24-hour Holter Electrocardiography Research Articles

Abstract 14070: Combination of Clinical, Electrocardiographic and Echocardiographic Parameters Predict the Onset of Atrial Fibrillation

Bacground: The ability to identify risk markers for first atrial fibrillation (AF) is critical to the development of preventive strategies. Prior studies have demonstrated that advanced age, diabetes, hypertension, and cardiovascular disease increase the risk of developing AF. Echocardiographic left atrial (LA) size and diastolic dysfunction are also shown to predict the onset of AF. Furthermore, a recent study has revealed that the addition of premature atrial contraction (PAC) count to a validated AF risk algorithm provides superior AF risk discrimination. However, it remains unknown whether a combination of clinical, electrocardiographic, and echocardiographic parameters predict the onset of AF. In the present study, we evaluated the predictive value of the combined score including these parameters. Methods: We retrospectively studied 1,040 patients without AF in whom both echocardiography and 24-hour Holter electrocardiography were performed from May 2005 to December 2010 and could be followed thereafter. During the follow-up period of 70.0±29.1 months, we investigated the new onset of AF. Results: Of the 1,040 patients, 103 developed AF. Patients who developed AF were older than patients who did not. Total heart rate, PAC count, max RR interval, and frequency of sinus arrest quantified by 24-hour electrocardiography were associated with the new onset of AF. Left atrial diameter (LAD) determined by echocardiography was also associated with the development of AF. In multivariate Cox analyses, age, PAC count, max RR interval, and LAD were independently associated with the development of AF (multivariable-adjusted hazard ratios per SD: age 1.49, PAC count 1.16, max RR interval 1.21, and LAD 1.34). Furthermore, the predictive value of the combined score using these 4 parameters (hazard ratios per SD: 1.80) was higher than that of each parameter. Conclusion: The combined score using age, PAC count, max RR interval, and LAD could help to identify risk of the new onset of AF.

Assessment of Microvolt T Wave Alternans in Children with Repaired Tetralogy of Fallot during 24‐Hour Holter Electrocardiography

We aimed to examine microvolt T wave alternans (MTWA) in 24-hour Holter electrocardiography (ECG) of children with repaired tetralogy of Fallot (TOF) to assess associations of MTWA with ventricular arrhythmias, ECG parameters, and echocardiographic findings. Holter ECG records and archive files of 56 repaired TOF patients (62.5% male) who were analyzed retrospectively. Subjects' ECG parameters and MTWA values were compared with age-sex-matched control group. T wave changes were analyzed by time-domain-modified moving average method from the three channels of 24-hour Holter ECG. Mean age was 123.4 ± 48.3 months. Median MTWA value was 55.5 μV in the control group, whereas 95.5 μV in patients group (P < 0.001). A significant weak positive correlation was found between the presence of ventricular extrasystoles and tricuspid regurgitation. There was no correlation between ECG parameters, echocardiographic findings, and MTWA. MTWA was increased in children with repaired TOF as reported before. To our knowledge, this is the first study analyzing MTWA with 24-hour Holter ECG in repaired TOF patients.

Multiscale Entropy of the Heart Rate Variability for the Prediction of an Ischemic Stroke in Patients with Permanent Atrial Fibrillation.

BackgroundAtrial fibrillation (AF) is a significant risk factor for ischemic strokes, and making a robust risk stratification scheme would be important. Few studies have examined whether nonlinear dynamics of the heart rate could predict ischemic strokes in AF. We examined whether a novel complexity measurement of the heart rate variability called multiscale entropy (MSE) was a useful risk stratification measure of ischemic strokes in patients with permanent AF.Methods and ResultsWe examined 173 consecutive patients (age 69±11 years) with permanent AF who underwent 24-hour Holter electrocardiography from April 2005 to December 2006. We assessed several frequency ranges of the MSE and CHA2DS2-VASc score (1 point for congestive heart failure, hypertension, diabetes, vascular disease, an age 65 to 74 years, and a female sex and 2 points for an age≥75 years and a stroke or transient ischemic attack). We found 22 (13%) incident ischemic strokes during a mean follow up of 3.8-years. The average value of the MSE in the very-low frequency subrange (90–300 s, MeanEnVLF2) was significantly higher in patients who developed ischemic strokes than in those who did not (0.68±0.15 vs. 0.60±0.14, P<0.01). There was no significant difference in the C-statistic between the CHA2DS2-VASc score and MeanEnVLF2 (0.56; 95% confidence interval, 0.43–0.69 vs. 0.66; 95% confidence interval, 0.53–0.79). After an adjustment for the age, CHA2DS2-VASc score, and antithrombotic agent, a Cox hazard regression model revealed that the MeanEnVLF2 was an independent predictor of an ischemic stroke (hazard ratio per 1-SD increment, 1.80; 95% confidence interval, 1.17–2.07, P<0.01).ConclusionThe MeanEnVLF2 in 24-hour Holter electrocardiography is a useful risk stratification measure of ischemic strokes during the long-term follow-up in patients with permanent AF.

