Risk of and risk factors for hypoglycemia and associated arrhythmias in patients with type 2 diabetes and cardiovascular disease: a cohort study under real-world conditions

AIMS

Severe hypoglycemia is one of the strongest predictors of adverse clinical outcomes in patients with type 2 diabetes. Our study addressed the question whether there is a relationship between hypoglycemic events (HE) and severe cardiac arrhythmias in type 2 diabetic patients with established clinical risk factors under real-world conditions.

METHODS

We included 94 patients with type 2 diabetes and documented cardiovascular disease, in which interstitial glucose values and Holter ECG were recorded for 5 days in parallel. Patients received a stable treatment with insulin and/or sulfonylurea and were instructed to record symptoms of hypoglycemia or arrhythmias.

RESULTS

Continuous glucose monitoring revealed 54 HE (interstitial glucose <3.1 mmol/l) in a total of 26 patients. Patients perceived only 39 % of HE during the day and 11 % of HE during the night. Patients with HE had a significantly higher number of severe ventricular arrhythmias [ventricular tachycardia (VT) 32.8 ± 60 vs. 0.9 ± 4.2, p = 0.019], and multivariate regression analysis revealed the duration of severe HE and TSH level as independent predictors of the occurrence of a VT.

CONCLUSIONS

In conclusion, our study suggests that hypoglycemia might be able to trigger at least under certain circumstances, such as low TSH, ventricular arrhythmias under real-world conditions. The large number of unrecognized HE and VT in vulnerable patients treated with insulin or sulfonylurea should encourage the practitioner to focus on stable glucose control and to search for silent HE.

Reduced left atrial myocardial deformation irrespective of cavity size: a potential cause for atrial arrhythmia in hereditary transthyretin amyloidosis

BACKGROUND

Cardiac amyloidosis (CA) is a myocardial disease and commonly under-diagnosed condition. In CA patients, atrial fibrillation might occur in the absence of left atrial (LA) enlargement.

OBJECTIVES

The aim of this study is to assess LA size and function, and its relationship with atrial arrhythmia in patients with hereditary transthyretin amyloidosis (ATTR).

METHODS

Forty-six patients with confirmed ATTR amyloidosis on abdominal biopsy were studied. Assessment with 2D echocardiography and 2D strain showed 31 patients had increased LV wall thickness (LVWT) (septal thickness >12 mm), and 15 had normal LVWT. In addition to conventional measurements, LV and LA global longitudinal strain (GLS%) and strain rate (SR) were obtained. Western blot analysis was done to assess fibril type. ATTR patients with increased LVWT were compared with 23 patients with hypertrophic cardiomyopathy (HCM) and 31 healthy controls. ATTR amyloidosis patients also underwent 24 hour Holter monitoring to determine the presence of atrial arrhythmia.

RESULTS

Atrial deformation during atrial systole was reduced in ATTR amyloidosis patients with increased LVWT independent of LA size and in contrast to HCM. Twenty of the ATTR amyloidosis patients (54%) had ECG evidence of significant atrial arrhythmic events. LA strain rate, during atrial systole, was the only independent predictor of atrial arrhythmia (β = 3.28, p = .012).

CONCLUSION

In ATTR cardiomyopathy with increased LVWT, LA myocardial function is abnormal, irrespective of atrial cavity size. Reduced LA myocardial SR during atrial systole, irrespective of cavity volume, E/e' and LV deformation, is also a strong predictor for atrial arrhythmic events.

Arrhythmogenic evidence for epicardial adipose tissue: heart rate variability and turbulence are influenced by epicardial fat thickness

BACKGROUND

Epicardial adipose tissue (EAT) is a local source of various hormones, cytokines, and vasoactive substances affecting the myocardium. EAT contains abundant ganglionic plexi that interact with the autonomic nervous system. Evidence of the association between EAT and arrhythmia is limited, with the exception of atrial fibrillation. This study aimed to investigate the relation between EAT and cardiac autonomic function using heart rate variability (HRV) and heart rate turbulence (HRT) parameters.

METHODS

All subjects underwent a 24-hour Holter recording to assess HRV and HRT parameters and a transthoracic echocardiography to measure EAT thickness. Patients were divided into two groups according to the median EAT thickness (3.9 mm). The higher EAT group consisted of 111 patients with a >3.9-mm thickness and the lower EAT group 113 patients with a ≤ 3.9-mm EAT thickness.

RESULTS

HRV and HRT parameters were significantly influenced in the higher EAT group. Moreover, we observed significant correlations between EAT thickness and Holter findings (standard deviation of all NN intervals [SDNN]: r = -0.462, P < 0.001; SDNN index: r = -0.349, P < 0.001; standard deviation of the average NN intervals: r = -0.465, P < 0.001; root mean square of successive differences: r = -0.251, P < 0.001; pNN50: r = -0.354, P < 0.001; turbulence onset: r = 0.172, P = 0.010; turbulence slope: r = -0.279, P < 0.001, HRT category: r = 0.169, P = 0.011). In multivariate regression analysis, EAT thickness was independently associated with all measures of HRV and HRT, with the exception of turbulence onset.

