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Objective: Ventricular extrasystole is one of the most common rhythm disorders in children, and almost all of them are characterized by normal cardiac functions without structural cardiac abnormalities. The aim of this study was to assess the clinical course of ventricular extrasystole in children who did not have cardiac structural abnormalities. Materials and Methods: This retrospective study analyzed 24-hour rhythm Holter recordings performed in our clinic in children. Patients diagnosed with isolated ventricular extrasystole in Holter records and without structural heart disease on echocardiography were included in the evaluation. Results: A total of 20 160 Holter results were evaluated in the study, and 226 patients (male; 66%) met the criteria. The mean follow-up time was 8.7 ± 3.2 years. While 81.8% of the patients were asymptomatic, the most common symptom was palpitation and 5 patients had syncope. Of the patients, 72 (31.8%) received medical therapy. Beta-blockers were the most often prescribed medication. Cardiomyopathy did not develop in any of the patients during the followup period. A partial reduction in the frequency of ventricular extrasystole was observed in 42% of the patients, while complete recovery was observed in 22%. Conclusion: Ventricular extrasystole in children generally has a good prognosis; most of them are asymptomatic, and the rates of spontaneous regression over time are quite high, regardless of the origin. [ABSTRACT FROM AUTHOR]

Background: Patients with both true and false arrhythmia alarms pose a challenge because true alarms might be buried among a large number of false alarms, leading to missed true events. Objective: To determine (1) the frequency of patients with both true and false arrhythmia alarms; (2) patient, clinical, and electrocardiographic characteristics associated with both true and false alarms; and (3) the frequency and types of true and false arrhythmia alarms. Methods: This was a secondary analysis using data from an alarm study conducted at a tertiary academic medical center. Results: Of 461 intensive care unit patients, 211 (46%) had no arrhythmia alarms, 12 (3%) had only true alarms, 167 (36%) had only false alarms, and 71 (15%) had both true and false alarms. Ventricular pacemaker, altered mental status, mechanical ventilation, and cardiac intensive care unit admission were present more often in patients with both true and false alarms than among other patients (P <.001). Intensive care unit stays were longer in patients with only false alarms (mean [SD], 106 [162] hours) and those with both true and false alarms (mean [SD], 208 [333] hours) than in other patients. Accelerated ventricular rhythm was the most common alarm type (37%). Conclusions: An awareness of factors associated with arrhythmia alarms might aid in developing solutions to decrease alarm fatigue. To improve detection of true alarms, further research is needed to build and test electrocardiographic algorithms that adjust for clinical and electrocardiographic characteristics associated with false alarms. [ABSTRACT FROM AUTHOR]

The purpose of this study was to monitor heart rate (HR) and rhythm during open water SCUBA dives. Nine children performed 25-min open water SCUBA dives to 8 m depth. Before, during and after these dives, ECG was recorded. Comparedwith predive heart rate, heart rate declined by -24 ± 8% (range -36%; -15%) during the dive. In some children a further decline in HR was observed within the last minutes of the dive. Older and taller subjects and those with a high initial HR showed a more pronounced decline in HR. Furthermore singular supraventricular and ventricular extrasystoles were observed in some children. Immersion as well as facial and skin cooling presumably account for the initial decline in heart rate. A further drop in HR within the last minutes of the dive might be related to mild hypothermia. Single supraventricular and ventricular extrasystoles might occur in healthy children during dives. [ABSTRACT FROM AUTHOR]

