Improved synthesis and resolution of β-(3-pyridyl)-DL-α-alanine

β-Benzamido-α-(3-pyridyl)-DL-α-alanine hydrochloride was synthesized from 3-pyridinecarboxyaldehyde via the azlactone which was hydrolyzed to the acrylic acid before hydrogenation. The methyl ester was effectively resolved with subtilisin. The optical purity of the D-isomer was established, since the D-isomer was used in synthesis of antagonists of the luteinizing hormone releasing hormone.     

Comparison of Different Regimens of Prednisone Therapy in Frequently Relapsing Nephrotic Syndrome

Abstract. The long-term results of four different regimens of prednisone therapy were compared in 32 children with steroid sensitive, frequently relapsing idiopathic nephrotic syndrome with minimal glomerular lesions on renal biopsy. Prednisone was adminstered according to the following dosage schedules: 1) long-term daily, 2) standard intermittent, 3) standard alternate-day, and 4) short-term daily. Over a mean observation period of 7 years patients without steroid dependency received a cumulative dosage of prednisone of 10 mg/m²/day and those with steroid dependency received 19 mg/m²/day. Relapse free intervals were the longest with long-term daily prednisone therapy compared to the other three regimens. In frequently relapsing patients without steroid dependency the relapse free intervals were similar with either intermittent or alternate-day prednisone therapy (median 75 d); however, they were significantly shorter with short-term prednisone therapy (median 33 d). In frequently relapsing patients with steroid dependency the time of remission was generally shorter than in patients without steroid dependency (median 25d vs. 69d) with no benefit of any of the different forms of short-term treatment.     

Birth asphyxia and the intrapartum cardiotocograph

Summary. The intrapartum cardiotocographs (CTGs) of 38 severely asphyxiated, term infants, born during a 17-month period, and those of 120 healthy term infants acting as controls were independently reviewed by three investigators who were unaware of the clinical outcome. Interobserver agreement was good (Kappa statistic = 0.74, P<0.0001). The investigators found that cardiotocographic abnormalities were present in 33 of the asphyxiated infants (87%) and in 35 of the controls (29%) and predicted that the abnormalities were severe enough to lead to significant fetal metabolic acidosis at delivery in 23 asphyxiated infants (61%) and in 11 controls (9%). The differences between the two groups were highly significant (P<0.001). Using the traditional diagnostic criteria for fetal distress, the investigators found that fetal blood sampling was indicated in 58% of cases in the asphyxia group and in 20% of controls but was only performed in 16% of asphyxiated infants and in 8% of controls. Furthermore, the median response times of delivery suite staff for abnormal fetal heart rate patterns were similar whether the FHR changes, classified using Krcbs' CTG scoring system, were moderate or severe: 80 min and 90 min, respectively. These findings suggest that interpretation of the intrapartum CTG continues to pose major problems for practising obstetricians.     

Ewing's sarcoma of the phalangeal bone

A rare case of Ewing's sarcoma of the toe bone is described and compared with three reported cases of phalangeal Ewing's sarcoma. The lesion in two cases was initially treated as infection and the diagnosis was delayed for several months. Roentgenographic and aspiration cytology examinations in cases with clinically unresolving infection of the hands and feet may prevent delayed diagnosis. Radical surgery alone may be curative if no metastases are found preoperatively in careful clinical investigations.     

Autonomic Effects of Dipyridamole Stress Testing on Frequency Distribution of RR and QT Interval Variability

Transient myocardial ischemia and associated changes in the autonomic nervous system may influence heart rate and ventricular repolarization to variable degrees. This study evaluated the effect of dipyridamole (DIP) induced ischemia on the autonomic balance by spectral analysis of RR and QT intervals variability. Patients with coronary artery disease undergoing DIP stress echocardiography were studied. From high resolution ECG recordings, RR and QT interval measurements were performed by a dynamic template-matching algorithm. A time-variant analysis was used to estimate power in the LF (0.05–0,15 Hz) and in the HF (0.15–0.4 Hz) band of RR and QT interval spectra. Patients were grouped in ischemic and nonischemic subgroups based on the echocardiographic detection of wall-motion abnormalities. In patients without ischemia (n = 28), DIP caused a decrease in LF power and an increase in HF power of the RR and QT interval variability, indicating concordant changes of both intervals. In contrast, patients with inducible ischemia (n = 11) showed a decrease in HF power of the RR interval spectra and an increase of HF power of QT interval spectra. Furthermore, LF power was increased for RR but decreased for QT interval spectra. Our study suggests that DIP induced ischemia causes a loss of autonomic coupling between heart rate and ventricular repolarization for sympathetic and parasympathetic activities. This lability in ventricular repolarization may constitute an arrhythmogenic substrate during acute ischemia in patients with coronary artery disease.     

The Tall R Wave in Lead V1 in Posterior Myocardial Infarction: A Reciprocal Sign or a His-Purkinje Conduction Disturbance?

