Effect of intracoronary balloon inflation at percutaneous transluminal coronary angioplasty on QT dispersion.

BACKGROUND: QT dispersion (QTd) has recently been used as a marker for arrhythmic death caused by adverse drug effect. However, the effect of acute ischemia on QTd is not well described. METHODS: To determine the effect of acute ischemia on QTd, 12-lead electrocardiograms were obtained at baseline and 2 minutes after intracoronary balloon inflation in 34 patients. QTd was calculated as a range between shortest (QTmin) and longest (QTmax) QT intervals. RESULTS: In 18 patients balloon inflation provoked ST elevation, increased QTd (43 +/- 20 msec to 61 +/- 19 msec, p = 0.012), and decreased QTmin (390 +/- 43 msec to 361 +/- 43 msec, p < 0.001) without significant effect on QTmax (433 +/- 42 msec to 423 +/- 47 msec). No significant changes in QT measures were observed in eight patients who had ST depression and in eight without ST changes. CONCLUSION: Acute transmural ischemia provoked by intracoronary balloon inflation increases QTd by reducing the QTmin interval, which may modify the electrophysiologic substrate.

Atrial natriuretic peptide and its potential role in pharmacotherapy.

Atrial natriuretic peptide (ANP) is a 28 amino-acid polypeptide secreted into the blood by atrial myocytes after atrial pressure and distension. Although its role in humans is not clear, it can produce a variety of physiologic effects including vasodilatation, natriuresis, and suppression of the renin-angiotensin-aldosterone axis. These actions are potentially useful in a variety of pathologic states such as hypertension and congestive heart failure, and diverse methods to augment the effects of ANP in these states have been devised. The results are exciting and, despite some problems, may lead to the pharmacologic use of enhancement of ANP actions in several clinical disorders.

[Clinico-angiographic correlations in intramural myocardial infarction]. / Kliniko-angiograficheskie sopostavleniia pri intramurl'nom infarkte miokarda.

The results of examination of 74 patients aged 33 to 65 years with intramural myocardial infarction (MI) are analyzed. It is established that as compared to patients with transmural MI, this group of patients showed recurrent attacks of angina pectoris and MI more frequently (during treatment at hospital). In addition, the exercise test in such patients was positive more often either (the data are statistically significant). The symptomatology of intramural MI is determined by the fact that the area of blood supply to tht subtotally stenosed infarction-dependent vessel is considerably larger as compared to the area of injury as a result of which the preserved myocardium experiences severe hypoxia. It is advised that in complicated intramural MI, angiography of the venous arteries may be carried out. Moreover, provided there are indications, endovascular or surgical revascularization of the myocardium may be considered.