in 701 consecutive patients treated with Edwards Sapien 3 valves and monitored with telemetry for 7 days in a single center. After excluding valve-in-valve procedures and patients with previous PM, 606 patients remained for analysis. Predictors of CAs requiring PM and the time of onset of CAs were analyzed. RESULTS: Of 606 patients 76 (12.5%) required a PM after TAVI. CAs requiring PM implantation occurred after 48 h in 22.4% (17 patients) and in 10.5% (8 patients) even after 5 days. Of the patients who developed high grade CAs requiring PM after 48 h, 47.1% had no CAs prior to TAVI, and 23.5% had neither pre-existing CAs nor new-developed CAs within the first 48 h after TAVI. CONCLUSION: After TAVI using a new-generation balloon-expandable valve, delayed development of CAs requiring PM implantation is not uncommon, even after 5 days. More importantly, 23.5% of patients eventually requiring a delayed PM implantation had still no CAs at 48 h after TAVI in this study. These results question the safety of early discharge and support ECG monitoring for a longer time period. The most optimal way to monitor these patients is yet to be determined.

The effect of intracoronary sodium nitrite on the burden of ventricular arrhythmias following primary percutaneous coronary intervention for acute myocardial infarction.

OBJECTIVE: Pre-clinical evidence suggests delivery of nitric oxide (NO) through administration of inorganic nitrite suppresses arrhythmias resulting from acute ischaemia and reperfusion (I/R). To date no assessment of whether inorganic nitrite might limit reperfusion arrhythmia has occurred in man, therefore we explored the effects on I/R-induced ventricular arrhythmias in the NITRITE-AMI cohort. METHODS: In the NITRITE-AMI cohort, Holter analysis was performed prior to and for 24 h after primary PCI in 80 patients who received either intra-coronary sodium nitrite (N = 40) or placebo (N = 40) during primary PCI for AMI. RESULTS: Ventricular rhythm disturbance was experienced by 100% patients; however, there was no difference in the number between the groups, p = .2196. Non-sustained ventricular tachycardia (NSVT) occurred in 67.5% (27/40) of nitrite-treated patients compared to 89% (35/39) of those treated with placebo (p = .027). There was a significant reduction in both the number of runs (63%, p ≤.0001) and total beats of NSVT (64%, p = .0019) in the nitrite-treated patients compared to placebo. Post-hoc analyses demonstrate a direct correlation of occurrence of NSVT with infarct size, with the correlation stronger in the placebo versus the nitrite group initiating an independent nitrite effect (Nitrite: r = 0.110, p = .499, placebo: r = 0.527, p = .001, p for comparison: 0.004). CONCLUSION: Overall no difference in ventricular rhythm disturbance was seen with intra-coronary nitrite treatment during primary PCI in STEMI patients, however nitrite treatment was associated with an important reduction in the incidence and severity of NSVT. In view of the sustained reduction of MACE seen, this effect warrants further study in a large-scale trial.

Bursts of reperfusion arrhythmias occur independently of area at risk size and are the first marker of reperfusion injury.

BACKGROUND: The presence of reperfusion ventricular arrhythmias (VA) has been shown to correlate with larger infarct size (IS). However it is unclear whether the initial area at risk (AAR), also a determining factor for IS, is responsible for this correlation. We hypothesized that IS would be significantly larger in the presence of VA, while AAR would not differ. METHODS: 68 STEMI patients from the MAST study with 24-hour, continuous, 12­lead Holter monitoring initiated prior to primary percutaneous coronary intervention (PCI) resulting in TIMI 3 flow post PCI were included. VA bursts were identified against subject-specific background VA rates using a previously validated statistical outlier method. IS, and infarct endocardial surface area (ESA) were obtained using CMR at mean 4.9 days after admission. Holter and CMR results were determined in core laboratories blinded to all other data. RESULTS: VA bursts were present in 69% (45/65) of patients. No significant differences were found for demographic characteristics, comorbidities, infarct location, number of diseased coronary vessels, or duration of ischemia between groups with and without VA burst. IS was significantly smaller in the group without VA bursts (median 9.3% vs 17.0%; p = 0.025). Infarct ESA did not significantly differ between the population with and without VA burst; median 24.3% vs 20.0%; p = 0.15. CONCLUSION: VA bursts are a marker for larger IS independent of AAR, assessed by surrogate markers. These findings support the hypothesis that VA bursts are a marker of reperfusion damage occurring downstream at myocellular level.

