Transthoracic DC Shock May Represent a Serious Hazard in Pacemaker Dependent Patients

External defibrillation is widely used for the termination of various atrial and ventricular tachyarrhythmias, including pacemaker patients. Our study was intended to evaluate the effects of DC shocks in 36 patients with unipolar pacemakers implanted in the right pectoral region (25 DDD, 10 VVI, 3 AAI). The shocks were delivered with paddles on the anterior surface of the thorax, as far as possible away from the pacemaker. The pacing output was programmed at 0.5 msec and 5 V (25 patients), 4 V (1 patient), and 2.5 V (10 patients). Transient loss of capture occurred in 18 patients (50%). These patients, compared with those without capture failure, received higher peak and cumulative shock energies, respectively, 216 ± 99 versus 123 ± 50 joules (P < 0.002) and 352 ± 62 versus 147 ± 98 joules (P < 0.004) and had a lower pacemaker pulse amplitude (4.0 ± 1.2 vs 4.6 ± 1.0 V, P = 0.11). Failure to capture lasted from 5 seconds to 30 minutes (mean 157 sec). In 15 patients the ventricular stimulation threshold was measured before and serially after cardioversion. A six-fold threshold increase was observed 3 minutes after the shock (P < 0.004) with gradual recovery to nearly baseline values at 24 hours. Transient sensing failure occurred in 7 of the 17 patients in whom it could be evaluated (41%). Furthermore, three cases of shock induced pacemaker malfunctions were observed requiring replacement of the stimulator in two patients. In conclusion, the incidence of loss of capture in pacemaker patients subjected to electrical cardioversion/defibrillation is high. The phenomenon is due to an abrupt rise in stimulation threshold, caused by the electrical shock, and may represent a serious hazard in pacemaker dependent patients. The risk of pacing failure could be reduced by utilizing low shock energies when possible, and by programming the pacemaker at its maximal output before cardioversion.     

Physiological time structure of the tibialis anterior motor activity during sleep in mice,rats and humans

The validation of rodent models for restless legs syndrome (Willis–Ekbom disease) and periodic limb movements during sleep requires knowledge of physiological limb motor activity during sleep in rodents. This study aimed to determine the physiological time structure of tibialis anterior activity during sleep in mice and rats, and compare it with that of healthy humans. Wild‐type mice (n = 9) and rats (n = 8) were instrumented with electrodes for recording the electroencephalogram and electromyogram of neck muscles and both tibialis anterior muscles. Healthy human subjects (31 ± 1 years, n = 21) underwent overnight polysomnography. An algorithm for automatic scoring of tibialis anterior electromyogram events of mice and rats during non‐rapid eye movement sleep was developed and validated. Visual scoring assisted by this algorithm had inter‐rater sensitivity of 92–95% and false‐positive rates of 13–19% in mice and rats. The distribution of the time intervals between consecutive tibialis anterior electromyogram events during non‐rapid eye movement sleep had a single peak extending up to 10 s in mice, rats and human subjects. The tibialis anterior electromyogram events separated by intervals <10 s mainly occurred in series of two‐three events, their occurrence rate in humans being lower than in mice and similar to that in rats. In conclusion, this study proposes reliable rules for scoring tibialis anterior electromyogram events during non‐rapid eye movement sleep in mice and rats, demonstrating that their physiological time structure is similar to that of healthy young human subjects. These results strengthen the basis for translational rodent models of periodic limb movements during sleep and restless legs syndrome/Willis–Ekbom disease.     

T lymphocyte function in patients with malignant biliary obstruction

Abstract The T lymphocyte function in 59 patients with malignant biliary obstruction undergoing pre-operative endoscopic drainage (group Ia, n = 24) or surgery (group Ib, n = 35) was evaluated by mitogen stimulation test with phytohaemagglutinin. The T lymphocyte function before endoscopic or surgical intervention was found to be impaired as compared with patients with gastric cancer (group II, n = 27) and with normal persons (group III, n = 19). Regression analysis showed a significant negative correlation between T lymphocyte function and the serum bilirubin level (correlation coefficient - 0.3, P = 0.01) and a positive correlation with serum albumin level (correlation coefficient 0.34, P = 0.01) and serum transferrin level (correlation coefficient 0.45, P = 0.001). After 18 ± 3 days of endoscopic biliary drainage, the T lymphocyte function of group Ia patients did not change substantially. At postoperative day 14, there were more patients in both groups Ia and Ib having deterioration of T lymphocyte function than those with improvement. The incidence of postoperative sepsis was found to be significantly higher in patients with deterioration than those with improvement of T lymphocyte function (18/31 vs 7/26, P = 0.036). It is concluded that endoscopic biliary drainage and surgery could not reverse the T lymphocyte dysfunction in patients with malignant biliary obstruction.     

