Holter Electrocardiography Research Articles

Epicardial Adipose Tissue Is Associated With Prevalent Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Prevalent atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) represents an important issue with regard to stroke events caused by embolization and is associated with high mortality. Increased epicardial adipose tissue (EAT), which shows high metabolic activity, can locally influence the activity of the autonomic ganglia, enhancing autonomic dysregulation and increasing the likelihood of AF. We tested the hypothesis that EAT is associated with prevalent AF in HCM patients. Sixty-two patients with idiopathic HCM diagnosed on the basis of ultrasound cardiography findings and histopathological evaluation of myocardium obtained by right ventricular biopsy underwent cardiac magnetic resonance imaging to estimate the extent of EAT. EAT area was significantly higher in the group with AF episodes than in the group without. An increased incidence of AF was found to be significantly related to an increase in EAT, and this association persisted after adjustment for body mass index, sex, and age. Time domain measures of heart rate variability measured by Holter electrocardiography, standard deviation of normal to normal, and standard deviation of the average of normal to normal were negatively related to EAT area. EAT was positively correlated with intraventricular septal thickness and cystatin C level and negatively correlated with the 24-hour creatinine clearance rate. Increased EAT area in HCM patients is significantly related to the presence of AF, which is associated with changes in baseline autonomic nervous tone, left ventricular mass, and chronic kidney disease.

A Canine Case of Sick Sinus Syndorome (Rubenstein-II) Successfully Treated with Cilostazol: Findings on Monitoring with Holter Electrocardiography

A Canine Case of Sick Sinus Syndorome (Rubenstein-II) Successfully Treated with Cilostazol: Findings on Monitoring with Holter Electrocardiography

Letter to the Editor Unexpected cause of syncope in a young woman

Letter to the Editor Unexpected cause of syncope in a young woman

Two-Dimensional Atrial Systolic Strain Imaging Predicts Atrial Fibrillation at 4-Year Follow-Up in Asymptomatic Rheumatic Mitral Stenosis

The aim of this study was to assess systolic left atrial (LA) reservoir function in patients with mitral stenosis (MS) using two-dimensional (2D) strain (ε) and strain rate imaging and its prognostic value in predicting atrial fibrillation (AF) at 4-year follow-up. One hundred one asymptomatic patients with pure rheumatic MS and 70 healthy controls were evaluated using standard Doppler echocardiography (mitral valve area, mean gradient, systolic pulmonary pressure, LA width, LA volumes, and LA ejection fraction) and 2D speckle-tracking. LA width, volumes, and systolic pulmonary pressure were significantly increased (P < .0001), and LA 2D ε and strain rate were significantly impaired in patients with MS (P < .0001). At 4-year follow-up, 20 patients (20%) showed AF on standard electrocardiography or 24-hour Holter electrocardiography. Patients with MS who had AF were older than those who did not, without significant differences in LA dimensions, volumes, ejection fraction, and compliance index. Instead, atrial myocardial systolic 2D ε was significantly impaired in patients with events. On multivariate analysis (age, LA volume, planimetric mitral area, average annular Ea, and LA strain) the best predictor of AF was average LA peak systolic ε (coefficient, 0.43; SE, 0.098; P<.01), with an area under the receiver operating characteristic curve of 0.761 (SE, 0.085; 95% confidence interval, 0.587-0.888, P= .002) for a cutoff value of 17.4%. The results of 2D ε imaging are abnormal in patients with asymptomatic MS and predict AF at 4-year follow-up.

QT and P wave dispersion and heart rate variability in patients with Dravet syndrome

SCN1A mutations are found in up to 80% of patients with Dravet syndrome (DS), and the sudden unexpected death in epilepsy (SUDEP) rate is higher in DS than in most forms of severe epilepsy. The aim of this study is to examine the autonomic cardiac function and the risk of arrhythmia in DS patients by evaluating QT and P wave dispersion and heart rate variability (HRV) using standard electrocardiography (ECG) and 24-h ECG. The study group consisted of 15 patients (9 boys and 6 girls aged 3.5-17years) who were genetically diagnosed with DS. The control group comprised 20 healthy subjects, 13 boys and 7 girls aged 4-17years. P wave dispersion (44.6±3.5ms), QT dispersion (58.8±7.5ms) and QTc dispersion (70.8±7.4ms) were significantly higher in DS patients as compared to the control group (p<0.001 for all values). However, there was no significant difference in PR, QT or QTc length between the groups. 24-h Holter ECG showed that all HRV parameters were significantly lower in patients with DS. The decreased HRV and increased P wave and QT dispersion seen in DS patients are important signs of autonomic dysfunction with increased adrenergic tone. To determine whether autonomic dysfunction is correlated with SUDEP in DS, long-term electrocardiographic monitoring and wider prospective studies are necessary.