Utility of heart rate turbulence and T-wave alternans to assess risk for readmission and cardiac death in hospitalized heart failure patients.

BACKGROUND: Heart failure (HF) patients have a higher risk of recurrent HF and cardiac death, and electrical remodeling is considered to be an important factor for HF progression. The present study aimed to validate the utility of electrocardiogram and Holter monitoring for the risk stratification of HF patients. METHODS: Our study comprised 215 patients (144 males, mean age 62 years) who had been hospitalized due to acute decompensated HF. Electrocardiogram (QRS duration and QTc interval) and 24-hour Holter monitoring (heart rate variability, heart rate turbulence, and T-wave alternans [TWA]) were performed in stable condition before discharge. The clinical characteristics and outcomes were then investigated. RESULTS: During a median follow-up period of 2.7 years, there were 83 (38.6%) cardiac events (rehospitalization due to worsening HF [n = 51] or cardiac death [n = 32]). The patients with cardiac events had a lower turbulence slope (TS) and higher TWA compared to those without cardiac events (TS, 3.0 ± 5.5 ms/RR vs. 5.3 ± 5.6 ms/RR, P = 0.001; TWA, 66.1 ± 19.6 µV vs. 54.7 ± 15.1 µV, P < 0.001). Univariable analysis showed that TS, TWA, QRS duration, and QTc interval were associated with cardiac events (P = 0.004, P < 0.001, P = 0.037, and P = 0.024, respectively), while the multivariable analysis after the adjustment of multiple confounders showed that TS and TWA were independent predictive factors of cardiac events with a hazard ratio of 0.936 and 1.015 (95% confidence interval [CI]: 0.860-0.974, P = 0.006; and 95% CI: 1.003-1.027, P = 0.016), respectively. CONCLUSION: The measurement of TS and TWA is useful for assessing risk for rehospitalization and cardiac death in HF patients.

Comparison of treatment outcomes between convergent procedure and catheter ablation for paroxysmal atrial fibrillation evaluated with implantable loop recorder monitoring.

INTRODUCTION: While catheter ablation (CA) is an established treatment for symptomatic paroxysmal atrial fibrillation (AF), convergent epicardial and endocardial ablation procedure (CVP) has been primarily used to treat persistent AF. The aim of this single-center, prospective, randomized study was to compare treatment efficacy of CA and CVP in paroxysmal AF patients by monitoring AF, atrial tachycardia (AT), and atrial flutter (AFL) recurrence with Implantable Loop Recorder (ILR). METHODS AND RESULTS: Fifty patients (74% male) with history of paroxysmal AF were randomized between CA and CVP. Outcomes were determined by ILRs; every episode of AF/AT/AFL lasting 6 minutes or more was defined as a recurrence. AF burden (AFB) and required AF reinterventions (cardioversions and repeat ablations) were quantified after a 3-month blanking period. Total procedural (266 ± 44 vs. 242 ± 39 minutes) and ablation duration (52 ± 10 vs. 48 ± 12 minutes) was similar in both groups. Recurrence of AF/AT/AFL was more likely in the CA group compared to the CVP group (OR 3.78 (95% CI (1.17, 12.19), P  =  0.048)). During the follow-up period (mean 30.5 ± 6.9 months), higher AF burden and more reinterventions for recurrent AF were recorded in the CA group. There were more periprocedural complications in the CVP group (12.5%) compared to the CA group (0%). CONCLUSION: Treatment of paroxysmal AF with CVP showed less arrhythmia recurrence compared to CA. In addition, patients after CVP had fewer reinterventions and lower AF burden, but more periprocedural complications.

Chronic vagus nerve stimulation reverses heart rhythm complexity in patients with drug-resistant epilepsy: An assessment with multiscale entropy analysis.