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

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

Dobutamine Stress Echocardiography in the Diagnosis of Asymptomatic Ischemic Heart Disease in Patients With Chronic Kidney Disease—Review of Literature and Single-Center Experience

BackgroundCoronary artery disease (CAD) may be present in kidney transplant (KT) candidates without the presence of CAD clinical symptoms. This study joins an ongoing discussion about appropriate noninvasive diagnostic approaches for ischemic heart disease (IHD) assessment and patient selection for revascularization procedures. The aim of this study was to evaluate the role of dobutamine stress echocardiography (DSE) in IHD diagnosis in initially asymptomatic maintenance hemodialysis (HD) patients. MethodsForty HD patients aged 52.4 ± 2.0 years, were studied for 2.5 years. At inclusion, they were free of both symptoms and history of IHD. Standard electrocardiography (ECG), chest X-ray, standard echocardiography, DSE, 24-hour Holter ECG, and Doppler ultrasonography (carotids and lower extremities) were performed. Results were analyzed according to a predefined diagnostic algorithm. ResultsDSE yielded negative results in all patients. Left ventricular (LV) ejection fraction ≤60%, LV hypertrophy, and Holter ECG silent ischemia features were noticed in 15%, 70%, and 10% of patients, respectively. Atherosclerotic lesions in lower extremities and carotid arteries were present in 50% and 37.5% of patients, respectively. During the follow-up, 9/40 patients died, including 6 cardiovascular (CV) deaths: 2 with intermediate and 4 with high CV risk according to the proposed algorithm. ConclusionsIn asymptomatic KT candidates, not only DSE, but also other noninvasive tests (eg, echocardiography and Doppler ultrasonography of the carotid and peripheral arteries) along with a detailed profile of the remaining CV risk factors should be performed and analyzed. Defined composition of risk factors and particular changes in noninvasive tests may be an indication for coronary angiography.

Effects of three month nasal continuous positive airway pressure treatment on electrocardiographic, echocardiographic and overnight polysomnographic parameters in newly diagnosed moderate/severe obstructive sleep apnea patients.

The objective of the study was to determine the effects of nasal continuous positive airway pressure (nCPAP) therapy on left ventricular (LV) function and electrocardiographic parameters in newly diagnosed moderate/severe obstructive sleep apnea (OSA) patients without cardiovascular comorbidities and medical treatments. We examined 44 patients who underwent overnight polysomnography together with 24-hour Holter electrocardiography, cardiopulmonary exercise testing including heart rate recovery at 1 minute (HRR-1), echocardiography, surface electrocardiography, and those who were diagnosed with moderate/severe OSA apnea--hypopnea index ≥ 15. After 3 months of nCPAP treatment, the above-mentioned examinations were repeated. Forty-four patients completed the treatment period. Twelve weeks on effective nCPAP induced a significant increase in the mitral E/A ratio (P = 0.001), as well as reductions in isovolumic relaxation time (P = 0.001) and mitral deceleration time (DT) (P = 0.002). There were no significant differences in LV ejection fraction, LV mass index, and pulsed wave Doppler parameters. Mean heart rate was 79.2 ± 12.5 pulses/minute, maximum P-wave duration 117.5 ± 8.6 msec, P-wave dispersion (PWd) 54.6 ± 10.2 msec, corrected QT interval (QTc) 436.5 ± 40.5 msec, and QT dispersion (QTd) 46.3 ± 7.1 msec, which significantly decreased to 70.4 ± 9.6 pulses/minute (P < 0.001), 111.5 ± 8.7 msec (P < 0.001), 51.6 ± 8.9 msec (P < 0.001), 418.4 ± 31.2 msec (P < 0.001), and 33.8 ± 3.4 msec (P < 0.001), respectively. Exercise capacity at baseline determined as 10.5 ± 2.2 metabolic equivalents (METS) and HRR-1 (20.6 ± 11.7 bpm) significantly increased (12.1 ± 1.5 METS and 27.4 ± 8.6 bpm). There was no significant difference in aortic root parameters. Three-month nCPAP therapy significantly increased LV shortening fraction, with no effect on systolic function or aortic root diameters and a positive effect on heart rate, PWd, HRR-1, QTc and QTd time following nCPAP therapy.