PREVALENCE AND RELATED FACTORS OF ARRHYTHMIAS IN PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY

ObjectivesWe aim to explore the incidence and risk factors of AF, dangerous ventricular arrhythmias and bradyarrhythmia in patients with HCM, and improve the awareness of clinicians on hypertrophic cardiomyopathy (HCM)...

Brain Natriuretic Peptide: A Relevant Marker to Rule Out Delayed Atrial Fibrillation in Stroke Patient

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

829 RELATION BETWEEN BLOOD PRESSURE AND THE CARDIAC AUTONOMIC NERVOUS ACTIVITY IN ELDERLY HYPERTENSIVE PATIENTS WITH CHRONIC KIDNEY DISEASE

Objective: To investigate relation between both blood pressure of the circadian variation and response to ten minutes walking and the autonomic nervous activity (ANA) in elderly hypertensive patients with chronic kidney disease (CKD). Methods: Subjects were admitted untreated elderly patients with CKD (69.4 ± 4.2 years) included 23 CKD patients with hypertension (CKDHT (+)), 25 CKD patients but without HT (CKDHT (-)). Diagnosis of CKD was performed according to the presentation by Kidney Disease Outcome Quality Initiative. The value of creatinine clearance of CKDHT (-) (72.5 ± 9.2 ml/min/1.73m2) were matched to that of CKDHT (+) (70.9 ± 10.8 ml/min/1.73m2). Their salt intake was reduced to 5 g per day. A non-invasive ambulatory BP monitor and Holter electrocardiography (ECG) were concurrently attached to the patients for 24 hours. A power spectrum analysis of the heart rate variability was done by the Holter ECG analyze system. The value of low frequency power and the ratio of LF to high frequency power, and HF were estimated as markers of sympathetic nervous activity and parasympathetic nervous activity, respectively. The twenty –four hours were divided into waking hours and sleeping hours Results: The values of BP, LF and LF/HF in both waking and sleeping hours and the same values while ten minutes walking were significantly higher (p < 0.05) in CKDHT (+) than in CKDHT (-). Conclusion: It is suggested that cardiac ANA might be accelerated in CKDHT (+) while active and rest.

Effect of Obstructive Sleep Apnea on Heart Rate, Heart Rate Recovery and QTc and P-wave Dispersion in Newly Diagnosed Untreated Patients

IntroductionObstructive sleep apnea syndrome (OSAS) is associated with autonomic dysfunction, whereas increased heart rate (HR), HR recovery time (HRR-1), QT-corrected interval (QTc) and P-wave dispersion (Pd) are associated with cardiovascular events. The aim of the current investigation was to clarify the influence of OSAS severity on these cardiac parameters. MethodsNinety newly diagnosed and untreated patients with OSAS underwent overnight polysomnography and cardiopulmonary exercise testing, including HRR-1, echocardiography, 24-hour Holter electrocardiography, surface electrocardiogram (ECG) and measurement of several metabolic parameters. The patients were divided into the following 4 groups: 26 with apnea-hypopnea index (AHI) <5, 20 with 5 ≤ AHI <15, 20 with 15 ≤ AHI <30 and 24 with AHI ≥30. QTc and Pd were calculated in all leads of the surface ECG. Mean HR was measured using 24-hour Holter ECG, and HRR-1 was measured using cardiopulmonary exercise testing. ResultsQTc was increased in patients with moderate-to-severe OSAS. Pd was significantly increased in patients with OSAS compared with those without OSAS. In addition, Pd was correlated with AHI and associated with the severity of disease. Mean HRs over a period of 24hours during wakefulness and sleep correlated significantly with AHI and the lowest SpO2 in patients with OSAS, whereas HRR-1 was inversely correlated with the severity of OSAS, as expressed by AHI. ConclusionWe showed that HR, Pd, HRR-1 and QT-corrected time are correlated with OSAS severity. Further studies are required in order to investigate the prognostic effect of HRR-1, Pd, HR and QTc in OSAS.

