ACC/AHA Guidelines for Ambulatory Electrocardiography. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the Guidelines for Ambulatory Electrocardiography). Developed in collaboration with the North American Society for Pacing and Electrophysiology

AI-enabled electrocardiography alert intervention and all-cause mortality: a pragmatic randomized clinical trial

The early identification of vulnerable patients has the potential to improve outcomes but poses a substantial challenge in clinical practice. This study evaluated the ability of an artificial intelligence (AI)-enabled electrocardiogram (ECG) to identify hospitalized patients with a high risk of mortality in a multisite randomized controlled trial involving 39 physicians and 15,965 patients. The AI-ECG alert intervention included an AI report and warning messages delivered to the physicians, flagging patients predicted to be at high risk of mortality. The trial met its primary outcome, finding that implementation of the AI-ECG alert was associated with a significant reduction in all-cause mortality within 90 days: 3.6% patients in the intervention group died within 90 days, compared to 4.3% in the control group (4.3%) (hazard ratio (HR) = 0.83, 95% confidence interval (CI) = 0.70-0.99). A prespecified analysis showed that reduction in all-cause mortality associated with the AI-ECG alert was observed primarily in patients with high-risk ECGs (HR = 0.69, 95% CI = 0.53-0.90). In analyses of secondary outcomes, patients in the intervention group with high-risk ECGs received increased levels of intensive care compared to the control group; for the high-risk ECG group of patients, implementation of the AI-ECG alert was associated with a significant reduction in the risk of cardiac death (0.2% in the intervention arm versus 2.4% in the control arm, HR = 0.07, 95% CI = 0.01-0.56). While the precise means by which implementation of the AI-ECG alert led to decreased mortality are to be fully elucidated, these results indicate that such implementation assists in the detection of high-risk patients, prompting timely clinical care and reducing mortality. ClinicalTrials.gov registration: NCT05118035 .

Low-Power Long-Term Ambulatory Electrocardiography Monitor of Three Leads with Beat-to-Beat Heart Rate Measurement in Real Time

A low-power long-term ambulatory ECG monitor was developed for the acquisition, storage and processing of three simultaneous leads DI, aVF and V2 with a beat-to-beat heart rate measurement in real time. It provides long-term continuous ECG recordings until 84 h. The monitor uses a QRS complex detection algorithm based on the continuous wavelet transform with splines, which automatically selects the scale for the analysis of ECG records with different sampling frequencies. It includes a lead-off detection to continuously monitor the electrode connections and a real-time system of visual and acoustic alarms to alert users of abnormal conditions in its operation. The monitor presented is based in an ADS1294 analogue front end with four channels, 24-bit analog-to-digital converters and programmable gain amplifiers, a low-power dual-core ESP32 microcontroller, a microSD memory for data storage in a range of 4 GB to 32 GB and a 1.4 in thin-film transistor liquid crystal display (LCD) variant with a resolution of 128 × 128 pixels. It has programmable sampling rates of 250, 500 and 1000 Hz; a bandwidth of 0 Hz to 50% of the selected sampling rate; a CMRR of -105 dB; an input margin of ±2.4 V; a resolution of 286 nV; and a current consumption of 50 mA for an average battery life of 84 h. The ambulatory ECG monitor was evaluated with the commercial data-acquisition system BIOPAC MP36 and its module for ECG LABEL SS2LB, simultaneously comparing the morphologies of two ECG records and obtaining a correlation of 91.78%. For the QRS detection in real time, the implemented algorithm had an error less than 5%. The developed ambulatory ECG monitor can be used for the analysis of the dynamics of the heart rate variability in long-term ECG records and for the development of one's own databases of ECG recordings of normal subjects and patients with cardiovascular and noncardiovascular diseases.

Does psychological treatment of major depression reduce cardiac risk biomarkers? An exploratory randomized controlled trial

BACKGROUND

Depression is associated with an increased risk for cardiovascular disease (CVD). Biological cardiac risk factors are already elevated in depressed patients without existing CVD. The purpose of this exploratory trial was to examine whether treating Major Depression (MD) with cognitive behavioral therapy (CBT) is associated with improvements in cardiac risk biomarkers and whether depressive symptom severity at baseline moderates treatment effects.

METHODS

Eighty antidepressant-free patients with MD were randomly assigned to CBT or waiting list (WL). Biological outcomes included long-term recordings (24-h, daytime, nighttime) of heart rate, heart rate variability (HRV), and blood pressure, as well as inflammatory markers such as C-reactive protein (CRP), interleukin (IL)-6, and tumor necrosis factor (TNF)-α. A sample of 40 age- and sex-matched non-clinical controls was also involved to verify biological alterations in MD at study entry.

RESULTS

Compared to WL, CBT was associated with a significant increase in overall HRV, as indexed by the 24-h and daytime HRV triangular index, as well as trend improvements in 24-h low-frequency HRV and daytime systolic blood pressure. Self-rated depressive symptom severity moderated (or tended to moderate) improvements in CBT for 24-h and daytime heart rate and several indices of HRV (especially daytime measures). Inflammatory treatment effects were not observed.

CONCLUSIONS

CBT increased overall HRV in patients with MD. Initially more depressed patients showed the most pronounced cardiovascular improvements through CBT. These exploratory findings may provide new insights into the biological effects of psychological treatment against depression and must be confirmed through future research.

Evaluation of Outpatients in the Post-COVID-19 Period in Terms of Autonomic Dysfunction and Silent Ischemia

INTRODUCTION AND OBJECTIVE

In this context, the objective of this study is to evaluate the 24-hour ambulatory electrocardiography (ECG) recordings, autonomous function with heart rate variability (HRV), and silent ischemia (SI) attacks with ST depression burden (SDB) and ST depression time (SDT) of post-COVID-19 patients.  Materials and methods: The 24-hour ambulatory ECG recordings obtained >12 weeks after the diagnosis of COVID-19 were compared between 55 consecutive asymptomatic and 73 symptomatic post-COVID-19 patients who applied to the cardiology outpatient clinic with complaints of palpitation and chest pain in comparison with asymptomatic post-COVID-19 patients in Kars Harakani state hospital. SDB, SDT, and HRV parameters were analyzed. Patients who had been on medication that might affect HRV, had comorbidities that might have caused coronary ischemia, and were hospitalized with severe COVID-19 were excluded from the study.

RESULTS

There was no significant difference between symptomatic and asymptomatic post-COVID-19 patients in autonomic function. On the other hand, SDB and SDT parameters were significantly higher in symptomatic post-COVID-19 patients than in asymptomatic post-COVID-19 patients. Multivariate analysis indicated that creatine kinase-myoglobin binding (CK-MB) (OR:1.382, 95% CI:1.043-1.831; p=0.024) and HRV index (OR: 1.033, 95% CI:1.005-1.061; p=0.019) were found as independent predictors of palpitation and chest pain symptoms in post-COVID-19 patients.

CONCLUSION

The findings of this study revealed that parasympathetic overtone and increased HRV were significantly higher in symptomatic patients with a history of COVID-19 compared to asymptomatic patients with a history of COVID-19 in the post-COVID-19 period. Additionally, 24-hour ambulatory ECG recordings and ST depression analysis data indicated that patients who experienced chest pain in the post-COVID-19 period experienced silent ischemia (SI) attacks.

Late Palpitations in Young Patients After Ablation for Tachyarrhythmias

Background

Patients after ablation for tachyarrhythmias may continue to experience palpitations in the setting of sinus rhythm. The objective of our study was to investigate if patients who have undergone ablation for tachyarrhythmia have palpitations and other somatic complaints more frequently than healthy controls.

Methods

Paediatric patients after ablation for tachyarrhythmia at BC Children's Hospital from 2009 to 2020 and healthy controls were invited to participate in a survey about palpitations. Demographics, palpitation symptoms, frequency, duration, and need for medical attention were collected and compared between patients and controls.

Results

We received responses from 111 patients (response rate of 27.5%; mean age = 20.0 ± 4.6 years, 52% male) and 62 controls (age = 19.8 ± 5.7 years, 40% male). Sixty-two (56%) patients experienced palpitations beyond the initial 4 weeks after ablation, of whom 77% (n = 48/62) reported their palpitations feeling different. Tachyarrhythmia recurrence rate after ablation was 7.2%. There was no difference in the prevalence of palpitations experienced between patients and controls (P = 0.74). Patients after ablation sought medical attention more often for their palpitations (P = 0.003) and chest symptoms (P = 0.001) compared to controls.

