Incidence and time course of early recovery of pulmonary vein conduction after catheter ablation of atrial fibrillation

Background: Although it is well recognized that recovery of pulmonary vein (PV) conduction is common among patients who fail atrial fibrillation (AF) ablation, little is known about the precise time course of recurrence.
Objective: To determine the incidence and time course of early recurrence of conduction after PV isolation during AF ablation.
Methods: The patient population was composed of 14 consecutive patients (9 men [64%]; age 56 ± 7 years) with AF who underwent radiofrequency catheter ablation via circumferential ablation with PV isolation, determined by a circular mapping catheter. After successful isolation of the PVs, repeat circular electrode recordings from each PV were obtained at 30 and 60 minutes.
Results: After complete isolation of all PVs, early PV recurrence was observed in 13 (93%) patients and 26 veins (50%). Seventeen veins (33%) showed a first recurrence at 30 minutes, while nine veins (17%) showed a first recurrence at 60 minutes.
Conclusion: The results reveal an extremely high rate of early recurrence of PV conduction following AF ablation. It is particularly notable that about one-fifth of the veins remained isolated at 30 minutes, but subsequently developed recurrence between 30 and 60 minutes. Of the veins that showed early recurrence, one-third developed a first recurrence at 60 minutes. These findings suggest that AF ablation procedures should incorporate a 60-minute waiting period after initial isolation in order to detect early recurrence of conduction.     

Efficacy and patient satisfaction with autoadjusting CPAP with variable expiratory pressure vs standard CPAP: a two-night randomized crossover trial

Expiratory pressure relief (C-Flex) technology monitors the patient’s airflow during expiration and reduces the pressure in response to the patient. Increased comfort levels associated with C-Flex therapy have potential to improve patient adherence to therapy. The purpose of this study was to assess the combination of autoadjusting CPAP (APAP) and C-Flex in terms of (1) treatment efficacy, and (2) patient preference when compared to standard CPAP. Fifteen patients who had previously undergone formal CPAP titration polysomnography were treated with either one night of the APAP with C-Flex or one night of conventional CPAP, in a crossover trial. Patient satisfaction levels were recorded using visual analog scales (VAS) on the morning after the study. Mean patient age was 50 ± 12 years, body mass index (BMI) was 36 ± 6 kg/m², baseline AHI was 53 ± 31 events/h, and CPAP Pressure was 11 ± 2 cm/H₂O. APAP with C-Flex was as effective as CPAP, with no differences detected in sleep latency (17 ± 5 vs 12.3 ± 3 min, p = 0.4), or respiratory indices (AHI of 4.2 ± 2 vs 2.4 ± 0.7 events/h, p = 0.1). VAS scores (scale 0–10) indicated a trend towards increased patient satisfaction while using APAP with C-Flex (7.9 vs 7.2, p = 0.07). 10 patients expressed a preference for APAP with C-Flex (VAS, 0 to10) over standard CPAP (total positive score of 68, mean score of 4.8 ± 4.3). One patient expressed no preference. Four patients expressed a preference for CPAP (total positive score of 13, mean score of 0.9 ± 1.9) (APAP with C-Flex vs standard CPAP, p < 0.01 paired t test). APAP with C-Flex eliminates sleep disordered breathing as effectively as standard CPAP. Patients indicated a preference for APAP with C-Flex suggesting a possible advantage in terms of patient adherence for this mode of treatment.     

Intraluminal filling defects on coronary angiography: more than meets the eye

Intraluminal filling defects are occasionally encountered on coronary angiography and often related with coronary thrombi. However, other conditions affecting the coronary arteries may present with similar angiographic findings causing diagnostic uncertainty. Accurate characterization of the angiographic filling defect is critical, particularly in patients planned for a percutaneous coronary intervention (PCI), as diagnosis of a coronary thrombus not only increases the risk of post procedural adverse events but also requires a specific therapeutic approach. In this paper, we report three patients in whom coronary angiography revealed intraluminal filling defects mimicking coronary thrombi. When further investigated with intravascular ultrasound (IVUS) as a part of the planned PCI, the thrombus was excluded and alternate etiology of the filling defect was confirmed in all patients. The angiographic "pseudothrombi" were produced by coronary dissection in one and by heavy calcification within the atherosclerotic plaque in two patients. The use of IVUS allowed accurate characterization of the angiographic filling defect and provided important information to guide management and optimize therapeutic approach.     

Pulmonary embolism: computer-aided detection at multidetector row spiral computed tomography