OBJECTIVE: Vagus nerve stimulation (VNS) is an adjunctive treatment in drug-resistant epilepsy. The alterations in heart rate dynamics through VNS are not well understood. This study aimed to determine changes in heart rhythm complexity in association with VNS and to relate the findings to the outcome of VNS treatment in patients with drug-resistant epilepsy. METHODS: We prospectively analyzed 32 patients with drug-resistant epilepsy, who underwent VNS implantation, and 32 age- and sex-matched healthy control subjects. The interictal heartbeat intervals were analyzed using the heart rhythm complexity with multiscale entropy (MSE) and traditional heart rate variability (HRV) analyses based on ambulatory 24-hour electrocardiograms (ECGs). RESULTS: Patients had significantly decreased complexity indices (Slope 5, Area 1-5, Area 6-15, Area 6-20) on MSE analysis and decreased HRV measurements (standard deviation of the heartbeat interval (SDNN), square root of the mean of sum of squares of the differences between adjacent RR intervals (RMSSD), pNN50, very low frequency (VLF), low frequency (LF), high frequency (HF), total power (TP)) in time and frequency domain analyses. After one year of VNS treatment in patients with drug-resistant epilepsy, there was a trend in an elevated MSE profile with significant higher values between the scales 1 and 9. Vagus nerve stimulation induces a more significant increase of MSE in VNS responders than those in the nonresponders. The conventional HRV measurements did not change. CONCLUSION: Our results suggest that heart rhythm complexity is impaired in patients with drug-resistant epilepsy, and this is at least partially reversed by VNS treatment. Furthermore, VNS-induced effects on heart rate complexity may be associated with the therapeutic response to VNS in patients with drug-resistant epilepsy.

Heart rate variability characteristics of patients with irritable bowel syndrome and associations with symptoms.

BACKGROUND: Disturbed brain-gut interactions are assumed to be of importance for symptom generation in patients with irritable bowel syndrome (IBS). The autonomic nervous system (ANS) is part of the bidirectional brain-gut communication, but previous studies in IBS show diverging results. We aimed to identify subgroups of IBS patients with distinct ANS characteristics differentiating them from healthy controls (HC), and to study associations between ANS status and symptoms. METHODS: Heart rate variability (HRV) was measured in IBS patients and HC (Holter monitoring: supine and standing positions with controlled respiration and ambulatory 24-hour period). Frequency (5 minutes, supine, standing) and time domains (24 hours, day, night) were analyzed. Validated questionnaires were used to measure gastrointestinal and psychological symptoms in patients. Patients and HC were compared on a univariate and multivariate level (principal component analysis [PCA] and orthogonal partial least squares discriminatory analysis (OPLS-DA)). KEY RESULTS: We analyzed 158 IBS patients (Rome III) and 39 HC. Patients differed significantly from HC in HRV parameters during daytime and in standing position. In the PCA, a majority of patients overlapped with HC, but the weighted means differed (P < .01). A subset of patients (n = 30; 19%) with an aberrant global HRV profile was identified through PCA and OPLS-DA; these patients reported more severe symptoms of frequent (P < .05) and loose stools (P = .03), as well as urgency (P = .01). CONCLUSIONS AND INFERENCES: Altered ANS function was demonstrated in patients with IBS, and this might be of particular relevance for symptoms in a subset of the patients.

Clinical Implications of Technological Advances in Screening for Atrial Fibrillation.

The incidence of atrial fibrillation (AF) continues to increase worldwide as people live longer. AF is the leading cause of stroke among patients older than 75 years and is responsible for at least 15% of all strokes. Industry has responded to this problem with a plethora of monitoring devices. These include single lead ECG adhesive sensors, implantable loop recorders, smartphone attachments and wearables. This review will concentrate on clinical studies using these technologies. There are wearables including watches and watch-like devices that will be mentioned but these have not been validated for clinical use. This review will begin with a background regarding screening for AF and at the end present findings from Cardiac Implantable devices that could influence use of the new mobile health technologies.

Wearable technology for cardiology: An update and framework for the future.

The field of cardiology has long used wearable medical devices to monitor heart rate and rhythm. The past decade has seen the emergence of many new wearable devices, including several that have been widely adopted by both physicians and consumers. In this review, we discuss existing and forthcoming devices designed to measure activity, heart rate, heart rhythm, and thoracic fluid. We also offer several frameworks to classify and better understand wearable devices, such that we may weigh their potential benefit in improving healthcare with the many challenges that must be addressed to reap these benefits.

The impact of supraventricular ectopic complexes in different age groups and risk of recurrent atrial fibrillation after antiarrhythmic medication or catheter ablation.

