24-hour Holter Electrocardiogram Research Articles

Should concomitant surgical ablation for atrial fibrillation be performed in elderly patients?

ObjectiveThe incidence of atrial fibrillation increases with age, and therefore many elderly patients presenting for cardiac surgery have atrial fibrillation. In recent publications, increasing age has been recognized as a predictor for ablation failure. Furthermore, many surgeons are reluctant to perform a surgical ablation in elderly patients. We investigated the safety and efficacy of concomitant surgical atrial fibrillation ablation in elderly patients. MethodsBetween 2003 and 2013, 556 patients underwent concomitant surgical atrial fibrillation ablation at the University Heart Center Hamburg and served as our primary study cohort. During follow-up, rhythm monitoring was established by 24-hour Holter electrocardiogram (70.5%) or an implantable loop recorder (29.5%) at 3, 6, and 12 months postoperatively. The primary end point of the study was freedom from atrial fibrillation at 12 months follow-up and the detection of deviations from a linear association between age and risk of atrial fibrillation recurrence. A multiple logistic regression model including age as a linear term was used to identify predictors for rhythm outcome. ResultsMean patients’ age was 68.4 ± 9.07 years, and 67.3% of the patients were male. Mean duration of atrial fibrillation was 3.5 ± 3.3 years, and mean left atrium diameters were enlarged with 50.5 ± 8.8 mm. There were no major ablation-related complications. The 30-day and 1-year survivals were 97.7% and 95.8%, respectively. The overall rate of freedom from atrial fibrillation ranged from 62% to 72% and was independent of age. The age-dependent risk of atrial fibrillation at 12 months was significantly increased in elderly patients undergoing a concomitant coronary artery bypass grafting surgery. Multiple logistic regression model revealed double valve procedures (odds ratio, 3.48; P = .020), preoperative persistent atrial fibrillation (odds ratio, 2.43; P = .001), and coronary artery bypass grafting surgery in elderly patients (odds ratio, 2.03; P = .009) as risk factors for recurrence of atrial fibrillation. Sinus rhythm at discharge (odds ratio, 0.39; P < .001) and bipolar ablation (odds ratio, 0.32; P < .001) were significant predictors for successful ablation. ConclusionsSurgical atrial fibrillation ablation was safe and effective independently of age. Sinus rhythm at discharge and bipolar ablation were significant predictors for successful ablation, whereas double valve procedures, preoperative persistent atrial fibrillation, and coronary artery bypass grafting surgery in elderly patients were risk factors for recurrence of atrial fibrillation.

P3754Comparison of the transdermal bisoprolol patch with the oral bisoprolol fumarate administration as a therapeutic agent for idiopathic frequent premature ventricular contractions

Abstract Background The transdermal bisoprolol patch (TB) was designed to maintain a sustained concentration of bisoprolol in plasma by higher trough concentration than the oral bisoporolol fumarate administration (OB). It is unclear whether the TB is as effective in treating idiopathic premature ventricular contractions (PVCs) as the OB. Purpose We compared the efficacy between the TB and OB in treating idiopathic PVCs while considering their duration of action. Methods Among 198 patients with a PVC count of ≥3,000 beats/24 hours, 84 patients were divided into groups treated with TB 4mg (n=50) or OB 2.5mg (n=34). The PVCs were divided into positive heart rate (HR)-dependent PVCs (P-PVCs) and non-positive HR-dependent PVCs (NP-PVCs) based on the relationship between the hourly PVCs density and hourly mean HR. To evaluate the efficacy, PVC counts by 24-hour Holter electrocardiograms were measured at baseline and at 1 month after the initiation of the therapy. Results There were no significant between-group differences for the mean HR, PVC count, or type of PVCs. Both the TB (from 16,692±9,737 to 10,442±10,711 beats/24 hours, P&lt;0.001) and OB (from 19,633±16,298 to 9,235±12,124 beats/24 hours, P&lt;0.001) significantly decreased the total PVC count after the initiation of therapy, and a comparison between the two drugs showed no significant difference (P=0.46). In the P-PVC group, both the TB and OB significantly decreased the total PVC count (P&lt;0.001, P=0.022 respectively), PVC count during the day-time (P&lt;0.001, P=0.030 respectively), and PVC count during the night-time (P=0.0038, P=0.022 respectively). In contrast, in the NP-PVC group, neither the TB nor OB made any significantly change in the total PVC count (P=0.079, P=0.10 respectively), PVC count during the day-time (P=0.35, P=0.12 respectively), or PVC count during the night-time (P=0.11, P=0.12 respectively). The TB exhibited a significant reduction during each time period regarding the changes within 24-hours in the P-PVC count from baseline, while the OB did not significantly reduce the P-PVC count from baseline during each time period between 0 and 5 o'clock. Conclusions Compared with the OB, the TB could be used with the same efficacy for reducing the PVC count. The TB could be a more useful therapeutic agent for idiopathic P-PVCs during a 24-hour period than the OB.

