Preexcitation in Hypertrophic Cardiomyopathy: A Case of a Fasciculoventricular Mahaim Fiber

STELLBRINK, C., et al .: Preexcitation in Hypertrophic Cardiomyopathy: A Case of a Fasciculoventricular Mahaim Fiber . A patient with hypertrophic cardiomyopathy (HCM) who presented with preexcitation pattern on the surface ECG suggestive of the Wolff-Parkinson-White (WPW) syndrome is described. Intracardiac electrophysiological study revealed a fixed anomalous QRS complex and a short fixed His-ventricular interval indicating a fasciculoventricular Mahaim fiber. As this specific form of accessory connection does not cause reentrant tachycardias, no treatment was required. It is important to distinguish this entity from atriofascicular or nodoventricular Mahaim fibers or the WPW syndrome in patients with HCM showing a preexcitation pattern in the surface ECG, as these may cause life-threatening arrhythmias in this patient population.     

Liposomal 1,25 (OH)2 vitamin D3 compounds block proliferation and induce differentiation in myelomonocytic leukaemia cells

The vitamin D₃ derived hormone 1,25 (OH)₂ vitamin D₃ (1,25 D₃) is able to induce growth arrest and differentiation in myelomonocytic leukaemia cells. In order to allow for specific delivery to leukaemic cells the lipophilic compound was incorporated into the lipid membranes of liposomes. Liposomal 1,25 D₃ reduced proliferation as measured by ³H-thymidine incorporation in HL60 leukaemia cells by up to 60%. When liposomes were prepared at different concentrations of 1,25 D₃ 65% inhibition was achieved at 48 n M . The MC 1288 stereoisomer of 1,25 D₃ was more potent and had the same activity at 48 n M .
The effect of the liposomal compounds was specific to myeloid cells as they reduced proliferation in myelomonocytic HL60, monoblastic U937 and monocytic Mono Mac 6 cells but not in the T-cell lines Jurkat and Molt 4.
The antiproliferative effect of liposomal 1,25 D₃ was associated with an induction of differentiation since treated HL60 cells showed a monocytic morphology, increased expression of CD14 and decreased expression of CD33.
When peripheral blood leukaemic cells from M4 and M5 acute myeloid leukaemia (AML) patients were admixed with liposomal compounds an antiproliferative effect was seen in all five cases, including the two cases where free compounds led to enhanced growth. Liposomal delivery of 1,25 (OH)₂ vitamin D₃ may offer a novel approach to treatment of myelomonocytic leukaemia.     

Recanalization of Chronically Occluded Coronary Arteries: Single-Center Experience in 400 Cases, Including Long-Term Angiographic Follow-Up

The study presented comprises the initial and angiographic long-term results of a consecutive series of recanaliza-tion procedures in a single center. Between 1988 and 1992, a total of 400 patients underwent transluminal recanalization for total coronary occlusions. In 82% of successfully attempted patients, the occlusion could be passed by a standard guidewire. The overall initial success rate was 75% (298 of 400). The highest success rates could be achieved in the left circumflex artery (84%) and left anterior descending coronary artery (77%). Complications were uncomplicated myocardial infarction in ten patients (2.5%) and death in two patients (0.5%). Angiographic follow-up 3–6 months after recanalization could be achieved in 263 (88%) of 298 patients. Significant restenosis (≥ 50% minimum lumen diameter) was found in 57 (22%) of 263, and reocclusion was present in 38 (14%) of 263 patients, resulting in a total recurrence rate of 36%. In conclusion, recanalization can be performed with an initial success rate of 75% using bare-wire technique under the prerequisite operator experience. If a nearly complete angiographic follow-up is performed, the overall recurrence rate is 36%, which seems to be very acceptable in comparison with PTC A results for incomplete obstructions published so far . (J Interven Cardiol 1996;9:73–79)     

Transcoronary Venous Radiofrequency Catheter Ablation of Ventricular Tachycardia

Coronary Venous Ablation of VT. Ventricular tachycardias in coronary artery disease arise mostly from endocardial sites. However, little is known about the site of origin in other diseases. We present the case of an incessant, adenosine-sensitive ventricular tachycardia arising from the lateral wall of the left ventricle in a patient with mildly reduced left ventricular function. Intracardiac mapping suggested an epicardial origin, and the tachycardia was successfully ablated from a coronary sinus branch. After ablation, left ventricular function returned to normal. Transcoronary venous radiofrequency catheter ablation is a new approach for the treatment of ventricular tachycardia. Its value in the management of other types of ventricular tachycardia has yet to he determined.     

Vecuronium titration for muscle relaxation in myotonic dystrophy

A 14-year-old boy with pronounced myotonic dystrophy and cardiac malformation had a normal ED₉₅ (53 μg·kg^?1) of vecuronium, whereas the recovery index (25-75% twitch recovery) was three times as long as in the absence of neuromuscular disease. We conclude that in young patients with dystrophic muscle disease individual titration of the muscle relaxant with the aid of a nerve stimulator does not preclude a considerable delay in the recovery of neuromuscular transmission.     

The impact of performance uncertainty on the postimperative negative variation

In a delayed matching-to-sample task, the impact of clear or ambiguous go versus clear no-go signals on the post-imperative negative variation (PINV) was examined in 11 patients with a chronic schizophrenic disorder (DSM-III-R) and in a control group of 13 healthy subjects matched to the patient sample by age, sex, and education. Size and spatial position of a visual S2 had to be matched to one of two visual patterns in the S1 presented 4 s earlier. In 96 trials, the S2 was identical in size with one of the two patterns of S1 (clear matching). These trials varied pseudorandomly, with 60 trials in which the S2 was of intermediate size. On a randomly interspersed additional 48 trials, an S2 differing in color and shape signaled no-go. The electroencephalogram was recorded from Fz, Cz, Pz, F3, F4, C3, C4, P3, and P4. Although groups did not differ in contingent negative variation amplitude the PINV was generally more pronounced in patients than in controls. In both groups, ambiguity of the to-be-matched S2 produced larger PINV amplitudes; the no-go signal elicited only a small PINV. Differential effects of ambiguity and no-go on PINV amplitude and its scalp distribution suggest that “performance” and “action” uncertainty contribute to PINV generation and that thresholds for both effects are reduced in schizophrenics.