bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Predictive Value of Exercise QRS Duration Changes for Post‐PTCA Coronary Events
Authors: Efrati Shai , Cantor Angel , Goldfarb Benjamin , Ilia Reuben 
Published: December 2004

Background: The sensitivity and predictive values of exercise ECG testing using ST‐T criteria after percutaneous transluminal coronary angioplasty (PTCA) are low, precluding its routine use for screening for restenosis. The predictive value of QRS duration criteria during exercise testing (ET) ECG after PTCA for future coronary events has not been reported. The aim of the study was to compare QRS duration changes with ST‐T criteria during ET, as a predictor of coronary events after PTCA. Methods: A prospective study of 206 consecutive patients who underwent ET at a mean of 34 ± 14 days after their first PTCA, and were the followed for a mean of 23 ± 9 months. Patients were divided by QRS duration into two groups—Q1: ischemic response (QRS duration prolongation of more than 3 ms relative to the resting duration), and Q2: normal response (QRS duration shortening or without change from resting duration). Patients were also divided by their ST‐T response, S1: ischemic response, and S2: normal response. Results: During follow‐up 52 patients (58%) experienced restenosis or MI, or underwent CABG—Q1: 44 (85%), Q2: 8(15%) (P < 0.0002), S1: 8 (15%), S2: 44 (85%), (P < 0.641), two patients died—Q1: 1 (1%) and Q2: 1 (1%). For QRS and ST‐T, the relative risk of having at least one of the coronary events was 4.02 (CI 2.1–9.9) versus 1.13 (CI 0.8–2.9), respectively. The sensitivity for future coronary events was 85% and 52% and the specificity was 48% and 98% for the QRS and ST‐T criteria, respectively. Conclusion: QRS prolongation during peak ET ECG after PTCA is a more sensitive marker than ST‐T criteria for detection of patients at risk for later coronary events.
Usefulness of Risk Stratification for Future Cardiac Events in Infarct Survivors with Severely Depressed Versus Near‐Normal Left Ventricular Function: Results From a Prospective Long‐Term Follow‐Up Study
Authors: Klingenheben Thomas , Hohnloser Stefan H. 
Published: December 2004

Background: Although primary preventive therapy with implantable cardioverter defibrillators has recently been shown to be effective in patients with coronary artery disease and left ventricular dysfunction, further identification of patients at particularly high risk for arrhythmic death would improve the cost effectiveness of device therapy. The value of risk stratification in postinfarction patients with versus those without left ventricular dysfunction has not been investigated in detail in infarct survivors treated according to contemporary therapeutic guidelines. Methods: Patients with acute myocardial infarction underwent coronary angiography including left ventricular angiography in an attempt to restore antegrade flow of the infarct‐related artery. Additionally, patients underwent noninvasive autonomic risk stratification by means of heart rate variability (HRV) and baroreflex sensitivity (BRS) measurements prior to hospital discharge. Results: A total of 411 patients were prospectively included in the study. The primary study endpoint of cardiac death and arrhythmic events was significantly more common in patients with LVEF ≤ 35% as compared to those with preserved LV function (27% vs 4%; P < 0.0001). In patients with LV dysfunction, HRV and BRS were significant risk predictors on univariate (P < 0.01 for BRS; P = 0.04 for HRV) and multivariate (P = 0.028 for BRS; P = 0.053 for HRV) analyses. In contrast, in patients with preserved LV function, only patency of the infarct artery but not autonomic markers was significantly predictive of cardiac death and arrhythmic events. Conclusion: The present study demonstrates that autonomic testing does not yield predictive power in infarct survivors with preserved left ventricular function. Accordingly, cost effectiveness of risk stratification and subsequent preventive therapy may be improved by restricting risk stratification to patients with impaired LV function.
Effects of P‐wave Dispersion on Atrial Fibrillation in Patients with Acute Anterior Wall Myocardial Infarction
Authors: Baykan Merih , Çelik Şükrü , Erdöl Cevdet , Durmuş İsmet , Örem Cihan , Küçükosmanoğlu Mehmet , Yilmaz Remzi 
Published: December 2004