Baroreflex sensitivity assessed with the sequence method is associated with ventricular arrhythmias in patients implanted with a defibrillator for the primary prevention of sudden cardiac death

Left ventricular ejection fraction lacks accuracy in predicting sudden cardiac death, resulting in unnecessary implantation of cardioverter defibrillators for the primary prevention of sudden cardiac death. Baroreflex sensitivity could help to stratify patients at risk of ventricular arrhythmia. To assess the association between cardiac baroreflex sensitivity and ventricular arrhythmias in patients implanted with an implantable cardioverter defibrillator for the primary prevention of sudden cardiac death after myocardial infarction. This case-control single-centre study took place between 2015 and 2016. Cases (n=10) had experienced ventricular arrhythmias treated by the implantable cardioverter defibrillator in the previous 3 years; controls (n=22) had no arrhythmia during the same period. Baroreflex sensitivity was assessed using the temporal sequence method (mean slope) and cross-spectral analysis (low-frequency gain and high-frequency gain). The mean age was 65 years; 94% of the patients were men. 24-hour Holter electrocardiogram autonomous nervous system variables, left ventricular ejection fraction and N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) concentration did not differ between cases and controls. The mean slope was lower in cases than in controls (8 vs. 15ms/mmHg [P=0.009] in the supine position; 7 vs. 12ms/mmHg [P=0.038] in the standing position). The mean slope in the supine position was still significantly different between groups after adjustment for age, left ventricular ejection fraction and NT-proBNP (P=0.03). By comparison, low-frequency gain and high-frequency gain did not differ between groups in either the supine or the standing position. Patients with ventricular arrhythmias had a lower mean slope compared with those who were free of arrhythmia. A prospective study is needed to confirm this association.

Ambient fine particulate matter (PM2.5) exposure is associated with idiopathic ventricular premature complexes burden: A cohort study with consecutive Holter recordings.

Epidemiological evidence has shown an association between ambient fine particulate matter (PM2.5) exposure and cardiovascular mortality. Increased ventricular premature complex (VPC) burden can cause left ventricular dilatation and dysfunction. We aimed to investigate the relationship between acute PM2.5 exposure and VPC burden in patients without structural heart disease. We reviewed 26 820 patients who underwent 24-hour Holter electrocardiogram (ECG) recordings between 1 Jan 2013 and 1 Dec 2016. We enrolled patients with significant idiopathic (structurally normal heart) VPC burden defined as ≥30 VPCs/h (Lown grade 2) who had at least two Holter ECG recordings. The VPC burden between the studies on high and low PM2.5 exposure dates was compared in 24 and 12 hours time periods. Sixty-seven patients (31 men, 56.49 ± 18.35 years) were enrolled. Patients were exposed to 25.63 ± 11.47 and 14.66 ± 7.51 μg/m 3 of PM2.5 during the high and low study dates, respectively. The overall VPC counts (10,490.69 ± 10,681.63/day) and burden (10.22% ± 10.17%) were significantly higher on the days with higher PM2.5 exposure compared with low PM2.5 exposure dates (8293.31 ± 9009.09; P = 0.014% and 9.14% ± 12.73%, P = 0.012, respectively). Compared with low PM2.5 exposure dates, the VPC burden on high exposure dates was significantly higher from 9 am to 9 pm(5.85% ± 6.41% vs 4.84% ± 6.97%; P = 0.025) but not at nocturnal periods. Our study demonstrated a significantly higher VPC burden on high PM2.5 exposure date. The burden was increased in the daytime but not at nighttime. This result suggests that daytime PM2.5 exposure may be associated with ventricular arrhythmia burden in the healthy population.