Conclusion

The prevalence of palpitations did not differ in ablation patients compared to healthy controls. Patients reported that their palpitations felt different after ablation and were more likely to seek medical attention for their palpitations. Paediatric patients with tachyarrhythmias may have heightened awareness due to their history. Clinicians can incorporate this into procedural counselling to reduce patient concern and need for medical attention.

Diagnostic yield of ambulatory cardiac monitoring in pediatric patients with palpitations

Background

Palpitations are a frequent reason for referral to pediatric cardiology providers and diagnostic workup includes ambulatory cardiac monitoring. While common practice, the diagnostic yield is unknown in the pediatric population. The objective is to evaluate the diagnostic yield of 24-h Holter and extended ambulatory cardiac monitoring in pediatric patients with palpitations.

Methods and Results

All pediatric patients aged 10-18 years who had ambulatory cardiac monitoring (1-30 days) through the Pocket Electrocardiogram (PocketECG™) system (Medi-Lynx) between January 2016 and July 2020 were included. Patients with an International Classification of Diseases-10 diagnosis code of palpitations (R00.2) during enrollment were evaluated separately. Tachyarrhythmia diagnoses included atrial fibrillation (AF), nonsustained supraventricular tachycardia (nSVT), supraventricular tachycardia (SVT), nonsustained ventricular tachycardia (nVT), and ventricular tachycardia (VT). Age, heart rates, arrhythmia type, and symptomatic transmission data were collected and analyzed. A total of 2388 patients (mean age 11.6 years, 58% F) with the R00.2 code had ambulatory cardiac monitoring (28% 24-h Holter, 72% extended) performed during the study period and there were 6287 total patients (mean age 13.9 years, 54% F) that underwent ambulatory cardiac monitoring (42% 24-h Holter, 58% extended) during that time. Of 2388 patients, 321 (13%) were diagnosed with tachyarrhythmia: AF (9), nSVT (192), SVT (59), and nVT (61). In the overall cohort, 764 (12%) patients were diagnosed with tachyarrhythmia: AF (22), nSVT (478), SVT (85), nVT (177), and VT (2). Symptomatic transmissions with normal cardiac rhythm were common in the R00.2 (n = 1697, 71%) and overall (n = 3848, 61%) groups. No episodes of nSVT, SVT, nVT, or VT were associated with symptomatic transmissions.

Conclusion

Ambulatory cardiac monitors are an integral part of the diagnostic workup for pediatric palpitations patients and have demonstrated a high yield of combined positive arrhythmia diagnoses and symptomatic normal transmissions. Further prospective study of this population with the integration of clinical information is warranted.

Prognostic importance of cardiovascular autonomic neuropathy on cardiovascular and mortality outcomes in individuals with type 2 diabetes: The Rio de Janeiro type 2 diabetes cohort

AIMS

To investigate whether tests for cardiovascular autonomic neuropathy (CAN) and 24-hour heart rate variability (HRV) could improve the prediction for outcomes in type 2 diabetes.

METHODS

541 type 2 diabetic individuals performed tests of CAN. A subsample (313) had 24-hour HRV (the standard deviation of all normal RR intervals [SDNN] and the standard deviation of the averaged normal RR intervals for all 5 min segments [SDANN]). Multivariate Cox regressions examined the associations between CAN/low HRV with cardiovascular events (CVEs) and all-cause mortality. The improvement in risk discrimination of adding CAN/HRV was tested by C-statistics and by the Integrated Discrimination Improvement (IDI) index.

RESULTS

25% had CAN, and 17-18% had low HRV, respectively by SDANN-SDNN. Over a median follow-up of 12 years, there were 177 CVEs and 236 all-cause deaths in the whole cohort, and 96 CVEs and 129 all-cause deaths in the subsample. CAN was associated with 40% excess risks of CVEs/all-cause mortality, low HRV was associated with 2-fold higher risks of outcomes. HRV improved risk discrimination for CVEs/mortality with increases in C-statistics up to 0.039 and IDIs up to 25%.

CONCLUSIONS

Low HRV was a better predictor of outcomes than tests of CAN, and it improved risk discrimination.

Association of Nonalcoholic Fatty Liver Disease with Ventricular Tachycardia and Sinus Arrest in Patients with Non-ST-Segment Elevation Myocardial Infarction

Nonalcoholic fatty liver disease (NAFLD) is an emerging driver of cardiac arrhythmias. However, the relationship between NAFLD and malignant arrhythmia in non-ST-segment elevation myocardial infarction (NSTEMI) patients is still unclear.In this study, 358 NSTEMI inpatients were enrolled. They all received 24-hour Holter monitoring after percutaneous coronary intervention. All inpatients were divided into two groups: the non-NAFLD group (236 cases, 65.9%) and the NAFLD group (122 cases, 34.1%). Compared with the non-NAFLD group, the NAFLD group had a significantly higher incidence of PVCs/hour > 5 (premature ventricular complexes, 32.0% versus 9.3%, P < 0.001), ventricular tachycardia (VT, 22.1% versus 5.9%, P < 0.001), and sinus arrest (SA, 7.4% versus 1.3%, P = 0.002). We found that NAFLD was closely associated with the occurrence of VT [unadjusted odds ratio (OR) 4.507, 95% confidence interval (CI) 2.263-8.974, P < 0.001] and SA (OR 6.186, 95%CI 1.643-23.291, P = 0.007). After adjusting for age, sex, body mass index, and other confounding factors, the above differences were still statistically significant (VT: OR 4.808, 95%CI 2.254-10.253, P < 0.001; SA: OR 9.589, 95%CI 2.027-45.367, P = 0.004).NAFLD is associated with the occurrence of VT and SA in NSTEMI patients. It indicates that NAFLD might be a risk factor for malignant arrhythmias in post-NSTEMI patients.

Using Multi-Task Learning-Based Framework to Detect ST-Segment and J-Point Deviation From Holter

Artificial intelligence is increasingly being used on the clinical electrocardiogram workflows. Few electrocardiograms based on artificial intelligence algorithms have focused on detecting myocardial ischemia using long-term electrocardiogram data. A main reason for this is that interference signals generated from daily activities while wearing the Holter monitor lowered the ability of artificial intelligence to detect myocardial ischemia. In this study, an automatic system combining denoising and segmentation modules was developed to detect the deviation of the ST-segment and J point. We proposed a ECG Bidirectional Transformer network that applied in both denoising and segmentation tasks. The denoising model achieved RMSEde, SNRimp, and PRD values of 0.074, 10.006, and 16.327, respectively. The segmentation model achieved precision, sensitivity (recall), and F1-score of 96.00, 93.06, and 94.51%, respectively. The system’s ability to distinguish the depression and elevation of the ST-segment and J point was also verified by cardiologists as well. From our ECG dataset, 103 patients with ST-segment depression and 10 patients with ST-segment elevation were detected with positive predictive values of 80.6 and 60% respectively. Using Holter ECG and transformer-based deep neural networks, we can detect subtle ST-segment changes in noisy ECG signals. This system has the potential to improve the efficacy of daily medicine and to provide a broader population-level screening for asymptomatic myocardial ischemia.

Pattern Changes in the Heart Rate Variability of Patients Undergoing Coronary Artery Bypass Grafting Surgery

Introduction

Coronary artery bypass grafting (CABG) with extracorporeal circulation is a key therapy for coronary artery disease (CAD). However, cardiovascular events and cardiac arrhythmias may still occur in these patients following surgery. Many studies have demonstrated a correlation between cardiac arrhythmias and heart rate variability (HRV). This study aimed to establish the temporal change pattern of HRV observed following CABG.

Methods

A prospective method was used to study 119 consecutive patients with stable CAD who were assessed using 24-hour Holter recordings 2 days before CABG and 1 week, 3 months, and 6 months after the surgery at Hanoi Heart Hospital from June 2016 to August 2018. Main results: All the time-domain and frequency-domain parameters of HRV decreased precipitately after CABG and were mostly recovered 3 months postoperatively. The percentage of decreased HRV before surgery was 28.6% and 51.8% after 7 days, 19.6% after 3 months, and 12.7% after 6 months. ASDNN and SDNN before and after surgery had the highest rates of change.