Continuous Stroke Unit Electrocardiographic Monitoring Versus 24-Hour Holter Electrocardiography for Detection of Paroxysmal Atrial Fibrillation After Stroke

Cardioembolism in paroxysmal atrial fibrillation (pxAF) is a frequent cause of ischemic stroke. Sensitive detection of pxAF after stroke is crucial for adequate secondary stroke prevention; the optimal diagnostic modality to detect pxAF on stroke units is unknown. We compared 24-hour Holter electrocardiography (ECG) with continuous stroke unit ECG monitoring (CEM) for pxAF detection. Patients with acute ischemic stroke or transient ischemic attack were prospectively enrolled. After a 12-channel ECG on admission, all patients received 24-hour Holter ECG and CEM. Additionally, ECG monitoring data underwent automated analysis using dedicated software to identify pxAF. Patients with a history of atrial fibrillation or with atrial fibrillation on the admission ECG were excluded. Four hundred ninety-six patients (median age, 69 years; 61.5% male) fulfilled all inclusion criteria (ischemic stroke: 80.4%; transient ischemic attack: 19.6%). Median stroke unit stay lasted 88.8 hours (interquartile range, 65.0-122.0). ECG data for automated CEM analysis were available for a median time of 64.0 hours (43.0-89.8). Paroxysmal AF was documented in 41 of 496 patients (8.3%). Of these, Holter detected pxAF in 34.1%; CEM in 65.9%; and automated CEM in 92.7%. CEM and automated CEM detected significantly more patients with pxAF than Holter (P<0.001), and automated CEM detected more patients than CEM (P<0.001). Automated analysis of CEM improves pxAF detection in patients with stroke on stroke units compared with 24-hour Holter ECG. The comparative usefulness of prolonged or repetitive Holter ECG recordings requires further evaluation.

The features of time characteristics of heart rate variability in chronic obstructive pulmonary disease

Aim. To study the features of time characteristics of heart rate variability during isolated chronic obstructive pulmonary disease, as well as in association with arterial hypertension and ischemic heart disease. Methods. The characteristics of heart rate variability using Holter electrocardiography monitoring, echocardiography and duplex scanning of carotid arteries were studied. The results of investigations of 298 individuals of both sexes aged 37-78 years were included into the analysis, including 79 patients with chronic obstructive pulmonary disease who were divided into three groups. The first group included 19 patients with isolated chronic obstructive pulmonary disease, the second group consisted of 25 patients with chronic obstructive pulmonary disease and arterial hypertension, the third group included 35 patients with chronic obstructive pulmonary disease and ischemic heart disease, who were divided into two subgroups: patients with (n=9) and without (n=26) a prior history of myocardial infarction. For comparison, examined were 48 patients with isolated hypertension, 132 patients with ischemic heart disease and 39 practically healthy individuals. Results. In patients with isolated chronic obstructive pulmonary disease an autonomic imbalance occurs in the form of a uniform decrease in the activity of the parasympathetic nervous system during the day and an increase of the night time heart rate, identifiable are the signs of subclinical cardiac pathology in the form of thickening of the «intima-media» complex and the formation of atherosclerotic plaques in the carotid arteries, hypertrophy of the myocardium and left ventricular diastolic dysfunction, reduced systolic velocity of the mitral valve fibrous annulus. If chronic obstructive pulmonary disease is combined with aerterial hypertension and ischemic heart disease, as opposed to isolated cardiac pathology, a monotonic tachycardia develops during the day. In cases of concomitant chronic obstructive pulmonary disease and arterial hypertension during a simultaneous decrease in all time characteristics of heart rate variability, in most patients hypertrophy of both ventricles can be visualized. Conclusion. In patients with chronic obstructive pulmonary disease the time characteristics of heart rate variability depend on the presence or absence of concomitant diseases of the cardiovascular system.

Arrhythmia and sleep-disordered breathing in patients undergoing cardiac surgery

BackgroundRecently, the role of sleep-disordered breathing (SDB) in cardiovascular disease has attracted attention. In this study, we investigated the influence of SDB on postoperative arrhythmias after cardiac surgery. Methods and resultsIn 89 patients undergoing cardiac surgery, postoperative portable monitoring for SDB and Holter electrocardiography were performed. The primary end-points were the apnea–hypopnea index (AHI) and occurrence of arrhythmia. The secondary end-points were: (1) patient background factors; (2) average heart rate; (3) maximum heart rate (total, daytime, and nighttime); (4) minimum heart rate (total, daytime, and nighttime); (5) minimum SaO2 during sleep; and (6) an independent predictor for arrhythmia.Twenty-six patients (29.2%) had an AHI≥15 and they were classified into the SDB group, while patients with an AHI<15 formed the non-SDB group (70.8%). Although there was no significant difference in atrial fibrillation, frequent nocturnal premature ventricular contractions were significantly more common in the SDB group (19.2%) than the non-SDB group (3.2%) (p=0.01). Maximum daytime and nighttime heart rates were also significantly higher in the SDB group. AHI was a significant predictor for frequent nocturnal premature ventricular contractions. ConclusionsThis study showed that SDB is common among patients undergoing cardiac surgery, and that SDB might be closely associated with arrhythmia in these patients.