The frequency of rhythm and conduction abnormalities and benefits of 24-hour Holter electrocardiogram on detecting these abnormalities in patients with acute rheumatic fever.

The frequency of rhythm and conduction abnormalities and benefits of 24-hour Holter electrocardiogram on detecting these abnormalities in patients with acute rheumatic fever.

Heart rate variability in juvenile systemic lupus erythematosus patients.

Başaran Ö, Çetin İİ, Aydın F, Uncu N, Çakar N, Ekici F, Çelikel Acar B. Heart rate variability in juvenile systemic lupus erythematosus patients. Turk J Pediatr 2019; 61: 733-740. Although neurological involvement has been well recognized in patients with systemic lupus erythematosus (SLE), autonomic nervous system (ANS) involvement has rarely been studied, and has shown conflicting results. The aim of this study was to evaluate the ANS functions by using heart rate variability (HRV) in juvenile patients with SLE. Sixteen juvenile-onset SLE patients and 16 healthy controls were enrolled in the study. All participants underwent 24-hour Holter electrocardiogram monitoring and HRV indices were assessed. The SLE disease activity index (SLEDAI) score was used to assess the disease activity. We analyzed the correlation between disease duration, the SLEDAI score, and the HRV domains. Overall HRV was diminished in patients with SLE compared to controls. There were negative correlations between day and night RMSSD (root-mean-square of the successive normal sinus NN interval differences) and PNN50 (percentage of successive normal sinus NN intervals > 50 ms) values, and SLEDAI (r= -0.588 p=0.017; r= - 0.607 p= 0.013; r= -0.498 p=0.049; r= -0.597 p=0.015, respectively). There were positive correlations between both day and night LF/HF values and SLEDAI (r=0.766 p=0.001; r=0.635 p=0.008, respectively). The results suggest that autonomic dysfunction exists in juvenile patients with SLE. As these children are at increased risk for cardiovascular disease, they need to be assessed for the development of autonomic dysfunction.

THE VARIABILITY OF HEART RHYTHM IN PATIENTS WITH STABLE ISCHEMIC HEART DISEASE AND DIABETES MELLITUS TYPE 2

The purpose of this study is to evaluate the time and spectral parameters of heart rate variability (HRV) in patients with stable type of coronary heart disease and type 2 diabetes mellitus by findings obtained by daily ECG Holter monitoring. Material and methods. The study involved 61 individuals aged 42-64 years (mean age 46.4±4.6 years) with IHD, stable exertional angina pectoris of II-III functional classes, of them 34 individuals (I group) were diagnosed to have diabetes mellitus 2 types, and 27 individuals (II group) were found to have no disorders of carbohydrate metabolism. The control group consisted of 15 individuals with essential hypertension of stage II without IHD and diabetes mellitus. All patients underwent 24-hour Holter electrocardiogram monitoring (HM ECG) with subsequent analysis of HRV parameters and evaluation of heart rhythm disturbances. Results and discussion. It was found that in both groups of IHD patients regardless the presence of diabetes, there was a decrease in the circadian index in comparison with patients with essential hypertension that probably indicates a vegetative "denervation" of the heart, the development of rigidity of the circadian circadian heart rate profile in IHD patients. With an increase in the level of glycosylated hemoglobin in the patients of I group, the temporal indices of the variability of the heart rhythm and the circadian index declined. The number of supraventricular and ventricular extrasystoles per day was statistically significantly higher in patients of I group (p &lt;0.001, p &lt;0.002, respectively) compared with the patients with IHD without diabetes. In the patients with coronary artery disease and diabetes, HM ECG data showed a decrease in HRV timing. This category of patients was found to have a general decrease in HRV: a SDNN decline, changes in spectral characteristics (a decrease in the high-frequency component of the spectrum (HF), an increase in the LF/HF ratio) with a shift of balance toward the sympathetic (low-frequency) component. Conclusions. Patients with stable form of ischemic heart disease and diabetes mellitus type 2 have a decrease in both temporal and spectral HRV indices that indicates a decrease in the total activity of neurohumoral effects on the heart rhythm. These changes are associated with an increase in the ectopic activity of the myocardium.

Coronary Artery Dominance May Predict Future Risk of Atrial Fibrillation.

