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INTRODUCTION: Implantation of an implantable cardioverter defibrillator (ICD) is standard care for primary prevention of sudden cardiac death. However, ICD-related complications are increasing as the population of ICD recipients grows. METHODS: ICD-related complications in a national DO-IT Registry cohort of 1442 primary prevention ICD patients were assessed in terms of additional use of hospital care resources and costs. RESULTS: During a median follow-up of 28.7 months (IQR 25.2-33.7) one or more complications occurred in 13.5% of patients. A complication resulted in a surgical intervention in 53% of cases and required on average 3.65 additional hospital days. The additional hospital costs were 6,876 per complication or 8,110 per patient, to which clinical re-interventions and additional hospital days contributed most. Per category of complications, infections required most hospital utilisation and were most expensive at an average of 22,892. The mean costs were 5,800 for lead-related complications, 2,291 for pocket-related complications and 5,619 for complications due to other causes. We estimate that the total yearly incidence-based costs in the Netherlands for hospital management of ICD-related complications following ICD implantation for primary prevention are 2.7 million. CONCLUSION: Complications following ICD implantation are related to a substantial additional need for hospital resources. When performing cost-effectiveness analyses of ICD implantation, including the costs associated with complications, one should be aware that real-world complication rates may deviate from trial data. Considering the economic implications, strategies to reduce the incidence of complications are encouraged.
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BACKGROUND: Dutch patients with an implantable cardioverter defibrillator (ICD) are restricted from driving for two months after implantation or shocks. This requires significant lifestyle adjustments and is one of the primary concerns of ICD patients. Previous studies indicated that compliance with the driving restrictions is poor, but insight in socio-demographic, clinical and psychological factors associated with compliance is limited. Hence, this study aimed to explore compliance with the driving restrictions and associated factors in a large sample of Dutch ICD patients. METHOD: Dutch ICD patients (N = 313) completed an elaborative set of questionnaires at time of implantation and at four months after implantation, assessing socio-demographic, psychological and driving-related characteristics. Clinical data were collected from the patients' medical records. RESULTS: A substantial subgroup (28%) of the patient sample (median age 64 (interquartile range = 55-71), 81% male) reported to have been noncompliant with the driving restrictions. Univariate analysis indicated that noncompliant patients more often considered refusing the ICD due to the restrictions, compared to compliant patients (19% versus 10%, p = 0.02). Multivariate analysis showed that the feeling of understanding the reason behind the driving restrictions was associated with better compliance (odds ratio = 2.16, 95% confidence interval 1.02-4.56, p = 0.04). No other socio-demographic, clinical, psychological or driving-related factors were associated with compliance. CONCLUSION: A large number of ICD patients does not comply with the driving restrictions after implantation. This study emphasised the importance of the patient's feeling of understanding the reason behind the restrictions.
ABSTRACT
BACKGROUND: Implantable cardioverter-defibrillators (ICDs) are widely used for the prevention of sudden cardiac death. At present, both clinical benefit and cost-effectiveness of ICD therapy in primary prevention patients are topics of discussion, as only a minority of these patients will eventually receive appropriate ICD therapy. METHODS/DESIGN: The DO-IT Registry is a nationwide prospective cohort with a target enrolment of 1,500 primary prevention ICD patients with reduced left ventricular function in a setting of structural heart disease. The primary outcome measures are death and appropriate ICD therapy for ventricular tachyarrhythmias. Secondary outcome measures are inappropriate ICD therapy, death of any cause, hospitalisation for ICD related complications and for cardiovascular reasons. As of December 2016, data on demographic, clinical, and ICD characteristics of 1,468 patients have been collected. Follow-up will continue up to 24 months after inclusion of the last patient. During follow-up, clinical and ICD data are collected based on the normal follow-up of these patients, assuming ICD interrogations take place every six months and clinical follow-up is once a year. At baseline, the mean age was 66 (standard deviation [SD] 10) years and 27% were women. CONCLUSION: The DO-IT Registry represents a real-world nationwide cohort of patients receiving ICDs for primary prevention of sudden cardiac death with reduced left ventricular function in a setting of structural heart disease. The registry investigates the efficacy of the current practice and aims to develop prediction rules to identify subgroups who will not (sufficiently) benefit from ICD implantation and to provide results regarding costs and budget impact of targeted supply of primary preventions ICDs.