OP-036 Assessment of Microvolt T-wave Alternans in Repaired Tetralogy of Fallot Patients with 24-hour Holter Electrocardiography

OP-036 Assessment of Microvolt T-wave Alternans in Repaired Tetralogy of Fallot Patients with 24-hour Holter Electrocardiography

Association between obstructive sleep apnea and premature supraventricular contractions

ObjectiveThe exact association between obstructive sleep apnea (OSA) and premature supraventricular contractions (PSVCs) has not been established. MethodsWe prospectively performed polysomnography together with 24-hour Holter electrocardiography in 431 patients who were clinically suspected of having OSA and examined the association between OSA severity and PSVCs during wakefulness and sleep. The patients were classified into 4 groups according to the apnea–hypopnea index (AHI) quartiles (Q1=patients with AHI<13.8, Q2=those with 13.8≤AHI<28.8, Q3=those with 28.8≤AHI<48.1, Q4=those with AHI≥48.1). ResultsThe number of PSVCs/hour during sleep differed significantly among the 4 groups, but the number of PSVCs/hour during wakefulness did not. The prevalence of PSVC≥5/hour during sleep was significantly higher in Q4 (21.0%) than the other 3 groups (Q1, 9.0%; Q2, 8.0%; Q3, 6.0%; all p<0.05 for Q4), but the prevalence of PSVC≥5/hour during wakefulness did not differ among the 4 groups. A multivariate logistic regression analysis showed that the highest AHI quartile was significantly associated with PSVC≥5/hour during sleep (odds ratio 3.04, 95% confidence interval 1.44–6.42, p=0.004). ConclusionsSevere OSA can cause PSVCs during sleep, but its effect appears not to be strong. Further studies are needed to clarify the clinical significance of this small but significant increase in PSVCs during sleep in severe OSA patients.

Comparative analysis of clinical, electrocardiographic, angiographic and echocardiographic data of indigenous and non-indigenous residents of Yakutia with coronary artery atherosclerosis

AimThe aim of the study is to compare clinical, angiographic, electrocardiographic, echocardiographic data between indigenous and non-indigenous residents of Yakutia.Study designWe performed cross-sectional analysis of the Registry of Selective Coronary Angiography (SCAG) of the Yakutsk Republican Hospital for the period from 2004 to 2007. All patients (n=1,233) were admitted to hospital from all 35 regions of the Sakha Republic (Yakutia). Initially, 12 (1%) patients, who had abnormal coronary arteries and 259 (21%) patients with normal coronary arteries were excluded from this study. From the remaining 962 (78%) patients with detected coronary artery atherosclerosis 394 (41%) patients were excluded for having congenital heart malformations due to possible influence on the outcomes of examination for myocardial hypertrophy. Finally, only 568 patients were selected for further examinations.MethodsWe analyzed clinical data, and the findings of selective angiography, multi-detector computed tomography (CT), electrocardiography (ECG), 24-hour Holter ECG monitoring and echocardiography.Results(a) In the Sakha Republic (Yakutia) single-vessel coronary disease, coronary stenosis with 50–75% and 75–90% of constriction were detected more often among indigenous males, while multiple-vessel coronary stenosis was detected more often among non-indigenous males as well as stenosis with more than 90% of constriction. Lower calcium score mean (349.1±129.8 vs. 621.8±115.2) was observed among indigenous patients compared to non-indigenous patients; (b) Painless myocardial infarction, painless ischaemia, arterial hypertension and atrial fibrillation were detected more often among indigenous male compared to non-indigenous participants; (c) Based on the results of ECG and echocardiographic examinations, left ventricular (LV) hypertrophy, particular eccentric type of hypertrophy, was found more commonly among indigenous than non-indigenous males; and (d) By laboratory findings, indigenous males had significantly lower triglyceride levels, while platelet counts were higher compared to non-indigenous patients. Obesity was observed less frequently among indigenous men compared to non-indigenous men.ConclusionThe differences observed in this study are disputable and call for further studies. Collection of reliable data for women should be the aim of future studies.