Conclusion

The early decrease in HRV observed 7 days after CABG may be related to the acute effects of the surgery. The recovery of HRV at 3 months after surgery, regardless of the preoperative state of the patients, implies that the autonomic nervous system (ANS) disorder may be improved at this time. At 6 months after surgery, the autonomic nervous injury was recovered in combination with improvement of reperfusion, resulting in improvement in almost all HRV indices compared with those indices preoperatively.

Myositis-Specific Autoantibodies and QTc Changes by ECG in Idiopathic Inflammatory Myopathies

OBJECTIVES

The aim of this study was to investigate cardiac involvement detected by electrocardiography (ECG) in patients with idiopathic inflammatory myopathies (IIM) and to evaluate possible associations between autoantibody profile and ECG changes in these patients.

METHODS

In a Scandinavian cross-sectional study, patients were included from two Danish centres and one Swedish centre. Resting 12-lead ECG was investigated in 261 patients with IIM compared with 102 patients with systemic sclerosis (SSc) and 48 healthy controls (HCs). ECG changes were correlated to clinical manifestations and myositis-specific (MSAs) and myositis-associated (MAAs) autoantibodies.

RESULTS

Patients with IIM had longer mean QTc duration and more frequently presented with prolonged QTc (≥ 450 ms; p= 0.038) compared with HCs. Longer QTc duration was recorded in SSc compared with IIM (433 ± 23 ms vs 426 ± 24 ms, p= 0.011), yet, no significant difference in the fraction with prolonged QTc (SSc: 22%, IIM: 16%; p= 0.19). In multivariable regression analyses, anti-Mi2 (p= 0.01, p= 0.035) and anti-Pl-7 (p= 0.045, p= 0.014) were associated with QTc duration and prolonged QTc in IIM. Elevated CRP was associated with prolonged QTc (p= 0.041).

CONCLUSION

Presence of QTc abnormalities was as common in patients with IIM as in patients with SSc, including prolonged QTc seen in almost one fifth of the patients. Anti-Mi2, anti-Pl-7, and elevated CRP may serve as biomarkers for cardiac disease in IIM, but needs to be confirmed in a larger prospective study.

High expression level of miR-1260 family in the peripheral blood of patients with ovarian carcinoma

The most common gynecologic cancers detected in women in Turkey are uterine cancer, ovarian cancer, and cervical cancer. These data reported that a mean of 3800 individuals were diagnosed with uterine cancer, 2790 were diagnosed with ovarian cancer, and 1950 were diagnosed with cervical cancer, and 400 individuals were diagnosed with other gynecologic cancers each year in Turkey. A mean of 14.270 individuals were detected to have been diagnosed with gynecologic cancers each year in the United States of America (USA). Ovarian cancer treatment is generally composed of chemotherapy, and surgery. In general, chemotherapy is administered after surgery. The identification of the molecular pathogenesis of ovarian cancer, and discovery of new moleculer biomarkers which facilitate the ovarian cancer treatment are required for an effective ovarian cancer treatment in clinics. miRNAs are reported to be the possible biologic indicators for various cancer types. We aimed to investigate 2 miRNAs which were suggested to have effect in ovarian cancer in our (previous) monozygotic twin study from miR-1260 microRNA family whose association with ovarian cancer yet has not been reported in the literature. We investigated the expression levels of miR-1260a, and miR-1260b miRNAs, in the peripheral blood lymphocytes of 150 familial and sporadic ovarian cancer patients, and of 100 healthy individuals of the control group who were matched for age, sex, and ethnicity with the patient group, and investigated their possible property of being a biologic indicator for ovarian cancer. The expression results of ovarian cancer patients were evaluated by comparison of the results of the control group in the study. The expression levels of miR-1260a, and miR-1260b in ovarian cancer patients were found highly increased compared with the levels in the control group. miR-1260a expression level in ovarian cancer patients was detected to have increased approximately 17 fold compared with the control group, and miR-1260b expression level in ovarian cancer patients was detected to have increased approximately 33 fold compared with the levels in the control group. The String Analyses showed that the miR-1260a was associated with the ribosomal protein family which was known to be effective in the translation stage of cell and that miR-1260b was associated with CHEK2 protein which was a member of the serine/threonine-protein kinase family. It should be investigated for larger cohorts in benign ovarian diseases and in different stages of patients receiving ovarian cancer treatment whether these two molecules are a noninvasive biomarker and therapeutic target to be used especially in the early diagnosis and prognosis of ovarian cancer in future.

The effect of age on the heart rate variability of healthy subjects

In this work we study the characteristics of heart rate variability (HRV) as a function of age and gender. Our analysis covers a wider age range than that studied so far. It includes results previously reported in the literature and reveals behaviours not reported before. We can establish basic scale relationships in different HRV measurements. The mean value of the RR intervals shows a power-law behaviour independent of gender. Magnitudes such as the standard deviation or pNN50 show abrupt changes at around the age of 12 years, and above that age they show gender dependence, which mainly affects short-time (or high frequency) scales. We present a unified analysis for the calculation of the non-linear α and β parameters. Both parameters depend on age; they increase in the extremes of life and reach a minimum at around one year of age. These gender-independent changes occur at low frequencies and in scale ranges that depend on age. The results obtained in this work are discussed in terms of the effects of basal metabolic rate, hormonal regulation, and neuronal activity on heart rate variability. This work finally discusses how these findings influence the interpretation of HRV measurements from records of different lengths.

Supraventricular Tachycardia and Postural Orthostatic Tachycardia Syndrome Overlap: A Retrospective Study

Postural orthostatic tachycardia syndrome (POTS) and supraventricular tachycardia (SVT) are disease states with distinctive features but overlapping clinical manifestations. Currently, studies on the presence of underlying SVT in patients with POTS are lacking. This retrospective study analyzed 64 patients [mean age: 43 years; 41 (61%) women] who had a POTS diagnosis and were found to have concomitant SVT during rhythm monitoring from September 1, 2013 to September 30, 2019 at our Syncope and Autonomic Disorders Clinic. The outcomes assessed were changes in disease severity, frequency of symptoms, heart rate, and blood pressure between before and after SVT ablation. The most frequent types of SVT noted on the electrophysiologic study were atrioventricular nodal reentrant tachycardia (57.81%), atrial flutter (29.68%), atrioventricular reentrant tachycardia (9.37%), atrial tachycardia (1.56%), and junctional tachycardia (1.56%). After SVT ablation, all 64 patients experienced an improvement in symptoms. Palpitations and lightheadedness experienced the most improvement after the procedure (72% vs. 31%; p < 0.001 and 63% vs. 22%; p < 0.001, respectively). There was a significant improvement in the resting heart rate (81.1 ± 12.8 vs. 75.8 ± 15.6 bpm; p < 0.002), but the orthostatic tachycardia on standing persisted (93.6 ± 16.5 vs. 77.3 ± 19.8 bpm; p = 0.14). Underlying SVT in patients with POTS can be missed easily. A strong suspicion and long-term ambulatory cardiac rhythm monitoring can help in diagnosing the condition.

Increased heart rate with sleep disordered breathing in hypertrophic cardiomyopathy

BACKGROUND

Current guidelines recommend medications with rate control properties for symptomatic patients with hypertrophic cardiomyopathy (HCM) based on the rationale that lowering heart rate (HR) improves their symptoms. Whether sleep disordered breathing (SDB) is associated with increased HR in HCM patients is not known.

METHOD

We diagnosed uncontrolled SDB (oxygen desaturation index ≥5) in consecutive echocardiographically confirmed HCM patients seen at Mayo Clinic, Rochester, and analyzed their HR as recorded by a 24-h Holter monitor. We compared mean, minimum, maximum HR between those with vs without SDB. In a pilot subanalysis of HCM patients with SDB who also underwent subsequent diagnostic polysomnography (PSG), we analyzed RR interval changes coinciding with obstructive sleep apnea and hypopnea episodes.

RESULTS

Of the 230 HCM patients included in this study (age 54 ± 16 years; 138 male; LVOT pressure gradient at rest 45 ± 39 mmHg), 115 (50%) patients had SDB. HCM patients with SDB were recorded to have higher mean HR (71 vs. 67 bpm; p = .002, adjusted p = .001), and this difference was most pronounced during night hours of 10 PM to 5 AM (61 vs. 67 bpm; p < .001). In the pilot analysis of the available PSG data, the release of obstructive sleep apneas and hypopneas coincided with fluctuation of HR.