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OBJECTIVE: In a prospective setting, we aimed to find associations between biomarkers of the hemostatic system and the occurrence of central venous catheter (CVC)-related thrombosis in patients with hematological malignancies undergoing intensive chemotherapy. METHODS: The study was conducted between July 2006 and August 2010 at the University Hospital Maastricht, the Netherlands. Consecutive adult patients with hematological malignancies who were going to receive a CVC for intensive chemotherapy were included. The primary end points were (a) symptomatic CVC-related thrombosis and (b) CVC-related infections. Blood samples were taken directly after catheterization, and easy to determine biomarkers (platelet count, leukocyte count, and hemoglobin level) in combination with blood group, factor VIII (FVIII), plasminogen activator inhibitor 1 (PAI-1), activated protein C (APC) resistance, and free protein S antigen were determined. RESULTS: Blood was collected and analyzed from 168 patients. The incidence of symptomatic CVC-related thrombosis was 9%. In univariate analysis, white blood cell count >10.6 × 109/L, mean FVIII activity, and PAI-1 >12.2 IU/mL were found to be associated with the development of symptomatic CVC-related thrombosis. CONCLUSION: Elevated leukocyte count, high PAI-1, and high FVIII were associated with an increased incidence of symptomatic CVC-related thrombosis. We hope in future that simple, easy to determine laboratory tests that reflect the hemostatic and fibrinolytic activity in combination with clinical parameters may help to identify hematological patients at highest risk of CVC-related thrombosis and help to tailor the management of thromboprophylaxis in hematological patients undergoing CVC placement.
Subject(s)
Biomarkers/blood , Central Venous Catheters/adverse effects , Hematologic Neoplasms/complications , Thrombosis/etiology , Female , Humans , Male , Middle Aged , Prospective StudiesABSTRACT
OBJECTIVE: The objective of the study was to examine whether cardiac resynchronisation therapy upgrade procedures are more complex and associated with more complications than de novo implantations. METHOD: We retrospectively compared 134 upgrade procedures performed between 2006-2012 with a random, equally sized, sample of de novo CRT device implantations in the same period. Procedural data and the occurrence of periprocedural (≤ 30 days) and long-term device-related (≤ 1 year) complications were analysed. Complications with consequences were defined as those in need of adjustment of standard care. RESULTS: Median time to upgrade was 57 (31-115) months. There were no significant differences in procedure duration, radiation time or total hospitalisation between upgrades and de novo implantations. Perioperative complications occurred in 6.7 % of upgrade patients and in 9.0 % of de novo patients. The most frequently seen complications were phrenic nerve stimulation, coronary sinus dissection and pocket haematoma. Procedure success was comparable (upgrade: 98.5 % versus de novo: 96.3 %). A total of 236 patients completed 1 year of follow-up. Ten (4.2 %) patients had a long-term device-related complication with consequences including phrenic nerve stimulation, lead dislodgement/dysfunction, and infection (upgrade: 3.5 % versus de novo: 4.9 %). CONCLUSION: Upgrade procedures are not more complex nor associated with more complications than de novo CRT implantations.