Backround: P‐wave dispersion (P dispersion), defined as the difference between the maximum and the minimum P‐wave duration (P minimum), and maximum P‐wave duration (P maximum) have been used to evaluate the discontinuous propagation of sinus impulse and the prolongation of atrial conduction time respectively. The aim of this study was to investigate whether early assessment of P dispersion predicts paroxysmal atrial fibrillation (AF) in patients with acute anterior wall myocardial infarction (MI). Methods: We prospectively evaluated 147 consecutive patients (45 women, 102 men; aged 55 ± 9 years) with a first acute anterior wall MI. All patients were evaluated by echocardiography to measure the left atrial diameter and left ventricular ejection fraction (LVEF). Electrocardiography was recorded from all patients on admission and every day during hospitalization. Results: AF occurred in 25 patients. In 122 patients, AF did not occur. P maximum was found to be significantly higher in patients with AF than in patients without AF (115 ± 17.3 ms vs 101 ± 14.7 ms, P = 0.001). P dispersion also was significantly higher in patients with AF than in patients without AF (50 ± 12.5 ms vs 43 ± 10.1 ms, P = 0.01). There was no significant difference between the two groups in P minimum (64 ± 12.5 ms vs 59 ± 11.7 ms, P = 0.057). The echocardiographically left atrial diameters were not significantly higher in the patients with AF than those without (25 ± 3.38 mm and 23 ± 3.36 mm, respectively, P = 0.76). LVEF was found to be significantly different in the patients who developed AF and in those who did not (37.96 ± 6.18% vs 47.70 ± 6.01%, P = 0.0001). Conclusions: Although P maximum and P dispersion are significant predictive factors of AF in patients with acute anterior wall MI in the univariate analysis, on the basis of multivariate analysis, only age and LVEF were independent predictive parameters for AF.
Effects of Slow Coronary Artery Flow on QT Interval Duration and Dispersion
Authors: Atak Ramazan , Turhan Hasan , Sezgin Alpay T , Yetkin Ozkan , Senen Kubilay , Ileri Mehmet , Sahin Onur , Karabal Orhan , Yetkin Ertan , Kutuk Emine , Demirkan Deniz 
Published: December 2004

Background: The coronary slow‐flow phenomenon is an angiographic phenomenon characterized by delayed opacification of vessels in the absence of any evidence of obstructive epicardial coronary disease. Several studies have demonstrated myocardial ischemia in patients with slow coronary artery flow. In the present study, we aimed at evaluating the effects of slow coronary artery flow on QT interval duration and QT dispersion as a possible indicator of increased risk for ventricular arrhythmias and sudden cardiac death. Methods: The study population included 49 patients with angiographically proven normal coronary arteries and slow coronary flow in all three coronary vessels (group I, 33 males, 16 females, mean age = 48 ± 9 years), and 71 patients with angiographically proven normal coronary arteries without associated slow coronary flow (group II, 47 males, 24 females, mean age = 50 ± 8 years). Coronary flow rates of all subjects were documented by thrombolysis in myocardial infarction frame count (TIMI frame count). QT interval duration and QT dispersion of all subjects were measured on the standard 12‐lead electrocardiogram. Results: There was no statistically significant difference between the two groups in respect to age, gender, presence of hypertension, and diabetes mellitus. There was a significant difference between the two groups in respect to the presence of cigarette smoking, typical angina, and positive exercise test results. TIMI frame counts of group I patients were significantly higher than those of group II patients for all three coronary arteries (P < 0.001). Maximum corrected QT interval (QTcmax) of group I did not differ from the QTcmax of group II (P > 0.05). However, minimum corrected QT interval (QTcmin) of group I was significantly lower than that for group II (P = 0.008). Consequently, corrected QT dispersion (QTcd) in group I was found to be significantly higher than in group II (P < 0.001). Conclusion: QTcd, indicating increased risk for ventricular arrhythmias and cardiovascular mortality, was found to be significantly higher in patients with slow coronary artery flow. However, further long‐term prospective studies should be carried out to establish the significance of QTcd as a risk factor for ventricular arrhythmias and subsequent sudden cardiac death in patients with slow coronary artery flow.
Utility of SAECG in Arrhythmogenic Right Ventricle Dysplasia
Authors: Nasir Khurram , Rutberg M.P.H., Julie , Tandri Harikrishna , Berger Ronald , Tomaselli Gordon , Calkins Hugh 
Published: December 2004

