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Arthur J Moss

Publications and source records attributed to Arthur J Moss.

117 records · Page 7Linked to original sources
PubMed2002

MADIT-II: clinical implications.

The MADIT-II trial showed that in patients with a prior myocardial infarction and ejection fraction </=0.30, prophylactic implantation of a defibrillator improves survival with a 31% reduction in mortality during an average follow-up of 20 months. Electrophysiologic inducibility was positive in 36% of patients at the time of ICD implantation. Inducibility was associated with increased ICD utilization for ventricular tachycardia during long-term follow-up, and decreased utilization for ventricular fibrillation. These preliminary findings raise questions about the clinical usefulness of electrophysiologic testing as a risk stratifier in patients with advanced left ventricular dysfunction.

Adult↗
PubMed2002

Repolarization dynamics in patients with long QT syndrome.

INTRODUCTION: Dynamics of ventricular repolarization may contribute to cardiac arrhythmias in subjects with the long QT syndrome (LQTS). The aim of the present study was to assess the dynamics of repolarization duration and the dynamics of repolarization complexity in LQTS patients and their unaffected family members. METHODS AND RESULTS: Twelve-lead 24-hour ambulatory ECG recordings were obtained from LQTS patients (n = 38) and unaffected family members (n = 20). The 24-hour dynamics of the QT interval, T wave complexity (TWC) index measured by principal component analysis, and the RR interval were analyzed using standard deviation (SD) and square root of the mean squared differences of successive values of the parameters (RMSSD). QT variability, mean TWC, and TWC variability were increased in the LQTS patients compared with unaffected family members (QT-SD: 38 +/- 20 msec vs 19 +/- 7 msec, P = 0.0001; QT-RMSSD: 36 +/- 20 msec vs 14 +/- 8 msec, P = 0.0001; TWC: 27.7% +/- 11.1% vs 20.4% +/- 6.7%, P = 0.003; TWC-SD: 6.7% +/- 2.8% vs 4.6% +/- 1.8%, P = 0.003; TWC-RMSSD: 5.3% +/- 2.8% vs 3.7% +/- 1.2%, P = 0.004, respectively). At the same time, the measures of heart rate variability were similar between the affected and unaffected LQTS subjects (SD of normal-to-normal RR intervals [SDNN]: 94 +/- 25 msec vs 89 +/- 37 ms, P = 0.56; RMSSD: 49 +/- 26 msec vs 49 +/- 34 ms, P = 0.97, respectively). CONCLUSION: Despite similar heart rate variability, QT variability and the variability of TWC are significantly increased in LQTS patients compared with unaffected family members, suggesting that disturbances in temporal dynamics of repolarization and repolarization complexity in LQTS patients possibly increase vulnerability to arrhythmias.

Adult↗
PubMed2002

Variable expression of long QT syndrome among gene carriers from families with five different HERG mutations.

OBJECTIVES: This study assessed the phenotypic variability of LQTS in carriers with the same and with different mutations in the LQT2 gene. BACKGROUND: Mutations of ion-channel genes are known to cause the long QT syndrome (LQTS), a disorder associated with distinctive genotypic-specific electrocardiographic patterns and variable clinical expression. METHODS: Clinical and electrocardiographic characteristics were assessed in five large LQTS families, each with a different mutation of the HERG gene (LQT2; n = 469, 69% genotyped, 102 carriers). One mutation was located on the N-terminus and the other four on the C-terminus of the HERG channel protein. RESULTS: The QTc duration and the frequency of cardiac events (syncope and LQTS-related cardiac arrest/death) were similar among carriers with the five HERG mutations. QTc was as variable in carriers of the same mutation as it was among carriers with different HERG mutations (P = 0.19). Qualitative assessment of the electrocardiograms revealed extensive intra-and interfamilial variability in T-wave morphology. Among carriers with multiple electrocardiograms extending over 2 to 7 years, variation in QTc over time was minimal. A strong association was found between QTc and the occurrence of cardiac events in carriers of all five mutations. CONCLUSIONS: The clinical expression of LQTS was equally variable in carriers from families with the same or different HERG mutations. These findings highlight the complexity of the clinical phenotype in this Mendelian dominant disorder and suggest that one or more modifier genes contribute to the variable expression of this syndrome.

Adult↗
PubMed2002

Influence of atropine on fractal and complexity measures of heart rate variability.

BACKGROUND: Measurement of short-term fractal-like correlation properties of heart rate dynamics has been shown to be a useful prognostic indicator of adverse events in cardiac patients. Complexity measurements of heart rate variability (HRV) have already provided important information in many cardiac conditions. However, data on the physiological background of these newer nonlinear measures of HRV are limited. METHODS: Nine healthy subjects (aged from 22 to 35 years, 6 males, 3 females) had an electrocardiographic (ECG) recording during controlled breathing in supine position. HRV was analyzed for 5 min periods before and after intravenous injection of 0.6 mg of atropine using conventional HRV measures and newer nonlinear HRV measures including the short-term scaling exponent (alpha(1)) and approximate entropy (ApEn). RESULTS: The short-term scaling exponent alpha(1) increased significantly after atropine injection (1.01 +/- 0.23 vs 1.43 +/- 0.19, P = 0.001). There was no significant difference between ApEn values before and after atropine injection (0.87 +/- 0.17 vs 0.70 +/- 0.31, respectively, P = 0.27). At baseline before atropine administration, alpha(1) had a significant negative correlation with SDNN, RMSSD, and HF (r = -0.70, -0.76, -0.67, respectively, P < 0.05 for all), and a significant positive correlation with heart rate (r = 0.76, P < 0.05). After atropine injection, alpha(1) did not have significant correlation with any of the HRV parameters or heart rate. There were no significant correlations between ApEn and any of the HRV measures or heart rate either before or after atropine administration. CONCLUSIONS: Vagal tone has an important influence on the values of the short-term scaling exponent alpha(1). However, vagal modulation is not a major determinant of the values of ApEn.

Adult↗
PubMedDate not supplied

Long QT Syndrome.

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Adrenergic beta-Antagonists↗