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The effects of coagulation factor concentrate infusion on restoring secondary haemostasis in patients with haemophilia are obvious. It is not known whether coagulation factor concentrate infusion affects primary haemostasis or induces an acute inflammatory response. In this study, the influence of a factor VIII (FVIII) concentrate bolus infusion on platelet activation and responsiveness, endothelial activation, and inflammation in adult patients with severe haemophilia A was assessed. VWF showed a mild, but significant decrease 15 min after FVIII infusion (85.02 IU dL(-1)) vs. before infusion (92.04 IU dL(-1) ; P = 0.017), while ADAMTS-13 levels also show a mild but significant decrease from 66.1 ng mL(-1) before infusion, to 53.9 ng mL(-1) (P = 0.012) 15 min after and 50.8 ng mL(-1) (P = 0.050) 60 min after infusion. Platelet P-selectin expression decreased 15 min (33.3 AU) and 60 min (38.7 AU) after infusion compared to before infusion (41.3 AU; P = 0.018 and 0.036). In conclusion, a single infusion of a high dose FVIII concentrate in haemophilia A patients may influence primary haemostasis by decreasing VWF, ADAMTS-13 and the number of circulating activated platelets. These effects possibly occur as a consequence of binding of the infused FVIII to VWF, influencing its processing. When treating severe haemophilia A patients with coagulation concentrate infusion, one should realize this does not merely correct FVIII levels but also may influence primary haemostasis.
Subject(s)
ADAM Proteins/metabolism , Factor VIII/therapeutic use , Hemophilia A/drug therapy , Hemophilia A/metabolism , von Willebrand Factor/metabolism , ADAM Proteins/blood , ADAMTS13 Protein , Adult , Blood Platelets/metabolism , Cytokines/biosynthesis , Cytokines/blood , Endothelial Cells/drug effects , Endothelial Cells/metabolism , Factor VIII/administration & dosage , Hemophilia A/blood , Humans , Inflammation/metabolism , Inflammation Mediators/blood , Inflammation Mediators/metabolism , Male , Middle Aged , Young AdultABSTRACT
Cardiac resynchronization therapy (CRT) is a disease modifying, device-driven treatment that can reduce morbidity and mortality in patients with heart failure. According to the current guidelines, the indication for CRT is only based on QRS duration and functional class of heart failure. However, a substantial amount of patients do not respond to therapy. In addition, CRT is accompanied by significant cost and potential morbidity. It is therefore vital to improve patient selection for CRT to improve patient outcome and minimize therapy-related complications. In this regard, cardiac sympathetic innervation may be of interest. This review addresses the currently available literature, 9 studies with a total number of 225 patients, on CRT and cardiac innervation scintigraphy with (123)I-metaiodobenzylguanidine.
Subject(s)
Cardiac Resynchronization Therapy/methods , Heart Failure/therapy , Heart/innervation , Sympathetic Nervous System/diagnostic imaging , Heart/diagnostic imaging , Humans , Radionuclide Imaging/methodsABSTRACT
The prevalence of obesity in patients with haemophilia (PWH) is increasing. We investigated the effect of obesity on bleeding frequency and clotting factor concentrate (CFC) usage in PWH and assessed whether prothrombotic changes observed in obesity differ between controls and PWH. Number of bleeds and CFC usage were compared between obese (N = 51) and non-obese (N = 46) haemophilia A patients. Markers of haemostasis and fibrinolysis were compared between PWH, and gender-, age- and body mass index (BMI)-matched non-haemophilic controls (N = 91). Median number of bleeds/patient-month was comparable between obese and non-obese patients with severe haemophilia (P = 0.791). Obese patients with severe haemophilia used 1.4 times more CFC/patient-month than non-obese patients (P = 0.036). When adjusting for weight this difference disappeared (P = 0.451). von Willebrand factor plasma concentration (VWF:Ag), factor VIII activity and endogenous thrombin potential were higher in obese than in non-obese controls. Obesity did not influence these markers in PWH. Plasminogen activator inhibitor type 1 levels were higher in obese vs. non-obese PWH (P < 0.001), whereas levels were comparable between PWH and controls (P = 0.912). Plasmin-α2-antiplasmin complex (PAP) levels appeared to be lower in obese vs. non-obese subjects, both within controls (P = 0.011) and PWH (P = 0.008). However, in PWH, PAP levels were higher than in controls (P < 0.001). Obesity is associated with an increase in net CFC usage in PWH, but has no effect on bleeding frequency. In addition, obesity attenuates hyperfibrinolysis in PWH. Future research investigating whether obese PWH need CFC treatment dosed on weight or whether a lower dosage would suffice to prevent and treat bleedings is needed.
