Spatial Resolution and Role of Pacemapping During Ablation of Accessory Pathways

The objectives of this study were: (1) to evaluate quantitatively the spatial resolution of pacemapping: and (2) to assess the predictive value and role of pacemapping for the catheter ablation of overt APs. Sixty-three unipolar leads were used instead of the standard 12-lead ECG to acquire more information and assess the intrinsic accuracy of pacemapping. Spatial resolution was evaluated in 19 patients for whom data were recorded during bipolar ventricular pacing near the AV ring using the three electrode pairs of a quadripolar ablation catheter with a 5mm interelectrode spacing. The predictive value was assessed in 27 patients with overt APs who underwent HF ablation: their data were recorded during pacing at the site of successful ablation and at one or two sites where HF energy delivery was ineffective. Data from different beats were compared visually by using body surface potential maps and quantitatively by computing average correlation coefficients (r). Heproducibility was high for paced beats (r = 0.98 ± 0.02). Displacements of 5 mm of the pacing site could be detected with a sensitivity of 90% and a specificity of 87%. Correlation between pacing at successful ablation sites and preexcited sinus rhythm was low (r = 0.79 ± 0.11) and the ablation outcome could be predicted with a negative prediction accuracy of 87% and a positive prediction accuracy of 49%. Despite an excellent spatial resolution, pacemapping is of limited value for the identification of successful AP ablation sites, probably because APs can be interrupted at some distance from their ventricular insertion point.     

Lack of evidence of human herpesvirus 8 DNA sequences in HIV-negative patients with various lymphoproliferative disorders of the skin

Human herpesvirus 8 (HHV-8) is a new virus which has been reported in Kaposi's sarcoma and some lymphoproliferative disorders such as Castleman's disease and body-cavity-based lymphoma. Because HHV-8 shares homology with Epstein-Barr virus (EBV), we searched for the presence of HHV-8 DNA sequences in various cutaneous T-and B-cell lymphoma by the polymerase chain reaction (PCR). Fortyseven HIV-negative patients with cutaneous lymphoma or large plaque parapsoriasis were enrolled in the study. For the detection of HHV-8 DNA sequences we used PCR followed by a hybridization with a digoxigenin-labelled probe and nested-PCR. HHV-8 DNA sequences could only be detected in a patient with large plaque parapsoriasis. Our study does not suggest any direct implication of HHV-8 in the pathogenesis of most cutaneous lymphoma. Serological studies will be helpful to appreciate if there is an epidemiological link between HHV-8 and cutaneous lymphomas.     

Usefulness of Transesophageal Echocardiography in the Isolation of Pulmonary Veins in the Treatment of Atrial Fibrillation

Background: New imaging strategies for atrial fibrillation (AF) ablation should enhance the safety of this technique. The role of transesophageal echocardiography (TEE) in this setting has not been prospectively evaluated.
Methods: Under general anesthesia, 85 patients underwent TEE-guided AF ablation. A hybrid technique was performed with circular pulmonary veins (PV) lesions and antrum and ostial electrical isolation guided by TEE. TEE excluded left atrial (LA) thrombus, guided transseptal puncture and catheter positioning, and helped to identify PV ostia and their velocities. The TEE probe localized the esophagus, its temperature (T°) and micro bubbles formation.
Results: Overall, one patient had a LA clot. The esophagus was located close to left PV in 38%, the right PV in 28%, midline in 17% and with an oblique course in 17% of patients. Right and left superior PV velocities were detected in 100%, left inferior PV in 88% and right inferior PV in 82% of patients. Microbubbles were detected in 9 patients (11%). Elevation of TEE T° occurred in 14 patients (16%) and was regularly observed when lesions were applied over the TEE probe shadow, in close proximity to the posterior wall. Two major complications (1 tamponade, 1 PV laceration) occurred and were detected early by TEE.
Conclusions: TEE offers advantages compared to a map-guided only approach. It is a reliable tool to assess esophagus T° and localization, guide transseptal puncture, delineate the PV ostia, and monitor complications.     

Sudden Death as a Presenting Symptom of Hypertrophic Cardiomyopathy: Treatment with an Implantable Cardioverter Defibrillator

Aborted sudden death as the presenting manifestation of hypertrophic Cardiomyopathy in a 14-year-old child is reported. Documented ventricular fibrillation was the cause of cardiac arrest. No ventricular arrhythmia was induced during programmed electrical stimulation. An implantable cardioverter-defibrillator was indicated. As the patient had a family history of myocardial disease, he had undergone a cardiovascular evaluation 4 years before the major event, and was found normal. It is suggested that normal physical examination, ECG, echocardiogram should not rule out the diagnosis of hypertrophic Cardiomyopathy when a family history is present. Left ventricular hypertrophy may develop during childhood in patients with hypertrophic Cardiomyopathy.     

Left Ventricular Pressure Measurement During Noninvasive Transcutaneous Cardiac Pacing

In a pacemaker-dependent patient, the hemodynamic response during external transcutaneous and endocardial sequential pacing was evaluated by left ventricular pressure monitoring. A single ventricular pacing mode with hemodynamic effect of atrioventricular asynchrony was shown during external pacing.     

Evaluation of a Pectin-based Barrier Under Tape to Protect Neonatal Skin

The use of a pectin-based barrier between tape and skin as a method of minimizing epidermal stripping while keeping monitoring equipment and other devices securely attached to infants was evaluated. From 45 subjects, 199 application/removal procedures were recorded. The pectin-based barrier under tape held appliances securely for an average of 5.5 days (range 1-23 days). In 72% of the observations, the barrier was removed for nonadhesive-related reasons. Skin condition remained grossly normal in 97% of the observations after the barrier removal. A pectin-based barrier under tape provides effective adhesion for certain appliances and protects neonatal skin from damage caused by tape removal.     

Human uterine smooth muscle exhibits a very low phosphocreatine/ATP ratio as assessed by in vitro and in vivo measurements

The purpose of the study was to investigate by in vitro and in vivo methods the phosphocreatine (PCr)/ATP ratio as an expression of the energy metabolic state of human myometrium in comparison with striated skeletal muscle. The contents of PCr and adenylates in biopsies of uterine smooth muscle and m. rectus abdominis from seven term pregnant women were determined in vitro and compared with results obtained in vivo by phosphorus magnetic resonance spectroscopy (³¹P-MRS) in the uterus and m. gastrocnemius of eight non-pregnant women. The PCr/ATP ratio in the striated skeletal muscle was about three times higher than that of the myometrium. The results of the in vitro biopsy part of the study and the in vivo ³¹P-MRS part conformed with each other. In the biopsies both PCr and ATP concentrations were significantly lower in the myometrium than in the rectus muscle, but the difference for PCr was more pronounced, accounting for the significantly lower PCr/ATP ratio in the uterine smooth muscle. The energy metabolic pattern of uterine smooth muscle differs from that of striated skeletal muscle regarding the contents of high-energy phosphocompounds and the PCr/ATP ratio. This in vivo finding is the first report on human smooth muscle using ³¹P-MRS.