CONCLUSIONS

SDB is independently associated with higher mean HR in patients with HCM, and this difference is most significant during sleep. Treatment of SDB, which is readily available, should be tested as a complementary modality to the currently recommended pharmacotherapy aimed at lowering HR in patients with symptomatic HCM.

Establishing reference ranges for ambulatory electrocardiography parameters: meta-analysis

Objective

Despite the widespread and increasing use of ambulatory electrocardiography (ECG), there is no consensus on reference ranges for ambulatory electrocardiogram parameters to guide interpretation. We sought to determine population distribution-based reference ranges for parameters measured during ambulatory electrocardiogram in healthy adults, based on existing literature.

Methods

We searched multiple databases from 1950 to 2020. Articles reporting original data from ≥24-hour ambulatory electrocardiogram monitoring in healthy adults were included. Data extraction and synthesis were performed according to Meta-analysis of Observational Studies in Epidemiology guidelines. The prevalence/mean and SD for common parameters (sinus pauses, conduction abnormalities and ectopy) were extracted by age group (18–39, 40–59, 60–79 and 80+ years).

Results

We identified 33 studies involving 6466 patients. Sinus pauses of >3 s were rare (pooled prevalence <1%) across all ages. Supraventricular ectopy of >1000/24 hours increased with age, from 0% (95% CI 0% to 0%) in those aged 18–39 years to 6% (95% CI 0% to 17%) in those aged 60–79 years. Episodes of supraventricular tachycardia increased from 3% (95% CI 1% to 6%) in those aged 18–39 years to 28% (95% CI 9% to 52%) in those aged 60–79 years. Ventricular ectopy of >1000/24 hours also increased with age, from 1% (95% CI 0% to 2%) in those aged 18–39 years to 5% (95% CI 1% to 10%) in those aged 60–79 years. Episodes of non-sustained ventricular tachycardia ranged from 0% (95% CI 0% to 1%) in those aged 18–39 years to 2% (95% CI 0% to 5%) in those aged 60–79 years.

Conclusion

Despite the limitations of existing published data, this meta-analysis provides evidence-based reference ranges for ambulatory electrocardiogram parameters and highlights significant age-dependent differences that should be taken into account during interpretation.

Identification of characteristics of overt myocarditis in adult patients with idiopathic inflammatory myopathies

Background

Myocarditis is a rare complication of idiopathic inflammatory myopathies (IIMs), which is usually underestimated because of limited applications of endomyocardial biopsy and cardiovascular magnetic resonance (CMR) in clinical routines.

Methods

From January 2014 to January 2019, 62 patients with initial untreated IIMs were enrolled, including 31 cases with myocarditis (case group) and 31 cases without cardiac involvement (control group). Myocarditis secondary to IIMs was defined based on definitions of IIMs. All medical data were retrieved from electrical medical records of PUMCH. The differences between two groups in symptoms, serum levels of cardiac troponin I (cTnI), creatine kinase-isozyme and N-terminal pro-brain natriuretic peptide (NT-proBNP) were analyzed. The comparisons of arrhythmia, left ventricular ejection fraction (LVEF) and restrictive diastolic dysfunction between two groups were conducted in the analysis of electrocardiogram and electrocardiogram. Besides, CMR data were analyzed to explore the characteristics of CMR in the identification of myocarditis. Meanwhile, 31 patients with myocarditis were divided into two subgroups based on the activity of anti-mitochondrial antibody M2 (AMA-M2), and the differences between two subgroups in the above tests were also analyzed.

Results

Compared with control group, patients with myocarditis exhibited shorter disease durations (defined as the period from onset symptoms of IIM to diagnosis of IIM), more symptoms associated with IIMs, more manifestations of heart failure, and higher frequency of positive AMA-M2 antibody (P<0.05). Patients with myocarditis exhibited elevated levels of cTnI, creatine kinase-isozyme and NT-proBNP compared with control group. In case group, the area under the curve indicating myocarditis for CK-MB, cTnI, and NT-proBNP was 0.654, 0.915 and 0.973, with optimal cut-off values of 24.4 µg/L, 0.1 ng/L and 531 pg/L, respectively. Ventricular arrhythmia, atrial arrhythmia, abnormal Q wave and left anterior fascicular block (LAFB) were showed in 76.7%, 53.3%, 74.2% and 51.6% of patients in case group (P<0.01). Patients of case group were featured as decreased LVEF and restrictive diastolic dysfunction compared with control group (P<0.05). Analyzing CMR data of patients of case group, the basal segments (74.2%) and mid-cavity segments (71.0%) were the most frequently involved areas of late gadolinium-enhancement (LGE), while intramural LGE (54.8%) and subendocardial LGE (51.6%) were reported more commonly than subepicardial LGE (19.4%). In patients with myocarditis and positive AMA-M2 antibody, LVEF and right ventricular ejection factor (RVEF) were decreased, and more cases presented diffuse LGE than those with negative AMA-M2 antibody (P<0.05).

Conclusions

Symptoms of heart failure and arrhythmias, elevated levels of cTnI and NT-proBNP, and positive AMA-M2 antibody play an important role in the identification of myocarditis in IIMs. Most frequently involved areas of LGE were found in the ventricular septal, basal and mid-cavity segments, as well as in the sub-endocardium and intramural myocardium. Diffuse LGE is common in the detection, which is correlated with AMA-M2 antibody in patients with myocarditis related to IIMs.

Detection and management of arrhythmias in peripartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) is an idiopathic dilated cardiomyopathy, in which previously healthy women present with heart failure secondary to left ventricular (LV) systolic dysfunction during the last months of pregnancy or up to 5 months postpartum. PPCM occurs worldwide. The incidence seems to be increasing, possibly due to increasing awareness of the condition and diagnosis thereof. Women diagnosed with PPCM present with symptoms and signs of heart failure, thromboembolism or arrhythmia. Although the incidence of arrhythmias in this condition is not well documented, patients with PPCM often have rhythm disturbances. Indeed, life-threating arrhythmias contribute significantly to sudden cardiac death (SCD) in this population, especially when patients have poor systolic function. In this review, we summarize the evidence on atrial and ventricular arrhythmias in PPCM, as detected by various diagnostic modalities. Furthermore, we summarize the management of arrhythmias in PPCM, as recommended by contemporary guidelines.

Temporal changes of noninvasive electrocardiographic risk factors for sudden cardiac death in post-myocardial infarction patients with preserved ejection fraction: Insights from the PRESERVE-EF study

BACKGROUND

Several noninvasive risk factors (NIRFs) have been proposed for sudden cardiac death risk stratification in post-myocardial infarction (post-MI) patients with preserved ejection fraction (EF). However, it remains unclear if these factors change over time.

METHODS

We evaluated seven electrocardiographic NIRFs as they were described in the PRESERVE-EF trial in 80 post-MI patients with EF ≥ 40%, at least 40 days after revascularization and 1 year later.

RESULTS

Mean patient age was 56 ± 10 years, and 88% were men. Mean EF was 50 ± 5%. The prevalence of (a) positive late potentials (27.5% vs. 28.8%, p = .860), (b) >30 premature ventricular complexes/hour (8.8% vs. 11.3%, p = .598), (c) nonsustained ventricular tachycardia (8.8% vs. 5%, p = .349), (d) standard deviation of normal RR intervals <75 ms (3.8% vs. 3.8%, p = 1.000), (e) QTc derived from 24-hr electrocardiography >440 ms (men) or >450 ms (women) (17.5% vs. 17.5%, p = 1.000), (f) deceleration capacity ≤4.5 ms and heart rate turbulence onset ≥0% and slope ≤2.5 ms (2.5% vs. 3.8%. p = 1.000), and (g) ambulatory T-wave alternans ≥65 μV in two Holter channels (6.3% vs. 6.3%, p = 1.000) were similar between the two measurements. However, five patients (6.3%) without any NIRFs during the first assessment had at least one positive NIRF at the second assessment and six patients (7.5%) with at least one NIRF at baseline had no positive NIRFs at 1 year.

CONCLUSIONS

While the prevalence of the examined electrocardiographic NIRFs between the two examinations was similar on a population basis, some patients without NIRFs at baseline developed NIRFs at 1 year and vice versa, highlighting the need for risk factor reassessment during follow-up.