Subject(s)
Blood Coagulation Factors/administration & dosage , Hemophilia A/blood , Hemorrhage/blood , Obesity/blood , Case-Control Studies , Cross-Sectional Studies , Fibrinolysis , Hemophilia A/complications , Hemorrhage/complications , Hemostasis , Humans , Male , Middle Aged , Obesity/complicationsABSTRACT
PURPOSE: Based on multiple large clinical trials conducted over the last decades guidelines for implantable cardioverter-defibrillator (ICD) implantations have been evolving. The increase in primary prophylactic ICD implantations challenges us to be critical towards the indications in certain patient populations. METHODS: We retrospectively collected patient characteristics and rates of appropriate and inappropriate ICD therapy, appropriate and inappropriate ICD shock and mortality of all patients who received an ICD in the University Medical Center Utrecht (UMCU) over the years 2006-2011. RESULTS: A total of 1075 patients were included in this analysis (74 % male, mean age 61 ± 13 years, left ventricular ejection fraction 30 ± 13 %); 61 % had a primary indication and 58 % had ischaemic heart disease. During a mean follow-up period of 31 ± 17 months, 227 of the patients (21 %) received appropriate ICD therapy (149 (14 %) patients received an appropriate ICD shock). Females, patients with a primary prophylactic indication and patients with non-ischaemic heart disease experienced significantly less ICD therapy. Only a few patients (54, 5 %) received inappropriate ICD therapy; 33 (3 %) patients received an inappropriate ICD shock. Fifty-five patients died within one year after ICD implantation and were therefore, in retrospect, not eligible for ICD implantation. CONCLUSION: Our study confirms the benefit of ICD implantation in clinical practice. Nevertheless, certain patients experience less benefit than others. A more patient-tailored risk stratification based on electrophysiological parameters would be lucrative to improve clinical benefit and cost-effectiveness.
ABSTRACT
Patients with haemophilia (PWH) are relatively protected from cardiovascular death. Recent insights have shown that this is not due to less formation of atherosclerosis than in non-haemophilic men, therefore protection from the final occlusive thrombus will be the major determinant. Prevalence and incidence rates of cardiovascular disease (especially non-fatal events) are scarce, although ongoing studies are addressing this issue. Meanwhile, because the haemophilia population is aging, we are increasingly confronted with cardiovascular events. The main cardiovascular risk factors that should be part of regular screening programs are hypertension, overweight, lipometabolic disorders and smoking. Anticoagulation therapy in haemophilia is feasible, provided that individual tailored coagulation therapy and close monitoring is provided. Here, we present our view on anticoagulation management in PWH. There is an absolute need for risk assessment tools and prospective validation of suggested anticoagulation management strategies in PWH. Until then, we are managing the unknown.