CONCLUSIONS

Sympathovagal imbalance, detected by HRV and HRT parameters, is related to EAT thickness. As sympathovagal imbalance is a predictor of arrhythmic events, EAT may play an important arrhythmogenic role not limited to atrial fibrillation.

Leadless atrio-ventricular synchronous pacing in an outpatient setting - early lessons learned on factors affecting atrio-ventricular synchrony

BACKGROUND

Leadless pacemakers (PMs) capable of atrio-ventricular (AV) synchronous pacing have recently been introduced. Initial feasibility studies were promising, but limited to just a few minutes of AV synchronous pacing. Real-world long-term data on AV synchrony and programming adjustments affecting AV synchrony in outpatients are lacking.

OBJECTIVE

To investigate AV synchrony and influences of PM programming adjustments in outpatients with leadless VDD PMs.

METHODS

All patients who received a leadless VDD PM (Micra™ AV, Medtronic, US) between 07/2020 and 05/2021 at our center were included in this observational study. AV synchrony was assessed repeatedly postoperatively and during follow-up using Holter ECG recordings. AV synchrony was defined as a QRS complex preceded by a p-wave within 300ms. The impact of programming changes during follow-up on AV synchrony was studied.

RESULTS

816 hours of Holter ECG from 20 outpatients were analyzed. During predominantly paced episodes (≥80% ventricular pacing), median AV synchrony was 91% (IQR 34-100%) when patients had sinus rates 50-80/min. Median AV synchrony was lower when patients had sinus rates >80/min (33%, IQR 29-46%, p<0.001). During a stepwise optimization protocol, AV synchrony could be improved (p<0.038). Multivariate analysis showed that a shorter maximum A3 window end (p<0.001), a lower A3 threshold (p=0.046), and minimum A4 threshold (p<0.001) improved AV synchrony.

CONCLUSION

Successful VDD pacing in the outpatient setting during higher sinus rates is more difficult to achieve than can be presumed based on the initial feasibility studies. The devices often require multiple reprogramming to maximize AV sequential pacing.

The evolution of ambulatory ECG monitoring

Ambulatory Holter electrocardiographic (ECG) monitoring has undergone continuous technological evolution since its invention and development in the 1950s era. With commercial introduction in 1963, there has been an evolution of Holter recorders from 1 channel to 12 channel recorders with increasingly smaller storage media, and there has evolved Holter analysis systems employing increasingly technologically advanced electronics providing a myriad of data displays. This evolution of smaller physical instruments with increasing technological capacity has characterized the development of electronics over the past 50 years. Currently the technology has been focused upon the conventional continuous 24 to 48 hour ambulatory ECG examination, and conventional extended ambulatory monitoring strategies for infrequent to rare arrhythmic events. However, the emergence of the Internet, Wi-Fi, cellular networks, and broad-band transmission has positioned these modalities at the doorway of the digital world. This has led to an adoption of more cost-effective strategies to these conventional methods of performing the examination. As a result, the emergence of the mobile smartphone coupled with this digital capacity is leading to the recent development of Holter smartphone applications. The potential of point-of-care applications utilizing the Holter smartphone and a vast array of new non-invasive sensors is evident in the not too distant future. The Holter smartphone is anticipated to contribute significantly in the future to the field of global health.

Brain natriuretic peptide: a relevant marker to rule out delayed atrial fibrillation in stroke patient

Detection of new atrial fibrillation (AF) after ischemic stroke is challenging. The aim of the TARGET-AF study was to identify relevant markers for ruling out delayed AF in stroke patients. Early and prolonged Holter electrocardiography (ECG) monitoring during hospitalization was performed systematically in consecutive acute stroke patients naive to AF (no history of AF or no AF on baseline ECG). All clinical and paraclinical data for routine etiologic assessment were collected. The diagnostic value of all parameters significantly associated with AF was assessed by comparison of area under the receiver operating characteristic curve (AUC). Of the 300 stroke patients enrolled (mean age, 62.5 ± 15.5 years; sex ratio: 1.7; mean National Institutes of Health Stroke Scale score, 7.1 ± 7.9, median duration of Holter ECG monitoring, 6.8 days), 52 (17.3%) had newly diagnosed AF. Parameters significantly associated with AF were classified by increasing AUC: anterior circulation localization (AUC, 0.604; 95% confidence interval [CI], 0.546-0.660), P-wave initial force (AUC, 0.608; 95% CI, 0.545-0.669), left atrial dilatation (AUC, 0.657; 95% CI, 0.600-0.711), National Institutes of Health Stroke Scale score (AUC, 0.667; 95% CI, 0.611-0.720), sex (AUC, 0.683; 95% CI, 0.627-0.736), age (AUC, 0.755; 95% CI, 0.707-0.797), CHA2DS2-VASc score (AUC, 0.796; 95% CI, 0.746-0.841), STAF (score for the targeting of AF) score (AUC, 0.842; 95% CI, 0.796-0.882), and plasma brain natriuretic peptide (BNP) level (AUC, 0.868; 95% CI, 0.825-0.904). The use of all parameters combined (AUC, 0.910; 95% CI, 0.872-0.940) was not significantly more efficient in diagnosing AF than BNP alone (P = .248). At the Youden plot, the diagnostic properties for BNP >131 pg/mL were sensitivity, 98.1% (95% CI, 89.7-99.7); specificity, 71.4% (95% CI, 65.3-76.9); and negative predictive value, 99.4% (95% CI, 96.9-99.9). Our data indicate that a BNP level ≤ 131 pg/mL might rule out delayed AF in stroke survivors and could be included in algorithms for AF detection.