Ischemia of the atria and conductive system of the heart results in greater atrial electrophysiological changes and propensity for atrial fibrillation. P wave duration and dispersion have been proposed to be useful for the prediction of paroxysmal atrial fibrillation (PAF). This study aimed to investigate the effect of coronary artery dominance on P wave duration and dispersion. The study population included 194 patients with left dominant circulation (LDC) and 200 age- and gender-matched controls with right dominant circulation (RDC) and without coronary artery disease based on invasive coronary angiography findings. P wave dispersion (PWD) was defined as the difference between the maximum and minimum P wave duration. Arrhythmias were identified by 24-hour Holter electrocardiogram at 3 years of follow-up. PWD was significantly prolonged in the patients with LDC compared to the controls with RDC (p = 0.001). There were positive correlations between PWD and age (r: 0.502, p = 0.009), left ventricular mass (LVM) (r: 0.614, p = 0.001), LVM index (r: 0.727, p < 0.001) and left atrium (LA) diameter (r: 0.558, p = 0.003) in the LDC group. Multivariate logistic regression analysis showed that age, LVM index, LA diameter and LDC were independent predictors of prolonged PWD. At 3 years of follow-up, 7 (3.9%) patients with LDC and 1 (0.5%) patient with RDC had PAF in Holter electrocardiogram (p < 0.001). LDC could lead to an increased risk of atrial fibrillation through prolonged PWD. We recommend following up these patients to assess the development of atrial fibrillation.

Relationship Between Ventricular Arrhythmias, Conduction Disorders, and Myocardial Fibrosis in Patients With Systemic Sclerosis.

Delayed-enhancement magnetic resonance imaging (DE-MRI) is a noninvasive diagnostic tool able to identify myocardial fibrosis. In patients with scleroderma, its relationship with arrhythmias and conduction disorders has not been fully explored. The aim of this study was to evaluate the possible correlations between ventricular arrhythmias, conduction disorders, and myocardial fibrosis in patients with systemic sclerosis. Thirty-six patients with diffuse or limited cutaneous scleroderma underwent 12-lead electrocardiogram (ECG), 24-hour Holter ECG monitoring, transthoracic echocardiography, and cardiac DE-MRI, with gadolinium administration in 33 patients. High-quality DE-MRI scans were obtained in 30 patients. Myocardial fibrosis was detected in 25 patients (83.3%). Eighteen patients (60%) had ventricular arrhythmias or conduction disorders. There was no significant difference in ventricular arrhythmia burden (the total number of premature ventricular contractions [PVCs]/24 hours) (48 ± 304 vs. 69 ± 236, P = 0.97), ventricular arrhythmia severity (couplets, triplets, runs) on Holter ECG, or in the presence of conduction disorders (36% vs. 40%, P = 0.86) between patients with and without myocardial fibrosis. In univariate analysis, diffuse fibrosis was weakly associated with the number of PVCs/24 hours (R = 0.157, P = 0.03). A number of at least 597 PVCs/24 hours had a sensitivity of 60% and a specificity of 92% in predicting the presence of diffuse fibrosis on DE-MRI (area under the curve = 0.640). Delayed-enhancement magnetic resonance imaging can identify myocardial fibrosis in a high percentage of scleroderma patients. Its presence does not seem to influence the ventricular arrhythmia burden and severity or the presence of conduction disorders, with the exception of diffuse myocardial fibrosis, which modestly influences the total number of PVCs/24 hours.

Effect of GWAS-Identified Genetic Variants on Maximum QT Interval in Patients With Schizophrenia Receiving Antipsychotic Agents: A 24-Hour Holter ECG Study.

Users of antipsychotics (APs) have a risk of sudden cardiac death (SCD). Sudden cardiac death in such patients is thought to be largely due to drug-induced QT prolongation. It has been reported that many subjects with drug-induced torsades de pointes (TdP) have risk alleles associated with subclinical congenital long QT syndrome. We investigated the effects of the risk alleles associated with long QT on the QT interval in patients receiving APs using 24-hour Holter electrocardiograms to take into account the circadian fluctuation of QT intervals. We investigated 8 single-nucleotide polymorphisms identified on a GWAS. We found that increased numbers of risk alleles at rs7188697 in NDRG4 and rs11970286 in PLN were the major predictors of an increased maximum QT interval over 24 hours in users of APs. It could be useful to perform a DNA-based analysis before the initiation of APs to reduce the risk of drug-induced torsades de pointes and SCD.

