Clinical Experience with Orthocor II Antitachycardia Pacing System for Recurrent Tachyarrhythmia Termination

Between June 1986 and December 1988, eight patients were treated with an Orthocor II 284 A antitachycardia pacemaker (Cordis Corp., Miami, FL, USA) forsupraventricular tachycardia (SVT) and ventricular tachycardia (VT) termination. Four patients had intra-AV nodal reentrant tachycardias; 1 patient had AV reentrant tachycardia with an atrio-nodal accessory bypass tract; 2 patients had AV reentrant tachycardias with concealed Kent bundle, and 1 patient had ventricular tachycardia. All patients had been treated with three or more drugs and were considered to be drug refractory. The programmed antitachycardia mechanism used for patients with SVT were: automatic overdrive in five patients and burst scanning in two patients. In the patient with VT, a critically timed double extrastimulus with fixed coupling interval was programmed. Follow-up ranged from 2 to 30 months. The pacemaker proved to be effective in terminating tachycardias in all cases with SVT; in the patient with VT, the programmed antitachycardia mechanism was effective for a long time, but after an episode of sustained VT not interrupted by the pacemaker, the patient underwent automatic cardioverter/defibrillator (AICD) implantation. Additional antiarrhythmic therapy was required in 3 patients to control their maximum sinus rate, in 1 patient to reduce tachycardia episodes and to enable termination, and in 2 patients to prevent spontaneous atrial fibrillation. It is concluded that Orthocor II is a flexible and versatile antitachycardia pacemaker providing a safe and effective control of recurrent tachycardia in selected patients.     

Oral Loading with Propafenone: A Placebo-Controlled Study in Elderly and Nonelderly Patients with Recent Onset Atrial Fibrillation

The efficacy and safety of propafenone as an oral loading dose (600-mg single oral dose) in converting recent-onset atrial fibrillation (≤ 7 days duration) to sinus rhythm were evaluated in a single-blind, placebo-controlled study according to patients' age. Overall, 240 hospitalized patients, NYHA Class ≤ 2 without signs or symptoms of heart failure were enrolled: among patients aged ≤ 60 years, 55 were allocated to propafenone treatment and 59 to placebo, respectively, and among patients aged > 60 years, 64 were allocated to propafenone treatment and 62 to placebo, respectively. Results: In each age group, the likelihood of conversion to sinus rhythm was significantly greater after propafenone compared with plocebo at 3 and 8 hours. For patients aged ≤ 60 years, corresponding odd ratios were 3.78 (95% CI = 1.80–7.92, P = 0.04) at 3 hours and 4.74 (95% CI = 2.12–10.54, P = 0.02) at 8 hours; for patients aged > 60 years odd ratios were 5.03 (95% CI = 2.08–12.12, P = 0.02) at 3 hours and 6.75 (95% CI = 3.28–73.86, P = 0.01) at 8 hours, respectively. Logistic regression analysis showed that conversion to sinus rhythm within 3 hours was predicted by age ≤ 60 years (P = 0.0064) and by propafenone treatment (P < 0.0001), and conversion to sinus rhythm within 8 hours was predicted by age ≤ 60 years (P = 0.0467) and by propafenone treatment (P < 0.0001). The occurrence of adverse effects was observed in 14%-16% of propafenone treated patients and in 8% of placebo treated patients without significant differences according to age. In conclusion, in patients with recent-onset atrial fibrillation without signs of heart failure, propafenone as a single oral loading dose is effective. It is also effective in selected elderly subjects with a favorable safety profile. Moreover, spontaneous conversion to sinus rhythm appears to occur less frequently in elderly patients.     

Near‐infrared spectroscopy correlates with continuous superior vena cava oxygen saturation in pediatric cardiac surgery patients

Background: Cerebral regional oxygen saturation (rSO₂) measured with near‐infrared spectroscopy (NIRS) has a well‐proven clinical utility. A goal‐oriented treatment based on the rSO₂ resulted in a significant reduction in major morbidity and in a shortening of postoperative hospital stay in patients undergoing coronary revascularization. In this study, we have compared the values of superior vena cava saturation (ScvO₂) continuously measured with a Pediasat catheter and the corresponding NIRS rSO₂ values obtained during cardiac operations in pediatric patients. Methods: This was a prospective observational study enrolling fifteen pediatric patients (age: 6 days–7 years) undergoing cardiac operations. ScvO₂ data obtained with the Pediasat during the operation were compared with simultaneously recorded NIRS rSO₂ values. Results: One hundred and seventeen matched sets of data were obtained during the operation. ScvO₂ continuously measured with the Pediasat was significantly correlated with the corresponding NIRS rSO₂ values. However, there was a constant positive bias (ScvO₂ values were higher than NIRS rSO₂ values) of 5.6%, with a precision of 10.4%. Time‐related percentage changes of NIRS rSO₂ were significantly correlated with the corresponding ScvO₂ percentage changes. A decrease in ScvO₂ is predictive for a decrease in rSO₂ with a sensitivity of 73.7% and a specificity of 85.7%. Conclusions: The continuous measurement of ScvO₂ values obtained by the Pediasat may provide useful information about the metabolic conditions of the brain during cardiac operations in pediatric patients if considered as percentage changes. Absolute values of ScvO₂ tend to overestimate the correspondent rSO₂ values.     

“A Case of Autosomal Recessive Form of Cranio-Metaphyseal Dysplasia with Unusual Features and with Bone Fragility”

A case of cranio-metaphyseal dysplasia (CMD) with unusual radiographic Findings and multiple spontaneous fractures is presented. The parental consanguinity is in favour of an autosomal recessive form. The differential diagnosis of this case among the various genetic entities with metaphyseal flaring and/or cranial hyperostosis is discussed.     

The influence of adrenalectomy on monoamine oxidase and NADH cytochrome c reductase in the rat heart

The effect of adrenalectomy on the activities of monoamine oxidase (MAO), NADH cytochrome c reductase (NCR), succinate dehydrogenase, malate dehydrogenase, fumarase, NAD⁺ nucleosidase and acid phosphatase in homogenates of rat hearts was examined. Besides MAO only the NCR activity increased. However, both the total and the rotenone-insensitive NCR activities increased, with that of the rotenone-insensitive being about half of the total, which indicated that the effect of adrenalectomy was exerted on components of this enzyme localized on both the inner and outer membranes of the mitochondrion. The lack of effect on the other enzymes suggests that adrenalectomy has a relatively selective action on MAO and NCR, and does not work by a generalized increase in protein synthesis or by an effect on the FAD cofactor. The MAO increase was seen with a variety of substrates, and was due to a rise in Vmax without change in Km. The response to adrenalectomy in the summer differed from that seen in the winter. The possible reasons for these effects of adrenalectomy are discussed.