Reversible Contraception like Activity of Embelin in Male Dogs (Canis indicus Linn)

In order to evaluate the long term metabolic effect of embelin on the testes, adult male dogs were fed with embelin (80 mg/kg b.w. each other day) for 100 days. Loss in weights of testes and spermatogenic elements was noticed. The epididymides were devoid of spermatozoa but the functional morphology remain unaltered. 250 days of recovery period brings about normal spermiogenesis with all 1-8 cell stages. Epididymal milieu showed functional physiology. A three tiered finding accompanying histology, tissue biochemistry and blood/serum profile of dogs treated with embelin showed that 100 days therapy inhibits spermatogenesis, whereas 250 days recovery restores it. Sexual potency and libido of the animals did not change. A reversible male contraception with the help of a plant benzoquinone (embelin) is promising.     

EXPERIMENTAL STUDY OF EMESIS WITH ETHER AND HALOTHANE

An experimental study of the emetic property of ether was carriedout in dogs, cats and monkeys. Emesis could not be producedby giving ether by inhalation, or through the intragastric,intravenous or Intracerebroventricular routes. On vomiting inducedcentrally by apomorphine, both ether and halothane were foundto exert a protective action. As there was no significant differencebetween the protective actions of halothane and ether againstapomorphine-induced vomiting, no specific anti-emetic actioncould be ascribed to halothane. A psychically medicated responseto the unpleasantness of ether could probably be the only explanationof the high sickness rate after ether anaesthesia in human beings.     

Radiofrequency Catheter Ablation of Multiple Morphologies of Ventricular Tachycardia by Targeting a Single Region of the Left Ventricle

Radiofrequency Ablation of Multiple VTs. Introduction : As treatment options for ventricular tachycardia (VT) continue to evolve, the use of radiofrequency catheter ablation is rapidly expanding. However, in the presence of multiple morphologies of VT, achieving successful results may seem less likely. We report two patients with multiple morphologies of VT who underwent successful radiofrequency ablation by application of adiofrequency energy to a single region in the left ventricle.
Methods and Results : Two patients, each without any apparent cardiac dysfunction and a history of documented VT, were referred to our institution for further management. They underwent an electrophysiologic study and were found to have easily inducible VT, of three morphologies in one patient and two in the other. Using a transaortic approach, left ventricular mapping was performed for detecting a site with presystolic potentials, earliest ventricular activation, or both. Application of radiofrequency energy to a single area in the left ventricle resulted in the elimination of all previously inducible VT in each patient.
Conclusion : VTs with distinctly different morphologies can occur in patients with no detectable structural heart disease. These VT circuits may share a common pathway and, therefore, may readily be amenable to therapy with radiofrequency catheter ablation.     

Spontaneous Reinitiation of Atrial Fibrillation Following Transvenous Atrial Defibrillation

Spontaneous reinitiation of atrial fibrillation (AF) has not been systematically looked at in patients undergoing transvenous AF. This study involved 11 patients, the mean age 60 ± 8 years. 3 male and 8 female, in whom transvenous atrial defibrillation successfully converted AF to sinus rhythm. Eight patients had paroxysmal AF and three patients had chronic persistent AF for 4 weeks or more. Four patients were taking antiarrhythmic medications at the time of testing. Multipolar transvenous catheters were positioned inside the coronary sinus, right atrium, and the right ventricle. Atrial defibrillation testing was performed using the METRIX atrial defibrillation system in nine patients and the Ventritex HVSO2 in the remaining two patients. A total of 64 therapeutic shocks (range 3–11) were delivered in the 11 patients, and 31 of these successfully converted AF to sinus rhythm. In four patients spontaneous AF was reinitiated following 12 successful transvenous atrial defibrillation episodes. The mean time to reinitiation of AF following shock delivery and restoration of sinus rhythm was 8.26 ± 5.25 seconds, range 1.8–19.9 seconds. All 12 episodes of spontaneous AF were preceded by a spontaneous premature atrial complex. The coupling interval of the premature atrial complexes was 443 ± 43 ms, range 390–510 ms. None of the patients taking antiarrhythmic medications or those demonstrating no premature atrial complexes had spontaneous reinitiation of AF. In conclusion, spontaneous reinitiation of AF can occur in a significant proportion of patients with AE undergoing transvenous atrial defibrillation. This phenomenon is preceded by the occurrence of atrial premature complex. Findings of this study may have significant clinical implications.(PACE 1998; 21:1105–1110)     