Background: Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by progressive replacement of RV myocardium with fibro‐adipose tissue thought to be responsible for the presence of late potentials (LP) detected by SAECG. The general consensus on the role of SAECG in the diagnosis and prognosis of patients with ARVD is lacking. The purpose of this systematic review was to better define the role of SAECG in ARVD. Methods: An extensive review of literature was done to specifically describe the prevalence of LP in ARVD and its determinants, explore the various options available to improve the diagnostic ability of SAECG, and provide recommendations for proper utilization of this technique. Results: LPs are frequent in ARVD (47–100%), and more prevalent in severe disease and in patients with documented spontaneous VT. SAECG is a useful test in following the characteristic evolutivity of the disease. 4–16% of normal family members of patients with ARVD also have abnormal SAECG results. Detection of LP in ARVD can be improved by employing a high‐pass filter of 25 Hz and specifically looking for changes in the Z leads. Conclusions: SAECG testing should be considered a standard part of the evaluation of patients with known or suspected ARVD. Further research is needed to confirm the value of SAECG testing in predicting arrhythmia risk and assessing the rate of disease progression, as well as to determine if greater prevalence of SAECG abnormalities in family members of patients with ARVD represents early detection of ARVD. The ongoing multidisciplinary study of right ventricular dysplasia will hopefully answer some of these questions.
Higher Energy Monophasic DC Cardioversion for Persistent Atrial Fibrillation: Is it Time to Start at 360 Joules?
Authors: Boos C , Thomas MD , Jones A , Clarke E , Wilbourne G , More RS 
Published: December 2004

Background: Electrical direct‐current cardioversion (DCCV) has become a routine therapy for atrial fibrillation (AF), although some uncertainty remains regarding the optimal energy settings. Aims: This study examines whether the use of a higher initial energy monophasic shock of 360 joules (J) for external DCCV, in patients with persistent AF would prove more effective, yet as safe, as the use of a lower initial energy 200 J shock. Methods: A cohort of 107 patients with persistent AF was prospectively randomized to an initial synchronized DCCV shock of 360 J versus 200 J (n = 50 vs 57), followed by a similar shock sequence thereafter of four further shocks of 360 J for the two groups. In all patients the levels of troponin I (cTnI) were measured precardioversion and 18–20 hours later, the following day. In a subgroup of 36 patients in each group, the levels of creatine kinase (CK) and aspartate transaminase (AST) were measured pre‐ and 18–20 hours postcardioversion. Results: The success rate for DCCV was significantly higher in the 360 J group compared to the 200 J group (96.0% vs 75.4%, P = 0.003). The mean CK IU/L levels (1137.5.0 vs 2411.8, P = 0.014) and AST levels (39.83 vs 52.86, P = 0.010) were significantly lower in the 360 J group compared to the 200 J group. There was no statistical rise in cTnI (μg/L) in either group (P = 1.00). The average number of shocks delivered (1.84 vs 2.56, P = 0.006) was significantly less in the 360 J group than in the 200 J group, although total energy requirements for DCCV were similar for the two groups (662.4 J vs 762.4 J, P = 0.67). Conclusion: For patients with persistent AF the use of a higher initial‐energy monophasic shock of 360 J achieves a significantly greater success rate, with less skeletal muscle damage (and no cardiac muscle damage) as compared with the traditional starting energy of a 200 J DC shock.
Heart Rate Turbulence following Ventricular Premature Beats in Healthy Controls
Authors: Grimm Wolfram , Sharkova Julia , Christ Michael , Schneider Raphael , Schmidt Georg , Maisch Bernhard 
Published: December 2004

Background: Heart rate turbulence (HRT) has recently been described as a strong, independent risk stratifier in postinfarct patients. To date, however, the incidence of false positive HRT findings in adults is unknown. Therefore, we performed a blinded, retrospective analysis of HRT in a prospectively collected database of 110 apparently healthy persons to determine the prevalence and clinical significance of abnormal HRT findings in healthy controls using previously published cut‐off values. Methods and Results: The study included 43 out of 110 apparently healthy adults, in whom a sufficient number of ventricular premature beats were available for HRT analysis on 24‐hour Holter recordings. The HRT slope was dichotomized at 2.5 ms per R‐R interval and HRT onset was dichotomized at 0% using previously established criteria to define an abnormal HRT analysis in postinfarct patients. Using these definitions, abnormal HRT results were found in 2 out of 43 controls (5%) for HRT slope and in 8 out of 43 controls (19%) for HRT onset without any cardiac deaths during 32 ± 15 months follow‐up. Conclusions: The incidence of false positive HRT results in healthy middle‐aged volunteers is low for HRT slope (5%), but not for HRT onset (19%) when previously published cut‐off values are used to define abnormal HRT results. Thus, HRT slope dichotomized at 2.5 ms per R‐R interval, but not HRT onset dichotomized at 0%, may be used as a relatively specific tool for risk stratification in middle‐aged persons.
Severity in Myocardial Dysfunction Contributed to Long‐term Fluctuation of Heart Rate, Rather than Short‐Term Fluctuations
Authors: Minamihaba Osamu , Yamaki Michiyasu , Tomoike Hitonobu , Kubota Isao 
Published: December 2004