Subject(s)
Anticoagulants/therapeutic use , Drug-Related Side Effects and Adverse Reactions/epidemiology , Evidence-Based Medicine , Hemophilia A/epidemiology , Hemorrhage/epidemiology , Thrombosis/epidemiology , Thrombosis/prevention & control , Causality , Comorbidity , Drug-Related Side Effects and Adverse Reactions/prevention & control , Hemophilia A/therapy , Hemorrhage/prevention & control , Humans , Risk AssessmentABSTRACT
Ageing haemophilia patients are increasingly confronted with ischaemic heart disease (IHD). Treatment is complex because of the delicate equilibrium between bleeding and thrombosis. In 2009, we developed an institutional guideline on how to treat IHD in this patient population. The aim of this study was to evaluate feasibility and safety of this guideline. Haemophilia patients who underwent coronary angiography or percutaneous coronary intervention between January 2009 and June 2012 were included in the current case series. Nine diagnostic or therapeutic cardiac catheterizations were performed in six haemophilia patients. One patient with moderate haemophilia B was included, whereas the other patients had mild haemophilia A. In six of nine procedures, access to the circulation was gained via the radial artery. Only bare-metal stents were implanted, after which dual antiplatelet treatment was given for at least 4 weeks. During cardiac catheterization/intervention and dual antiplatelet treatment, clotting factor levels were corrected. No thrombotic or clinically relevant bleeding complications occurred. In one patient, a low-titre inhibitor recurred 10 months after catheterization. In-stent restenosis was diagnosed in one patient. This case series indicates that treatment according to the guideline is feasible and safe. Furthermore, based on the case series and developments in new guidelines for non-haemophilic patients with IHD, some adjustments on the 2009 guideline are proposed.
Subject(s)
Cardiac Catheterization , Hemophilia A/diagnosis , Hemophilia B/diagnosis , Myocardial Ischemia/drug therapy , Platelet Aggregation Inhibitors/therapeutic use , Aged , Coronary Angiography , Guidelines as Topic , Hemophilia A/complications , Hemophilia B/complications , Humans , Male , Middle Aged , Myocardial Ischemia/complications , Prospective Studies , Radial Artery/diagnostic imaging , StentsABSTRACT
Patients with haemophilia (PWH) are relatively protected from cardiovascular death. Recent insights have shown that this is not due to less formation of atherosclerosis than in non-haemophilic men, therefore protection from the final occlusive thrombus will be the major determinant. Prevalence and incidence rates of cardiovascular disease (especially non-fatal events) are scarce, although ongoing studies are addressing this issue.Meanwhile, because the haemophilia population is aging, we are increasingly confronted with cardiovascular events. The main cardio vascular risk factors that should be part of regular screening programs are hypertension, overweight, lipometabolic disorders and smoking. Anticoagulation therapy in haemophilia is feasible, provided that individual tailored coagulation therapy and close monitoring is provided.Here, we present our view on anticoagulation management in PWH. There is an absolute need for risk assessment tools and prospective validation of suggested anticoagulation management strategies in PWH. Until then, we are managing the unknown.
ABSTRACT
Von Willebrand factor (VWF) is a large multimeric glycoprotein that plays a major role in haemostasis, illustrated by the bleeding tendency in von Willebrand disease (VWD), the most common hereditary bleeding disorder caused by VWF deficiency or dysfunction. Elevated VWF levels are strongly associated with an increased risk of ischemic cardiovascular events. Whether this relation is causal, or whether increased VWF levels reflect disturbances of endothelial function remains to be elucidated. One possibility is that VWF participates in the process of atherogenesis. The aim of the current review is to determine whether VWF deficiency provides protection against the development of atherosclerosis in humans and animals. Results from animal studies suggest that, at arterial branch point predilection sites, VWF deficiency or blockage has a protective effect against atherosclerosis. Based on the available evidence, this potential protective effect of VWF deficiency can most likely be tracked to the VWF-platelet interaction. Sites involved in this interaction could prove attractive targets in future treatment and prevention of cardiovascular disease, an option that is already being explored in humans. An unequivocal protective effect of VWD on atherosclerosis has not been demonstrated in humans. However the interpretation of these results is hampered by several methodological weaknesses. In conclusion, VWF is probably a significant player in the multifaceted interaction between the haemostatic system and the atherosclerotic process which deserves further study.