Effects of Initial Polarity on Defibrillation Threshold with Biphasic Pulses

Background : Previous studies have shown that the polarity of epicardial patches significantly affects the defibrillation efficacy of monophasic shocks. Howevar, whether this improvement can he extended to different pulsing methods and lead systems, such as biphasic shocks using endocardial defibrillating electrodes, is unknown. Methods : Twenty consecutive patients undergoing testing and permanent implant using an Endotak lead system with a biphasic device were included in the study. In each patient the defibrillation threshold was determined delivering biphasic pulses with the distal coil as the cathode and the proximal coil as the anode during the positive phase and with the polarity reversed. The initial electrode polarity tested was chosen randomly. The defibrillation threshold was defined as the lowest pulse amplitude that effectively terminated ventricular fibrillation induced with 60-H z alternating current. For each biphasic pulse peak voltage, pulse duration, resistance, and stored energy were recorded. Results : Of the 20 patients, 12 (60%) had lower defibrillation threshold when the proximal coil was negative, whereas only 2 patients had a lower defibrillation threshold when the distal coil was negative. In four patients a subcutaneous patch would have been required if only the biphasic pulse with the distal coil as negative had been tested. The mean stored defibrillation threshold energy was lower with the configuration using the proximal coil as cathode (16.3 ±8.8 J vs 21.5 ±11 J; P < 0.01). Conclusion : Change in the initial polarity of biphasic shocks may influence defibrillation efficacy and should, therefore, be assessed in each patient to achieve a more satisfactory safety margin and minimize the use of more invasive lead configurations.     

Electroanatomic Mapping to Identify Breakthrough Sites in Recurrent Typical Human Flutter

SRA, J., et al. : Electroanatomic Mapping to Identify Breakthrough Sites in Recurrent Typical Human Flutter. The accuracy of conventional techniques in localizing previous radiofrequency (RF) ablation sites and thus breakthrough sites of recurrent atrial flutter is somewhat limited. We investigated the role of electroanatomic mapping for identifying breakthrough sites or "gaps" at the tricuspid annulus and inferior vena cava (IVC)/eustachian ridge isthmus to help RF ablation in patients with recurrent typical flutter. Twelve patients (  8 men, 4 women, age 63 ± 10 years  ) with recurrent typical atrial flutter were included in the study. An electroanatomic mapping system (CARTO) was used to create a voltage map and activation and propagation patterns in the right atrium. Detailed voltage, activation, and propagation mapping of the tricuspid annulus and IVC/eustachian ridge isthmus allowed precise identification of gaps in all 12 patients at the tricuspid annulus (eight sites), IVC ridges (two sites), mid-isthmus region (one site), and tricuspid annulus and IVC ridges (one site). Radiofrequency energy directed at these sites eliminated atrial flutter in all 12 patients, confirmed by noninducibility of atrial flutter and demonstration of conduction block during atrial pacing on either side of the lesion lines. During a mean follow-up of  14.8 ± 3.5 months  (  range 8–19 months  ), paroxysmal atrial flutter recurred in only one patient and was subsequently treated with amiodarone, although this had been ineffective prior to ablation. Electroanatomic mapping can precisely identify gaps in the lesion line responsible for breakthrough of recurrent typical atrial flutter at the tricuspid annulus and at the IVC/eustachian ridge isthmus. These sites can be targeted with RF ablation with a high degree of success.