Cryoablation versus Radiofrequency Ablation for Atrioventricular Nodal Reentrant Tachycardia: Patient Pain Perception and Operator Stress

Background: Cryoablation (CRYO) is an alternative to radiofrequency (RF) ablation in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT). This study aims to evaluate the differences in patient pain perception and operator stress between CRYO and RF ablation in the treatment of AVNRT. Methods: Patients with supraventricular tachycardia underwent electrophysiology study. Twenty patients (eight males, age 46.5 ± 12.5 years) diagnosed with AVNRT were randomized to receive CRYO (11) with a 6‐mm‐tip catheter or RF (nine) with a 4‐mm‐tip catheter. Patients’ pain perception and operator stress were assessed with a visual analogue scale (VAS) from 0 to 10 at the end of procedure. Results: There was no significant difference in acute procedural success (CRYO 100% vs RF 89%, P = 0.257). There was no complication of permanent atrioventricular block in either group. The number of energy applications was significantly higher in the CRYO group (2.8 ± 1.2 vs 1.6 ± 0.9, P = 0.02). The fluoroscopic time was significantly reduced in the CRYO group (6.0 ± 4.9 vs 10.9 ± 5.4 minutes, P = 0.049) with no difference in procedure time (CRYO 49.3 ± 12.5 vs RF 54.5 ± 17.0 minutes, P = 0.462). Patients in the CRYO group experienced significantly less pain than patients in the RF group (VAS 2.3 ± 2.8 vs 5.4 ± 3.4, P = 0.024). The operator also experienced significantly less stress during CRYO than RF (VAS 1.9 ± 0.8 vs 6.2 ± 1.6, P < 0.001). There was no recurrence in both groups at 6‐month follow‐up. Conclusions: CRYO, as compared with RF, produces less pain in patients and less stress in operator in the treatment of AVNRT. (PACE 2011; 2–7)     

The psychopathological characteristics of treatment discontinuation group in 6‐month treatment with paliperidone ER

Objective: To examine the demographic and psychopathological characteristics of the treatment discontinuation group compared with patients who completed with paliperidone ER treatment for 6 months. Methods: A total of 984 patients meeting the DSM‐IV criteria for schizophrenia who switched their antipsychotics were recruited from 61 sites in five countries in Southeast Asia. The patients with early discontinuation were then compared with those who completed the 6‐month treatment in terms of demographic and psychopathological variables at baseline and also at the end of the evaluation period, which included PANSS score, sleep quality, daytime drowsiness, PSP score, ESRS score and clinical global impression‐severity (CGI‐S) score. Finally, logistic regression analysis was applied to determine predictive factors that were associated with discontinuation. Results: Of 984 patients, 284 patients (28.9%) discontinued without completing the 6‐month treatment period with paliperidone. Significant differences in patient baseline characteristics for the discontinuation group compared with the completion group were observed for gender, number of previous hospitalisations with psychosis, PANSS total score and all of its subscales, daytime drowsiness score, total ESRS score, CGI‐S, PSP and Insight. Patients who completed the study period had significantly better scores in all psychopathology variables compared with the discontinuation group at the end of the evaluation period. Numbers of previous hospitalisations because of psychosis, being exposed with first generation antipsychotics, gender and PANSS total scores were found to be significant predictors of discontinuation. Conclusion: Patients who discontinued early from a 6‐month treatment period with Paliperidone have some characteristic differences compared with completion patients. Many factors including frequent hospitalisations, female gender, high PANSS score (indicating more disease severity) and previous exposure to first generation of antipsychotic agent might lead patients to discontinue from treatment.     

Incompetent Great Saphenous Veins Treated with Endovenous 1,320-nm Laser: Results for 71 Legs and Morphologic Evolvement Study

BACKGROUND: Endovenous lasers with various wavelengths have been utilized with good outcomes in treating leg varicose veins. The natural history and evolution of treated veins after endovenous procedures, however, have seldom been addressed. OBJECTIVE: This study determines the efficacy vein ablation and serial venous morphologic evolution of incompetent great saphenous veins (GSVs) after endovenous 1,320-nm laser treatment. METHODS: Fifty patients with symptomatic varicose veins secondary to GSV insufficiency treated with 1,320-nm endovenous laser ablation were enrolled. The treated varicose veins in each limb were mapped and sized before laser treatment. Vein wall diameters were measured with duplex ultrasound at follow-up visits. RESULTS: Seventy-one limbs in 50 patients were enrolled. During the mean 13.1-month follow-up, closure of GSVs was observed in 94% of limbs (67/71). Vein diameters at 3 cm below saphenofemoral junction level were reduced to 81% at 2 days, 75% at 1 month, 48% at 3 months, and 39% at 5 months. Average mean duration for treated GSVs to narrow as fibrotic cords (internal diameter,<2.5 mm) was 5.8 months. CONCLUSION: The endovenous 1,320-nm laser ablation procedures have excellent efficacy in treating incompetent GSVs. This excellent shrinkage behavior may be the basis for nice long-term results of patients treated with 1,320-nm Cooltouch endovenous laser.