The significance of the tall R wave in lead V1 with an R/S ratio greater than or equal to 1 in posterior myocardial infarction (PMI) was investigated in 28 patients during programmed electrical stimulation. The patients had been admitted with acute PMI documented by electrocardiogram and proven by enzymatic increase. Electrophysiological study was performed 3 weeks after acute PMI. In 17 of the 28 patients (group 1), the tall R wave in V1 disappeared during stimulation: In 13 of them a premature atrial extrastimulus was responsible for an abrupt normalization of QRS complex in V1 related to an increase in AH or HV interval. In the 4 remaining patients the disappearance of the tall R wave in V1 was related to a sinus pause. In 14 patients of group 1, a different prematurity in atrial stimulation induced a right or left bundle branch block (BBB). In 11 of the 28 patients (group 2) the tall R wave in V1 was unchanged but a premature atrial extrastimulus induced a right BBB in 5 patients and a left BBB in 6. In conclusion, the normalization of QRS complex in lead V1 during atrial stimulation or alterations in cycle length suggests that the tall R wave in V1 in PMI is not a simple reciprocal sign of leads V8 V9. Its association with different varieties of BBB and changes in AH or HV intervals could suggest a relationship with a His-Purkinje conduction disturbance in some patients.     

P Wave and Far-Field R Wave Detection in Pacemaker Patient Atrial Electrograms

This study was undertaken to develop and test a morphology-based adaptive algorithm for real-time detection of P waves and far-field R waves (FFRWs) in pacemaker patient atrial electrograms. Cardiac event discrimination in right atrial electrograms has been a problem resulting in improper atrial sensing in implantable devices; potentially requiring clinical evaluation and device reprogramming. A morphologybased adaptive algorithm was first evaluated with electrograms recorded from 25 dual chamber pacemaker implant patients. A digital signal processing (DSP) system was designed to implement the algorithm and test real-time detection. In the second phase, the DSP implementation was evaluated in 13 patients, Atrial and ventricular electrograms were processed in real-time following algorithm training performed in the first few seconds for each patient. Electrograms were later manually annotated for comparative analysis. The sensitivity for FFRW detection in the atrial electrogram during off-line analysis was 92.5% (± 10.9)and the positive predictive value was 99.1% (± 1.8). Real-time P wave detection using a DSP system had a sensitivity of 98,9% (± 1.3) and a positive predictivity of 97.3% (± 3.5). FFRW detection had a sensitivity of 91.0% (± 12.4) and a positive predictivity of 97.1% (± 4.2) in atrial electrograms. DSP algorithm tested can accurately detect both P waves and FFRWs in right atrium real-time. Advanced signal processing techniques can be applied to arrhythmia detection and may eventually improve detection, reduce clinician interventions, and improve unipolar and bipolar lead sensing.     

Clinical Performance of the St. Jude Medical Riata Defibrillation Lead in a Large Patient Population

Clinical Performance of the St. Jude Medical Riata Defibrillation Lead in a Large Patient Population . Objective: The purpose of this large multicenter study was to evaluate the long‐term reliability of an implantable cardioverter defibrillator (ICD) lead to determine the incidence of adverse events (AEs). Background: A recent concern has been the performance of cardiac defibrillator leads. There have been conflicting reports regarding the rate of lead perforation and other AEs. Methods: Medical records from patients implanted from 6‐1‐2001 to 11‐27‐2007 with the St. Jude Medical Riata family of RV leads at 23 US (N = 12,969) and 5 German (N = 2,418) centers were reviewed for chronic lead‐related AEs. These included perforation, dislodgment, conductor fracture and insulation damage. The mean follow‐up period was 18.0 months. AEs were defined as those that required Riata lead revision, extraction, or replacement. Results: The incidence of lead AEs was <1% for each AE type. Perforation occurred in 0.38%, dislodgement in 0.93%, conductor fracture in 0.18%, and insulation damage in 0.21% of patients studied. Conclusions: During the follow‐up of the 15,387 patients with Riata leads, the incidence of AEs which included perforation, dislodgement, conductor fraction and insulation damage was low and within the range of what is considered clinically acceptable. (J Cardiovasc Electrophysiol, Vol. 21, pp. 551‐556, May 2010)     

Favorable Outcome Using an Abbreviated Procedure for Catheter Ablation of AVNRT: Results from a Prospective Randomized Trial

Introduction: Radiofrequency catheter ablation aiming slow pathway modulation is a widely established procedure with high success and low recurrence rates in patients with atrioventricular nodal reentry tachycardia (AVNRT). However, the necessity of a waiting period following successful slow pathway modulation to increase the long-term success rates has not been systematically evaluated thus far.
Methods and Results: This prospective study comprised 138 consecutive patients (mean age 50.3 ± 15.1 years) with AVNRT. These patients were randomly assigned to two groups: in group I (n = 70), a waiting period of 30 min was part of the procedure, whereas in group II (n = 68), the procedure ended without a waiting period. Electrophysiological standard parameters, i.e., ERP of RA, fast and slow pathway, RV as well as antegrade and retrograde AV node conduction capacity, were assessed prior to and after the ablation.
During a follow-up period of 22.8 ± 5.9 months, four patients in group I and three patients in group II developed recurrence of AVNRT (4.9%; P = 0.4). The mean procedure time was 115.1 ± 23.6 min in the group with and 88.9 ± 23.3 min in the group without waiting period (P = 0.009). No high degree AV-node conduction block was observed during the study.
Conclusion: In the present study we could show that no long-term benefit results from a 30 min waiting period for patients who underwent an acutely successful catheter ablation for AVNRT. We therefore conclude that a 30-min waiting period can be omitted in standard procedures, thus resulting in significant shorter procedure durations.