BACKGROUND: We aimed to evaluate the feasibility and performance of a computer-aided detection (CAD) tool for automated detection of segmental and subsegmental pulmonary emboli. METHODS: A CAD tool (ImageChecker CT, R2 Technology, Inc) for automated detection of pulmonary emboli was evaluated on multidetector-row CT studies of varying diagnostic quality in 23 patients (13 female, mean age 52 y) with pulmonary embolism (PE) and of 13 patients (all female, mean age 49 y) without PE. A collimation of 16 x 1 mm and a reconstructed section width of 1.25 mm had been used in each patient. The performance of the CAD tool for the detection of emboli in the segmental and subsegmental pulmonary arterial tree was assessed. Consensus reading of the same studies by 2 radiologists, with a third for adjudication, for the identification of segmental and subsegmental pulmonary emboli was used as the standard of reference. RESULTS: Consensus reading revealed 130 segmental pulmonary emboli and 107 subsegmental pulmonary emboli in the 23 patients with PE. All 23 patients with PE were correctly identified as having PE by the CAD system. In a vessel-by-vessel analysis, the sensitivity of the CAD algorithm was 92% (119/130) for the detection of segmental pulmonary emboli and 90% (92/107) for subsegmental pulmonary emboli. The overall specificity, positive predictive value (95% confidence interval) and negative predictive value (95% confidence interval) of the algorithm were 89.9%, 63.2% (57.9%-68.2%) and 97.7% (96.7%-98.4%), respectively. The average false positive rate of the CAD algorithm was 4.8 (range 1 to 9) false positive detection marks per case. CONCLUSION: CAD of segmental and subsegmental pulmonary emboli based on 1-mm multidetector-row CT studies is feasible. Application of CAD tools may improve the diagnostic accuracy and decrease the interpretation time of computed tomographic angiography for the detection of pulmonary emboli in the peripheral arterial tree and further enhance the acceptance of this test as the first line diagnostic modality for suspected PE.     

C-reactive protein in cardiovascular risk assessment: a review of the evidence

C-reactive protein (CRP) is an inflammatory biomarker that is strongly associated with coronary heart disease, inflammation, and the metabolic syndrome. Large-scale prospective cohort trials have shown that measurement of CRP may add predictive accuracy to the Framingham risk score, but interpretation of these data are conflicting. In the primary prevention setting, CRP can be used to reclassify patients in low or intermediate Framingham risk score groups to a higher risk category, thus making them eligible for more intensive pharmacologic interventions.     

Deletion of hensin/DMBT1 blocks conversion of beta- to alpha-intercalated cells and induces distal renal tubular acidosis

Acid-base transport in the renal collecting tubule is mediated by two canonical cell types: the β-intercalated cell secretes HCO(3) by an apical Cl:HCO(3) named pendrin and a basolateral vacuolar (V)-ATPase. Acid secretion is mediated by the α-intercalated cell, which has an apical V-ATPase and a basolateral Cl:HCO(3) exchanger (kAE1). We previously suggested that the β-cell converts to the α-cell in response to acid feeding, a process that depended on the secretion and deposition of an extracellular matrix protein termed hensin (DMBT1). Here, we show that deletion of hensin from intercalated cells results in the absence of typical α-intercalated cells and the consequent development of complete distal renal tubular acidosis (dRTA). Essentially all of the intercalated cells in the cortex of the mutant mice are canonical β-type cells, with apical pendrin and basolateral or diffuse/bipolar V-ATPase. In the medulla, however, a previously undescribed cell type has been uncovered, which resembles the cortical β-intercalated cell in ultrastructure, but does not express pendrin. Polymerization and deposition of hensin (in response to acidosis) requires the activation of β1 integrin, and deletion of this gene from the intercalated cell caused a phenotype that was identical to the deletion of hensin itself, supporting its critical role in hensin function. Because previous studies suggested that the conversion of β- to α-intercalated cells is a manifestation of terminal differentiation, the present results demonstrate that this differentiation proceeds from HCO(3) secreting to acid secreting phenotypes, a process that requires deposition of hensin in the ECM.     

Risk analysis of deep sternal wound infections and their impact on long-term survival: a propensity analysis

The objectives of this study are to determine risk factors associated with deep sternal wound infections (DSWIs) following cardiac surgery, and to describe their impact on long-term survival. Data was obtained from a departmental database. Analysis included 7,978 consecutive patients who underwent cardiac surgery between 1997 and 2003. To identify risk factors for DSWI, regression analysis was performed. The probability scores obtained from logistic regression were used for propensity analysis of 2 groups. Kaplan-Meier analysis with log-rank test and Cox proportional hazard models were then used in survival analysis. DSWI developed in 123 of 7,978 patients (1.5%). Preoperative predictors of DSWI were body mass index >30 kg/m(2) (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1 to 2.4; P < 0.05), diabetes mellitus (OR, 2.4; 95% CI, 1.6 to 3.4; P < 0.001), urgent operation (OR, 1.7; 95% CI, 1.2 to 2.6; P < 0.05), smoking history within past year (OR, 2.7; 95% CI, 1.5 to 4.9; P < 0.001), smoking history within past 2 weeks (OR, 2.6; 95% CI, 1.5 to 4.5; P < 0.001), and a history of stroke (OR, 1.9; 95% CI, 1.1 to 3.1; P < 0.005). In addition, total length of hospital stay (OR, 1.01; 95% CI, 1.01 to 1.02; P < 0.05) and sepsis and/or endocarditis following surgery (OR, 5.1; 95% CI, 2.9 to 9.0; P < 0.001) were also predictive of DSWI. Patients with DSWI had a prolonged total length of hospital stay (40.3 days versus 16.1 days; P < 0.001), and higher 30-day mortality (1.6% versus 7.3% in DSWI group, P < 0.05). There were no differences between groups in 4-year and 8-year survival rates, with 77.2% and 61.8%, respectively, in patients with DSWI compared with 78.0% and 67.5% in patients without DSWI (P = 0.16). After adjustments for preoperative, intraoperative, and postoperative factors, the adjusted hazard ratio of long-term mortality for patients with DSWI was 0.9 (95% CI, 0.6 to 1.2, P = 0.39). Though DSWIs are associated with increased early mortality, patients undergoing cardiac surgery complicated by DSWI do not experience worse long-term survival.