Search

Objective: The recommendations for complete lead extraction because of local complications at the site of implantable devices have changed in the last 10 years. We analyze the outcome of patients who required an intervention because of a local complication between 2002 and 2010, in our Hospital., Methods: We retrospectively studied 83 patients with a local complication that was classified according to skin integrity: 1. Integrity, and 2. Open skin. We analyzed the type of intervention: 1. Conservative approach, 2. Incomplete extraction, 3. Complete extraction. The endpoints were the needing a later intervention and a complete removal during follow up., Results: The group of patients with complete system extraction showed a lower rate of re-intervention during an average follow up of 1000 days, when compared to other two groups (6.7% vs. 57.7 and 43.8%, P<.01). Incomplete extraction and conservative approach had a similar outcome, needing a complete extraction 25% and 37.5%, respectively. The skin integrity did not seem to be relevant for outcome in these two groups. An 8.4% incidence of endocarditis was observed; all of them had a previous history of incomplete extraction or conservative approach., Conclusions: Local complications treated with either a conservative approach or incomplete extraction are associated with a high rate of re-interventions, regardless of skin integrity, frequently needing final complete extraction and are associated to endocarditis., (Copyright © 2013 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.)

Background: Few experimental studies have analyzed the effects of selective radiofrequency (RF) lesions upon ventricular fibrillation (VF). The RF-induced isolation of selected zones would make it possible to determine whether these zones are essential for existence of the arrhythmia., Methods: In 31 Langendorff-perfused rabbit hearts, the characteristics and inducibility of VF were analyzed before and after the induction of RF lesions comprising: (1) the posterior zone of the septum and of the walls of both ventricles (n = 10); (2) the anterior zone of the septum and of the walls of both ventricles (n = 11); and (3) the midseptal zone (n = 10)., Results: Complete isolation of the zone encompassed by the lesions was obtained in 5, 6, and 5 experiments of series 1, 2, and 3, respectively. In these experiments, the arrhythmia was only induced from within the zone encompassed by the lesions in one experiment belonging to series 2 (P < 0.05 with respect to baseline). In contrast, in all but one of the cases in series 2, VF could be induced from outside the isolated zone (ns vs baseline). Partial isolation was obtained in five experiments of each series. In these experiments, on pacing from within the partially isolated zone, sustained VF was not induced in any experiment (P < 0.05 with respect to baseline), while in all cases VF could be induced on pacing from the external zone (ns vs baseline)., Conclusion: In the experimental model used, the three zones studied were not essential for maintaining VF. In most cases, their partial or total isolation avoided inducibility of the arrhythmia in those zones, though not in the remaining myocardium.

Introduction and Objectives: The best therapeutic approach for persistent atrial fibrillation has yet to be defined. Our aim was to investigate the effects of cardioversion in unselected patients with persistent atrial fibrillation who were treated according to a strict protocol involving pretreatment, cardioversion, and follow-up., Methods: Consecutive patients with persistent atrial fibrillation of at least 1 months' duration were included prospectively in a cardioversion protocol that involved standard antiarrhythmic pretreatment, with amiodarone being offered first, and follow-up., Results: The study included 295 patients, 87.5% of whom were taking the antiarrhythmic drug amiodarone. Sinus rhythm was restored in 92.5%, with pharmacologic cardioversion occurring in 9.5%. The recurrence rate was 33.5% in the first month and 54.9% by month 12. Antiarrhythmic treatment had to be modified in 10.8% of patients. Independent risk factors for recurrence during the first year after cardioversion were an atrial fibrillation duration greater than one year, previous cardioversion, and left ventricular dilatation. A simple risk scoring system was able to differentiate between subgroups of patients with a low, intermediate or high risk of recurrence in the first year after cardioversion., Conclusions: Sinus rhythm was maintained for 1 year after effective cardioversion in 45.1% of patients who received homogeneous antiarrhythmic pretreatment. There were few side effects. Recurrence can be predicted using clinical variables such as left ventricular dilatation, arrhythmia duration, and previous cardioversion.

Introduction and Objectives: The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution., Methods: Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle., Results: Linear regression analysis showed that there was a good correlation between the dominant frequency obtained using the two signal analysis methods: frequency (spectral analysis) = 1.01 x frequency (time-frequency analysis) -- 0.4 (r=0.9; P< .0001; standard error of the estimate, 2.2 Hz). In all cases except one, the dominant frequency exhibited a significant temporal variation on a short timescale (time-frequency analysis); the coefficient of variation was between 0.19 (0.06) and 0.24 (0.07) (NS). In all cases, there were significant differences between regions. The location at which the frequency was highest varied according to the timepoint considered, though it was predominantly in the apical or anterior zone., Conclusions: In the absence of external modulating factors, the frequency of ventricular fibrillation exhibits temporal and spatial variations which can be observed at short timescales. In the free wall of the left ventricle, the dominant frequency is highest in the apical and anterior zones, and the maximum frequencies are most often found in these zones.

We report a case of a woman presenting a giant cementoossifying fibroma depending of the mandibular gingivae. The evolution of the process was 20 years. Cemento-ossifying fibroma is a relatively rare tumour classified between fibroosseous lesions. This lesion appears within the bone although in some occasions it involves the gingivae soft tissues, as the case we present. It is a slow-growing and well-defined tumorous lesion, because of this, it is considered as a benign lesion. The histologic findings alone may be similar to other pathologies such as osteoblastoma, low-grade osteosarcoma and particularly to fibrous dysplasia. An accurate diagnosis requires careful clinical, radiological and histological correlation in order to make an optimal treatment and an excellent outcome.

Because of its electrophysiological effects, hypothermia can influence the mechanisms that intervene in the sustaining of ventricular fibrillation. We hypothesized that a rapid and profound reduction of myocardial temperature impedes the maintenance of ventricular fibrillation, leading to termination of the arrhythmia. High-resolution epicardial mapping (series 1; n = 11) and transmural recordings of ventricular activation (series 2; n = 10) were used to analyze ventricular fibrillation modification during rapid myocardial cooling in Langendorff-perfused rabbit hearts. Myocardial cooling was produced by the injection of cold Tyrode into the left ventricle after induction of ventricular fibrillation. Temperature and ventricular fibrillation dominant frequency decay fit an exponential model to arrhythmia termination in all experiments, and both parameters were significantly correlated (r = 0.70, P < 0.0001). Termination of the arrhythmia occurred preferentially in the left ventricle and was associated with a reduction in conduction velocity (-60% in left ventricle and -54% in right ventricle; P < 0.0001) and with activation maps predominantly exhibiting a single wave front, with evidence of wave front extinction. We conclude that a rapid reduction of temperature to <20 degrees C terminates ventricular fibrillation after producing an important depression in myocardial conduction.