Blunted cyclic variation of heart rate predicts mortality risk in post-myocardial infarction, end-stage renal disease, and chronic heart failure patients

Aims

Cyclic variation of heart rate (CVHR) associated with sleep-disordered breathing is thought to reflect cardiac autonomic responses to apnoeic/hypoxic stress. We examined whether blunted CVHR observed in ambulatory ECG could predict the mortality risk.

Methods and results

CVHR in night-time Holter ECG was detected by an automated algorithm, and the prognostic relationships of the frequency (F_CV) and amplitude (A_CV) of CVHR were examined in 717 patients after myocardial infarction (post-MI 1, 6% mortality, median follow-up 25 months). The predictive power was prospectively validated in three independent cohorts: a second group of 220 post-MI patients (post-MI 2, 25.5% mortality, follow-up 45 months); 299 patients with end-stage renal disease on chronic haemodialysis (ESRD, 28.1% mortality, follow-up 85 months); and 100 patients with chronic heart failure (CHF, 35% mortality, follow-up 38 months). Although CVHR was observed in ≥96% of the patients in all cohorts, F_CV did not predict mortality in any cohort. In contrast, decreased A_CV was a powerful predictor of mortality in the post-MI 1 cohort (hazard ratio [95% CI] per 1 ln [ms] decrement, 2.9 [2.2–3.7], P < 0.001). This prognostic relationship was validated in the post-MI 2 (1.8 [1.4–2.2], P < 0.001), ESRD (1.5 [1.3–1.8], P < 0.001), and CHF (1.4 [1.1–1.8], P = 0.02) cohorts. The prognostic value of A_CV was independent of age, gender, diabetes, β-blocker therapy, left ventricular ejection fraction, sleep-time mean R-R interval, and F_CV.

Conclusion

Blunted CVHR detected by decreased A_CV in a night-time Holter ECG predicts increased mortality risk in post-MI, ESRD, and CHF patients.

[Options and limitations of heart rate measurement and analysis of heart rate variability by mobile devices: A systematic review]

BACKGROUND

Heart rate (HR) and heart rate variability (HRV) have been established in the last few years as a non-invasive method for recording the demands on the cardiovascular system. The development enables us today to measure the interbeat intervals with different technologies for calculating HR and HRV.

MATERIALS AND METHODS

This review is based on a systematic literature search in PubMed for validity of different measurement techniques and their pros and cons for the measurement of HR and the analysis of HRV.

RESULTS

Measurement equipment for recording of interbeat intervals should have a high storage capacity and a sampling rate of 1000 Hz ideally. The quality criteria of freedom of feedback (small, little disruptive), robustness and a non-invasive measurement (e. g. freeze-electrodes or sensors) have to be fulfilled. In addition to the Holter ECG, several portable heart rate watch and chest belt systems provide adequate validity and good applicability.

DISCUSSION

The Holter ECG is still the gold standard for the measurement of NN intervals and for the analysis of HRV. Modern heart rate watches show a good correlation with the conformance of freedom from discomfort, robustness and non-invasive measurement and are a good alternative due to the lower disturbance of test persons.

Persistent tachycardia in clozapine treated patients: A 24-hour ambulatory electrocardiogram study

Tachycardia is associated with cardiovascular mortality. Tachycardia is also a known clozapine adverse effect. However, whether clozapine-associated tachycardia is persistent is not known. Thirty clozapine-treated patients with clinical tachycardia were investigated with 24-hour ambulatory electrocardiography (ECG). Baseline peripheral heart rate (HR) was 106.7±7.8. The ambulatory ECG 24-hour-HR was 98.7±9.7. Baseline HR and 24-hour-HR correlated strongly (r=0.74, p=0.000003). Daytime HR was 106.4±9.9 and nighttime HR 89.2±12.0. Low dose bisoprolol reduced HR significantly. The high 24-hour-HR indicates a persistent tachycardia. Tachycardia should not discourage from clozapine use but the findings indicate a need of guidelines for detection and treatment of clozapine-associated tachycardia.

Holter electrocardiography findings and P-wave dispersion in pediatric patients with transcatheter closure of atrial septal defects

BACKGROUND

This study aimed to determine the frequency of postintervention arrhythmia and factors associated with the development of arrhythmia, including the correlation between arrhythmia and P-wave dispersion, and the effects of the latter on transcatheter closure of atrial septal defects (ASDs).