Clinical Trial Registration URL: . Unique Identifier: NCT00697359. Objectives To evaluate rhythm control up to two years after atrial fibrillation (AF) ablation and its relation to reported symptoms. Background The implantable loop recorder (ILR) continuously records the electrocardiogram (ECG), has an automatic AF detection algorithm, and has a possibility for patients to activate an ECG recording during symptoms. Methods Fifty-seven patients (mean age 57 ± 9 years, 60% male, 88% paroxysmal AF) underwent AF ablation following ILR implantation. Device data were downloaded at the ablation and three, six, 12, 18, and 24 months after ablation. Results Fifty-four patients completed the two-year follow-up. Thirteen (24%) patients had no AF episodes detected by ILR during follow-up. Ten of 41 patients (24%) with AF recurrence were only detected by ILR and AF recurrences were detected earlier by ILR (P < 0.001). The median AF burden in patients with AF recurrence was 5.7% (interquartile range 0.4-14.4) and was even lower in patients with AF only detected by ILR (P = 0.001). Forty-eight % of the patients indicated symptoms via the patient activator but 33% of those recordings were not due to AF. Early AF recurrence (within 3 months) was highly associated with later AF recurrence (P < 0.001). AF burden >0.5% and longest AF episode >6 hours before the ablation were independent predictors of AF recurrence during intermittent but not continuous monitoring. Conclusions After AF ablation, the AF burden was low throughout the 24 months follow-up. Nevertheless, symptoms were commonly indicated but one-third of patient-activated recordings did not show AF. Continuous monitoring was superior to intermittent follow-up in detecting AF episodes and assessing the AF burden. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to examine the effects of atomoxetine on heart rhythm using 12-lead electrocardiography (ECG) and 24 h Holter monitoring. Methods: Children and adolescents who were diagnosed with attention deficit-hyperactivity disorder according to DSM-IV-TR were referred to a pediatric cardiology clinic for cardiologic examination before and after 4 or 5 weeks of atomoxetine treatment. Cardiac examination, complete blood count, biochemistry, thyroid function tests, 12-lead ECG and 24 h Holter monitoring were performed routinely in all patients. Each subject underwent 24 h Holter ECG monitoring before atomoxetine was started and after 4 or 5 weeks of effective dose atomoxetine treatment. Results: Forty-one patients were included in this prospective study. No statistically significant change was found in QT, QTc or QT interval dispersion or blood pressure before and after 4 or 5 weeks of atomoxetine treatment. There was a statistically significant increase in heart rate (both during the day and at night) and QRS duration, and a statistically significant decrease in P wave dispersion. Three patients had rhythm disturbances. All of these three patients were asymptomatic and none of these arrhythmias reached clinical significance. Conclusion: Atomoxetine did not cause significant changes in ECG or Holter variables. In two patients, who had undiagnosed subclinical extrasystoles, extra beats were increased after 4th week of treatment, but still remained clinically insignificant. Before and after atomoxetine treatment, listening to the heart sounds for a longer time, may help clinicians to notice an extra beat. If an extra beat is identified then 24 Holter monitoring is recommended. [ABSTRACT FROM AUTHOR]

Introduction: Serum uric acid (SUA) may contribute to the increased cardiovascular damage through direct injury to the endothelium and alteration of cardiovascular function. Aim: To evaluate the association of SUA with the presence of the most recurrent electrographic alterations and with the length of the main ECG intervals in a large sample of general population. Methods: For this study, on the database of the Brisighella Heart Study, we evaluated the available data of 790 men and 849 women, excluding subjects affected by gout or taking antihyperuricemic agents, those taking drug increasing the QT interval and those using beta-blockers or non-dihydropyridine calcium channel blockers at the moment of the ECG registration. Multiple ascending stepwise regression analyses were carried out to determine the independent predictors of the predefined ECG alterations. Results: The prevalence of predefined ECG alterations was comparable between genders, with the exception of sinus bradicardia, left-anterior fascicular block, atrio-ventricular blocks and left ventricular hypertrophy (LVH), which appeared to be more frequent in men. The multivariate analysis revealed that SUA was associated to ischaemic alterations, LVH, sinus tachycardia and tachyarrhytmias. Age was associated to all evaluated ECG alterations beyond sinus tachycardia and LVH. Male sex was associated to sinus bradicardia, atrio-ventricular blocks, anterior-left fascicular block and LVH. Blood pressure was associated to different ECG alterations, but with clinically relevant OR with ischaemic alterations and LVH. Conclusion: SUA level is related the prevalence of both organic and rhythm ECG alterations in a wide sample of general population. [ABSTRACT FROM AUTHOR]