Diagnostic approach for cardiac involvement in sarcoidosis

Aims

Cardiac sarcoidosis (CS) is a potentially life-threatening condition. Early detection of CS is therefore important. The aim of this study was to eludicate the usefulness of different investigations in a subgroup of patients with sarcoidosis regarded as having an increased risk for cardiac involvement.

Methods

42 sarcoidosis patients, who had an abnormal resting electrocardiogram (ECG) and/or symptoms indicating possible cardiac involvement (i.e. palpitations, pre-syncope or syncope), were included in the study. They were identified in a consecutive manner among patients followed-up at outpatient clinics for respiratory disorders. Holter monitoring, exercise test, transthoracic echocardiogram (TTE), cardiovascular magnetic resonance (CMR) and analysis of N-terminal pro B-type natriuretic peptide (NT-pro-BNP) in serum were performed. Note, that the role of FDG-PET was not investigated in this study.

Results

In the group with a pathologic ECG 11/25 (44%) were ultimately diagnosed with CS (all with pathologic CMR). However, in the group with only symptoms but a normal ECG just 1/17 got the diagnosis CS (p<0.05). This patient had a pathologic Holter monitoring. The risk for CS was increased if serum NT-pro-BNP was elevated (i.e. NT-pro-BNP>125 ng/L), sensitivity 78% (p<0.05), specificity 67%. By adding a pathologic ECG to an elevated NT-pro-BNP increased specificity to 93% and sensitivity remained at 78%.

Conclusion

Our findings indicate that CMR should be performed at an early stage in sarcoidosis patients with an abnormal resting ECG. Holter monitoring and elevated levels of NT-pro-BNP may enhance the diagnostic accuracy whereas exercise testing and TTE in this study had less impact on the identification of CS.

Appropriate utilisation of cardiac telemetry monitoring: a quality improvement project

For hospitals located in the United States, appropriate use of cardiac telemetry monitoring can be achieved resulting in cost savings to healthcare systems. Our institution has a limited number of telemetry beds, increasing the need for appropriate use of telemetry monitoring to minimise delays in patient care, reduce alarm fatigue, and decrease interruptions in patient care. This quality improvement project was conducted in a single academic medical centre in Kansas City, Kansas. The aim of the project was to reduce inappropriate cardiac telemetry monitoring on intermediate care units. Using the 2004 American Heart Association guidelines to guide appropriate telemetry utilisation, this project team sought to investigate the effects of two distinct interventions to reduce inappropriate telemetry monitoring, huddle intervention and mandatory order entry. Telemetry utilisation was followed prospectively for 2 years. During our initial intervention, we achieved a sharp decline in the number of patients on telemetry monitoring. However, over time the efficacy of the huddle intervention subsided, resulting in a need for a more sustained approach. By requiring physicians to input indication for telemetry monitoring, the second intervention increased adherence to practice guidelines and sustained reductions in inappropriate telemetry use.

Usefulness of Heart Rate Control in Atrial Fibrillation Patients With Obstructive Sleep Apnea

In patients without atrial fibrillation and flutter (AF), obstructive sleep apnea (OSA) is associated with cyclic and often marked changes in heart rate (HR). We aimed to assess whether presence of OSA impacts optimal HR control in patients in AF. We retrospectively correlated diurnal HR patterns (recorded by 24-hour Holter monitoring) in patients with AF who independently also underwent diagnostic polysomnography. Exclusion criteria were paced rhythm or inadequate recordings from polysomnography and Holter monitoring. The relationship between the presence and severity of OSA and the mean, minimum, maximum HR, as well as pauses (>2 seconds) and their diurnal variation were studied. Of the 494 studied patients (age 69 ± 10 years; 26% women) mild-moderate OSA (apnea hypoxia index ≥5 and <20) was present in 171 (34%) and severe OSA (apnea hypoxia index ≥20) in 254 (51%). Mean 24-hour HR in patients with severe OSA and mild-moderate OSA was similar to those without OSA (78 vs 80 vs 79 beats per minute; p = 0.39), and there was no significant difference observed in minimum and maximum HR of these groups. However, the frequency of short pauses was greater in OSA patients (p = 0.009), with a prominent nocturnal distribution. In conclusion, OSA was not associated with increased HR in patients with AF suggesting that adequate HR control was similarly achievable in patients with and without OSA. The increased frequency of nocturnal pauses in OSA patients may function as a clinical hallmark, and the timing of pauses (during sleep vs wakefulness) should be noted before making therapeutic decisions regarding HR control.

Newer technologies for detection of atrial fibrillation

Atrial fibrillation is a common arrhythmia that is associated with increased risk of stroke, which can be reduced with appropriate anticoagulation treatment. However, it remains underdiagnosed in contemporary clinical practice using conventional detection methods, resulting in missed opportunities to implement appropriate treatment. Newer technologies developed in recent years can potentially enhance the detection of atrial fibrillation and overcome certain limitations of the conventional methods. However, uncertainties remain about their use and the significance of atrial fibrillation detected by some of these newer technologies. This review examines the evidence supporting the use of some of these technologies and evaluates their applications in certain clinical scenarios.

Obstructive Sleep Apnea is Common and Associated with Heart Remodeling in Patients with Chagas Disease

BACKGROUND

Chagas Disease (CD) is an important cause of morbimortality due to heart failure and malignant arrhythmias worldwide, especially in Latin America.

OBJECTIVE

To investigate the association of obstructive sleep apnea (OSA) with heart remodeling and cardiac arrhythmias in patients CD.

METHODS

Consecutive patients with CD, aged between 30 to 65 years old were enrolled. Participants underwent clinical evaluation, sleep study, 24-hour Holter monitoring, echocardiogram and ambulatory blood pressure monitoring.

RESULTS

We evaluated 135 patients [age: 56 (45-62) years; 30% men; BMI: 26 ± 4 kg/m2, Chagas cardiomyopathy: 70%]. Moderate to severe OSA (apnea-hypopnea index, AHI, ≥ 15 events/h) was present in 21% of the patients. OSA was not associated with arrhythmias in this population. As compared to patients with mild or no OSA, patients with moderate to severe OSA had higher frequency of hypertension (79% vs. 72% vs. 44%, p < 0.01) higher nocturnal systolic blood pressure: 119 ± 17 vs. 113 ± 13 vs. 110 ± 11 mmHg, p = 0.01; larger left atrial diameter [37 (33-42) vs. 35 (33-39) vs. 33 (30-36) mm, p < 0.01]; and a greater proportion of left ventricular dysfunction [LVEF < 50% (39% vs. 28% vs. 11%), p < 0.01], respectively. Predictor of left atrial dimension was Log10 (AHI) (b = 3.86, 95% CI: 1.91 to 5.81; p < 0.01). Predictors of ventricular dysfunction were AHI > 15 events/h (OR = 3.61, 95% CI: 1.31 - 9.98; p = 0.01), systolic blood pressure (OR = 1.06, 95% CI: 1.02 - 1.10; p < 0.01) and male gender (OR = 3.24, 95% CI: 1.31 - 8.01; p = 0.01).

CONCLUSIONS

OSA is independently associated with atrial and ventricular remodeling in patients with CD.

Filtering of ECG signals distorted by magnetic field gradients during MRI using non-linear filters and higher-order statistics

The electrocardiogram (ECG) is the state-of-the-art signal for patient monitoring and gating in cardiovascular magnetic resonance (CMR) imaging applications. However, ECG signals are severely distorted during MRI scans due to the effects of static magnetic fields, radio frequency pulses and fast-switching gradient magnetic fields. Gradient-induced artifacts that cause high frequency peaks in the ECG signal especially hamper a correct and reliable QRS detection. To cope with this problem, a new median-based real-time gradient filter (M1) approach was developed. To improve the filter results, a preprocessing step based on higher-order statistics (M2) was added to this. For the evaluation of the filtering techniques, ECG signals were acquired in a 3T MRI scanner during different MR sequences. A qualitative comparison was made using the mean square error as well as the signal power before and after filtering and the results of the QRS detection. Here, reliable results were achieved (detection error rate [DER] M1: 0.23%, DER M2: 0.74%). It was shown that the two developed techniques allowed a reliable suppression of the gradient artifacts in real time.

