Takahiko Miki

Echocardiographic findings in 104 professional cyclists with follow-up study

To assess the effect of long-term athletic training on the heart, 104 professional cyclists and 40 sedentary controls (69 younger cyclists and 26 controls aged 20 to 39 and 35 older cyclists and 14 controls aged 40 to 60) were examined by using M-mode and pulsed Doppler echocardiography. Cyclists had larger and more hypertrophied left ventricle than did controls (p < 0.001) and had normal percentages of fractional shortening (%FS). The ratio of left ventricular late-to-early diastolic peak filling velocity (A/R) of younger cyclists was normal, but the A/R of older cyclists was larger than that of controls (p < 0.001). Of the 104 cyclists, 95 continued cycling and were reexamined 2 years later; 9 of 40 older cyclists retired and were reexamined 20 +/- 8 months after retirement. During the follow-up period for the active cyclists, left ventricular dilatation, hypertrophy, and %FS of both younger and older cyclists and the A/R of younger cyclists did not change. However, the A/R of older cyclists increased (p < 0.01). For the nine retired cyclists, left ventricular dimension decreased (p < 0.001), left ventricular wall thickness and %FS did not change, and A/R increased (p < 0.05) after retirement. We concluded that (1) cyclists had large and hypertrophied left ventricles with normal systolic function, and (2) some cyclists with long-term athletic training may have partly irreversible left ventricular hypertrophy with impaired left ventricular diastolic filling.

Effect of argatroban on thrombus formation during acute coronary occlusion after balloon angioplasty

Abstract Acute coronary occlusion is a life-threatening complication of percutaneous transluminal coronary angioplasty (PTCA). Many recent studies have shown that the rate of acute occlusion after PTCA ranges from 4% to 8%(1,2). It may be caused by several mechanisms, and the formation of acute coronary thrombus at the dilated site appears to be one of the most important events(3,4). Sakamoto et al. have reported that marked thrombin generation was induced by PTCA despite pretreatment with a standard aspirin and heparin regimen. This thrombin generation was blocked by a potent synthetic thrombin inhibitor, argatroban, rather than by ordinary heparin(5). These findings suggest that heparin failed to prevent thrombin generation in situ, while argatroban did it after PTCA. However, heparin is unable to inhibit local thrombin generation at the site of PTCA. The purpose of the present study is to assess whether adjunctive antithrombotic treatment with argatroban, in combination with repeated dilation. is an effective therapeutic strategy for the management of acute coronary occlusion.

Identical twins with arrhythmogenic right ventricular dysplasia

Abstract Identical twins with ARVD are reported, and the findings strongly suggest that ARVD is caused by a genetic disorder.