A Decrease in Pulmonary Vein Diameter After Radiofrequency Ablation Predicts the Development of Severe Stenosis

A decrease in ostial pulmonary vein (PV) diameter was observed in patients on the day after radiofrequency ablation of atrial fibrillation (AF). This study examined whether a relative reduction in PV diameter on day 1 (RRPVD1) after the procedure predicts the late development of severe PV stenosis (PVS). The study included 104 consecutive patients (mean age = 55 years, range 46–61, 34 women) with drug refractory AF. Pulmonary vein diameter was measured using MR angiography (MRA) on the day before and on day 1 after the ablation procedure. The MRA was repeated every 3 months after the procedure. Severe PVS was defined as a >70% diameter reduction from the initial ostial diameter. The cut-off of RRPVD1 was prespecified as 25% decrease in initial diameter. The data are presented as medians and interquartile range. A total of 357 PV were treated. The RRPVD1 was 0.0% (0.0–11.1%). Severe PVS was found in 18 PV during a follow-up of 12 months (range 6–13). The log-rank analysis confirmed a strong association between a RRPVD1 ≥25% and the development of PVS (hazard ratio: 7.1; 95% confidence interval 3.8–13.5, P < 0.0001). By multivariate Cox regression model, after adjustment of procedure variables, RRPVD1 was the strongest predictor of development of severe PVS. RRPVD1 ≥25% was a strong independent predictor of development of severe PVS.     

Acute Efficacy and Chronic Follow-Up of Patients with Non-Thoracotomy Third Generation Implantahle Defibrillators

Non-thoracotomy implantation of implantable cardioverter defibrillators (ICDs) has simplified the process of device inserfion, promising to decrease associated procedural coniplications while providing sudden death protection at least equal to epicardial systems. This study presents the acute and chronic results of 110 patients who underwent attempted non-thoracotomy ICD impiuntation wiih the Medtronic Transvene lead system and PCD model 7217 or 7219. Of the 110 patients attempted, 100 (91%) had the system successfully implanted without the need for an epicar-dial patch. One patient died 1 week postoperatively of septic shock related to the implantation (0.9% perioperative mortality). During folloiv-up of 16 ± 11 months, 45% of the patients had an event detected as ventricular tachycardia; 26% of these detections were felt clinically to be due to supraventricular rhythms. Of the remainder, 87% were successfully treated with the first VT therapy, and 98% were terminated by the final therapy; 66% of the patients had at least one episode of ventricular fibrillation, of which 5% were felt to be inappropriate detections; 65% of the appropriate episodes were successfully treated with the first VF therapy, and all were converted by the final therapy. Total mortality at 6, 12, and 24 months was 3%, 11%, and 19% respectively. Only one patient had sudden cardiac death, occurring at 13 months postimplant. Overall, the non-thoracotomy lead system for this ICD displayed infrequent implant complications and proved to be reliable ai terminating arrhythmias and maintaining a low rate of sudden cardiac death in this high risk popuiation.     

The Feasibility of Fully Automated Pacemaker Advise in Treating Atrial Tachyarrhythmias

Background: Modern pacemakers continuously store significant cardiac‐related events. Interpreting these data and reprogramming the pacemaker can be time‐consuming and demands expert knowledge. A software‐based expert system, the therapy advisor (TA), was developed, which analyzes stored data and provides reprogramming recommendations. This study addresses whether pacemaker experts consider the messages that are automatically generated appropriate in the management of atrial tachyarrhythmias/atrial fibrillation (AT/AF). Methods: This observational, international, multicenter study follows 150 patients with suspected or documented atrial arrhythmias who received a dual‐chamber pacemaker (model Vitatron T‐70, Medtronic Inc., Minneapolis, MN, USA) incorporating the TA. The TA summarizes technical and clinical data stored in the pacemaker into key messages and may suggest programming changes. Twenty‐five cardiologists examined their patients per normal practice during two follow‐up visits. They reported the therapy changes they deemed necessary without initially reviewing the TA messages. Next, they rated their satisfaction with and the clinical relevance of the TA messages and recorded the final therapy changes. Results: The TA generated (mostly AT/AF‐related) main observations in 49% and programming advice in 33% of the patients. The experts rated 95% of the TA messages as satisfactory and deemed therapy changes necessary in roughly half the patients. Pacemaker changes in AT/AF therapy or general settings were prompted primarily by the diagnostic information stored in the device. Medication changes were mostly led by the symptoms reported by the patient. Conclusion: This study demonstrates that experienced cardiologists agree with 95% of the observations and programming suggestions that the TA automatically generates. (PACE 2010; 605–614)     

Developmental Toxicity of Inhaled Methyl Ethyl Ketone in Swiss Mice

Developmental Toxicity of Inhaled Methyl Ethyl Ketone in SwissMice. Schwetz, B. A., Mast, T. J., Weigel, R. J., Dill, J. A.,and Morrissey, R. E. (1991). Fundam. Appl. Toxicol. 16, 742–748.Methyl ethyl ketone (MEK) is a widely used industrial solventto which there is considerable human exposure. To assess thepotential for MEK to cause developmental toxicity in rodents,groups of Swiss (CD-1) mice were exposed to 0, 400, 1000, or3000 ppm MEK vapors 7 hr/day on Days 6–15 of gestation.Groups consisted of about 30 bred females each. Exposure ofpregnant mice to these concentrations of MEK did not resultin overt maternal toxicity although there was a slight, treatment-relatedincrease in relative liver weight which was statistically significantin the 3000 ppm group. Mild developmental toxicity was observedin the 3000 ppm group in the form of a reduction in mean fetalbody weight. This reduction was statistically significant forthe males only, although the relative decrease from the controlvalues was the same for both sexes. There was no increase inthe incidence of resorptions or the number of litters with resorptionsamong mice exposed to MEK. There was no significant increasein the incidence of any single malformation, but several malformationswhich were not observed in the concurrent control group or thecontrols of contemporary studies were present at a low incidence—cleftpalate, fused ribs, missing vertebrae, and syndactyly. Therewas also a significant trend for increased incidence of misalignedsternebrae, a developmental variation. In summary, pregnantSwiss (CD-1) mice were relatively insensitive to the toxic effectsof MEK at the inhaled concentrations used in this study. However,the offspring of the mice exhibited significant signs of developmentaltoxicity at the 3000 ppm exposure level. Neither maternal nordevelopmental toxicity was observed at 1000 ppm MEK or below.     