INTRODUCTION: Supraventricular ectopic complexes (SVEC) are known risk factors of recurrent atrial fibrillation (AF). However, the impact of SVEC in different age groups is unknown. We aimed to investigate the risk of AF recurrence with higher SVEC burden in patients ±57years, respectively, after treatment with antiarrhythmic medication (AAD) or catheter ablation (CA). METHODS: In total, 260 patients with LVEF >40% and age ≤70 years were randomized to AAD (N=132) or CA (N=128) as first-line treatment for paroxysmal AF. All patients underwent 7-day Holter monitoring at baseline, and after 3, 6, 12, 18 and 24months and were categorized according to median age ±57years. We used multivariate Cox regression analyses and we defined high SVEC burden at 3months of follow-up as the upper 75th percentile >195SVEC/day. AF recurrence was defined as AF ≥1min, AF-related cardioversion or hospitalization. RESULTS: Age >57years were significantly associated with higher AF recurrence rate after CA (58% vs 36%, p=0.02). After CA, we observed a higher SVEC burden during follow-up in patients >57years which was not observed in the younger age group treated with CA (p=0.006). High SVEC burden at 3months after CA was associated with AF recurrence in older patients but not in younger patients (>57years: HR 3.4 [1.4-7.9], p=0.005). We did not find any age-related differences after AAD. CONCLUSION: We found that younger and older patients respond differently to CA and that SVEC burden was only associated with AF recurrence in older patients.

Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction: The CAMERA-MRI Study.

BACKGROUND: Atrial fibrillation (AF) and left ventricular systolic dysfunction (LVSD) frequently co-exist despite adequate rate control. Existing randomized studies of AF and LVSD of varying etiologies have reported modest benefits with a rhythm control strategy. OBJECTIVES: The goal of this study was to determine whether catheter ablation (CA) for AF could improve LVSD compared with medical rate control (MRC) where the etiology of the LVSD was unexplained, apart from the presence of AF. METHODS: This multicenter, randomized clinical trial enrolled patients with persistent AF and idiopathic cardiomyopathy (left ventricular ejection fraction [LVEF] ≤45%). After optimization of rate control, patients underwent cardiac magnetic resonance (CMR) to assess LVEF and late gadolinium enhancement, indicative of ventricular fibrosis, before randomization to either CA or ongoing MRC. CA included pulmonary vein isolation and posterior wall isolation. AF burden post-CA was assessed by using an implanted loop recorder, and adequacy of MRC was assessed by using serial Holter monitoring. The primary endpoint was change in LVEF on repeat CMR at 6 months. RESULTS: A total of 301 patients were screened; 68 patients were enrolled between November 2013 and October 2016 and randomized with 33 in each arm (accounting for 2 dropouts). The average AF burden post-CA was 1.6 ± 5.0% at 6 months. In the intention-to-treat analysis, absolute LVEF improved by 18 ± 13% in the CA group compared with 4.4 ± 13% in the MRC group (p < 0.0001) and normalized (LVEF ≥50%) in 58% versus 9% (p = 0.0002). In those undergoing CA, the absence of late gadolinium enhancement predicted greater improvements in absolute LVEF (10.7%; p = 0.0069) and normalization at 6 months (73% vs. 29%; p = 0.0093). CONCLUSIONS: AF is an underappreciated reversible cause of LVSD in this population despite adequate rate control. The restoration of sinus rhythm with CA results in significant improvements in ventricular function, particularly in the absence of ventricular fibrosis on CMR. This outcome challenges the current treatment paradigm that rate control is the appropriate strategy in patients with AF and LVSD. (Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction [CAMERA-MRI]; ACTRN12613000880741).

Diagnostic yield of asymptomatic arrhythmias detected by mobile cardiac outpatient telemetry and autotrigger looping event cardiac monitors.