METHODS

Holter ECG recordings were performed before and after the intervention and 6 and 12 months later in 47 of the 59 patients who had undergone transcatheter ASD closure and once in the healthy control subjects.

RESULTS

A statistically significant correlation was identified between the patients' arrhythmia grade according to Lown's system and each of the following: the number of defects, the size of the atrioventricular valve rim, the presence of an atrial septal aneurysm.

CONCLUSION

The frequency of arrhythmia increases after transcatheter ASD closure, gradually decreases within the next year, and is most frequently of a benign nature. Lown's arrhythmia grading of patients occluded with either the Amplatzer septal occluder (ASO) or the Cardio-O-Fix septal occluder (CSO) were compared, and the arrhythmia frequency was higher with the latter. One day after the intervention, the P maximum (Pmax ) and the P dispersion(Pdis ) values were not increased but in fact slightly reduced in patients occluded with either ASO or CSO. An improvement in the electrical system resulting from early anatomical and mechanical healing following transcatheter ASD occlusion may explain the reduction in the Pmax and Pdis values.

Relationship between J Waves and Vagal Activity in Patients Who Do Not Have Structural Heart Disease

BACKGROUND

J waves are associated with increased vagal activity in patients with idiopathic ventricular fibrillation in several studies to date. However, the relationship between J waves and autonomic nervous activity in patients without structural heart disease remains under investigation. We investigated whether the presence of a J wave on the surface electrocardiogram (ECG) was related to increased vagal activity in patients without structural heart disease.

METHODS

This retrospective study included 684 patients without structural heart disease who had undergone Holter ECG and surface ECG monitoring. Based on the presence of J waves on the surface ECG, patients were divided into two groups: those with J waves (group 1) and those without J waves (group 2). We compared heart rate variability (HRV), reflecting autonomic nervous activity, using 24-h Holter ECG between the groups.

RESULTS

J waves were present in 92 (13.4%) patients. Heart rate (HR) in group 1 was significantly lesser than that in group 2 (P = 0.031). The ratio of low-frequency (LF) components to high-frequency (HF) components (LF/HF) in group 1 was significantly lower than that in group 2 (P = 0.001). The square root of the mean squared differences of successive NN intervals in group 1 was also significantly higher than that in group 2 (P = 0.047). In a multivariate regression analysis, male sex, HR, and LF/HF ratio remained independent determinants for the presence of J waves (P = 0.039, P = 0.036, and P < 0.001, respectively).

CONCLUSION

In patients without structural heart disease, the presence of a J wave was associated with a slow HR, male sex, and increased vagal activity, independently.

Age and Sex Specific Prevalence of Clinical and Screen-Detected Atrial Fibrillation in Hospitalized Patients

BACKGROUND

The prevalence of atrial fibrillation (AF) is high in older patients. The present study aimed to estimate the age and sex specific prevalence of clinical and screen-detected atrial fibrillation (AF) in hospitalized patients.

METHODS

The STAR-FIB cohort study was a prospective cohort study recruiting participants from a large source population of hospitalized patients aged 65-84 years. The estimated size of the source population was 26,035 (95% CI 25,918-26,152), and 795 consenting patients without clinical AF were included in the cohort study after stratification by sex and age (49.2% females; mean age 74.7 years). Patients in the cohort study underwent three seven-day Holter ECGs in intervals of two months to screen for AF.

RESULTS

In the source population, the estimated prevalence of clinical AF was 22.2% (95% CI 18.4-26.1), 23.8% for males (95% CI 20.9-26.6) and 19.8% for females (95% CI 17.3-22.4; p for difference between sexes, 0.004). There was a linear trend for an increase in the prevalence of clinical AF with increasing age, overall and in both sexes. In the cohort study, AF was newly diagnosed in 38 patients, for an estimated prevalence of screen-detected AF of 4.9% overall (95% CI 3.3-6.6), 5.5% in males (95% CI 3.2-7.8) and 4.0% in females (95% CI 2.0-6.0; p for difference between sexes, 0.041). The estimated prevalence of screen-detected AF in the source population was 3.8% overall, 4.2% in males and 3.2% in females.

CONCLUSION

In a large hospital-based patient population aged 65-84 years, the prevalence of clinical AF and of screen-detected AF was 22.2% and 3.8%, respectively, and significantly higher in males than females.

High Nighttime Heart Rate is Associated with Increased Risk of All-Cause Mortality in Patients with Heart Failure and Reduced Ejection Fraction