Verification of Linear Lesions Using a Noncontact Multielectrode Array Catheter versus Conventional Contact Mapping Techniques

INTRODUCTION: Creation of linear lesions is an established ablation goal. Verification of complete conduction block at the ablation line is required to determine ablation success. Conventional mapping techniques are sequential endocardial activation mapping and documentation of double potentials. Recently, a noncontact multielectrode array catheter was developed that allows instantaneous three-dimensional mapping by simultaneous reconstruction of > 3,000 electrograms. In this study, we prospectively compared the accuracy of noncontact mapping to identify discontinuities in linear lesions and to verify a conduction block with that of conventional mapping techniques. METHODS AND RESULTS: In 12 patients with atrial flutter, radiofrequency pulses were applied between the tricuspid annulus and either the inferior vena cava or the eustachian ridge. Following each application, pulse propagation at the ablation line was determined during pacing by conventional mapping techniques. The findings were compared to high-density isopotential mapping using the noncontact multielectrode array catheter. It was found that noncontact mapping reliably distinguished conduction delays from a conduction block as defined by contact mapping. In addition, noncontact mapping instantaneously identified the area where a discontinuity in the line of block was present. In these patients, complete conduction block was achieved by radiofrequency pulses guided by the noncontact mapping system. CONCLUSION: Noncontact mapping is highly accurate in distinguishing conduction delays from a complete conduction block. By providing an instantaneous high-density propagation vector at all sites along the ablation line, three-dimensional isopotential mapping is helpful in localizing discontinuities of linear lesions and, thus, may facilitate the creation of a complete conduction block.     

Adrenal carcinoma with intravenous extension into the tricuspid valvular plane in a patient with patent foramen ovale

We report on an adrenal carcinoma growing via the inferior venacava into the right atrium and prolapsing into the right ventricle.A patent foramen ovale determined the pathophysiological andclinical appearance. Instead of an expected caval congestionthe main features were paroxysmal dyspnoea and cyanosis. The patient was investigated using echocardiography, magneticresonance tomography and angiography.     

A study of lung-specific, cell-mediated immunity in chronic pulmonary diseases

Lung-specific, cellular hypersensitivity was studied in patients with chronic pulmonary diseases. To do this, a leucocyte migration inhibition assay was performed using patient and control leucocytes incubated in the presence and absence of a soluble lung extract. Control antigens consisted of liver and kidney extracts. The immunological reactivity of these control antigens was tested by measuring migration, subsequent to incubation of leucocytes from patients with hepatic or renal disease with the liver and kidney extracts, respectively. As a second in vitro test of cell-mediated immunity, a lymphocyte cytotoxicity assay was performed, using as target cells normal chromium-labelled human lung cells. Leucocyte migration inhibition was produced by the lung extract in four out of six patients with chronic bronchitis, five out of seven patients with tuberculosis, one out of five patients with sarcoidosis and in the single patient studied with rheumatoid lung disease. Inhibition did not occur with the leucocytes from control subjects. Neither was migration inhibited when leucocytes from the patients with lung disease were incubated with the control antigens. The reactivity of these control antigens was confirmed by the fact that leucocyte inhibition occurred in two out of three patients with hepatic disease, studied using the liver extract, and in two out of three patients with renal disease, studied with the kidney extract. The cytotoxic potential of anti-lung lymphocytes was demonstrated by the fact that significant target cell cytotoxicity occurred using lymphocytes from two out of four patients with chronic bronchitis, four out of five patients with tuberculosis and in two out of four patients with sarcoidosis.     

Comparison of Cryoballoon and Radiofrequency Ablation of Pulmonary Veins in 40 Patients with Paroxysmal Atrial Fibrillation: A Case‐Control Study

Introduction: Ablation of pulmonary veins (PV) is an established therapeutic option for patients with symptomatic drug‐refractory paroxysmal atrial fibrillation (AF). Radiofrequency (RF) is currently the most widespread energy source for PV ablation. Cryothermal energy applied with a cryoballoon technique as an alternative has recently evolved. Methods and Results: In a case‐control setting, we compared 20 patients with paroxysmal AF who underwent their first PV ablation with the cryoballoon technique to 20 matched patients with conventional RF ablation. In the case of persistent electrical potentials after cryoballoon ablation, it was combined with ablation with a conventional cryocatheter. All patients performed daily event recording for 3 months after ablation procedure. Ablation parameters and success rate after 3 and 6 months were compared. In the cryoballoon group, the overall success rate was 55% (50% in the cryoballoon only group [14 patients] and 66% in the combination group [6 patients]), as opposed to the RF group with 45%. AF episode burden was lower after cryoballoon ablation. There was no significant difference between cryoballoon and RF ablation regarding procedure parameters. In the cryoballoon group, 3 phrenic nerve palsies occurred using the 23 mm balloon that resolved spontaneously. Conclusion: PV ablation with the cryoballoon technique is feasible and seems to have a similar success rate in comparison to RF ablation. Procedure‐ and fluoroscopy duration are not longer than in conventional RF ablation.