Assessment of a novel transdermal selective β1-blocker, the bisoprolol patch, for treating frequent premature ventricular contractions in patients without structural heart disease

BackgroundThe autonomic nervous system involves the genesis of premature ventricular contractions (PVCs). Previous studies demonstrated that heart rate (HR) dependency of idiopathic PVCs has different autonomic mechanisms. Recently, the bisoprolol patch, a novel transdermal β1-blocker formulation containing bisoprolol, became clinically available. We examined the efficacy of the bisoprolol patch for treating frequent PVCs in patients without structural heart disease (SHD) regarding the HR dependency of PVCs. MethodsThis prospective study included 44 consecutive patients without SHD (25 men, mean age, 63.6±12.3 years) with PVC counts≥3000 beats as measured by 24-hour Holter electrocardiograms (ECGs). PVCs were divided into positive HR-dependent PVCs (P-PVCs) and non-positive HR-dependent PVCs (NP-PVCs) based on the relationship between the hourly PVC density and hourly mean HR. A bisoprolol patch was administered once daily at a dose of 4mg. The 24-hour Holter ECGs were performed before and 1 month after the initiation of the therapy. ResultsIn 44 patients, there were 24 P-PVCs and 20 NP-PVCs. The bisoprolol patch reduced the PVC count significantly (from 16,563±10,056 to 7892±8817 beats/24hours, p<0.001) in the P-PVC group, while the PVC count did not change significantly (from 16,409±9571 to 13,476±12,191beats/24hours, p=0.34) in the NP-PVC group. Moreover, in the P-PVC group, the patients with mean HRs ≥80 beats/minute had a significantly higher percent improvement in the PVC count than those with mean HRs <80 beats/minute (p=0.0080). The bisoprolol patch resulted in a significant reduction in the PVC count from baseline during each time period for the changes within a 24-hour period in the P-PVC group. ConclusionsThe transdermal bisoprolol patch was effective for a PVC reduction in patients with P-PVCs, particularly in those with faster mean HRs. Furthermore, it demonstrated a stable PVC-reducing effect during the 24-hour period in the P-PVC group.

STRUCTURAL AND FUNCTIONAL CHANGES EVALUATED BY ECHOCARDIOGRAPHY IN PATIENTS WITH SYSTEMIC SCLEROSIS AND HEART RATE VARIABILITY

Objective: to estimate heart rate variability (HRV) in patients with systemic sclerosis (SS) and to investigate their relationship to echocardiographic structural and functional changes in the heart. Subjects and methods. The investigation enrolled 125 patients with SS and 50 gender- and age-matched apparently healthy individuals who made up a control group. In addition to clinical examinations, 73 patients underwent HRV assessment from 24-hour Holter electrocardiogram (ECG) monitoring results and 121 patients had echocardiography (EchoCG). 24-hour Holter ECG monitoring was carried out in all control individuals. Results and discussion . Examination of the main parameters of time-domain HRV in patients with SS revealed a significant decline in all temporal and spectral indices, except for the mean R–R interval duration (meanNN), as compared with the control group. EchoCG detected a variety of changes, primarily the induration and calcification of aortic and mitral valves in most patients. Left ventricular diastolic dysfunction was encountered in almost half of the patients with SS. Eight patients had a lower left ventricular ejection fraction (LVEF), which was <55%. Studying the association of HRV values with separate EchoCG parameters revealed significant inverse correlations of the mean standard deviation of R–R intervals in 5-minute recording segments during 24 hours with the thickness of the interventricular septum (r = -0.18; p < 0.05) and with the induration of the aortic valve (r = -0.18; p < 0.05); the square root mean squared of successive differences (RMSSD, ms) for R–R intervals and the percentage of adjacent R–R intervals that varied by more than 50 ms (pNN50) correlated with the induration of the aortic valve (r = -0.23; p<0.05 and r = -0.25; p < 0.05, respectively), with the presence of pericarditis (r = -0.24; p < 0.05 and r = -0,27; p < 0.05, respectively), and with the level of pulmonary artery systolic pressure (r = -0.23; p < 0.05 and r = -0.27; p < 0.05, respectively). There was also a direct correlation of rMSSD and pNN50 with LVEF (r = 0.27; p < 0.05 and r = 0.29, respectively; p < 0.05). A significant decrease in rMSSD and pNN50 was ascertained in hypertensive patients as compared to non-hypertensive patients (18.1±4.8 and 24.9±13.3; 2.3±1.8 and 5.7±6.5, respectively; p < 0.05). Conclusion. Comprehensive examination using EchoCG and 24-hour Holter ECG monitoring revealed the high frequency and severity of significant cardiac changes in SS. The temporal spectrum analysis of HRV could confirm a significant reduction in the function of both the sympathetic and parasympathetic parts of the autonomic nervous system. Decreased HRV was associated with SS severity and activity, traditional cardiovascular risk factors, and cardiac structural changes.