Schlafapnoescreening kardiovaskulärer Patienten im klinischen Alltag

Sleep apnea syndromes (SAS) are highly prevalent in cardiovascular patients. Because diagnostics are cost and labor intensive, these patients often remain undiagnosed. For this reason, simple screening methods for SAS in daily clinical practice are very important. Standardized questionnaires are one way to screen patients, i.e., simple standardized questionnaires have been shown to be highly predictive in OSA, but not in CSA patients. Simple ambulatory screening devices use oxymetry and/or nasal flow to determine the apnea-hypopnea index (AHI). These devices have been shown to be highly effective in screening for OSA and CSA. In addition, algorithms that calculate the electrocardiography (ECG)-derived AHI using heart rate variability and/or QRS morphology from Holter ECG recordings are also promising. Especially the latter method could become a simple tool for cardiologists to screen for SAS in clinical routine.

Taurine effects on the occurrence of cardiac arrhythmias and QT interval dispersion in patients with postinfarction cardiosclerosis and chronic heart failure: a comparative randomised study

Aim. To study the effects of taurine therapy on the occurrence of cardiac arrhythmias and QT interval dispersion (dQT) among patients with postinfarction cardiosclerosis (PICS) and subsequent chronic heart failure (CHF). Material and methods. The study included 40 patients with previous myocardial infarction (MI), left ventricular ejection fraction (LVEF) &lt;45 %, and Functional Class (FC) II-III CHF (NYHA). The participants were randomised into two groups: the main group (MG) included 20 patients receiving standard CHF treatment and taurine, while the control group (CG; n=20) was administered standard CHF treatment only. Both groups were comparable by the main clinical and anamnestic parameters. The therapy phase lasted 3 months. The analysis of taurine effects on the occurrence of cardiac arrhythmias and dQT was performed in the subgroups defined according to the CHF FC. dQT was assessed by 12-lead electrocardiography (ECG), while the arrhythmia occurrence was assessed by Holter ECG monitoring. The examined parameters were measured at baseline and after 3 months of the therapy. Results. In PICS patients with CHF, taurine demonstrated beneficial effects on the dynamics of dQT and cardiac arrhythmia occurrence. Conclusion. Taurine could be included in the complex treatment of PICS patients with FC II-III CHF.

Optimal Timing and Duration of Continuous Electrocardiographic Monitoring for Detecting Atrial Fibrillation in Stroke Patients

Several studies have suggested that after ischemic stroke, continuous electrocardiographic (ECG) monitoring (CEM) increases the atrial fibrillation (AF) detection rate. However, optimal CEM terms of use are not clear. The aim of our study was to evaluate the usefulness of CEM in detecting AF and define optimal terms of the use of CEM. We prospectively enrolled consecutive patients with acute ischemic stroke who were admitted to the stroke unit without AF on baseline ECG. We compared 2 strategies of AF detection: the first using CEM and the second with routine clinical practice (24-hour Holter ECG and additional ECGs). Adjusted odds ratios for the association between AF diagnosis and the use of CEM stratified by monitoring duration were calculated using multivariate logistic regression analysis. Of the 1166 patients included, 220 (18.87%) had AF on baseline ECG and were excluded. Of the 946 remaining patients, 592 underwent CEM. The prevalence of AF using CEM was 12.50% compared 2.26% using the routine strategy. After adjustment (demographic data, vascular risk factors, and National Institutes of Health Stroke Scale scores), using CEM increased 5.29 fold the odds of finding AF (95% confidence interval [CI] 2.43-11.55) compared to the routine strategy. The adjusted odds ratio (9.82; 95% CI 3.01-32.07) was maximum for the first day of monitoring and decreased later. Beyond 5 days, CEM usefulness was not significantly higher than the routine strategy. We suggest that in order to enhance the detection rate of AF, CEM could be generalized in the stroke unit. It must be started early in patients with acute stroke and prolonged over a minimum of 4 days.