High heart rate (HR) is associated with increased risks of adverse outcomes in patients with heart failure. This study aimed to evaluate which measures of HR were associated with all-cause mortality in patients with heart failure and reduced ejection fraction (HFrEF). This study involved 741 HFrEF patients (age 65.1 ± 14.7 years, 71% male) who underwent 24 hour Holter electrocardiogram and resting electrocardiogram within 7 days between 2011 and 2015. We examined the associations of resting, 24 hour, and nighttime HRs with all-cause mortality. Nighttime and 24 hour HRs were determined as the mean HRs between 11:00 p.m. and 7:00 a.m. and over 24 hours, respectively. Nighty patients (12.1%) died during the 2-year follow-up. Resting, nighttime, and 24 hour HRs were significantly associated with all-cause mortality, also after adjusting for conventional risk factors. Resting HR did not remain as an independent factor when 24 hour HR (hazard ratio 1.10, 95% confidence interval 1.04-1.18) was included in the model. Including nighttime HR (hazard ratio 1.11, 95% confidence interval 1.05-1.17) in the model also eliminated 24 hour HR as an independent variable. Compared with the lowest quartile of nighttime HR (< 65 beats/minute), the highest quartile of nighttime HR (> 87 beats/minute) was significantly associated with a higher risk of all-cause mortality (hazard ratio 2.89, 95% CI 1.49-5.60). In conclusion, 24 hour HR and nighttime HR were significantly associated with an increased risk of mortality in patients with HFrEF. Nighttime HR appeared to be more strongly associated with all-cause mortality compared with 24 hour HR.

Continuous Electrical Monitoring in Patients with Arrhythmic Myocarditis: Insights from a Referral Center

Background. The incidence and burden of arrhythmias in myocarditis are under-reported. Objective. We aimed to assess the diagnostic yield and clinical impact of continuous arrhythmia monitoring (CAM) in patients with arrhythmic myocarditis. Methods. We enrolled consecutive adult patients (n = 104; 71% males, age 47 ± 11 year, mean LVEF 50 ± 13%) with biopsy-proven active myocarditis and de novo ventricular arrhythmias (VAs). All patients underwent prospective monitoring by both sequential 24-h Holter ECGs and CAM, including either ICD (n = 62; 60%) or loop recorder (n = 42; 40%). Results. By 3.7 ± 1.6 year follow up, 45 patients (43%) had VT, 67 (64%) NSVT and 102 (98%) premature ventricular complexes (PVC). As compared to the Holter ECG (average 9.5 exams per patient), CAM identified more patients with VA (VT: 45 vs. 4; NSVT: 64 vs. 45; both p < 0.001), more VA episodes (VT: 100 vs. 4%; NSVT: 91 vs. 12%) and earlier NSVT timing (median 6 vs. 24 months, p < 0.001). The extensive ICD implantation strategy was proven beneficial in 80% of the population. Histological signs of chronically active myocarditis (n = 73, 70%) and anteroseptal late gadolinium enhancement (n = 26, 25%) were significantly associated with the occurrence of VTs during follow up, even in the primary prevention subgroup. Conclusion. In patients with arrhythmic myocarditis, CAM allowed accurate arrhythmia detection and showed a considerable clinical impact.

ANMCO/AIIC/SIT Consensus Information Document: definition, precision, and suitability of electrocardiographic signals of electrocardiographs, ergometry, Holter electrocardiogram, telemetry, and bedside monitoring systems

The electrocardiogram (ECG) signal can be derived from different sources. These include systems for surface ECG, Holter monitoring, ergometric stress tests, and telemetry systems and bedside monitoring of vital parameters, which are useful for rhythm and ST-segment analysis and ECG screening of electrical sudden cardiac death predictors. A precise ECG diagnosis is based upon correct recording, elaboration, and presentation of the signal. Several sources of artefacts and potential external causes may influence the quality of the original ECG waveforms. Other factors that may affect the quality of the information presented depend upon the technical solutions employed to improve the signal. The choice of the instrumentations and solutions used to offer a high-quality ECG signal are, therefore, of paramount importance. Some requirements are reported in detail in scientific statements and recommendations. The aim of this consensus document is to give scientific reference for the choice of systems able to offer high quality ECG signal acquisition, processing, and presentation suitable for clinical use.

The fluctuation in sympathetic nerve activity around wake-up time was positively associated with not only morning but also daily glycemic variability in subjects with type 2 diabetes

AIMS

It is known that autonomic nerve activity (ANA) affects glucose metabolism by regulating the secretion of insulin and glucagon. Sympathetic nerve stimulation results in increased blood glucose levels. ANA also showed a circadian variation, and sympathetic nerve activity was minimal at night and began to rise at arousal. Therefore, a drastic alteration in ANA around wake-up would be associated with glycemic variability (GV) known risk factor for cardiovascular disease. We investigated the relation between ANA around wake-up and either morning or daily GV.

METHODS

We simultaneously performed Holter ECG and continuous glucose monitoring system in 41 patients with type 2 diabetes (T2D). ANA was assessed by heart rate variability (HRV) analysis. Delta (Δ) wake-up was defined as the difference between the maximum and minimum value during 1 h before and after wake-up time, before breakfast.

RESULTS

Δ of low frequency/high frequency (LF/HF) around wake-up time (Δ LF/HF _wake-up) was positively associated with Δ glucose _wake-up, standard deviation (SD) glucose _wake-up, the mean amplitude of glucose excursions (MAGE_24h), and SD glucose_24h after adjustment for age, sex, BMI, the duration of diabetes, and the prevalence of diabetic polyneuropathy (β = 0.47, p = 0.011, β = 0.48, p = 0.009, β = 0.54, p = 0.002 and β = 0.41, p = 0.0025, respectively). No association was found between Δ LF/HF_wake-up and either mean blood glucose for 24 h, or HbA1c as parameters of chronic hyperglycemia.

