Cardioversion for atrial fibrillation – how to prevent thromboembolic complications?

Abstract

Cardioversion is an essential component of rhythm control strategy for atrial fibrillation. The thromboembolic risk of cardioversion is well established and the mechanisms behind the phenomenon have been comprehensively described. There are several clinical aspects that are important to take into consideration when assessing the safety of cardioversion. Before proceeding to cardioversion, the probability of early treatment failure and antiarrhythmic treatment options to prevent recurrences should be carefully evaluated to avoid the risks of repeated futile cardioversions. Effective periprocedural anticoagulation is the mainstay in thromboembolic complication prevention and the first week after rhythm conversion is the most vulnerable period in this respect. Early timing of cardioversion appears to be another important measure to decrease the risk of thromboembolic complications. Transoesophageal echocardiography is useful in clinical scenarios where early cardioversion is desirable due to debilitating clinical symptoms and a short duration of arrhythmia or the adequacy of preceding anticoagulation is uncertain. However, it does not lessen the need for effective anticoagulation after cardioversion. This review summarizes the recent scientific discoveries to improve the safety of cardioversion for atrial fibrillation.

• Key messages

• Cardioversion for atrial fibrillation entails a significant risk of thromboembolic complications, especially during the first week after the procedure.

• The intensity of periprocedural anticoagulation and the timing of cardioversion appear to be significant determinants of the risk of thromboembolism.

• Awareness of the clinical aspects influencing cardioversion safety should be raised.

     

Esophagocardiomyotomy for achalasia. Long-term clinical and endoscopic evaluation of transabdominal vs. transthoracic approach.

Modified Heller's myotomy for achalasia of the esophagus was performed via a left thoracotomy in 34 cases (group A) and via an upper midline abdominal incision in 30 (group B). There were no perioperative deaths. Complications arose in ten cases. After follow-up averaging 13 years (range 3-24 years) 4% of the group A patients reported dysphagia for solids, but none for liquids, and in group B the corresponding figures were 52% and 26%. Reflux symptoms were present in 30% of the group A and 60% of the group B cases, and the respective incidence of microscopic esophagitis was 30% and 43%. There were three esophageal strictures, all in group B, and three cases of Barrett's epithelium, all in group A. Because of the high incidence of esophagitis and its complications following esophagomyotomy for achalasia, yearly endoscopy with biopsy and brush cytology is recommended. When myotomy is performed, an antireflux operation should be added.     

Decision-making models of Finnish nurses and public health nurses

This study described nursing decision-making models and variables related to these models For this purpose a 56-item Likert-type questionnaire was constructed according to the Dreyfus model of skill acquisition as applied to nursing by Benner and information processing theory The target group consisted of 100 registered nurses working in inpatient clinics and 100 public health nurses working in preventive health care The decision-making variables explored were nurses' experience, education and knowledge as well as the nature of the nursing task and context The results revealed four different types of decision-making (a) unquestioning/questioning decision-making, (b) creative—diversive decision-making, (c) patient/nurse-oriented decision-making, and (d) rule- and situation-based decision-making The most important factors related to decision-making were experience and the nature of the nursing task and context     

Impact of the Leu7Pro polymorphism of preproNPY on diurnal NPY and hormone secretion in type 2 diabetes.

Neuropeptide Y (NPY) is a sympathetic neurotransmitter that plays a role in e.g. circulation, hormone release and angiogenesis. Earlier studies have shown that the Leucine 7 to Proline 7 (Leu7Pro) polymorphism of preproNPY is associated with increased risk for vascular complications in type 2 diabetes. The mechanism for this maybe altered transmitter and hormone levels or altered cardiovascular functions, which have been observed in healthy subjects having the Leu7Pro polymorphism. The current study was undertaken to explore if the Leu7Pro polymorphism has an impact on these functions in subjects with type 2 diabetes. Diurnal measurements were performed for Finnish Caucasian type 2 diabetes patients of two preproNPY genotypes (matched by sex, age, BMI, duration of diabetes and HbA1c) in resting position to prevent sympathetic stimulation. Standard meals were offered during the 24-hour study period. Nine subjects with the Leu7Pro polymorphism and ten subjects without this polymorphism were studied. Plasma concentrations of NPY, glucose, insulin, cortisol, prolactin and leptin were measured by taking blood samples at 20 time points (from 8 a.m. to 8 a.m.). Heart rate and blood pressure were measured at the same time points. The results show that NPY concentrations were similar in both preproNPY genotypes. Glucose, insulin, cortisol and leptin concentrations as well as heart rate and blood pressure were also similar. However, a significant difference between genotypes was found in the association of NPY concentrations with cortisol concentrations (p for difference=0.002). Also a statistically significant negative association of plasma NPY levels with plasma glucose levels was found in both genotypes. Since no impact of preproNPY genotype on mean NPY or hormone levels were detected in subjects with type 2 diabetes, the mechanisms for the increased risk for diabetic complications in the subjects with the Leu7Pro polymorphism need to be further explored.     