Subject(s)
Atherosclerosis/etiology , Cardiovascular Diseases/etiology , von Willebrand Diseases/complications , Animals , Atherosclerosis/pathology , Cardiovascular Diseases/pathology , Disease Models, Animal , Humans , Mice , Swine , von Willebrand Diseases/pathologyABSTRACT
BACKGROUND: Hemophilia A patients have a lower cardiovascular mortality rate than the general population. Whether this protection is caused by hypocoagulability or decreased atherogenesis is unclear. OBJECTIVES: To evaluate atherosclerosis and endothelial function in hemophilia A patients with and without obesity as well as in matched, unaffected controls. METHODS: Fifty-one obese (body mass index [BMI] ≥ 30 kg m(-2)) and 47 non-obese (BMI ≤ 25 kg m(-2)) hemophilia A patients, and 42 obese and 50 matched non-obese male controls were included. Carotid and femoral intimamedia thickness [IMT] and brachial flow-mediated dilatation (FMD) were measured as markers of atherogenesis and endothelial function. RESULTS: The overall population age was 50 ± 13 years. Carotid IMT was increased in obese subjects (0.77 ± 0.22 mm) as compared with non-obese subjects (0.69 ± 0.16 mm) [mean difference 0.07 mm (95% confidence interval [CI] 0.020.13, P = 0.008)]. No differences in mean carotid and femoral IMT between obese hemophilic patients and obese controls were found (mean difference of 0.02 mm [95% CI ) 0.070.11, P = 0.67], and mean difference of 0.06 mm [95% CI ) 0.130.25, P = 0.55], respectively). Thirty-five per cent of the obese hemophilic patients and 29% of the obese controls had an atherosclerotic plaque (P = 0.49), irrespective of the severity of hemophilia. Brachial FMD was comparable between obese hemophilic patients and obese controls (4.84% ± 3.24% and 5.32% ± 2.37%, P = 0.45). CONCLUSION: Hemophilia A patients with obesity develop atherosclerosis to a similar extent as the general male population. Detection and treatment of cardiovascular risk factors in hemophilic patients is equally necessary.
Subject(s)
Atherosclerosis/etiology , Hemophilia A/complications , Adult , Atherosclerosis/diagnosis , Body Mass Index , Cardiovascular Diseases/etiology , Carotid Intima-Media Thickness , Case-Control Studies , Endothelium, Vascular/physiopathology , Hemophilia A/mortality , Humans , Male , Middle Aged , Obesity , Risk , Survival RateABSTRACT
Since the introduction of clotting factor concentrates, life expectancy of haemophilia patients is increasing and now approaches that of the general male population. Increasingly, haemophilia patients are confronted with age-related co-morbidity, including ischaemic cardiovascular disease. Treatment of stable angina pectoris and the acute coronary syndrome with antithrombotic therapy and percutaneous coronary intervention in haemophilia patients is feasible, but requires a tight co-operation between all specialists involved. As evidence-based guidelines are lacking, we developed a protocol on how we will treat haemophilia patients with ischaemic heart disease.
Subject(s)
Acute Coronary Syndrome/surgery , Hemophilia A/surgery , Myocardial Ischemia/surgery , Acute Coronary Syndrome/epidemiology , Acute Coronary Syndrome/genetics , Angioplasty, Balloon, Coronary , Clinical Protocols , Fibrinolytic Agents/therapeutic use , Hemophilia A/epidemiology , Hemophilia A/genetics , Humans , Male , Myocardial Ischemia/epidemiology , Myocardial Ischemia/genetics , Practice Guidelines as Topic , Risk Factors , StentsABSTRACT
Mortality due to ischemic heart disease in hemophilia patients is lower as compared to the general male population. Differences in the prevalence of cardiovascular risk factors cannot explain this finding. The hypocoagulable state of hemophilia patients might have a protective effect on thrombus formation, which precipitates infarction. It remains unclear whether the deficiency of coagulation factor VIII or IX exerts a protective effect on the development of atherosclerosis. Despite the relative protection against cardiovascular events, the incidence of ischemic cardiovascular disease in hemophilia patients is increasing, because life expectancy of these patients now approaches that of the general population. This review focuses on what is currently known about cardiovascular risk factors, atherosclerosis, arterial thrombosis and ischemic cardiovascular disease in hemophilia patients.