CONCLUSIONS

In T2D, the fluctuation in fasting sympathetic nerve activity around wake-up was positively associated with not only morning but also daily GV.

Current Use and Future Needs of Noninvasive Ambulatory Electrocardiogram Monitoring

Remarkable progress has been seen in monitoring systems using noninvasive ambulatory electrocardiograms (ECGs). In the Holter ECG system, 12-channel formats have been utilized as diagnostic tools, particularly for the detection of transient or silent myocardial ischemia and dynamic electrical disorders. In patients diagnosed with cryptogenic stroke, despite negative results on standard ECG tests, continuous ambulatory ECG monitoring for up to 30 days has been shown to increase the detection rate of transient atrial fibrillation. At present, a waterproof Holter ECG system is available. Recently, continuous late potential measurements using the time domain method and frequency domain T-wave alternans using the spectral analysis method for 24 hours have been applied to the Holter ECG and developed as novel risk stratification markers. Wearable ECG monitors that are built into belts, vests, wristbands, adhesive patches, and mobile smartphones have been used as fitness products for athletes and healthcare products for the general population. In the future, such devices may be used as remote monitoring tools for the detection of arrhythmias.

Night-to-night variability of sleep apnea detected by cyclic variation of heart rate during long-term continuous ECG monitoring

Background

Sleep apnea is common in patients with cardiovascular disease and is a factor that worsens prognosis. Holter 24‐h ECG screening for sleep apnea is beneficial in the care of these patients, but due to high night‐to‐night variability of sleep apnea, it can lead to misdiagnosis and misclassification of disease severity.

Methods

To investigate the long‐term dynamic behavior of sleep apnea, seven‐day ECGs recorded with a patch ECG recorder in 120 patients were analyzed for the cyclic variation of heart rate (CVHR) during sleep periods as determined by a built‐in three‐axis accelerometer.

Results

The frequency of CVHR (Fcv) showed considerable night‐to‐night variability (coefficient of variance, 66 ± 35%), which was consistent with the night‐to‐night variability in apnea‐hypopnea index and oxygen desaturation index reported in earlier studies. In patients with presumed moderate‐to‐severe sleep apnea (Fcv > 15 cph at least one night), it was missed on 62% of nights, and on at least one night in 88% of patients. The CV of Fcv was negatively correlated with the average of Fcv, suggesting that patients with mild sleep apnea show greater night‐to‐night variability and would benefit from long‐term assessment. The average Fcv was higher in the supine position, but the night‐to‐night variability was not explained by the night‐to‐night variability of time spent in the supine position.

Conclusions

CVHR analysis of long‐term ambulatory ECG recordings is useful for improving the reliability of screening for sleep apnea without placing an extra burden on patients with cardiovascular disease and their care.

Detection of unknown atrial fibrillation by prolonged ECG monitoring in an all-comer patient cohort and association with clinical and Holter variables

OBJECTIVES

Prolonged ECG monitoring is clinically useful to detect unknown atrial fibrillation (AF) in stroke survivors. The diagnostic yield of prolonged ECG monitoring in other patient populations is less well characterised. We therefore studied the diagnostic yield of prolonged Holter ECG monitoring for AF in an unselected patient cohort referred from primary care or seen in a teaching hospital.

METHODS

We analysed consecutive 7-day ECG recordings in unselected patients referred from different medical specialities and assessed AF detection rates by indication, age and comorbidities.

RESULTS

Seven-day Holter ECGs (median monitoring 127.5 hours, IQR 116 to 152) were recorded in 476 patients (mean age 54.6 (SD 17.0) years, 55.9% female) without previously known AF, requested to evaluate palpitations (n=241), syncope (n=99), stroke or transient ischaemic attack (n=75), dizziness (n=29) or episodic chest pain (n=32). AF was newly detected in 42/476 (8.8%) patients. Oral anticoagulation was initiated in 40/42 (95.2%) patients with newly detected AF. Multivariate logistic regression, adjusted for age, sex and monitoring duration found four clinical parameters to be associated with newly detected AF: hypertension OR=2.54, (1.08 to 8.61) (adjusted OR (95% CI)), p=0.034; previous stroke or TIA OR=4.14 (1.81 to 13.01), p=0.001; left-sided valvular heart disease OR=5.07 (2.48 to 18.70), p<0.001 and palpitations OR=2.86, (1.33 to 10.44), p=0.015.

CONCLUSIONS

Open multispeciality access to prolonged ECG monitoring, for example, as part of integrated, cross-sector AF care, can accelerate diagnosis of AF and increase adequate use of oral anticoagulation, especially in older and symptomatic patients with comorbidities.