Bac kground: Few studies evaluated left ventricular (LV) involvement in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). The aim of this study is to determine the frequency, clinical presentation, and pattern of LV involvement in ARVD/C (LV-ARVD/C). Methods: We retrospectively evaluated the cardiac magnetic resonance (CMR) in 202 patients referred between 2008 and 2012 to our institution, and we determined the presence or the absence of CMR criteria in the revised task force criteria 2010 for the diagnosis of ARVD/C. A total of 21 patients were diagnosed with ARVD/C according to the revised task force criteria 2010. All included patients had no previous history of myocarditis, acute coronary syndrome, or any other cardiac disease that could interfere with the interpretations of structural abnormalities. The LV involvement in ARVD/C was defined by the presence of one or more of the following criteria: LV end-diastolic volume (LVEDV; .95 mL/m2), LV ejection fraction (LVEF; ,55%), LV late enhancement of gadolinium (LVLE) in a non-ischemic pattern, and LV wall motion abnormalities (WMAs). In the follow-up for the occurrence of cardiac death, ventricular tachycardia (VT) was obtained at a mean of 31 20.6 months. Results : A total of 21 patients had ARVD/C. The median age was 48 (33-63) years. In all, 11 patients (52.4%) had LV-ARVD/C. The demographic characteristics of patients with or without LV were similar. There was a higher frequency of left bundle-branch block (LBBB) VT morphology in ARVD/C (P 0.04). In CMR, regional WMAs of right ventricle (RV) and RV ejection fraction (RVEF; ,45%) were strongly correlated with LV-WMAs (r 0.72, P 0.02, r 0.75, P 0.02, respectively). RV late enhancement of gadolinium (RVLE) was associated with LV-WMs and LVLE (r 0.7, P 0.03; r 0.8, P 0.006). LVLE was associated with LV-WMAs, LVEF, and LVEDV (r 0.9, P 0.001; r 0.8, P 0.001; r 0.8, P 0.01). Conclusion: LV involvement in ARVD/C is common and frequently associated with moderate to severe right ventricular (RV) abnormalities. The impact of LV involvement in ARVD/C on the prognosis needs further investigations. [ABSTRACT FROM AUTHOR]

Predictors of LV Dysfunction with Idiopathic PVC Introduction Patients with frequent premature ventricular complexes (PVCs) might be at risk for the developing or exacerbation of left ventricular (LV) dysfunction. However, some patients with a high-PVC burden do not develop cardiomyopathy, while other patients with low-PVC burden can develop cardiomyopathy. The purpose of this study was to evaluate the positive predictors of idiopathic PVCs-induced cardiomyopathy. Methods and Results We investigated 214 patients undergoing successful ablation of PVCs who had no other causes of cardiomyopathy. We divided the study cohort into 2 groups: ejection fraction (EF) ≥ 50% (normal LV) and EF < 50% (LV dysfunction). We analyzed the clinical characteristics, including the electrocardiogram and findings at electrophysiology study. Among these patients, 51 (24%) had reduced LVEF and 163 (76%) had normal LV function. Patients with LV dysfunction had significantly longer coupling interval (CI) dispersion (maximum-CI-minimum-CI) and had significantly higher PVC burden compared to those with normal LV function (CI-dispersion: 115 ± 25 milliseconds vs. 94 ± 19 milliseconds; P < 0.001; PVC burden: 19% vs. 15%; P = 0.04). Furthermore, patients with LV dysfunction had significantly higher body mass index (BMI) compared to those with normal LV function (BMI > 30 kg/m2; 37% vs. 13%; P = 0.001). Logistic regression analysis showed that CI-dispersion, PVC burden, and BMI (>30 kg/m2) are independent predictors of PVC-induced cardiomyopathy. Conclusions In addition to the PVC burden, the CI-dispersion and BMI are associated with PVC-induced cardiomyopathy. [ABSTRACT FROM AUTHOR]

