Atrial size reduction appears to predict the success of sinus conversion with the RF maze procedure used in conjunction with valvular surgery.

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SUMMARYThe optimal methods to perform external cardioversion of atrial fibrillation (AF) have yet to be conclusively determined. This study was performed to examine the relative efficacy of different pad positions on cardioversion success and the relationship between the transthoracic impedance (TTI) and energy requirement for AF cardioversion.Seventy patients with persistent AF undergoing elective cardioversion were randomly assigned to an electrode pad position situated either over the ventricular apex-right infraclavicular area (AL group, n = 31) or over the right lower sternal border-left infrascapular area close to the spine (AP group, n = 39). Energy was delivered at an initial 100 joules (J) and then increased to 150 J, 200 J, 300 J, and 360 J if needed. Energy and TTI readings were recorded.Mean TTI was significantly lower in the AP group than in the AL group. However, the cumulative success rates at each energy level were similar in the two groups (23% vs 19.4%, 41% vs 45.2%, 66.7% vs 74.2%, 79.5% vs 77.4%, and 84.6% vs 83.9% at 100 J, 150 J, 200 J, 300 J and 360 J, respectively). In the AP group, converters showed slightly lower TTI compared to nonconverters. In the AL group, converters showed significantly lower TTI compared to nonconverters. However, for all patients as a group, TTI was the only predictor for cardioversion success and showed a significant relationship to the energy required for cardioversion, which can be described by a quadratic equation.Rather than pad position, TTI is the single factor that significantly affects cardioversion and correlates with energy requirement. The relationship between energy requirement and TTI further allows estimation of energy requirements to achieve a successful cardioversion. (Jpn Heart J 2003; 44: 921-932) Key words: Atrial fibrillation, Cardioversion, Impedance, Electrode pad position EXTERNAL direct current (DC) cardioversion, which is useful for cardioversion of atrial fibrillation (AF), has conventionally been performed by delivering an energy shock starting at 100 joules (J) followed by 200 J, 300 J, and 360 J,

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SUMMARYAtrial fibrillation, the most common chronic arrhythmia, results in an increased risk of stroke. Anticoagulation therapy can reduce this risk, but appears to be underused. The objective of this study was to examine the use of warfarin and prevalence of stroke in patients with rheumatic, nonrheumatic valvular and nonvalvular atrial fibrillation.Between January 1993 and December 1998, 457 chronic atrial fibrillation patients with continuous follow-up in our hospital were identified as having rheumatic heart disease (n = 114); nonrheumatic valvular disease (n = 65); or nonvalvular disease (n = 278). Warfarin was used less often in patients with nonrheumatic valvular (16.7%) and nonvalvular diseases (20.1%) than in those with rheumatic heart disease (81.6%, p < 0.001). In contrast, the prevalence of stroke among patients with nonvalvular disease was 40.3% which was similar to the 33.3% found in patients with rheumatic heart disease but significantly higher than the 24.6% found in patients with nonrheumatic valvular disease (p < 0.05). A history of stroke did not alter the trend of use of warfarin among the three groups of patients. Only 20.6% of patients on warfarin received monthly monitoring of prothrombin time.In conclusion, the anticoagulation therapy in our patients with chronic atrial fibrillation, regardless of their associated valvular diseases, is significantly underutilized. This underuse could account for a high prevalence of stroke. This risk of stroke, however, is less in patients with nonrheumatic valvular disease than in those with nonvalvular atrial fibrillation. (Jpn Heart J 2001; 42: 55-65)

Endothelial dysfunction may be particularly important in the pathogenesis of young patients with acute myocardial infarction (AMI), because they have different clinical characteristics compared with older patients. We investigated endothelial function in relation to AMI in this young age group. From January 2005 to March 2008, 29 of 31 consecutive patients with acute ST-elevation myocardial infarction (STEMI) who were <40 years old and received direct percutaneous coronary intervention (PCI) were enrolled in the study. We compared the coronary risk factors and flow-mediated vasodilation (FMD) in the brachial artery between the acute STEMI patients and 29 age- and gender-matched controls that did not have AMI. Baseline brachial artery diameter and responses to glyceryl trinitrate were similar between the two groups. In contrast, FMD was significantly lower in the young acute STEMI group than in the control (3.47 ± 4.08 vs. 7.45 ± 4.67%, p = 0.001) and correlated with the Thrombolysis in Myocardial Infarction (TIMI) risk score. The impaired FMD in the acute STEMI group was independent of smoking, hyperlipidemia, hypertension, nitrate use, or body mass index. In multiple logistic regression analysis, only FMD and age, not traditional cardiovascular risk factors, were found to be significantly associated with acute STEMI (odds ratio = 0.75, 95% CI 0.63-0.90, p < 0.01). In conclusion, independent of conventional risk factors, severe endothelial dysfunction occurs in young acute STEMI patients and correlates with TIMI score. In addition to age, impaired FMD is the only significant factor associated with acute STEMI in this young population.