72 hour Holter monitoring, 7 day Holter monitoring, and 30 day intermittent patient-activated heart rhythm recording in detecting arrhythmias in cryptogenic stroke patients free from arrhythmia in a screening 24 h Holter

Introduction

According to recent studies, silent atrial fibrillation (AF) is a common cause of cryptogenic ischemic stroke (CIS). 12-lead electrocardiogram (ECG) and 24 h Holter are not efficient to reveal an occult arrhythmic cause of stroke.

Objectives

The aim of the study was to evaluate 72 h Holter, 7 day Holter monitoring, and intermittent single-lead ECG recording in patients with CIS to identify cases with the arrhythmic cause of stroke in patients with CIS in whom 24 h ECG Holter was free from arrhythmia.

Methods

72 patients (aged 60 ± 9 years, 44 males) with CIS and no arrhythmic findings in 24 h Holter were enrolled. All patients had 7 day Holter monitoring and received handheld ECG recorder (CheckMe, Viatom) for ambulatory 30 ± 3 days ECG recording. AF, supraventricular tachycardia (SVT runs of ≥5 QRS), and other arrhythmias were assessed in the first 72 h of Holter recording, in 7 day-recording, and in handheld ECG strips.

Results

72 h-recording revealed AF in four cases (5.6%) and SVT in 18 (25%) cases. 7 day Holter confirmed AF in seven patients (10%) and SVT in 27 patients (37.5%). There was no difference in regards to CHADS2VASc score between patients with SVT and non-arrhythmic group (3.6 ± 1.1 vs 3.4 ± 1.6; p = NS). Symptoms did not correlate with findings. Patient-activated handheld ECG recorders were used with good compliance. The mean number of recordings was 49 ± 30. Except for PACs, there was only one case of AF documented in 3,531 strips.

Conclusions

7 day Holter performs better than 72 h and reveals supraventricular arrhythmias in every third and AF in 10% of CIS patients who were free from arrhythmia in 24 h ECG monitoring. 30 day intermittent ECG monitor does not yield diagnostic value in CIS.

A Post Hoc Holter ECG Analysis of Olodaterol and Formoterol in Moderate-to-Very-Severe COPD

Background

Patients with chronic obstructive pulmonary disease (COPD) are at risk of developing cardiac arrhythmias and elevated heart rate. A theoretical mechanistic association based on the interaction of long-acting β₂-agonists (LABAs) with adrenoreceptors in the heart and vasculature is assumed as a potential class-related risk. Therefore, we performed a pooled analysis of Holter electrocardiogram (ECG) data from four 48-week, randomized, double-blind, placebo-controlled, parallel-group, Phase III clinical trials evaluating olodaterol (5 μg or 10 μg) or formoterol (12 µg) versus placebo.

Methods

We analyzed Holter ECG data from a representative subset of 775 patients with Global Initiative for Chronic Obstructive Lung Disease stage 2–4 COPD from four studies (1222.11–14) assessing olodaterol (5 μg and 10 μg) and formoterol (12 µg) versus placebo.

Results

No statistically significant (P>0.3) or clinically relevant differences in the shift from baseline of premature supraventricular or ventricular beats were observed among the active treatment and the placebo groups. Minor and transient differences were observed in the adjusted mean heart rate from baseline during treatment in all groups. There was a numerically small but statistically significant increase for formoterol at Week 24, olodaterol 5 μg at Weeks 12 and 40, and olodaterol 10 μg at Week 40 (all less than 3.0 beats per minute). Mean heart rates returned to a statistically non-significant change at Week 48 for all treatment groups. No increase in major adverse cardiovascular events was observed.

Conclusion

Treatment with olodaterol or formoterol is not associated with arrhythmias or a persistent increase in heart rate as assessed by Holter ECG in patients with COPD.

Trial Registration

ClinicalTrials.gov identifiers: NCT00782210 (1222.11); NCT00782509 (1222.12); NCT00793624 (1222.13); NCT00796653 (1222.14).

No Influence on Cardiac Arrhythmia or Heart Rate from Long-Term Treatment with Tiotropium/Olodaterol versus Monocomponents by Holter ECG Analysis in Patients with Moderate-to-Very-Severe COPD

Background

Patients with chronic obstructive pulmonary disease (COPD) and cardiovascular comorbidities may have an increased risk of medication-related cardiac arrhythmias. We therefore performed an analysis of Holter electrocardiogram (ECG) data from two large, long-term, controlled clinical COPD trials to investigate whether tiotropium/olodaterol increased the risk of cardiac arrhythmia and mean heart rate.

Methods

We analyzed Holter ECG data from a representative subset of patients (N=506) from the two pooled replicate studies (TONADO 1 and 2) assessing tiotropium/olodaterol 5/5 µg therapy versus tiotropium 5 µg or olodaterol 5 µg monotherapy, inhaled once daily (two single inhalations) using the Respimat® Soft Mist™ inhaler device. Additionally, major adverse cardiac events (MACE) with tiotropium/olodaterol were assessed versus the respective monotherapies.