Objective. RA associates with an increased rate of sudden cardiac death (SCD). A prolonged QTc interval has been associated with arrhythmogenic and SCD in patients with long QT syndrome. Despite the previously reported contemporary association of CRP with SCD, thus far no studies have examined the association of QTc with mortality in RA, a condition characterized by high inflammatory burden. The aim of this study was to examine the role of electrocardiography (QT corrected interval) in predicting all-cause mortality in patients with RA who have an increased rate of SCD and a high inflammatory burden.Methods. Three hundred and fifty-seven RA patients with detailed baseline clinical characterization and 12-lead ECGs were followed up for a mean of 73.0 (s.d. 18.3) months. Linear and Cox regression analyses were used to identify variables that associate with QTc and examine its association with all-cause mortality.Results. The patients’ mean age was 60.6 (s.d. 12.0) years, 267 (74.8%) were females and 54 (15.1%) died during the follow-up period. Age (β = 0.231, P < 0.001), gender (β = 0.137, P = 0.008) and CRP (β = 0.144, P = 0.006) associated independently with QTc in RA patients. The crude hazard ratio (HR) for total mortality per 50-ms increase in QTc was 2.17 (95% CI 1.21, 3.90). This association remained significant [HR = 2.18 (95% CI 1.09, 4.35)] after adjustment for identified confounders (cardiovascular and RA specific), but was lost [HR = 1.73 (95% CI 0.83, 3.62)] when CRP was included in the model.Conclusion. A 50-ms increase in QTc interval associates with a doubling of the hazard for all-cause mortality in patients with RA. The observed contemporary association of QTc with CRP levels indicates a potentially hazardous interplay between inflammation and arrhythmogenesis. Future studies are needed to confirm the above findings and explore underlying mechanisms. [ABSTRACT FROM PUBLISHER]

Aims and objectives To determine the relationship between quality of life and perceived self-reported symptoms in an older, ambulatory, urban population living with heart failure. Background While arrhythmias in older individuals with heart failure are well documented, the association between perceived arrhythmia symptoms and quality of life is not well-defined. Design Prospective, cross-sectional single-centre study. Methods A single-centre, prospective study was conducted with heart failure patients recruited from an urban outpatient cardiology clinic in the United States. Fifty-seven patients completed a baseline quality of life survey with 42 of these completing the six-month follow-up survey. Quality of life was evaluated with the SF-36v2™ and frequency of symptoms with the Atrial Fibrillation Severity Scale. Subjects wore an auto triggered cardiac loop monitor (LifeStar AF Express®) for two weeks to document arrhythmias. Data analysis utilised Spearman's rank correlation and logistic regression. Results Baseline and six-month quality of life measures did not correlate with recorded arrhythmias. However, perceptions of diminished general health correlated significantly with symptoms of exercise intolerance, lightheadedness/dizziness, palpitations and chest pain/pressure. By multivariable logistic regression, more severe perceived episodes, symptoms of exercise intolerance and lightheadedness/dizziness were independently associated with diminished quality of life. Conclusion Quality of life was significantly worse in patients with perceptions of severe arrhythmic episodes and in those with symptoms of dizziness and exercise intolerance. Relevance to clinical practice The findings of this study indicate that symptomatic heart failure patients suffer from poor quality of life and that interventions are needed to improve quality of life and decrease symptom severity. Nurses who care for heart failure patients play an essential role in symptom evaluation and management and could significantly improve overall quality of life in these patients by carefully evaluating symptomatology and testing interventions and educational programmes aimed at improving quality of life. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate HRV in children requiring intensive care unit stays due to TCA poisoning between March 2009 and July 2010. In the time-domain nonspectral evaluation, the SDNN(P < 0.001), SDNNi (P < 0.05), RMSDD(P < 0.01), and pNN50 (P < 0.01) were found to be significantly lower in the TCA intoxication group. The spectral analysis of the data recorded during the first 5 minutes after intensive care unit admission showed that the values of the nLF (P < 0.05) and the LF/HF ratio (P = 0.001) were significantly higher in the TCA intoxication group, while the nHF (P = 0.001) values were significantly lower. The frequency-domain spectral analysis of the data recorded during the last 5 minutes showed a lower nHF (P = 0.001) in the TCA intoxication group than in the controls, and the LF/HF ratio was significantly higher (P < 0.05) in the intoxication group. The LF/HF ratio was higher in the seven children with seizures (P < 0.001). These findings provided us with a starting point for the value of HRV analysis in determining the risk of arrhythmia and convulsion in TCA poisoning patients. HRV can be used as a noninvasive testing method in determining the treatment and prognosis of TCA poisoning patients. [ABSTRACT FROM AUTHOR]