Neurobehavioral toxicity with low doses of sarin and soman

The acute effects of single subtoxic doses (1/48-1/9 of LD50) of two potent organophosphates (OPs), sarin (12.5 and 50 micrograms/kg i.p.) and soman (4 and 20 micrograms/kg i.p.), were studied on behavior, motor performance and nociception in male Wistar rats. On the elevated plus-maze with two open + two closed arms, higher doses of soman and sarin decreased the proportion of entries made onto open arms (p less than 0.05), while the total number of entries onto open + closed arms was unchanged. On the narrow elevated horizontal bridge, the latencies to reach the safe platform were prolonged with the higher dose of sarin (p less than 0.05) but not with that of soman. On the broad and rod bridges, the latencies of OP-treated rats did not differ significantly from those of controls. OPs did not significantly impair either learning frequency in one-trial passive avoidance test, rotarod performance or nociception in hot plate test. The results suggest that in acutely nontoxic doses sarin and soman affect the behavior of rats, and that the action profiles of the OPs differ from each other. Both soman and sarin change the behavior of rats in the plus-maze test but only sarin seems likely to impair motor coordination/balance.     

Absence of carrier specificity in an adoptive secondary response

Different NIP (4-hydroxy-3-iodo-5-nitrophenylacetic acid) conjugates were used to study carrier specificity in normal and adoptive secondary responses. When rats were primed with NIP—HSA conjugate and boosted with either NIP—HSA or NIP—CG 45 days later, there was a clear carrier specificity; the homologous carrier caused a stronger response than the heterologous carrier. When the interval between the first and the second injection was extended to 4 months, carrier specificity was much less strict. Adoptive secondary responses were not carrier-specific whether the time between the priming injection and transfer plus restimulation was short (21 days) or long (4 months). Adoptive secondary IgM responses were less dependent on stimulation with the homologous carrier than the simultaneous IgG responses of the same animal.     

Multiple-modified desialylated low density lipoproteins that cause intracellular lipid accumulation. Isolation, fractionation and characterization.

BACKGROUND: The basic differences between sialylated (sialic acid rich) and desialylated (sialic acid poor) human low density lipoproteins (LDL) are not fully defined. It is not known whether there are any differences in the LDL composition of coronary atherosclerosis patients and healthy individuals. EXPERIMENTAL DESIGN: Sialylated (45 to 94% of total LDL) and desialylated (6 to 55%) LDL were separated by affinity chromatography on Ricinus communis agglutinin-agarose, and their chemical composition and physical properties were examined. RESULTS: Sialic acid contents in sialylated LDL fractions of healthy subjects and patients were the same and 1.5 to 3-fold higher than in desialylated LDL. Desialylated LDL had smaller sizes and greater electrophoretic mobility than sialylated ones. Desialylated, but not sialylated LDL, induced 1.5- to 4-fold accumulation of neutral lipids in human aortic smooth muscle cells and human blood monocytes. Subfractions of desialylated LDL containing lower amount of sialic acid revealed higher ability to accumulate lipids in cultured cells. Desialylated LDL contained lower amounts of cholesteryl esters, free cholesterol and triglycerides as compared with sialylated LDL. On the other hand, concentration of di-, monoglycerides and free fatty acids in desialylated LDL was 2 to 3-fold higher than in sialylated lipoproteins. Desialylated LDL fraction was characterized by lower levels of phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, but higher content of lysophosphatidylcholine. Freshly isolated sialylated and desialylated LDL contained equal amounts of thiobarbituric acid reactive substances, but oxidation of desialylated LDL was more pronounced in presence of Cu(2+)-ions. Desialylated LDL had higher level of oxysterols and lower amounts of vitamin A and E. Content of free amino groups of lysine in desialylated LDL of patients was 2-fold lower than in sialylated LDL. This difference was partially due to masking of amino groups caused by conformational change in the tertiary structure of apolipoprotein, partially to chemical modification of amino groups. When subfractionated by density gradient ultracentrifugation, desialylated LDL was represented by higher density particles than sialylated LDL. Sialic acid content in desialylated LDL subfractions decreased with rise of lipoprotein density. Higher density desialylated LDL and in less extent sialylated LDL contained smaller amounts of free and esterified cholesterol and phospholipids. Only the densest subfractions of desialylated LDL from healthy subjects caused intracellular lipid accumulation. Ability of patients' desialylated LDL to accumulate cholesterol in cells increased with particle density. CONCLUSIONS: Extensive biochemical and biophysical analysis performed in this study shows that desialylated LDL differ from these sialylated LDL in many respects. The LDL of coronary atherosclerosis patients differ from those in healthy individuals in several parameters.     

Gingival bleeding after chlorhexidine rinses with or without mechanical oral hygiene

In a previous paper a slight increase in gingival bleeding tendency was reported after the use of chlorhexidine rinses in dental students with clinically healthy gingivae. For further clarification of this finding the study was repeated using a split mouth approach. 30 dental students brushed the teeth in either the left or the right side of their mouth twice daily during a 7-day period. After each brushing, they rinsed for 1 min with 10 ml of a 0.2% chlorhexidine digluconate solution. Both the Plaque Index (P1I) scores and the bleeding tendency after massage of the gingival margin were low at the initial examination. The low P1I scores at baseline were further reduced on both sides of the jaws. On the side which was only rinsed the P1I scores were higher than on the side of combined mechanical and chemical cleaning. The gingival bleeding tendency was found to decrease on the brushed side and to increase on the side which was only rinsed. An increased bleeding tendency was most often observed in those individuals whose gingivae were the healthiest at baseline. A SEM analysis of the 2 sides of the dentition indicated that bleeding after chlorhexidine rinses may be associated with irritation from debris which, after the 7-day period of no mechanical oral hygiene measures, seemed to obliterate the gingival sulcus.