Results

After 12 weeks of treatment, there was no difference in the number of patients who had an increase or decrease from baseline in 24-hour supraventricular premature beats or ventricular premature beats between tiotropium/olodaterol 5/5 µg combination therapy and its monocomponents. Compared with baseline, a small but statistically significant increase in adjusted mean heart rate was observed for tiotropium 5 µg (+1.6 beats per minute [bpm]; P=0.0010), but no difference was observed for olodaterol 5 µg (+0.3 bpm; P=0.2778) or tiotropium/olodaterol 5/5 µg (-0.1 bpm; P=0.4607). MACE and fatal MACE were limited to 1 to 3 patients across treatment groups.

Conclusion

Compared with the compounds given as monotherapy, treatment with tiotropium/olodaterol fixed-dose combination therapy is not associated with medically relevant or statistically significant effects on arrhythmia as assessed by Holter ECG. Based on these findings, there is no evidence to assume a clinically relevant impact on cardiac function from dual tiotropium/olodaterol treatment.

Trial Registration

TONADO 1 (ClinicalTrials.gov: NCT01431274); TONADO 2 (ClinicalTrials.gov: NCT01431287).

Objective assessment of mental stress in individuals with different levels of effort reward imbalance or overcommitment using heart rate variability: a systematic review

BACKGROUND

Workloads are increasing and could cause mental stress, e.g., in the form of subjective effort reward imbalance (ERI) and overcommitment (OC). The heart rate variability (HRV) is a valid method for objective monitoring of workload. The aim of this project is to systematically evaluate the literature on HRV as an objective indicator for mental stress in individuals with different levels of ERI or OC.

METHODS

A systematic literature review examining HRV of employees in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement for reporting systematic reviews was performed. Electronic databases used were PubMed, Ovid, Cochrane Libary, Scopus and Web of Science, PsyInfo, Psyndex, and Livio. Only articles from 2005 to 2021 were included. Inclusion criteria were case-control studies, intervention studies, cross-sectional studies, or longitudinal studies with different levels of ERI and/or OC, >10 participants in each group, measurement of 24h HRV by using Holter ECG or chest belt, and full-text in English or German language. The methodological quality was evaluated by using a modified STARD for HRV.

RESULTS

Five studies matched the inclusion criteria by using HRV (24-h ECG) with a different HRV analysis at day and night. It showed an adaptation of HRV with higher ERI or OC with reduced parasympathetic HRV parameters, but the studies were not comparable.

CONCLUSIONS

There is a need for occupational health studies that examine strains and stress of different employees with predominantly mental stress. The well-established parasympathetic mediated HRV parameters seem to be suitable parameters to objectify the stress.

[Systematic implementation of transthoracic echocardiography, transesophageal echocardiography and 24-hour Holter ECG for the detection of cardiac sources of embolism in patients with stroke or transient ischemic attack. A retrospective study of 220 patients]

INTRODUCTION

Embolism of cardiac origin accounts for around 20% of ischemic strokes. ECG and transthoracic echocardiography (TTE) are commonly obtained during the evaluation of patient of ischemic stroke but specific indications for the transesophageal (TEE) echocardiography and 24-hour Holter ECG (Holter) remain uncertain.

OBJECTIVES

The aim of this study is to report the contribution of TTE, TEE and Holter performed as a routine during the evaluation of patients with ischemic stroke (IS) or transient ischemic attack (TIA).

METHODS

This is a retrospective single-center study of 220 patients hospitalized between 1st January 2007 and 31st December 2010 for a first IS or TIA.

RESULTS

One hundred and forty-three IS and 77 TIA are identified. The average age of patients was 66 years (18-88 years). TTE/TEE/24-hour Holter allowed the diagnosis of cardiac sources of embolism in 135 patents (61.3%). TTE/TEE identified potential source of cardiogenic embolism in 126 patients (52.2%). Twenty four-hour Holter ECG tracked supraventricular arrhythmia in 15 patients (6.7%), 9 (4%) which had non-contributory ultrasound assessment.

CONCLUSION

The systematic implementation of TTE/TEE/Holter is useful for identifying potential sources of cardiogenic embolism. The performance of TEE remains above the TTE. Holter should be recommended because it is a cost effective and non-invasive tool.

QT Interval Prolongation in Patients with Systemic Sclerosis-Are the Holter ECG Recordings a Better Option for QT Interval Evaluation?

Background and Objectives: Cardiac involvement in systemic sclerosis has important consequences on patient survival. Myocardial fibrosis and microcirculation involvement can generate arrhythmic complications, which can be associated with a higher death risk. QT interval prolongation is considered as a risk factor for ectopic ventricular events and can be evaluated using standard short ECG recordings or 24-h Holter ECG recordings. Materials and Methods: 39 patients with systemic sclerosis were submitted to a standard ECG recording at admission and 24-h Holter ECG monitoring. Results: QT interval values resulted from Holter ECG monitoring are higher than the values generated by the short-term ECG recordings. Holter ECG monitoring permits the detection of ventricular ectopy in patients with no events on standard ECG. Conclusions: In patients with systemic sclerosis, 24-h Holter ECG recordings can realize a more precise evaluation of the extent of QTc interval prolongation and ventricular ectopic events associated with myocardial involvement.