Abstract 2753: Initial and 24h After Admisson DWI Can Predict Recurrence of Ischemic Event of TIA Patients

Background and Purpose Our aim is to investigate the diagnostic utility of diffusion weighted magnetic resonance imaging (DWI) for transient ischemic attack (TIA), not only admission but also 24 h after first study. Methods We prospectively enrolled TIA patients who were admitted within 24 h of onset. We examined trans-thoracic echocardiography, 24 h Holter electrocardiography, and carotid duplex ultrasonography in order to give the best medication. All of patients received DWI immediately after admission. At first, when we observed hyper-intense lesion considered as ischemia, additional DWI examination was not conducted. When there was no hyper-intense lesion on initial DWI study, we conducted follow-up DWI 24 h after initial examination. We defined a recurrence of ischemic event as an occurrence of symptomatic ischemic stroke or TIA at 3 months after onset. Regarding initial DWI study, we compared proportional frequency of recurrence between patients with ischemic lesion (i-positive group) and without any lesion (i-negative group), and also compared recurrence rate between patients with ischemic lesion on initial and/or follow-up studies (if-positive group) and without any lesion on both studies (if-negative group). Results We registered 100 TIA patients (men; 63, median age; 74 years, ABCD2 score &lt;3; 32). On initial DWI study, 34 patients had ischemic lesion (i-positive group) and 66 had no lesion (i-negative group). Among 66 patients of i-negative group, 12 (19%) had hyper-intense lesion in follow-up study. Finally, there were 46 patients in if-positive group and 54 in if- negative. Recurrence ischemic event occurred in 19 (19%) of 100 patients. There was no significant difference of recurrence rate between i-positive and i-negative groups (27% vs. 16%, p=0.172). However, recurrence rate was significantly higher in if-positive group than these of if-negative group (29% vs. 12%, p=0.024) Conclusions New ischemic lesions on follow up DWI appeared in approximately 20% of TIA patients who did not have ischemic lesion on initial DWI. Only initial DWI but initial and follow-up DWI was important role of predicting the recurrence of ischemic events in TIA patients.

The Influence of Subclinical Hyperthyroidism on Blood Pressure, Heart Rate Variability, and Prevalence of Arrhythmias

The impact of subclinical hyperthyroidism (sHT) on the cardiovascular system still needs to be elucidated. The aim of the study was to prospectively assess blood pressure (BP), variability in heart rate, and the prevalence of arrhythmias in patients with sHT, both before and after they are restored to the euthyroid state.The study group consisted of 44 normotensive patients (37 women, 7 men), aged 22-65 years (mean±SD: 45.9±11.0) with sHT. Enrolled patients were drawn from 1080 patients referred to our department for treatment of hyperthyroidism. Study patients were treated with radioiodine treatment to restore the euthyroid state. Ambulatory BP monitoring and Holter electrocardiography were performed (i) when sHT was diagnosed and (ii) at least 6 months after they became euthyroid.sHT in comparison to the euthyroid state was associated with higher (109.3±7.1 vs. 107.1±7.7 mmHg) nocturnal systolic mean BP (p=0.035) and BP load (14.8 vs. 10.2%, p=0.033), mean diastolic BP (66.4±6.6 vs. 64.8±6.6 mmHg, p=0.047), and mean arterial pressure (80.8±43.1 vs. 79.3±43.6 mmHg, p=0.049). Moreover, significant changes in both the time and frequency domain measures of heart rate variability (HRV) were observed: decrease of the square root of the mean squared differences of successive NN intervals (rMSSD) (45.68±34.1 vs. 65.09±50.6 ms, p=0.03) and the low frequency power (LF) (5.71±0.99 vs. 6.0±1.01 ms(2), p=0.049) as well as increase of QT interval dispersion (58.25±28.5 vs. 46.90±12.1 ms, p=0.020). This was accompanied by a clinically insignificant increase in the frequency of ventricular extrasystoles (VES) (3.1±7.4 vs. 0.6±1.2 per hour, p=0.048) and increased mean heart rate (78.4±6.8 vs. 76.0±8.0 beats/min, p=0.004). Some of the parameters correlated positively with thyroid hormones: nocturnal diastolic BP with free triiodothyronine (FT(3)) (r=0.397, p=0.008), rMSSD with free thyroxine (FT(4)) (r=0.389, p=0.013), and QT interval dispersion with FT(4) (r=0.450, p=0.004).The study suggests that sHT in comparison to euthyroid status may be associated with a statistically significant but probably clinically insignificant increase of QT interval dispersion, prevalence of VES, elevated nocturnal arterial BP, and changes in HRV. These findings broaden our understanding of the cardiovascular effects of sHT.