Background: It is known that heart rate shows complex behavior, long‐term fluctuation of heart rate, and short‐term fluctuations in heart failure. Analyzing these properties and examining the relationship to the disease, severity may increase the understanding of the background of heart rate variability (HRV). Methods: In 61 patients (mean age 65 ± 9 years, 32 ischemic heart disease, 29 cardiomyopathy), with myocardial dysfunction, 24‐hour ambulatory electrocardiography was performed. After the construction of the time series of R‐R intervals, 15 HRV parameters were measured, including mean heart rate, standard deviation of N‐N intervals (SDNN), ratio of low frequency/high frequency power (LF/HF), HRV triangular index (TI), and ratio of length/width at the 90% level of all scattered points. Results: By using the multiple regression analysis, we tested which HRV parameter (HR, SDNN, LF/HF, TI, or length/width) independently correlated with left ventricular ejection fraction (EF) or left ventricular diastolic dimension (EDD). The results demonstrated that TI and SDNN independently correlated with EF (multiple R = 0.59). Moreover, TI and SDNN independently correlated with EDD (multiple R = 0.45). Conclusion: TI and SDNN were indicators of the disease severity in myocardial dysfunction, while LF/HF, indicators of autonomic tone, did not have such an ability. It was of interest that the disease severity contributed to long‐term fluctuations (TI, SDNN) of heart rate, rather than short‐term fluctuations (LF/HF).
Chronic Inappropriate Sinus Tachycardia in Elderly Females
Authors: Lopera Gustavo , Castellanos Agustin , Moleiro Federico , Huikuri Heikki V , Myerburg Robert J 
Published: December 2004

Background: The vast majority of reports of inappropriate sinus tachycardia (IST) had included predominantly young females with ages ranging between 15 and 46 years. In contrast, the present study presents the findings in four elderly females (aged 61–71 years) with long‐standing symptoms of palpitations, more than 15 years, in whom IST was diagnosed in their 6th or 7th decade. Methods: Clinical and laboratory examinations including electrocardiograms, echocardiograms, and heart rate variability studies were retrospectively reviewed in four of the nine elderly female patients with long‐standing cardiac symptoms. Indices of heart rate variability were compared to four age‐matched asymptomatic elderly females with no structural heart disease. Results: The resting electrocardiograms were normal but one had voltage criteria for left ventricular hypertrophy. All traditional time‐ and frequency‐domain indices were significantly decreased in the symptomatic elderly females as compared to the controls. Echocardiograms showed normal ejection fraction, and in three patients evidence of diastolic dysfunction and mild left ventricular hypertrophy. Blood pressures were elevated, with systolic blood pressure ranging from 170 to 190 and diastolic blood pressure ranging from 94 to 106. Anxiety disorders were diagnosed in all patients. Conclusions: This study demonstrates that IST can be present in a wide spectrum of patient populations, including elderly populations. It seems that some cases of IST can become chronic if not treated adequately. Apparently, earlier identification and treatment could have improved the quality of life of the patients. Traditional HRV indices may not be valuable to support either a sympathetic or parasympathetic mechanism. Therefore, further studies should consider the potential usefulness of the nonlinear method such as, for example, approximate entropy and detrended fluctuation analysis.
Heart Rate Variability in Obstructive Sleep Apnea: A Prospective Study and Frequency Domain Analysis
Authors: Gula Lorne J , Krahn Andrew D , Skanes Allan , Ferguson Kathleen A , George Charles , Yee Raymond , Klein George J 
Published: December 2004