Objective: Eating disorders, in particular anorexia nervosa (AN), are associated with cardiovascular complications and risk of arrhythmias. In a recent published study, it was found that patients with eating disorders, especially those affected by bulimia nervosa (BN) and a history of AN have abnormal late ventricular potentials (LPs). LPs are electrocardiographic markers used in detecting abnormal depolarization and increased risk of arrhythmias. Given the paucity of knowledge regarding the affects of eating disorders on cardiac depolarization, our aim was to further explore LPs in patients with eating disorders. Method: The study group included 30 hospitalized patients with eating disorders (14 with AN, 10 with BN with no history of AN, and 6 with BN and history of AN). Signal averaged electrocardiography was conducted on all patients usingthe Frank corrected orthogonal lead system. Results: No patient with either eating disorder tested positive for LPs. Discussion: Hospitalized patients with eating disorders, medically monitored and treated for several weeks, had normal serum electrolytes, started to normalize their weight, and did not appear to be prone to arrhythmias associated with abnormal depolarization. The prognostic significance of LPs in risk stratification of patients with eating disorders should be further evaluated by large cohort studies and longer follow-up studies. © 2011 by Wiley Periodicals, Inc. (Int J Eat Disord 2011;45:900-904) [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to investigate the impact that extreme exercise had on cardiac repolarization and other electrophysiological factors. Researchers evaluated the electrocardiograms of 198 healthy men who participated in a marathon. They found that cardiac repolarization was significantly altered immediately after a marathon, coincident with hypomagnesemia and hypokalemia, and that runners' inflammatory and electrolyte statuses returned to baseline values within 72 hours of running the marathon.

Patients with heart failure (HF) are at increased risk for drug-induced torsades de pointes (TdP) due to unknown mechanisms. Our objective was to determine if sensitivity to drug-induced QT interval lengthening is enhanced in patients with HF. In this multicenter, prospective study, 15 patients with atrial fibrillation or flutter requiring conversion to sinus rhythm were enrolled: 6 patients with New York Heart Association class II to III HF (mean ejection fraction [EF], 30% ± 9%), and 9 controls (mean EF, 53% ± 6%). Patients received ibutilide 1 mg intravenously. Blood samples and 12-lead electrocardiograms were obtained prior to and during 48 hours postinfusion. Serum ibutilide concentrations at 50% maximum effect on Fridericia-corrected QT (QTF) intervals (EC50) were determined, and areas under the effect (QTF interval vs time) curves (AUECs) were calculated. Ibutilide concentration–QTF relationships were best described by a sigmoidal Emax model with a hypothetical effect compartment. Median [interquartile range] AUEC from 0 to 4 hours was larger in the HF group than in controls (1.86 [1.86-1.93] vs 1.82 [1.81-1.84] s·h; P = .04). Median EC50 was lower in the HF group (0.48 [0.46-0.49] vs 1.85 [1.10-3.23] μg/L; P = .008). Sensitivity to drug-induced QT interval lengthening is enhanced in patients with systolic HF, which may contribute to the increased risk of drug-induced TdP. [ABSTRACT FROM PUBLISHER]

Most clinical studies of the clinical profile of Brugada syndrome (BS) have been conducted in either Asia, Europe, or America and their applicability to North African populations is largely unknown. The aim of the study was to analyze the clinical profile of BS in Tunisian patients. The clinical and follow-up data of 24 patients (22 men, mean age: 40.8 ± 13.7 years) were collected since 2002. Baseline characteristics, morbidity, and mortality data were obtained from medical records. One patient (4.16%) survived sudden cardiac death (SCD), four patients (16.3%) had syncope, and 19 patients (79.1%) were asymptomatic. Eleven patients (45.8%) had a family history of SCD. Twenty patients showed a spontaneous coved-type ST-segment elevation on electrocardiogram and after medical challenge on the four remnants. An electrophysiological study was performed in 15 of 24 patients (62.5%), during which ventricular fibrillation was induced in six patients (40%); three of the six patients were previously asymptomatic. An implantable cardioverter defibrillator (ICD) was implanted in 14 patients (58.3%). After a mean follow-up of 26 ± 21 months, one patient died from a noncardiac cause and one patient (with a history of aborted SCD) received an appropriate shock from his ICD. None of the asymptomatic and noninducible patients experienced a cardiac event. BS is present in the North African population and is probably under-recognized. Tunisian patients with BS share with their western and Asiatic counterparts similar clinical profile. (PACE 2011; 47-53) [ABSTRACT FROM AUTHOR]