Subject(s)
Cardiovascular Diseases/etiology , Hemophilia A/complications , Atherosclerosis , Hemophilia B/complications , Humans , Incidence , Risk Factors , ThrombosisABSTRACT
BACKGROUND: Paroxysmal atrial fibrillation is associated with various symptoms, including dizziness, which presumably reflects hemodynamic deterioration. Given the importance of the autonomic nervous system in mitigating the hemodynamic effect of atrial fibrillation, we hypothesized that autonomic function would be predictive of the severity of dizziness. METHODS: The study group comprised 73 patients with paroxysmal atrial fibrillation (mean age 54.1 years, 51 males). Forty-three (59%) patients had lone atrial fibrillation. Mean ventricular rate during atrial fibrillation was 99+/-16 beats/min. On average, patients had a 3-year history of one paroxysm per week lasting 2 h. Autonomic function was assessed using autonomic function tests, including noninvasive measurement of baroreflex sensitivity. Head up tilting was used to test vasovagal reactivity. Severity of dizziness at onset of atrial fibrillation was quantified by the patients using a five-point scale (1=none; 2=light; 3=mild; 4=moderate; and 5=severe). Multivariate analysis was performed to identify the independent predictors of the severity of dizziness. RESULTS: Mean severity of dizziness was 3.36+/-1.65. Multivariate predictors of moderate-to-severe dizziness as opposed to none-to-mild dizziness were a low 30-15 ratio after standing up and low baroreflex sensitivity. Though syncope was never reported nine patients showed a full vasovagal response during head up tilting. CONCLUSIONS: It is concluded that dizziness in patients with "treated" atrial fibrillation in the setting of none to mild structural heart disease is predicted by impaired autonomic function. Vasovagal reactivity appears not to be involved in this connection.
Subject(s)
Atrial Fibrillation/complications , Atrial Fibrillation/physiopathology , Autonomic Nervous System Diseases/complications , Autonomic Nervous System Diseases/physiopathology , Dizziness/etiology , Dizziness/physiopathology , Adult , Aged , Blood Pressure/physiology , Dizziness/psychology , Female , Health Status Indicators , Humans , Male , Middle Aged , Predictive Value of Tests , Sensitivity and Specificity , Severity of Illness Index , Surveys and Questionnaires , Valsalva Maneuver/physiology , Work of Breathing/physiologyABSTRACT
OBJECTIVES: Our purpose was to determine whether patients with persistent atrial fibrillation (AF) and patients with paroxysmal AF show alterations in potassium channel expression. BACKGROUND: Persistent AF is associated with a sustained shortening of the atrial action potential duration and atrial refractory period. Underlying molecular changes have not been studied in humans. We investigated whether a changed gene expression of specific potassium channels is associated with these changes in patients with persistent AF and in patients with paroxysmal AF. METHODS: Right atrial appendages were obtained from 8 patients with paroxysmal AF, 10 with persistent AF and 18 matched controls in sinus rhythm. All controls underwent coronary artery bypass surgery, whereas most AF patients underwent Cox's MAZE surgery (atrial arrhythmia surgery to cure AF) (n = 12). All patients had normal left ventricular function. mRNA (ribonucleic acid) levels were measured by semiquantitative polymerase chain reaction and protein content by Western blotting. RESULTS: mRNA levels of transient outward channel (Kv4.3), acetylcholine-dependent potassium channel (Kir3.4) and ATP-dependent potassium channel (Kir6.2) were reduced in patients with persistent AF (-35%, -47% and -36%, respectively, p < 0.05), whereas only Kv4.3 mRNA level was reduced in patients with paroxysmal AF (-29%, p = 0.03). No changes were found for Kv1.5 and HERG mRNA levels in either group. Protein levels of Kv4.3, Kv1.5 and Kir3.1 were reduced both in patients with persistent AF (-39%, -84% and -47%, respectively, p < 0.05) and in those with paroxysmal AF (-57%, -64%, and -40%, respectively, p < 0.05). CONCLUSIONS: Persistent AF is accompanied by reductions in mRNA and protein levels of several potassium channels. In patients with paroxysmal AF these reductions were observed predominantly at the protein level and not at the mRNA level, suggesting a post-transcriptional regulation.