Background: Cyclic variation of the heart rate is observed during apneic spells in obstructive sleep apnea (OSA). We hypothesized that autonomic changes would affect frequency‐domain measures of heart rate variability (HRV). Methods: We studied 20 patients (15 men, 5 women, mean age 47.2 ± 12.2 years) with suspected OSA undergoing overnight polysomnography, and five patients (4 men, 1 woman, mean age 49.2 ± 8.6 years) with recently diagnosed sleep apnea undergoing polysomnography while wearing continuous positive airway pressure (CPAP). Holter monitors were applied during sleep studies and data were analyzed in 5‐minute blocks over the course of the night. Using spectral analysis, low frequency (LF) and high frequency (HF) powers were calculated for each interval. Overall mean and standard deviation (SD) for LF power, HF power, and the LF:HF ratio were recorded for each patient. Comparisons were made between patients with severe OSA (apnea hypopnea index (AHI) > 30, n = 8), moderate OSA (AHI 1–30, n = 5), without OSA (AHI < 10, n = 7), and patients wearing CPAP (n = 5). Results: Assessment of overnight LF or HF power revealed no significant difference between the four groups. The LF:HF ratio, which represents sympathovagal balance, was higher among those with moderate disease compared to normals and those with severe OSA (both P = 0.037). The standard deviation of the LF:HF ratio was higher among those with moderate disease compared to normals (P = 0.0064) and those with severe OSA (P = 0.0006). OSA patients receiving CPAP behaved like patients with moderate OSA, with increased SD of the LF:HF ratio. Conclusions: The observed changes in the LF:HF ratio and its SD suggest an increased sympathetic tone and discordance in sympathovagal activity in moderate OSA, which is blunted in severe OSA. CPAP may restore autonomic defects, characteristic of severe OSA, to moderate levels.
Effects of Right Coronary Artery PTCA on Variables of P‐Wave Signal Averaged Electrocardiogram
Authors: Budeus Marco , Hennersdorf Marcus , Dierkes Stefan , Preik Michael , Heintzen Matthias P. , Kelm Malte , Perings Christian 
Published: December 2004

Background: P‐wave signal averaged ECG has been used to detect atrial late potentials that were found in paroxysmal atrial fibrillation. Ischemia is supposed to trigger ventricular late potentials, which indicate an elevated risk for ventricular tachycardia. Preexistent ventricular late potentials measured by ventricular signal averaged ECG is supposed to be eliminated by successful PTCA. Methods: We examined the incidence of atrial late potentials in patients with a proximal stenosis of the right coronary artery and new onset of atrial fibrillation. Furthermore, we investigated the anti‐ischemic effect of a successful percutaneous transluminal coronary angioplasty.(PTCA) of the right coronary artery. P‐wave signal averaged ECG from 23 patients who had a PTCA of the right coronary artery (group A) were compared to age, sex, and disease‐matched control subjects (group B) one day before, one day after, and one month after PTCA. Results: A new appearance of paroxysmal atrial fibrillation was presented in eight patients before PTCA (group A1) of group A. Patients with a stenosis of the right coronary artery had a significantly higher incidence of supraventricular extrasystoles in a 24‐hour‐Holter ECG (131.1 ± 45.4 vs 17.1 ± 18.9, P < 0.0002). The duration of the filtered P wave was longer (124.8 ± 11.9 vs 118.5 ± 10.1 ms, P < 0.04) and the root mean square of the last 20 ms (RMS 20) was significantly lower in group A than in group B (2.87 ± 1.09 vs 3.97 ± 1.12 μV, P < 0.01). A successful PTCA caused an increase in RMS 20 (2.87 ± 1.11 vs 4.19 ± 1.19 μV, P < 0.02) and a decrease in filtered P‐wave duration (124.8 ± 11.9 vs 118.4 ± 10.4 ms, P < 0.04). Preexistent atrial late potentials were found among 15 patients before PTCA. After successful PTCA only 3 out of 15 patients were affected (P < 0.0004) after one day, as well as after one month. All patients with a history of atrial fibrillation did not suffer from an arrhythmic recurrence within the following six months after successful PTCA. Conclusion: A stenosis of the right coronary artery is associated with atrial late potentials. A successful PTCA of the right coronary artery eliminates preexistent atrial late potentials and may reduce the risk of atrial fibrillation.