Predictors of Long-term Success After Concomitant Surgical Ablation for Atrial Fibrillation

According to guidelines, atrial fibrillation (AF) ablation success should be measured by 24-hour Holter electrocardiogram (ECG). However, information on long-term success, especially obtained by 24-hour Holter ECG, is rare. We therefore analyzed rhythm course and long-term outcomes of our patients undergoing concomitant surgical AF ablation. Between January 2003 and April 2011, 486 patients underwent concomitant surgical AF ablation in our institution. Patients with 24-hour Holter ECG rhythm status available between 5 and 10 years postoperatively were included in this retrospective data analysis (n = 155). Ablation lesions were limited to either a pulmonary vein isolation (n = 31, 20%), a more complex left atrial lesion set (n = 89, 57%), or biatrial lesions (n = 35, 23%). Primary end point of the study was freedom from AF during long-term follow-up. Mean patient age was 68.1 ± 8.4 years; 57.4% were male. Mean follow-up time was 5.9 years. Surgical AF ablation provided freedom from AF rate of 56.6% during long-term follow-up, with significantly better results in patients with paroxysmal than in those with persistent AF (67.2% vs 51.8% P = 0.03). A stable rhythm course was observed during follow-up, without statistically significant differences between 12 months and latest follow-up (63.2% vs 56.6%; P = 0.25). In multivariate analysis, preoperative paroxysmal AF, duration of AF, and left atrial diameter were predictors of long-term ablation success. Surgical AF ablation provided freedom from AF rate of 56.6% during long-term follow-up. Statistically significant predictors of ablation success at latest follow-up were preoperative paroxysmal AF, duration of AF, and a preoperative smaller left atrial diameter.

Predicting Intermittent Atrial Fibrillation in Outpatient Clinics.

Background and ObjectivesPalpitations are the most common complaint in cardiology outpatient clinics. These palpitations may be derived from paroxysmal atrial fibrillation (AF) and can be easily overlooked. It is unclear whether inter-atrial conduction time (ICT) may predict the paroxysmal AF in out-patients that present with palpitations. We evaluated the ability of the ICT to predict paroxysmal AF in these patients.Subjects and MethodsThe study group consisted of 199 patients (110 female). All patients underwent 24-hour Holter electrocardiogram (ECG) monitoring (total of 327 Holter ECG monitorings, mean: 1.64 times per patient). Brief episodes of AF were documented in 35 patients (20 female, Group 1). The remaining patients without AF were designated as Group 2 (90 female). All patients underwent routine transthoracic echocardiographic examination. ICT was also measured by echocardiography.ResultsThe mean age in Group 1 was greater than in Group 2 (63.02±14 vs. 51.27±16 years, p<0.001). The left atrium was larger in Group 1 than in Group 2 (39.7±3.4 vs. 37.29±4.3 mm, p<0.001). The other echocardiographic variables were comparable between the two groups. The mean ICT was significantly higher in Group 1 than in Group 2 (138±14 vs. 114±12 msn, p<0.001). The ICT of 127 ms was predictive for AF with a sensitivity of 86% and specificity of 87% (p<0.001).ConclusionOur findings show that ICT was prolonged in patients with palpitations who developed a brief episode of AF in Holter ECG monitoring. ICT prolongation may be used to identify patients with palpitation that are at risk of an AF episode. Holter ECG monitoring should be repeated to detect AF episodes in patients with prolonged ICT.

Brucella Infection Associated with Complete Atrioventricular Block.

