Clinical Significance of High-Frequency, Low-Amplitude Electrocardiographic Signals. and QT Dispersion in Patients Operated on for Tetralogy of Fallot

by PTMC was less optimal in patients with a more severe valve deformity, and there was the tendency toward a mild decrease in mitral valve area at follow-up examinations. Therefore, mitral restcnosis is expected to occur in these patients after several years. If restcnosis results from refusion of the commissures, repeat PTMC may be effective. However. if restenosis occurs mainly because of a markedly restricted opening of the anterior leaflet due to inexorable.progress of the fibrotic process, mitral valve surgery should be recommended. As a last resort, emergency PTMC was performed in 3 premoribund patients. These patients escaped the critical state after PTMC, and 1 of the 3 patients underwent mitral valve replacement several days later. This limited experience shows that if the clinical and hemodynamic state contraindicates open heart surgery, PTMC may be available as a bridge to open heart surgery after hemodynamic improvements. Three of the 9 patients at surgical high risk died during follow-up, but the remaining 6 patients have continued to improve clinically without restenosis. Our data show that clinical improvement has been sustained for several years even in these patients. When rcstenosis occurs in these patients, PTMC may be repeated with equally successful results. In conclusion, to evaluate the efficacy and safety of PTMC for mitral stenosis patients with markedly severe valve deformity, we performed PTMC in 17 patients with severe mitral stenosis assessed by echocardiography (echo score 212). This study demonstrates that PTMC can be performed safely and is