Influence of exercise on QT dispersion in ischemic heart disease.

UNLABELLED: QT dispersion (QTd: maximum QT interval-minimum QT interval) is associated with severe cardiac arrhythmia and with abnormal ventricular repolarization. We investigated the influence of exercise on QTd in patients with ischemic heart disease. On standard 12-lead electrocardiograms, QTd was measured before and after treadmill exercise in 7 normal subjects, 17 patients with effort angina pectoris (and > or = 75% stenosis on coronary arteriography), and 33 patients with old myocardial infarction. Bazett's formula was used to obtain the corrected QTd (QTcd). The pre-exercise resting QTcd was 45.9 +/- 10.6, 44.3 +/- 15.2, and 74.8 +/- 28.1 msec in the respective groups, being significantly greater in the infarct group (p < 0.05). The QTcd at 5 min after exercise was respectively 49.3 +/- 9.0, 58.8 +/- 19.9, and 75.4 +/- 30.9 msec (p = 0.0347, infarct vs. controls). The difference in QTcd was significant for the angina group before and after physical exercise (p = 0.0003). There was a significant increase of QTcd after exercise in the angina group whether or not the patients were receiving beta-blockers. The infarct patients without beta-blocker therapy showed an increase of QTcd after exercise, while those receiving beta-blockers showed a decrease. The post-exercise difference between these subgroups was significant (p = 0.0351). CONCLUSIONS: QTcd was significantly increased by exercise in the angina group, possibly reflecting impaired repolarization due to ischemia. Inhibition of the increase in QTd by beta-blockers suggested a possible preventive effect on severe arrhythmias due to nonhomogeneous ventricular repolarization.

A randomized trial of aspirin versus cilostazol therapy after successful coronary stent implantation.

Percutaneous transluminal coronary angioplasty (PTCA) is widely used to treat patients with ischemic heart disease, but the procedure involves a number of problems, including acute coronary occlusion and restenosis. Although stents have proved useful for preventing post-PTCA restenosis, especially elastic recoil during the acute phase, no method has yet been established to prevent restenosis caused by vascular smooth muscle cell proliferation in the late phase. Cilostazol selectively inhibits the 3'5'-cyclic-nucleotide phosphodiesterase (PDE) III (cyclic guanosine monophosphate-inhibited PDE) of the cyclic adenosine monophosphate PDE family; it also has antithrombotic and vasodilating effects, as well as an inhibitory effect on vascular smooth muscle cell proliferation through PDE III inhibition. From November 1995 to March 1997, the usefulness of cilostazol versus aspirin in preventing subacute thrombosis and restenosis was studied in 70 patients (55 men and 15 women; 82 total lesions) who had undergone successful elective Palmaz-Schatz stent implantation. Patients were randomly allocated to receive aspirin 81 mg/d (40 patients with 45 lesions) or cilostazol 200 mg/d (30 patients with 37 lesions) alone. There was no difference in patients or angiographic characteristics between these groups. No subacute thrombosis, acute complications (ie, death, emergent coronary artery bypass grafting, or hemorrhagic complications), or drug side effects were found in the cilostazol group. The minimal lumen diameter (mean +/- SD) at follow-up was 1.89 +/- 1.08 mm in the aspirin group (41 lesions, 5.63 +/- 1.74 months after stent implantation) and 2.34 +/- 0.74 mm in the cilostazol group (35 lesions, 5.14 +/- 1.91 months after stent implantation), revealing statistically significant dilatation in the cilostazol group. The restenosis rate was 26.8% in the aspirin group, compared with 8.6% in the cilostazol group; this difference was statistically significant. Administration of cilostazol alone after the implantation of intracoronary Palmaz-Schatz stents was useful for the prevention of subacute thrombosis and restenosis.

Comparative study of magnetic resonance and CT scan imaging in cases of severe head injury.

The distribution, frequency, and appearance of head injuries were evaluated with MRI and CT in a prospective study of 155 patients with acute (n = 124) and chronic (n = 31) head injuries. MRI was significantly more sensitive than CT in the detection of intraaxial injury at any stage. In severe cases, central structure lesions were detected in approximately 80% of patients. Severity on admission was compatible with MR findings. However it was difficult to decide on neurobehavioural prognosis from initial MRI findings only.