The clinical spectrum of Brucella infection is quite diverse and characterized by multi-system involvement. Patients present with myocarditis, endocarditis, or pericarditis. Infective endocarditis is the most common cardiovascular complication in patients with brucellosis. Although conduction abnormalities are seen in cases with endocarditis, they are reported very rarely in the setting of cardiac Brucella infection. An eight and a half-year-old male patient was referred to our clinic due to inadequate response to cotrimaxazole plus streptomycin treatment at the 15th day of admission. Although local hospital records on the patient showed a heart rate of 80 bpm, we determined a heart rate of 46 bpm. The electrocardiogram showed complete atrioventricular (AV) block. The average heart rate was determined as 48 bpm with 24-hour Holter electrocardiogram (ECG) monitoring. The echocardiographic examination showed normal-sized heart chambers and the absence of valvular involvement. An agglutination test for brucellosis was found to be positive with a titer of 1/320. High fever, arthralgia, and splenomegaly regressed following doxycycline plus rifampicin therapy, but there was no improvement in the AV block. A permanent pacemaker was implanted because of the detection of an average heart rate of 48 bpm. Because cardiac failure and rhythm abnormalities are reported in the course of Brucella infection and may be associated with significant outcomes, cases with brucellosis should be evaluated carefully in terms of cardiac involvement. This report aims to draw attention to complete AV block as an extremely rare complication of Brucella infection.

The effect of sleep apnea severity on cardiac autonomic activity during night time in obstructive sleep apnea patients

ABSTRACT CONTEXT AND OBJECTIVE: Impaired autonomic cardiac function is an important consequence of obstructive sleep apnea (OSA). This impairment is mainly due to intermittent hypoxia episodes following apneas. However, the impact of apnea severity on autonomic cardiac function remains unclear. The aim of this study was to evaluate the relationship between the severity of sleep apnea and heart rate turbulence (HRT) and heart rate variability (HRV) in OSA. DESIGN AND SETTING: Observational cross-sectional study conducted in the Departments of Cardiology and Pulmonary Diseases, Afyon Kocatepe University, Turkey. METHODS: 106 patients with OSA and 27 healthy volunteers were enrolled. Based on apnea hypopnea index (AHI) values, obstructive sleep apnea severity was classified as follows: mild OSA (AHI ≥ 5 and &lt; 15), moderate OSA (AHI ≥ 15 and ≤ 30) and severe OSA (AHI &gt; 30). HRV and HRT parameters were assessed via 24-hour digital Holter electrocardiogram recordings for all subjects. RESULTS: HRV and HRT results were significantly lower among OSA patients than among control subjects (P &lt; 0.05). However, there were no significant differences in HRT and HRV between the three patient subgroups. Correlations did emerge between AHI and the NN-interval parameter RMSSD and between oxygen desaturation and turbulence slope (respectively: r = -0.22, P = 0.037; and r = -0.28, P = 0.025). CONCLUSION: HRT and HRV results deteriorate in OSA. Correlations between apnea severity and these parameters seem to be present.

Usefulness of an Implantable Loop Recorder to Detect Clinically Relevant Arrhythmias in Patients With Advanced Fabry Cardiomyopathy

Patients with genetic cardiomyopathy that involves myocardial hypertrophy often develop clinically relevant arrhythmias that increase the risk of sudden death. Consequently, guidelines for medical device therapy were established for hypertrophic cardiomyopathy, but not for conditions with only anecdotal evidence of arrhythmias, like Fabry cardiomyopathy. Patients with Fabry cardiomyopathy progressively develop myocardial fibrosis, and sudden cardiac death occurs regularly. Because 24-hour Holter electrocardiograms (ECGs) might not detect clinically important arrhythmias, we tested an implanted loop recorder for continuous heart rhythm surveillance and determined its impact on therapy. This prospective study included 16 patients (12 men) with advanced Fabry cardiomyopathy, relevant hypertrophy, and replacement fibrosis in "loco typico." No patients previously exhibited clinically relevant arrhythmias on Holter ECGs. Patients received an implantable loop recorder and were prospectively followed with telemedicine for a median of 1.2years (range 0.3 to 2.0years). The primary end point was a clinically meaningful event, which required a therapy change, captured with the loop recorder. Patients submitted data regularly (14 ± 11 times per month). During follow-up, 21 events were detected (including 4 asystole, i.e., ECG pauses ≥3seconds) and 7 bradycardia events; 5 episodes of intermittent atrial fibrillation (>3minutes) and 5 episodes of ventricular tachycardia (3 sustained and 2 nonsustained). Subsequently, as defined in the primary end point, 15 events leaded to a change of therapy. These patients required therapy with a pacemaker or cardioverter-defibrillator implantation and/or anticoagulation therapy for atrial fibrillation. In conclusion, clinically relevant arrhythmias that require further device and/or medical therapy are often missed with Holter ECGs in patients with advanced stage Fabry cardiomyopathy, but they can be detected by telemonitoring withanimplantable loop recorder.