Validation of a smartphone-based event recorder for arrhythmia detection

INTRODUCTION

Ambulatory cardiac monitoring devices such as external loop recorders (ELRs) are often used in the outpatient clinic to evaluate palpitations. However, ELRs can be bulky and uncomfortable to use, especially in public, at work, or in social situations. An alternative approach is a smartphone-based electrocardiographic (ECG) recorder/event recorder (Kardia Mobile [KM]), but the comparative diagnostic yield of each approach has not been studied.

METHODS

Thirty-three patients with palpitations wore an ELR and carried a KM for a period of 14-30 days. They were instructed to transmit ECGs via KM and also to activate the ELR whenever they had symptoms. The tracings obtained from both devices were independently analyzed by two cardiologists, and the overall arrhythmia yield, as well as patient preference and compliance, were evaluated. The paired binomial data obtained from both devices were compared using an unconditional test of noninferiority.

RESULTS

Of the 38 patients enrolled in the study, more patients had a potential diagnosis for their symptoms (i.e., at least one symptomatic recording during the entire monitoring period) with KM than with the ELR (KM = 34 [89.5%] vs ELR = 26 [68.4%]; χ²  = 5.1, P = 0.024). In the per protocol analysis, all 33 patients (100%) had a potential diagnosis using the KM device, which was significantly higher compared to 24 patients (72.2%) using the ELR (χ²  = 10.4, P = 0.001).

CONCLUSIONS

KM is noninferior to an ELR for detecting arrhythmias in the outpatient setting. The ease of use and portability of this device make it an attractive option for the detection of symptomatic arrhythmias.

Evaluation of ECG algorithms designed to improve detect of transient myocardial ischemia to minimize false alarms in patients with suspected acute coronary syndrome

BACKGROUND

Patients hospitalized for suspected acute coronary syndrome (ACS) are at risk for transient myocardial ischemia. During the "rule-out" phase, continuous ECG ST-segment monitoring can identify transient myocardial ischemia, even when asymptomatic. However, current ST-segment monitoring software is vastly underutilized due to false positive alarms, with resultant alarm fatigue. Current ST algorithms may contribute to alarm fatigue because; (1) they are not designed with a delay (minutes), rather alarm to brief spikes (i.e., turning, heart rate changes), and (2) alarm to changes in a single ECG lead, rather than contiguous leads.

PURPOSE

This study was designed to determine sensitivity, and specificity, of ST algorithms when accounting for; ST magnitude (100μV vs 200μV), duration, and changes in contiguous ECG leads (i.e., aVL, I, - aVR, II, aVF, III; V1, V2, V3, V4, V5, V6, V6, I).

METHODS

This was a secondary analysis from the COMPARE Study, which assessed occurrence rates for transient myocardial ischemia in hospitalized patients with suspected ACS using 12-lead Holter. Transient myocardial ischemia was identified from Holter using >100μV ST-segment ↑ or ↓, in >1 ECG lead, >1min. Algorithms tested against Holter transient myocardial ischemia were done using the University of California San Francisco (UCSF) ECG algorithm and included: (1)100μV vs 200μV any lead during a 5-min ST average; (2)100μV vs 200μV any lead >5min, (3) 100μV vs 200μV any lead during a 5-min ST average in contiguous leads, and (4) 100μV vs 200μV>5min in contiguous leads (Table below).

RESULTS

In 361 patients; mean age 63+12years, 63% male, 56% prior CAD, 43 (11%) had transient myocardial ischemia. Of the 43 patients with transient myocardial ischemia, 17 (40%) had ST-segment elevation events, and 26 (60%) ST-segment depression events. A higher proportion of patients with ST segment depression has missed ischemic events. Table shows sensitivity and specificity for the four algorithms tested.

CONCLUSIONS

Sensitivity was highly variable, due to the ST threshold selected, with the 100μV measurement point being superior to the 200μV amplitude threshold. Of all the algorithms tested, there was moderate sensitivity and specificity (70% and 68%) using the 100μV ST-segment threshold, integrated ST-segment changes in contiguous leads during a 5-min average.

Chronic obstructive pulmonary disease as a risk factor for ventricular arrhythmias independent of left ventricular function

BACKGROUND

The association between chronic obstructive pulmonary disease (COPD) and sudden cardiac death has not been fully elucidated.

OBJECTIVE

The purpose of this study was to investigate whether decreased left ventricular ejection fraction (LVEF) can explain the increased rate of ventricular tachycardia (VT) in COPD.

METHODS

This retrospective study included consecutive adult patients who underwent pulmonary function testing (PFT), Holter monitoring, and transthoracic echocardiography. COPD was correlated with the frequency of VT in a multivariate analysis that adjusted for known confounders including LVEF. Long-term all-cause mortality of patients with COPD and VT was examined.

RESULTS

Of the 6351 patients included in this study (age 66 ± 15 years; 48% woman; 92% Caucasian, LVEF 59% ± 12%), 2800 (44%) had PFT indicative of COPD. VT was nearly twice as likely to occur during Holter monitoring in COPD patients (13% vs 23%; P <.001), and the severity of COPD correlated with the risk of VT (21% vs 28% vs 37% for mild-moderate, severe, and very severe COPD; P <.001). COPD and VT remained independently associated (P <.001) even after adjusting for LVEF, demographics, and comorbidities (age, sex, body mass index, hypertension, chronic kidney disease, coronary artery disease, cancer history, diabetes mellitus). COPD was associated with all-cause mortality independently of LVEF (P <.001).

CONCLUSION

COPD patients are at higher risk for VT and mortality. This may not be fully attributed to the confounding effect of systolic heart failure measured by LVEF. Further studies are needed to explore the mechanistic interactions between VT and COPD in order to determine whether antiarrhythmic strategies would apply especially to patients with severe COPD.

Cardiac Abnormalities in Adult Patients With Polymyositis or Dermatomyositis as Assessed by Noninvasive Modalities

OBJECTIVE

Cardiac events are a major cause of death in patients with idiopathic inflammatory myopathies. The study objective was in a controlled setting to describe cardiac abnormalities by noninvasive methods in a cohort of patients with polymyositis (PM) or dermatomyositis (DM) and to identify predictors for cardiac dysfunction.

METHODS

In a cross-sectional study, 76 patients with PM/DM and 48 matched healthy controls (HCs) were assessed by serum levels of cardiac troponin I, electrocardiography, Holter monitoring, echocardiography with tissue Doppler imaging, and quantitative cardiac (99m) Tc-pyrophosphate ((99m) Tc-PYP) scintigraphy.

RESULTS

Compared to HCs, patients with PM/DM more frequently had left ventricular diastolic dysfunction (LVDD) (12% versus 0%; P = 0.02) and longer QRS and QT intervals (P = 0.007 and P < 0.0001, respectively). In multivariate analysis, factors associated with LVDD were age (P = 0.001), disease duration (P = 0.004), presence of myositis-specific or -associated autoantibodies (P = 0.05), and high cardiac (99m) Tc-PYP uptake (P = 0.006). In multivariate analysis of the pooled data for patients and HCs, a diagnosis of PM/DM (P < 0.0001) was associated with LVDD.

CONCLUSION

Patients with PM or DM had an increased prevalence of cardiac abnormalities compared to HCs. LVDD was a common occurrence in PM/DM patients and correlated to disease duration. In addition, the association of LVDD with myositis-specific or -associated autoantibodies and high cardiac (99m) Tc-PYP uptake supports the notion of underlying autoimmunity and myocardial inflammation in patients with PM/DM.

Expiration-Triggered Sinus Arrhythmia Predicts Outcome in Survivors of Acute Myocardial Infarction

BACKGROUND

Respiratory sinus arrhythmia (RSA), a measure of cardiac vagal modulation, provides cardiac risk stratification information. RSA can be quantified from Holter recordings as the high-frequency component of heart rate variability or as the variability of RR intervals in individual respiratory cycles. However, as a risk predictor, RSA is neither exceptionally sensitive nor specific.

OBJECTIVES

This study aimed to improve RSA determination by quantifying the amount of sinus arrhythmia related to expiration (expiration-triggered sinus arrhythmia [ETA]) from short-term recordings of electrocardiogram and respiratory chest excursions, and investigated the predictive power of ETA in survivors of acute myocardial infarction.

METHODS

Survivors of acute myocardial infarction (N = 941) underwent 30-min recordings of electrocardiogram and respiratory chest excursions. ETA was quantified as the RR interval change associated with expiration by phase-rectified signal averaging. Primary outcome was 5-year all-cause mortality. Univariable and multivariable Cox regression was used to investigate the association of ETA with mortality.

