Conduction gaps after pulmonary vein isolation due to high contact force ablation in patients with atrial fibrillation

Background

Catheter ablation for atrial fibrillation (AF) with high contact force (CF) has been reported to lead to the gaps after pulmonary vein isolation (PVI), and the appearance of the gaps depends on the site in the left atrium (LA).

Purpose

The aim of this study is to clarify the relationship between the gaps appearance and high CF.

Methods

In the clinical study, 74 consecutive patients (39 males, age 71±9, 46 with paroxysmal AF) underwent conventional PVI with a point-by-point radiofrequency (RF) ablation using a CF sensing catheter (TactiCath SETM). RF energy (J), number of RF point, Lesion index (LSI), force-time integral (FTI), average CF (g), and the degree of LA depression with high CF were evaluated. In the experimental study (figure), the relationship between the ablation area and the degree of depression with high CF using bovine left ventricular wall.

Results

In the clinical study, the gaps were found in 175 of 1182 sites after first path PVI ablation. The CF in the gap sites was higher than without the gap sites in RPV roof, anterior RSPV and anterior RPV carina (18.9±6.8 vs 15.0±5.7g p=0.0262, 26.4±11.6 vs 19.5±6.0g p=0.0029, 22.7±6.4 vs 19.1±5.5g, p=0.0161). Meanwhile, there were no differences in RF energy, number of RF point, LSI, FTI. High CF (≥30g) showed a depression of 3 mm or more in only RPV roof and anterior RPV (figure). In the experimental study, the ablation range narrowed as the indentation deepened with more than 30g CF (r=0.6417, p=0.0625).

Conclusion

Catheter ablation for AF with high contact force might lead to the gaps in RPV roof and anterior RPV site by the reduction of the ablation area due to depression caused by the pressure.

Extension of each contact force

Funding Acknowledgement

Type of funding source: None

Lesion characteristics of acute myocardial infarction: an investigation with intravascular ultrasound

OBJECTIVE

To use intravascular ultrasound (IVUS) to compare plaque morphology in acute myocardial infarction and stable angina pectoris.

DESIGN

Retrospective study.

SETTING

Primary care hospital.

PATIENTS

59 consecutive cases of acute myocardial infarction and 50 consecutive cases of stable angina pectoris.

METHODS

IVUS was used before coronary intervention.

MAIN OUTCOME MEASURES

Plaque morphology (incidence of eccentric plaque, subtle dissections, low echoic thrombus, calcification, echolucent areas, and bright speckled echo material), assessed visually using IVUS.

RESULTS

There were no significant differences in plaque eccentricity or calcification between the two groups, but low echoic thrombus (acute myocardial infarction 15% v stable angina pectoris 0%), subtle dissections (37% v 4%), echolucent areas (31% v 0%), and bright speckled echo material (90% v 0%) were more common in the infarction group than in the stable angina group (p < 0.001 for all). There was a longer time between the onset of symptoms and the IVUS examination in patients with low echoic thrombus than in those without (p < 0.03).

CONCLUSIONS

Low echoic thrombus, subtle dissections, echolucent areas, and bright speckled echo material are morphological characteristics associated with plaque at the time of acute myocardial infarction. These findings correspond pathologically to ruptured plaque.

The increase of memory T cell subsets in children with idiopathic nephrotic syndrome

Two-color and three-color flow cytometry was carried out to determine whether the memory T cells (CD45RO+ T cells) play a major role in lymphocyte dysfunction of 26 children with idiopathic nephrotic syndrome (INS). The INS patients were divided into three groups: (1) 10 patients who were not receiving glucocorticoid hormone (GCH) and were suffering from acute nephrotic state were referred to as N1; (2) 8 patients who were in remission maintained by GCH therapy alone were referred to as N2; (3) 8 patients who were free of GCH therapy for at least 4 months were referred to as N3. Group N1 demonstrated a significant increase in the percentage of CD45RO+CD4+ T cells and CD45RO+CD8+ T cells (p < 0.05) compared with 11 controls, and these subsets were noted to have a tendency to decrease to control levels in groups N2 and N3. Furthermore, interleukin-2 receptor-alpha expressed subsets in CD45RO+CD4+ T cells (CD45RO+CD4+CD25+ T cells) were also increased only in group N1 (p < 0.02). A similar tendency of absolute counts was observed in these subsets. These results suggest that activated memory T cells reflect lymphocyte dysfunction at initial onset or relapse in INS children.

Subcellular localization of glucocorticoid receptor protein in the human kidney glomerulus

BACKGROUND

The detailed mechanisms of glucocorticoid action in idiopathic nephrotic syndrome and progressive glomerulonephritides have not been clearly elucidated. The pharmacological actions of glucocorticoids are mediated by their binding to an intracellular protein, the glucocorticoid receptor (GR). The determination of GR localization in normal glomerular cells is essential to elucidate the mechanisms of glucocorticoid action in various glomerular diseases.

METHODS

We carried out an immunoblot examination using antihuman GR-specific antibody and homogenates of isolated normal human glomeruli and mesangial cells in culture. Immunohistochemical examinations were also performed on normal human kidney specimens at light and electron microscopic levels. The nuclear translocation of GRs elicited by ligand binding was further investigated by confocal laser-scanning microscopic inspection of freshly isolated glomeruli and mesangial cells cultured with dexamethasone.

RESULTS

An immunoblot examination demonstrated the presence of a 94 kDa protein, a molecular weight consistent with that of GRs, in the homogenates of glomeruli and cultured mesangial cells. By light microscopic examination, GRs were strongly detected in the nucleus and moderately in the cytoplasm of all glomerular cells, parietal and visceral epithelial cells, endothelial cells, and mesangial cells. By electron microscopic examination, the nuclear GRs of all glomerular cells were found to be diffusely distributed in the euchromatin. Additionally, the immunofluorescence intensities of nuclear GRs in isolated glomeruli and mesangial cells in culture became more intense by the addition of dexamethasone.

CONCLUSIONS

Our findings suggest that all subsets of human glomerular cells definitely express the GR protein, which potentially undergoes translocation by glucocorticoids.

Paraneoplastic pemphigus: the first case report from Japan

Paraneoplastic pemphigus is a rare skin disease characterized by painful mucosal ulcerations and polymorphous skin lesions in association with an underlying neoplasm. A 54-year-old Japanese man, who had received chemotherapy and radiation therapy due to a diagnosis of non-Hodgkin's lymphoma, developed marked stomatitis, conjunctivitis and blisters. Histologic examination showed suprabasal cleft formation with acantholysis and keratinocyte necrosis. Direct immunofluorescence revealed the deposition of IgG at the cell surface of the keratinocytes and C3 at the basement membrane zone. Indirect immunofluorescence on normal human skin and rat bladder sections revealed circulating autoantibodies to the cell surface of both keratinocytes and transitional epithelia. Immunoprecipitation disclosed antibodies reactive to the 250-kD, 230-kD, 210-kD and 170-kD proteins. From these results, a diagnosis of paraneoplastic pemphigus was made. This is the first report of paraneoplastic pemphigus from Japan.