Letter by Diomedi et al Regarding Article “Continuous Stroke Unit Electrocardiographic Monitoring Versus 24-Hour Holter Electrocardiography for Detection of Paroxysmal Atrial Fibrillation After Stroke”

We read with interest the article by Rizos et al.1 The authors reported on the efficacy of continuous stroke unit ECG monitoring (CEM) in the detection of paroxysmal atrial fibrillation(AF) compared with 24-hour Holter ECG. With a median recording time of 64 hours, CEM proved to be superior with a significant higher percentage of paroxysmal AF diagnosis. We totally agree with the authors on the unnecessary use of 24-hour Holter ECG in addition to CEM in the in-hospital setting because the latter allows longer-recording time …

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.

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 effects on cardiac functions and arterial blood gases of totally occluding nasal packs and nasal packs with airway

To evaluate the effects on cardiac functions and blood arterial gases of totally occluding nasal packs and nasal packs with airway. Prospective, randomized trial. Thirty-nine adults without any comorbidities underwent septoplasty or septorhinoplasty and had nasal packs placed postoperatively; 19 nasal packs with airways and 20 totally occluding nasal packs. Twenty-four-hour Holter monitorization was done pre- and postoperatively. Arterial blood gas analysis was performed both before the operation and after application of nasal packs. Application of packs with airway did not cause any significant changes in blood gas parameters. Packing with totally occluding nasal packs caused a significant decrease in HCO(3) and pCO(2), and insignificant changes in pO(2), O(2) saturation, and pH. No serious arrhythmias were observed in any patient. In both groups, nasal packing resulted in a significant increase in minimum heart rates, a significant decrease in maximum heart rates, and insignificant changes in the mean heart rates. Heart rate variability obtained from 24-hour Holter electrocardiography was analyzed by power spectral analysis. An increase in the high-frequency (HF) domain, a decrease in the low-frequency (LF) domain, and a decrease in the LF/HF ratio were observed after packing in both groups. Nasal pack-induced cardiac complications may occur due to increased vagal stimuli secondary to nasal mucosa compression rather than obstruction-related hypoxia. The use of nasal packs in the elderly patients with cardiopulmonary disease warrants close observation. Nasals packs with airways should be preferred in patients susceptible to hypoxia.

Normal limits for heart rate as established using 24-hour ambulatory electrocardiography in children and adolescents

To the best of our knowledge, normal limits of heart rate with respect to gender, and as established using 24-hour ambulatory Holter electrocardiography, have yet to be published for the entire age range of children and adolescents. To establish the normal limits for heart rate in newborns, infants, children, and adolescents of both genders. We obtained 24-hour Holter recordings from 616 healthy subjects aged from birth to 20 years with structurally normal hearts. The subjects were not receiving medication, and had not been submitted to prior cardiac intervention. Off-line analysis was performed with Mars 8000 scanners, analysing 5 consecutive RR intervals by the software available for automatic calculation of heart rate. All subjects were in sinus rhythm. Best-fit non-linear regressions were applied to correlate age and gender with minimum and mean heart rate, as well as with maximal RR-interval, and to calculate the 5th, 25th, 75th and 95th percentiles. We observed significant gender-dependent differences in heart rate for persons aged 10 years and older, with the males exhibiting lower minimal and mean heart rates, and higher RR-intervals, than the females. Correlation of heart rate with age and gender could be established with sufficient accuracy using non-linear regression (p less than 0.0001): Minimum heart rate (male: R(2)=0.778, female: R(2) = 0.664) and mean heart rate (male: R(2) = 0.820, female: R(2) = 0.736) decreased with age, while the maximal RR-interval prolonged (male: R(2) = 0.562, female: R(2) = 0.486). Age and gender-related graphs of centiles were constructed. Heart rate, as documented using Holter recodings, can be correlated with age and gender, permitting establishments of normal gender-specific limits for children and adolescents.