RESULTS

ETA was a strong predictor of mortality, both in univariable and multivariable analysis. In a multivariable model including respiratory rate, left ventricular ejection fraction, diabetes mellitus, and GRACE score, ETA ≤0.19 ms was associated with a hazard ratio of 3.41 (95% confidence interval: 1.10 to 5.89, p < 0.0001). In patient subgroups defined by abnormal left ventricular ejection fraction, increased respiratory rate, high GRACE score, or presence of diabetes mellitus, patients were classified as high or low risk on the basis of ETA.

CONCLUSIONS

Expiration-triggered sinus arrhythmia (ETA) is a potent and independent post-infarction risk marker.

Ambulatory electrocardiogram monitoring devices for evaluating transient loss of consciousness or other related symptoms

Capturing electrocardiograms (ECGs) during spontaneous events is the most powerful available tool to identify or exclude an arrhythmic cause of symptoms, and often can elucidate the definite diagnosis for different conditions, such as transient loss of consciousness (T-LOC), lightheadedness, or palpitations. Current ambulatory ECG monitoring technologies include 24-hour Holter, wearable event recorder, external loop recorder (ELR), and insertable cardiac monitoring (ICM). Of them, Holter ECG is most frequently used in daily practice in Japan, while ELR and ICM are less frequently used. However, the appropriate monitor choice should be based on the expected frequency of symptoms. Frequent events may be adequately detected by Holter ECG, but less frequent symptoms are more effectively assessed by longer-term monitoring (i.e., ELR or ICM). In this report, based on our clinical experience, we review the usefulness of ambulatory ECG monitoring devices, especially of ELR, for evaluating T-LOC and other potentially arrhythmia-related symptoms. Specifically, we focus on the use of ELR and ICM for evaluating Japanese patients with T-LOC.

Heart Rate Variability in Patients with Acute Ischemic Stroke at Different Stages of Renal Dysfunction: A Cross-sectional Observational Study

Background:

Renal function is associated with mortality and functional disabilities in stroke patients, and impaired autonomic function is common in stroke, but little is known regarding its effects on stroke patients with renal dysfunction. This study sought to evaluate the association between autonomic function and stroke in patients with renal dysfunction.

Methods:

This study comprised 232 patients with acute ischemic stroke consecutively enrolled from February 2013 to November 2014 at Guangdong Provincial Hospital of Chinese Medicine in China. All patients recruited underwent laboratory evaluation and 24 h Holter electrocardiography (ECG). Autonomic function was measured based on the heart rate variability (HRV) using 24 h Holter ECG. Renal damage was assessed through the estimated glomerular filtration rate (eGFR), and stroke severity was rated according to the National Institutes of Health Stroke Scale (NIHSS). The Barthel index and modified Rankin score were also determined following admission. All the clinical covariates that could potentially affect autonomic outcome variables were adjusted with linear regression.

Results:

In the patients with a mild or moderate decreased eGFR, the values for the standard deviation of the averaged normal-to-normal RR interval (SDANN) index (P = 0.022), very low frequency (VLF) (P = 0.043), low frequency (LF) (P = 0.023), and ratio of low-to-high frequency power (LF/HF) (P = 0.001) were significantly lower than those in the patients with a normal eGFR. A multinomial linear regression indicated that eGFR (t = 2.47, P = 0.014), gender (t = −3.60, P < 0.001), and a history of hypertension (t = −2.65, P = 0.008) were the risk factors of LF/HF; the NIHSS score (SDANN index: t = −3.83, P < 0.001; VLF: t = −3.07, P = 0.002; LF: t = −2.79, P = 0.006) and a history of diabetes (SDANN index: t = −3.58, P < 0.001; VLF: t = −2.54, P = 0.012; LF: t = −2.87, P = 0.004) were independent factors for the SDANN index, VLF, and LF; the Oxfordshire Community Stroke Project (t = −2.38, P = 0.018) was related to the SDANN index.

Conclusions:

Autonomic dysfunction is aggravated with the progression of eGFR stage in patients with acute ischemic stroke; the eGFR is an independent factor of LF/HF in the adjusted models. Stroke severity and a history of diabetes are more significantly associated with HRV in patients with acute ischemic stroke at different stages of renal dysfunction.

2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry

Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. The details in this document provide background and framework from which to apply AECG techniques in clinical practice, as well as clinical research.

Effects of Transendocardial Stem Cell Injection on Ventricular Proarrhythmia in Patients with Ischemic Cardiomyopathy: Results from the POSEIDON and TAC-HFT Trials

Transendocardial stem cell injection in patients with ischemic cardiomyopathy (ICM) improves left ventricular function and structure but has ill-defined effects on ventricular arrhythmias. We hypothesized that mesenchymal stem cell (MSC) implantation is not proarrhythmic. Post hoc analyses were performed on ambulatory ECGs collected from the POSEIDON and TAC-HFT trials. Eighty-eight subjects (mean age 61 ± 10 years) with ICM (mean EF 32.2% ± 9.8%) received treatment with MSC (n = 48), Placebo (n = 21), or bone marrow mononuclear cells (BMC) (n = 19). Heart rate variability (HRV) and ventricular ectopy (VE) were evaluated over 12 months. VE did not change in any group following MSC implantation. However, in patients with ≥ 1 VE run (defined as ≥ 3 consecutive premature ventricular complexes in 24 hours) at baseline, there was a decrease in VE runs at 12 months in the MSC group (p = .01), but not in the placebo group (p = .07; intergroup comparison: p = .18). In a subset of the MSC group, HRV measures of standard deviation of normal intervals was 75 ± 30 msec at baseline and increased to 87 ± 32 msec (p =.02) at 12 months, and root mean square of intervals between successive complexes was 36 ± 30 msec and increased to 58.2 ± 50 msec (p = .01) at 12 months. In patients receiving MSCs, there was no evidence for ventricular proarrhythmia, manifested by sustained or nonsustained ventricular ectopy or worsened HRV. Signals of improvement in ventricular arrhythmias and HRV in the MSC group suggest a need for further studies of the antiarrhythmic potential of MSCs. Stem Cells Translational Medicine 2017;6:1366-1372.

Prognostic indices among hypertensive heart failure patients in Nigeria: the roles of 24-hour Holter electrocardiography and 6-minute walk test

Background

Hypertensive heart failure (HHF) is associated with a poor prognosis. There is paucity of data in Nigeria on prognosis among HHF patients elucidating the role of 24-hour Holter electrocardiogram (ECG) in concert with other risk factors.

Objective

The aim of this study was to determine the prognostic utility of 24-hour Holter ECG, the 6-minute walk test (6-MWT), echocardiography, clinical and laboratory parameters among HHF patients.

Methods

A total of 113 HHF patients were recruited and followed up for 6 months. Thirteen of these patients were lost to follow-up, and as a result only 100 HHF patients were analyzed. All the patients underwent baseline laboratory tests, echocardiography, 24-hour Holter ECG and the 6-MWT. HHF patients were analyzed as “mortality vs alive” and as “events vs no-events” based on the outcome at the end of 6 months. Events was defined as HHF patients who were rehospitalized for heart failure (HF), had prolonged hospital stay or died. No-events group was defined as HHF patients who did not meet the criteria for the events group.

Results

HHF patients in the mortality group (n = 7) had significantly higher serum urea (5.71 ± 2.07 mmol/L vs 3.93 ± 1.45 mmol/L, p = 0.003) than that in those alive. After logistic regression, high serum urea conferred increased mortality risk (p = 0.035). Significant premature ventricular complexes (PVCs) on 24-hour Holter ECG following logistic regression were also significantly higher (p = 0.015) in the mortality group than in the “alive” group (n = 93) at the end of the 6-month follow-up period. The 6-minute walk distance (6-MWD) was least among the HHF patients who died (167.26 m ± 85.24 m). However, following logistic regression, the 6-MWT was not significant (p = 0.777) for predicting adverse outcomes among HHF patients. Patients in the events group (n = 41) had significantly higher New York Heart Association (NYHA) class (p = 0.001), Holter-detected ventricular tachycardia (VT; p = 0.009), Holter-detected atrial fibrillation (AF; p = 0.028) and PVCs (p = 0.017) following logistic regression than those in the no-events group (n = 59).

