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The effects of monatepil, a new calcium antagonist with alpha 1-blocking activity, and nitrendipine on lipoprotein and carbohydrate metabolism in 86 patients with mild-to-moderate hypertension were examined in a randomized, open-label, multicenter (32 hospitals) study. Thirty-nine patients treated with monatepil and 33 patients treated with nitrendipine completed the 12-week study. Monatepil and nitrendipine each significantly decreased both systolic and diastolic blood pressure. Changes in heart rate were not seen in either group. Monatepil administration significantly decreased total cholesterol, low density lipoprotein (LDL) cholesterol, the LDL cholesterol to high density lipoprotein (HDL) cholesterol ratio, apolipoprotein (Apo) B levels, and HbA1c levels, whereas no changes in these measurements were observed in nitrendipine-treated patients. Monatepil also significantly decreased lipoprotein(a) levels, but there were no significant changes in HDL cholesterol, Apo-AI, or Apo-E levels. After nitrendipine treatment, the C peptide concentration decreased significantly, although no significant changes were observed in fasting blood glucose or immunoreactive insulin levels. On the basis of these results, it can be concluded that monatepil belongs to a new class of antihypertensive calcium antagonist with favorable carbohydrate metabolism and lipid-lowering activity, although the clinical importance of these findings has not been established.

The QRS axis of 130 consecutive patients with coronary artery disease undergoing percutaneous transluminal coronary angioplasty (PTCA) were measured before balloon inflation and just before balloon deflation. Patients were divided into two groups. Group A (103) had angina pectoris and/or non-transmural old myocardial infarction with no abnormal Q waves; group B (27) had an old transmural myocardial infarction with abnormal Q waves. In group A, the QRS axis had significantly shifted to the left in patients with left anterior descending artery (LAD) occlusion (from 68.0 +/- 42.7 degrees to 40.2 +/- 44.6 degrees, P < 0.001); however in those patients without involvement of the major septal branch, significant axis changes were not observed (from 53.6 +/- 34.1 degrees to 49.8 +/- 33.1 degrees). When the right coronary artery (RCA) was occluded in group A, the QRS axis shifted to the right significantly (from 63.2 +/- 40.0 degrees to 89.8 +/- 30.1 degrees. P < 0.01); during left circumflex artery (LCX) occlusion, no significant axis shift was observed. In group B, no significant axis shift was observed either in patients with occlusion of the LAD or the RCA. It is concluded that transient left axis deviation reflects an obstructive lesion of the proximal portion of the LAD with involvement of the major septal branch, and transient right axis deviation reflects an obstructive lesion of the RCA.

Study objective – The aim was to investigate whether the use dependent effects of antiarrhythmic drugs on the Na+ current could be applied to explain their effects on impulse conduction. Design – Trains of rapid stimuli were applied to guinea pig papillary muscles via an electrode in the presence of quinidine (20 and 60 μmol·litre−1), and the conduction velocity was determined from the time difference between two signals of the maximal rate of rise (dV/dtmax) of the action potentials at two separate sites. The relationship of the time constants of the onset and recovery from the use dependent inhibition induced by quinidine was determined for the dV/dtmax and the conduction velocity. Experimental material – Six male Hartley guinea pigs weighing 200 to 300 g were killed by a blow to the head and the papillary muscles were rapidly excised from the right ventricles. The preparations were superfused with Tyrode solution. Measurements and main results – The rate of onset of the use dependent inhibition of conduction velocity and that of the square of conduction velocity were both faster than the simultaneously measured rate of onset of dV/dtmax inhibition induced by 20 μmol·litre−1 quinidine at high frequency stimulation. The relation between the rates of onset of the use dependent inhibition of conduction velocity (and the square of conduction velocity) and dV/dtmax became weak with low frequency stimulation and in the presence of 60 μmol·litre−1 quinidine. However, the recovery of conduction velocity (and the square of conduction velocity) from quinidine induced use dependent blockade, as measured by the extrastimulation method, appeared to be slower than the recovery of dV/dtmax. These results may be explained by a transient change in intracellular and intercellular conditions, such as an increase in internal resistance. Conclusions – The onset and recovery of the use dependent inhibition of conduction by antiarrhythmic drug may not always parallel the changes of the dV/dtmax of action potential in multicellular muscle preparations.

Study objective – To examine the effect of 9-amino-1,2,3,4-tetrahydroacridine (THA), a compound similar to the K+ blocker 4-aminopyridine, on potassium channels in the sinoatrial node. Design – The pace making portion of rabbit sinoatrial nodes was studied using the double microelectrode voltage clamp method in the presence of THA at various concentrations. Measurements and results – Above 1 μmol·litre−1, THA prolonged the spontaneous cycle length and the transmembrane action potential duration at 50% repolarisation. Above 10 μmol·litre−1, the compound also decreased the maximum rate of rise, the action potential amplitude, and the rate of diastolic depolarisation. Under voltage clamp conditions, THA reduced the time dependent K+ current (IK) in a dose dependent manner. Neither the decay process of IK nor its activation process were altered by THA. Conclusions – THA depresses sinoatrial node IK without changing its kinetics. Thus it may inhibit the open state of the potassium channels.

The effects of trimebutine maleate on electrical activity in guinea-pig isolated papillary muscles and rabbit sino-atrial nodes have been studied by means of a standard microelectrode method. In papillary muscles, trimebutine (above 10 μM) decreased the maximum rate of rise (V̇max) and the action potential duration at 90% repolarization (APD90), whereas the resting potential was not significantly altered. As to a decrease in V̇max, trimebutine produced a negative shift of the curve relating V̇max to the resting potential along the voltage axis. Trimebutine also depressed the slow action potentials of papillary muscles produced by 27 mM K and 0·2 mitt Ba. In spontaneously beating sino-atrial node preparations, trimebutine (above 10 μ) decreased the heart rate, V̇max and the rate of diastolic depolarization. These results indicate that trimebutine maleate possesses a depressant action on the electrical activities of the fast- and slow-response fibres of the heart mainly due to inhibitions of both fast Na+ and slow Ca2+ channels.

A case of an aneurysm associated with four coronary artery fistulae originating from three vessels is reported. The patient, a 52-year-old woman, had chest heaviness and palpitations. Coronary arteriography revealed the four fistulae originating from three coronary vessels with an aneurysm draining into the left ventricle and the main pulmonary artery. The patient's symptoms were relieved after fistulectomy and the aneurysmectomy, suggesting that a coronary steal phenomenon through the fistulae was the cause of her symptoms. This case is of interest because of its rarity, since this is the first case report of an aneurysm associated with four coronary artery fistulae from three vessels.