Quetiapine-induced frequent premature ventricular contraction

A 17-year-old female diagnosed with bipolar II disorder was treated for emotional lability with quetiapine. Two-lead electrocardiography revealed frequent monomorphic premature ventricular contraction (PVC) during an electroencephalography examination. Twenty-four-hour Holter electrocardiography revealed 0.6% uniform frequent PVCs and indicated that the readministration and second-time withdrawal of quetiapine markedly increased (7.1%) and decreased the frequency of PVC (1.1%), respectively. This case indicates that quetiapine can cause PVC as a serious side effect.

Cardiac effects of granisetron in a prospective crossover randomized dose comparison trial

Cardiac side effects of granisetron have been studied mostly in adult patients that are using cardiotoxic chemotherapeutics. There is limited evidence in pediatric age group and no information in pediatric oncology patients with non-cardiotoxic chemotherapeutics. In this prospective, crossover randomized study, the cardiac side effects of granisetron are compared in pediatric oncology patients who had carboplatin based chemotherapy. They were randomized to receive either 10 or 40 μg kg(-1) dose(-1) of granisetron before each cycle of chemotherapy. We drew blood for creatine phosphokinase (CPK), CPK-muscle band (MB) and Troponin-T before and 24 h after administering granisetron. Electrocardiography (ECG) tracings were taken at 0, 1, 2, 3, 6 and 24 h of granisetron. Twenty-four hours Holter ECG monitorisation was performed after each granisetron infusion. A total of 16 patients (median 8.7 years of age) were treated with weekly consecutive courses of carboplatin. There was bradycardia (p = 0.000) in patients that had granisetron at 40 μg/kg and PR interval was shortened in patients that had granisetron at 10 μg/kg dose (p = 0.021). At both doses of granisetron, QTc interval and dispersion were found to be similar. CPK, CK-MB and Troponin-T values were found to be normal before and 24 h after granisetron infusion. As the first study that has studied cardiac side effects of granisetron in patients that are not using cardiotoxic chemotherapeutics, we conclude that granisetron at 40 μg kg(-1) dose(-1) causes bradycardia only. We have also demonstrated that granisetron does not cause any clinically cardiac side effects either at 10 or 40 μg kg(-1) dose(-1). However, our results should be supported by prospective randomized studies with larger samples of patient groups.

5. めまいと不整脈

Cardiac arrhythmia is an uncommon cause of faintness and presyncope. Both bradycardia and tachycardia may induce a transient drop of blood pressure followed by reduction of cerebral blood flow, which evokes faintness and presyncope. The most frequent cause of faintness/presyncope is a neurally mediated reflex, and cardiac arrhythmia is the second common cause in the general population. Since several severe types of arrhythmias may induce sudden death, it is important to recognize faintness and presyncope as a warning sign for further potentially lethal arrhythmic events in selected patients. Taking a detailed medical history and recognition of the accompanied symptoms allows the practitioner to distinguish cardiogenic faintness/presyncope from a neurally mediated one. A definitive diagnosis of cardiogenic faintness/presyncope should be performed by clarifying the direct relationship between the symptoms and documented arrhythmia. However, conventional 12-lead electrocardiography (ECG) and ultrasound echocardiography are useful for risk stratification of faintness/presyncope even after disappearance of the symptoms. Holter ECG and event recorders are widely used for detection of arrhythmic events related with faintness/presyncope. Bradycardia may evoke faintness. However, bradycardia without significant cardiac pause usually accompanies shortness of breath, but not faintness or presyncope. Sudden cardiac pause, with or without preceding tachycardia, is a major cause of faintness/presyncope. Tachycardia is the most important cause of faintness and presyncope. Both supraventricular tachycardia and ventricular tachycardia can cause faintness/presyncope. Of note, faintness and presyncope related with ventricular tachycardia in patients with impaired cardiac function should be evaluated carefully by assessing the risk of sudden cardiac death. Several types of ventricular tachycardia and fibrillation, including Brugada's syndrome, also may cause sudden death. A thorough examination must be performed to clarify the risk of sudden death in patients having these conditions. In conclusion, careful evaluation of faintness and presyncope taking possible involvement of arrhythmia into consideration is important to predict and prevent sudden cardiac death.