INTRODUCTION: Asymptomatic arrhythmias can have important therapeutic implications in certain patient populations, for example, atrial fibrillation in patients with prior ischemic stroke. We sought to compare the diagnostic yield of two commercially available monitoring systems with automated arrhythmia detection algorithms. METHODS: We queried a large, proprietary database containing rhythm data for patients receiving ambulatory EKG monitoring (BioTelemetry, Malvern, PA, USA). We compared all patients prescribed mobile cardiac outpatient telemetry (MCOT™, Braemar Manufacturing, LLC, Eagan, MN, USA) versus autotrigger looping event recorder (AT-LER) devices over a consecutive 8-month period. Data from both device types were analyzed for diagnostic yields in detecting asymptomatic (device-triggered) arrhythmias consisting of atrial fibrillation (of any detected duration), bradycardia (ventricular rate ≤ 40 bpm), ventricular pause (≥ 3 seconds), supraventricular tachycardia (≥ 6 consecutive supraventricular beats), and ventricular tachycardia (≥ 4 consecutive premature ventricular contractions). The mean time to first diagnosis of each arrhythmia for each device was determined. Physician-designated diagnostic codes for patients prescribed each device were also determined from the database. RESULTS: The MCOT™ device had significantly higher diagnostic yields of all evaluated asymptomatic arrhythmias than the AT-LER. The MCOT™ device also produced an earlier mean time to diagnosis for all evaluated asymptomatic arrhythmias. These findings were noted despite a shorter average prescription length for MCOT™ monitored patients. CONCLUSIONS: In patients with conventional diagnostic monitoring indications, MCOT™ had significantly higher diagnostic yields for five asymptomatic arrhythmias compared to the AT-LER.

Excessive atrial ectopic activity as an independent risk factor for ischemic stroke.

BACKGROUND: Excessive atrial ectopic activity (EAEA) has been related with an increased risk of atrial fibrillation (AF) and stroke but different cutoff values have been used. We aimed to determine the association between EAEA and stroke, AF and overall death. METHODS: Consecutive 24-hour Holter monitoring performed between 2005 and 2010 in a single center was evaluated. Patients with a previous diagnosis of stroke or AF were excluded. The number of premature atrial contractions (PACs) during 24h was analyzed in 2480 subjects and according to that 3 sub-groups were defined: >97PACs/h (above the top 5th percentile of the population) (EAEA+); intermediate value of PACs/h (below the top 5th percentile but above 30PACs/h) (EAEA+/-) and <30PACs/h (EAEA-). RESULTS: After adjusting for risk factors, laboratory findings and medication, EAEA+ was associated with ischemic stroke (hazard ratio [HR] 2.83; 95% confidence interval [CI], 1.65-4.84, p<0.001). Both EAEA+ and EAEA+/- were independently associated with AF (HR 2.05; 95% CI 1.31-3.23, p=0.010 for EAEA+ and HR 1.90; 95% CI 1.10-2.78, p=0.020 for EAEA+/-) and overall death (HR 2.17; 95% CI 1.48-3.28, p=0.031 for EAEA+; HR 2.01; 95% CI 1.06-2.52, p=0.029 for EAEA+/-). CONCLUSION: In this population, having >30PACs/h was independently associated with a higher risk of AF and overall death but only subjects with >97PACs/h had a higher risk of ischemic stroke. In the majority of subjects with stroke and EAEA+, AF has not been detected before stroke event.

Long-term vagal stimulation for heart failure: Eighteen month results from the NEural Cardiac TherApy foR Heart Failure (NECTAR-HF) trial.

BACKGROUND: The NECTAR-HF study evaluated safety and feasibility of vagal nerve stimulation (VNS) for the treatment of heart failure patients. The first six-month randomized phase of the study did not show improvement in left ventricular remodelling in response to VNS. This study reports the 18-month results and provides novel findings aiming to understand the lack of efficacy of VNS, including a new technique assessing the effects of VNS. METHODS: Ninety-six patients were randomized 2:1 to active or inactive VNS for 6months, thereafter VNS was activated for all patients. The primary safety endpoint was 18-month all-cause mortality. RESULTS: Ninety-one patients continued in the long-term evaluation with active VNS. The on-therapy survival estimate at 18months was 95% with a 95% one-sided lower confidence limit of 91%, (better than the predefined criterion). Left ventricular systolic volume decreased in the crossover group (VNS OFF→ON; 144±37 to 139±40, p<0.05) after VNS activation; LVESD (5.02±0.77 to 4.96±0.82, p>0.05) and LVEF (33.2±4.9 to 33.3±6.5, p>0.05) did not change. A new technique to detect subtle heart rate changes during Holter recordings, i.e. "heat maps", revealed that VNS evoked heart rate response in only 13/106 studies (12%) at 6 and 12months with active VNS. CONCLUSIONS: Although a favourable long-term safety profile was found, improvements in the efficacy endpoints were not seen with VNS. A new technique for detecting acute heart rate responses to VNS suggests that the recruitment of nerve fibres responsible for heart rate changes were substantially lower in NECTAR-HF than in pre-clinical models.