Fate of Left Atrial Function as Determined by Real-Time Three-Dimensional Echocardiography Study After Radiofrequency Catheter Ablation for the Treatment of Atrial Fibrillation

Radiofrequency catheter ablation has been demonstrated to be effective in the treatment of patients with atrial fibrillation. However, its impact on left atrial (LA) function has not been widely studied. The purpose of the present study was to evaluate the impact of radiofrequency catheter ablation on LA function in patients with atrial fibrillation. Thirty-eight patients with symptomatic drug-refractory atrial fibrillation were treated with circumferential pulmonary vein ablation (CPVA). LA volumes and function were assessed with real-time 3-dimensional echocardiography before and 6 months after the procedure. The effectiveness of CPVA was evaluated at 6-month follow-up. Recurrence of the arrhythmia was defined as any documented (clinically or on 24-hour Holter electrocardiography) atrial tachyarrhythmia lasting>30 seconds after the first 12 weeks after the procedure. CPVA induced a reduction of maximum LA volume (from 55+/-15 to 48+/-16 ml, p<0.001), without impairment in LA function, measured as the active emptying percentage of total volume (32+/-29% vs 39+/-33%, p=NS). At follow-up, 21 patients (61.8%) had no recurrences. Maximum LA volumes were significantly larger in patients who presented with recurrences compared with those who did not (64+/-18 vs 50+/-11 ml, p=0.01). In conclusion, CPVA induces a reduction in LA volume without a deleterious impact on function, and, of importance, real-time 3-dimensional echocardiography is a useful noninvasive imaging tool to follow up LA remodeling and function in these patients.

Effects of Cilostazol on Heart Rate and its Variation in Patients With Atrial Fibrillation Associated With Bradycardia

Heart-rate (HR) variability is an important predictor of mortality in patients with heart disease. We examined the effects of cilostazol, a quinolinone derivative, on HR and HR variability in patients with chronic atrial fibrillation associated with bradycardia episodes. Thirteen patients with chronic atrial fibrillation associated with bradycardia episodes (minimal HR <40/min and/or pauses, ie, episodes with an RR interval > 2.5 sec) received cilostazol (100 or 200 mg/day) orally for at least 2 months and 24-hour Holter electrocardiography was performed before and after the start of cilostazol administration. Minimal HR was significantly increased, by an average of 14 beats/min (bpm), at 3.3 +/- 0.8 weeks (mean +/- SD) after the start of cilostazol treatment. The number of pauses was significantly decreased. As a consequence, mean HR was increased by an average of 18 bpm. Maximal HR was also increased by an average of 19 bpm. The circadian variation of the HR, determined by cosine fitting, was not changed by cilostazol treatment. The time-domain HR variabilities, ie, the SD of the mean RR interval and the SD of the 5-minute mean RR intervals, were also unchanged. New York Heart Association functional class was significantly improved and the plasma atrial natriuretic polypeptide level was significantly decreased after the initiation of cilostazol treatment. Cilostazol improves the slow HR episodes associated with chronic atrial fibrillation and maintains the HR circadian variation and time-domain variability, indicating that cilostazol has therapeutic utility for the treatment of the slow HR associated with chronic atrial fibrillation.

Randomized, placebo-controlled, crossover, double-blind comparison of immediate- and sustained-release formulations of Gallopamil in elderly patients with stable effort angina

Background The pharmacokinetics, efficacy, and safety of calcium channel blockers have rarely been investigated in the elderly. Gallopamil, a methoxy derivative of verapamil with calcium antagonistic properties, has been shown to be effective in the treatment of angina pectoris. Objective The aim of this study was to assess the anti-ischemic action of gallopamil, its effects on left ventricular and autonomic function, and its pharmacodynamics and safety in elderly patients. Methods We studied immediate-release (IR) and sustained-release (SR) formulations of gallopamil in 12 sedentary elderly patients with stable effort angina and angiographically documented coronary artery disease in a randomized, placebo-controlled, crossover, double-blind trial. Following a run-in period, patients received either IR gallopamil 50 mg TID or SR gallopamil 100 mg BID for 28 days, after which patients crossed over to the alternate regimen. A washout period of 4 days was incorporated between the 2 treatment phases. Antianginal efficacy was assessed by monitoring the number of angina episodes per week and the amount of sublingual nitroglycerin consumed per week as well as sequential cycloergometer exercise testing 2 and 6 hours postdose. Patients underwent clinical examination, electrocardiography (ECG), echocardiography, 24-hour Holter ECG monitoring, and blood testing at the beginning of the study and at the end of each phase. On the last day of the active treatment period, sequential blood samples were collected to determine plasma levels of gallopamil. Results Both IR and SR gallopamil reduced the number of angina episodes and the amount of nitroglycerin consumed per week. Gallopamil also reduced the number of ECG signs of ischemia at peak exercise testing, as well as symptomatic and asymptomatic ischemic episodes on 24-hour Holter ECG monitoring. IR and SR gallopamil did not affect left ventricular diameters, ejection fraction, and average heart rate, nor did they cause significant changes in heart rate variability. Peak plasma levels of gallopamil were reached rapidly after ingestion of the IR and SR formulations. The plasma concentrations of gallopamil and the norgallopamil metabolite were similar during the first 2 hours after administration of IR and SR gallopamil. Thereafter, patients who received the SR formulation showed significantly higher gallopamil ( P < 0.05) and norgallopamil ( P < 0.05) plasma concentrations than patients who received the IR formulation. The area under the concentration-time curve for SR gallopamil was significantly larger than for IR gallopamil; however, half-life, clearance, and peak plasma concentration were similar after IR and SR gallopamil treatment. Adverse effects, which were observed in 25% of patients, were minor and were not related to plasma levels of gallopamil; no patient suffered hemodynamic or major cardiac conduction abnormalities attributable to gallopamil. Conclusions Our data suggest that both IR and SR gallopamil were effective in reducing signs and symptoms of ischemia in elderly patients with stable effort angina, with few adverse effects.