Conclusion

High NYHA class, elevated serum urea, Holter ECG-detected AF and ventricular arrhythmias are predictive of a poor outcome among HHF patients. The 6-MWT was not a useful prognostic index in this study.

Unplanned transfer from the telemetry unit to the intensive care unit in hospitalized patients with suspected acute coronary syndrome

BACKGROUND

Most patients presenting with suspected acute coronary syndrome (ACS) are admitted to telemetry units. While telemetry is an appropriate level of care, acute complications requiring a higher level of care in the intensive care unit (ICU) occur.

PURPOSE

Among patients admitted to telemetry for suspected ACS, we determine the frequency of unplanned ICU transfer, and examine whether ECG changes indicative of myocardial ischemia, and/or symptoms preceded unplanned transfer.

METHOD

This was a secondary analysis from a study assessing occurrence rates for transient myocardial ischemia (TMI) using a 12-lead Holter. Clinicians were blinded to Holter data as it was used in the context research; off-line analysis was performed post discharge. Hospital telemetry monitoring was maintained as per hospital protocol. TMI was defined as >1mm ST-segment ↑ or ↓, in >1 ECG lead, >1minute. Symptoms were assessed by chart review.

RESULTS

In 409 patients (64±13years), most were men (60%), Caucasian (93%), and had a history of coronary artery disease (47%). Unplanned transfer to the ICU occurred in 9 (2.2%), was equivalent by gender, and age (no transfer 64±13years vs transfer 67±11years). Four patients were transferred following unsuccessful percutaneous coronary intervention (PCI) attempt, four due to recurrent angina, and one due to renal and hepatic failure. Mean time from admission to transfer was 13±6hours, mean time to ECG detected ischemia was 6±5hours, and 8.8±5hours for symptoms prompting transfer. In two patients ECG detected ischemia and acute symptoms prompting transfer were simultaneous. In five patients, ECG detected ischemia was clinically silent. All patients eventually had symptoms that prompted transfer to the ICU. In all nine patients, there was no documentation or nursing notes regarding bedside ECG monitor changes prior to unplanned transfer. Hospital length of stay was longer in the unplanned transfer group (2days ± 2 versus 6days ± 4; p=0.018).

CONCLUSIONS

In patients with suspected ACS, while unplanned transfer from telemetry to ICU is uncommon, it is associated with prolonged hospitalization. Two primary scenarios were identified; (1) following unsuccessful PCI, and (2) recurrent angina. Symptoms prompting unplanned transfer occurred, but happened on average 8.8 hours after hospital admission; whereas ECG detected ischemia preceding unplanned transfer occurred on average 6 hours after hospital admission.

Clinical Logistics in 24-Hour Ambulatory Electrocardiographic Monitoring

In total, 493 ambulatory ECG recordings were studied. Women were preponderant (62.3% vs 37.7%). The average age of women and men patients was 66.9 and 64.7 years, respectively. Of the ECGs studied, 71.4% showed abnormalities and 28.6% appeared completely normal. Urgent abnormalities were noted in 1.4% of the recordings and significant abnormalities were present in 14.6%. Subjective complaints were noted in their logbooks by 18.8% of patients, but correlation of complaints with the electrocardiographic abnormalities was noted in only 1.2% of cases. The attending cardiologist concluded that 23.9% of the tests supported reasons of valid necessity for performance. Two hundred seventy-three recordings were clas sified as electrocardiographically abnormal (55.4%) but were clinically insignificant. General practitioners requested 59.8% of the tests versus 40.2% by specialists. Preponderant abnor malities included premature atrial and ventricular contractions, supraventricular tachycardia, and atrial fibrillation. Less frequent abnormalities included ventricular tachycardia (4.6%), atrial flutter, atrioventricular block, artificial pacemaker rhythm, nodal rhythm, and intermit tent bundle branch block.

Effects of transcutaneous electrical nerve stimulation (TENS) on arterial stiffness and blood pressure in resistant hypertensive individuals: study protocol for a randomized controlled trial

BACKGROUND

Resistant hypertension (RH) treatment requires an adequate and intense therapeutic approach. However, the results are not always satisfactory despite intensive treatment. Of the different pathophysiological mechanisms involved in the pathogenesis of RH, sympathetic overstimulation and therapies that block the sympathetic system have been widely studied. These approaches, however, are invasive and expensive. Another possible approach is by transcutaneous electrical nerve stimulation (TENS), a noninvasive method that modulates activity by using low-frequency transcutaneous electrical stimulation to inhibit primary afferent pathways. Thus, the current study will evaluate the effect of applying TENS in the cervicothoracic region of subjects with RH and will seek to develop a new low-cost and readily available therapy to treat this group of hypertensive individuals.

METHODS/DESIGN

This is a randomized, single blind (subject), parallel-assignment study controlled with a sham group and including participants aged 40 to 70 years with resistant hypertension. The trial has two arms: the treatment and control (sham group). The treatment group will be submitted to the stimulation procedure (TENS). The sham group will not be submitted to stimulation. The primary outcomes will be a reduction in the peripheral blood pressure and adverse events. The secondary outcomes will be a reduction the central blood pressure. The study will last 30 days. The sample size was calculated assuming an alpha error of 5 % to reject the null hypothesis with a statistical power of 80 %, thereby resulting in 28 participants per group (intervention versus sham).

DISCUSSION

In recent decades, RH has become very common and costly. Adequate control requires several drugs, and in many cases, treatment is not successful. Sympathetic nervous system inhibition by renal denervation and central inhibition have significant effects in reducing BP; however, these treatments are costly and invasive. Another type of sympathetic nervous system inhibition can also be noninvasively achieved by electric current. Therefore, the application of TENS may be a new therapeutic option for treating resistant hypertensive individuals.

TRIAL REGISTRATION

Clinical Trials NCT02365974.

Palpitations and Arrhythmias and Sudden Cardiac Arrest/Sudden Cardiac Death in Children and Adolescents

Palpitations are a common complaint, particularly in teenagers, with etiologies ranging from no detectable cardiac dysrhythmia to life-threatening dysrhythmias. Despite the fact that as many as 50% of children and adolescents may be asymptomatic prior to experiencing sudden cardiac arrest, the occurrence of palpitations may afford the opportunity to detect a potentially lethal arrhythmia condition. This article discusses the evaluation of palpitations in the pediatric population by focusing on the two most common life-threatening arrhythmia diagnoses that may initially manifest itself in the pediatric population with the chief complaint of palpitations-Wolff-Parkinson-White syndrome and the long QT syndrome.

Heart rate variability and arrhythmic patterns of 24-hour Holter electrocardiography among Nigerians with cardiovascular diseases

BACKGROUND

Facilities for Holter electrocardiography (ECG) monitoring in many Nigerian hospitals are limited. There are few published works in Nigeria on the use of 24-hour Holter ECG in cardiac arrhythmic evaluation of patients with cardiovascular diseases.

OBJECTIVE

To study the clinical indications, arrhythmic pattern, and heart rate variability (HRV) among subjects referred for 24-hour Holter ECG at our Cardiac Care Unit.

METHODS

Three-hundred and ten patients (134 males and 176 females) were studied consecutively over a 48-month period using Schiller type (MT-101) Holter ECG machine.

RESULTS

Out of the 310 patients reviewed, 134 were males (43.2%) and 176 were females (56.8%). The commonest indication for Holter ECG was palpitation followed by syncope in 71 (23%) and 49 (15.8%) of subjects, respectively. Premature ventricular complex and premature atrial complex were the commonest types of arrhythmia in 51.5% and 15% subjects, respectively. Ventricular arrhythmia was more prevalent in dilated cardiomyopathy patients (85.7%). The HRV of subjects with palpitation, stroke, and diabetes mellitus with autonomic neuropathy, using standard deviation of normal to normal intervals average (milliseconds), were 107.32±49.61, 79.15±49.15, and 66.50±15.54, respectively. The HRV, using standard deviation of averages of normal to normal intervals average (milliseconds), of patients with palpitation, stroke, and diabetes mellitus with autonomic neuropathy were 77.39±62.34, 57.82±37.05, and 55.50±12.71, respectively.

CONCLUSION

Palpitation and syncope were the commonest indications for Holter ECG among our subjects. The commonest arrhythmic patterns were premature ventricular complex and premature atrial complex, with ventricular arrhythmia being more prevalent in dilated cardiomyopathy. There was a reduction in HRV in patients with stroke and diabetic autonomic neuropathy.