A case of Andersen-Tawil syndrome with typical bidirectional ventricular tachycardia recorded in 24-hour Holter electrocardiogram

A case of Andersen-Tawil syndrome with typical bidirectional ventricular tachycardia recorded in 24-hour Holter electrocardiogram

Sleep related bradyarrhythmic events and heart rate variability in apparently healthy individuals.

Objective:It is thought that abnormal cardiac impulses of the autonomic nervous system during sleep are responsible for sleep-related bradyarrhythmias. Despite a proposed common etiopathogenesis and having common name of “sleep-related bradyarrhythmias,” precise importance of sinoatrial or atrioventricular (AV) node involvement remains elusive. This study aimed to determine whether there is a difference in sleep-related bradyarrhythmias from the point of view of heart rate variability (HRV).Methods:Patients were evaluated using 24-hour Holter electrocardiogram monitor. After careful medical evaluation, apparently healthy individuals with sleep-related sinus pauses ≥2 seconds on at least 1 occasion or those in whom Mobitz type I AV block occurred were included. Frequency and time domain analyses were conducted for daytime, nighttime, and 24-hour period.Results:Total of 37 patients with sinus pause(s), 40 patients with Mobitz type I AV block(s), and 40 healthy controls were included. On HRV analyses, all time and frequency domain parameters were better in sinus pause group for daytime, nighttime, and 24-hour average (p<0.05 for all). Results of heart rate-corrected HRV analyses still showed significantly better total power (TP) and very low frequency (VLF) in the sinus pause group compared with AV block group (TP: 7.1×10-3 vs. 5.4×10-3, p=0.011; VLF: 4.9×10-3 vs. 3.7×10-3, p=0.007).Conclusion:Despite proposed common autonomic mechanisms, sleep-related sinus pause cases demonstrated better HRV profile in comparison with Mobitz type I AV block.

Autonomic regulation therapy suppresses quantitative T-wave alternans and improves baroreflex sensitivity in patients with heart failure enrolled in the ANTHEM-HF study

Autonomic regulation therapy (ART) with chronic vagus nerve stimulation improves ventricular function in patients with chronic heart failure, but its effects on quantitative T-wave alternans (TWA), ventricular tachycardia (VT), baroreflex sensitivity, and autonomic tone remained unknown. Effects on TWA, a marker of risk of life-threatening arrhythmias; heart rate turbulence (HRT), an indicator of baroreflex sensitivity; heart rate variability; and VT incidence were studied in 25 patients with chronic symptomatic heart failure and reduced ejection fraction enrolled in the ANTHEM-HF study (NCT01823887). Twenty-four-hour ambulatory electrocardiographic recordings made before ART system (Cyberonics, Inc., Houston, TX) implantation involving the left or right vagus nerve and after 6 and 12 months of chronic therapy (10-Hz frequency, 250-μs pulse width, maximum tolerable current amplitude after 10 weeks of titration) at low-intensity (<2 mA; n = 10, 40%) or high-intensity (≥2 mA; n = 15, 60%) stimulation levels were analyzed. At 12 months, peak TWA levels were reduced by 29% from 71.0 ± 4.6 to 50.5 ± 1.8 μV (P < .0001). The number of patients with severely abnormal TWA (≥60 μV) was reduced by 76% from 17 to 4 (P < .0005), and the number of patients with nonsustained VT decreased by 73% from 11 to 3 (P < .025). HRT slope (P < .025), high frequency heart rate variability (HRV) (P = .05), and square root of the mean squared differences of successive normal-to-normal interval HRV (P = .013) increased. The mean heart rate derived from 24-hour Holter electrocardiograms decreased by 10% from 77 ± 2 to 69 ± 2 beats/min (P = .0002). HRT onset was unchanged. Chronic ART in patients with symptomatic heart failure improves cardiac electrical stability, as reflected by reduced TWA levels and heart rate, suppresses VT, and increases baroreceptor sensitivity. These observations deserve study in a larger population.