Arrhythmia risk stratification in idiopathic dilated cardiomyopathy based on echocardiography and 12-lead, signal-averaged, and 24-hour Holter electrocardiography

Background To date, considerable controversy exists regarding noninvasive arrhythmia risk stratification in idiopathic dilated cardiomyopathy (IDC). Methods and Results Between 1992 and 1997, 202 patients with IDC without a history of sustained ventricular tachycardia (VT) underwent echocardiography, signal-averaged electrocardiogram (ECG), and 24-hour Holter ECG in the absence of antiarrhythmic drugs. During 32 ± 15 months of prospective follow-up, major arrhythmic events, including sustained VT, ventricular fibrillation, or sudden death, occurred in 32 (16%) of 202 patients. After adjusting for baseline medical therapy and antiarrhythmic therapy during follow-up, multivariate Cox regression analysis identified a left ventricular (LV) end-diastolic diameter ≥70 mm and nonsustained VT on Holter as the only independent arrhythmia risk predictors. The combination of an LV end-diastolic diameter ≥70 mm and nonsustained VT was associated with a 14.3-fold risk for future arrhythmic events (95% confidence interval 2.3-90). To further elucidate the prognostic value of LV ejection fraction, multivariate Cox analysis was repeated with ejection fraction forced to remain in the model. In the latter model, an ejection fraction ≤30% combined with nonsustained VT on Holter was found to be a significant arrhythmia risk predictor with a relative risk of 14.6 (95% confidence interval 2.2-97). Conclusions The combination of an LV end-diastolic diameter ≥70 mm and nonsustained VT on Holter, and the combination of LV ejection fraction ≤30% and nonsustained VT on Holter, identify a subgroup of patients with IDC with a 14-fold risk for subsequent arrhythmic events. These findings have important implications for the design of future studies evaluating the role of prophylactic defibrillator therapy in patients with IDC. (Am Heart J 2000;140:43-51.)

The cox maze III procedure: Parallel normalization of sinus node dysfunction, improvement of atrial function, and recovery of the cardiac autonomic nervous system

Objective: The Cox maze III procedure includes isolation of the pulmonary veins and multiple incisions in both atria in what corresponds to partial autotransplantation and partial denervation of the heart. The aim of this prospective longitudinal study was to identify physiologic effects of reinnervation on changes in heart rate at rest and in response to various stimulations and on atrial function after the Cox maze III procedure. Patients and methods: Power spectral analysis of heart rate variability, exercise testing, 24-hour Holter monitoring, electrocardiography, and transthoracic and transesophageal echocardiography were performed in 30 adult patients after the combined Cox maze III procedure and mitral valve surgery (maze group). They were prospectively followed up at 1, 3, 6, and 12 months after the operation. The results were compared with those of 15 heart transplant recipients (transplant group) and normal probands (healthy adults, n = 12). Results: The physiologic effects of denervation with no differences in cardiac autonomic activity between the groups were seen early after the operation. Later, evidence of autonomic reinnervation was observed only in the maze group but not in the transplant group. Inappropriate heart rate responses during physical exercise were clearly evident in both groups after 1 and 3 months, with progressive improvement seen between 6 and 12 months only in the maze group. Left atrial function after the Cox maze procedure improved parallel to the recovery of sinus node function. Conclusion: Progressive improvement of sinus node function and atrial contractions with significant functional normalization 1 year after the Cox maze procedure corresponded to functional reinnervation and recovery of the autonomic nervous system. (J Thorac Cardiovasc Surg 1999;118:287-96)