Subject(s)
Atrial Fibrillation/physiopathology , Gene Expression Regulation/physiology , Heart Atria/physiopathology , Potassium Channels, Voltage-Gated , Potassium Channels/metabolism , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , RNA, Messenger/analysis , Shal Potassium Channels , Ventricular Function, LeftABSTRACT
INTRODUCTION: Activation of the endothelin system is an important compensatory mechanism that is activated during left ventricular dysfunction. Whether this system plays a role at the atrial level during atrial fibrillation (AF) has not been examined in detail. The purpose of this study was to investigate mRNA and protein expression levels of the endothelin system in AF patients with and without concomitant underlying valve disease. METHODS AND RESULTS: Right atrial appendages of 36 patients with either paroxysmal or persistent AF were compared with 36 controls in sinus rhythm. The mRNA amounts of pro-endothelin-1 (pro-ET-1), endothelin receptor A (ET-A), and endothelin receptor B (ET-B) were studied by semiquantitative polymerase chain reaction. Protein amounts of the receptors were investigated by slot-blot analysis. mRNA amounts of pro-ET-1 were increased (+40%; P = 0.002) only in AF patients with underlying valve disease. ET-A and ET-B receptor protein amounts were significantly reduced in patients with paroxysmal AF (-39% and -47%, respectively) and persistent AF with underlying valve disease (-28% and -30%, respectively) and in persistent AF without valve disease (-20% and -40%, respectively). ET-A mRNA expression was unaltered in paroxysmal and persistent AF, whereas ET-B mRNA was reduced by 30% in persistent AF with (P < 0.001) or without (P = 0.04) valve disease, but unchanged in paroxysmal AF. CONCLUSION: Substantial changes in gene expression of the endothelin system were observed in human atria during AF, especially in the presence of underlying valve disease. Alterations in endothelin expression associated with AF could play a role in the pathophysiology of AF and the progression of underlying heart disease.
Subject(s)
Atrial Fibrillation/physiopathology , Endothelins/metabolism , Aged , Endothelin-1 , Endothelins/genetics , Female , Glyceraldehyde-3-Phosphate Dehydrogenases/metabolism , Heart Atria , Humans , Male , Middle Aged , Myocardium/metabolism , Protein Isoforms/metabolism , Protein Precursors/genetics , Protein Precursors/metabolism , RNA, Messenger/metabolism , Reference ValuesABSTRACT
INTRODUCTION: Many relapses of atrial fibrillation (AF) occur, especially during the first week(s) after electrical cardioversion (ECV). The aim of the present study was to compare in a randomized design the efficacy of verapamil (intracellular calcium lowering) versus digoxin (calcium increasing) for maintenance of sinus rhythm after ECV. METHODS AND RESULTS: Ninety-seven patients with persistent AF were randomized to verapamil (n = 49) or digoxin (n = 48) for 1 month before and 1 month after ECV. The first month after ECV, patients recorded heart rhythm using daily transtelephonic monitoring. No additional antiarrhythmic drugs were given. Of the 97 patients, 43 patients (20 verapamil) underwent ECV per protocol. Median previous AF duration was 18 and 26 days for verapamil and digoxin, respectively. There were no differences in atrial dimensions and underlying heart disease between the two groups. The success rate of ECV was 75% versus 83% (P = NS). After 1 month, 47% versus 53% (P = NS) had recurrence of AF. Median time to recurrence was 5 days (range 0 to 26) versus 8 days (range 2 to 28) (P = NS), respectively. CONCLUSION: Stand-alone intracellular calcium lowering by verapamil around ECV does not enhance cardioversion outcome.