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Biomedical subjects

H J G M Crijns

Publications and source records attributed to H J G M Crijns.

18 recordsLinked to original sources
PubMed2007

Antithrombotic drug prescription in atrial fibrillation and its rationale among general practitioners, internists and cardiologists in The Netherlands--The EXAMINE-AF study. A questionnaire survey.

The objective of the EXAMINE-AF study was to record and compare antithrombotic treatment in patients with atrial fibrillation (AF) in daily clinical practice of general practitioners, internists and cardiologists in the Netherlands. Eighty-six general practitioners, 93 internists and 99 cardiologists responded to postal questionnaires and enrolled 1596 patients: 365, 351 and 880 respectively. A cardiologist was indicated to be the main treating physician for AF in 82% of all patients; current antithrombotic treatment was initiated in 80% by a cardiologist. Of all patients, 84% were at high risk for stroke and therefore were eligible for oral anticoagulation treatment, but only 64% actually received this. Cardiologists instituted appropriate antithrombotic treatment best, compared with general practitioners and internists (70% vs. 58% and 55%; p < 0.001). Positive predictive factors for oral anticoagulation prescription were previous stroke/transient ischaemic attack (OR, 2.31; 95% CI, 1.33-4.02) and heart failure (OR, 1.72; 95% CI, 1.23-2.42). Contraindications for oral anticoagulation (OR, 0.46; 95% CI, 0.32-0.68), treatment by a general practitioner (OR, 0.29; 95% CI, 0.20-0.42) or internist (OR, 0.24; 95% CI, 0.15-0.39) were important factors for withholding treatment. Antithrombotic treatment in AF patients is well instituted in primary and secondary care in the Netherlands. Cardiologists play a key role in the diagnosis and management of the majority of AF patients, even in those regularly attending other physicians. Factors for oral anticoagulation prescription are heart failure, physician specialty and contraindications. Availability of guidelines seems instrumental for application of appropriate antithrombotic treatment.

Adolescent↗
PubMed2006

Which factors are associated with the application of reperfusion therapy in ST-elevation acute coronary syndromes?. Lessons from the Euro Heart Survey on Acute Coronary Syndromes I.

BACKGROUND/AIMS: A large proportion of patients with a ST-elevation acute coronary syndrome do not receive reperfusion therapy. In order to contribute to a better understanding of the clinical decision making process, we analyzed which factors are associated with the application of reperfusion therapy. METHODS: From the Euro Heart Survey of Acute Coronary Syndromes I, 4,260 patients with ST-elevation acute coronary syndrome were selected for the current analysis, of which 1,539 (36%) patients received fibrinolysis and 904 (21%) primary percutaneous coronary intervention (PCI). The analysis contained 32 variables on demographics, medical history, admission parameters and reperfusion therapy. RESULTS: A short pre-hospital delay, arrival in a hospital with PCI facilities, severe ST-elevation, and participation in a clinical trial were the strongest predictors for receiving reperfusion therapy. Primary PCI was more likely to be performed than fibrinolysis in patients with a long pre-hospital delay, arriving in a hospital with PCI facilities, not participating in a clinical trial, and with at least one previous PCI. CONCLUSION: Hospital facilities and culture, pre-hospital delay and infarction size play a major role in management decisions regarding reperfusion therapy in ST-elevation acute coronary syndrome. This analysis indicates which factors require special attention when implementing and reviewing the reperfusion guidelines.

Aged↗
PubMed2005

A-type lamins are essential for TGF-beta1 induced PP2A to dephosphorylate transcription factors.

Diseases caused by mutations in lamins A and C (laminopathies) suggest a crucial role for A-type lamins in different cellular processes. Laminopathies mostly affect tissues of mesenchymal origin. As transforming growth factor-beta1 (TGF-beta1) signalling impinges on the retinoblastoma protein (pRB) and SMADs, we tested the hypothesis that lamins modulate cellular responses to TGF-beta1 signalling, via the regulation of these transcription factors in mesenchymal cells. Here, we report that A-type lamins are essential for the inhibition of fibroblast proliferation by TGF-beta1. TGF-beta1 dephosphorylated pRB through PP2A, both of which, we show, are associated with lamin A/C. In addition, lamin A/C modulates the effect of TGF-beta1 on collagen production, a marker of mesenchymal differentiation. Our findings implicate lamin A/C in control of gene activity downstream of TGF-beta1, via nuclear phosphatases such as PP2A. This biological function provides a novel explanation for the observed mesenchymal dysfunction in laminopathies.

Animals↗
PubMed2005

[Cardiac sarcoidosis: improved prognosis through new diagnostic tests and treatment].

Cardiac sarcoidosis was diagnosed in 3 patients: 2 men aged 52 and 51 years, respectively, and a woman aged 55 years. Both men had ventricular tachycardia. In the first man, a right-ventricle biopsy revealed a non-caseating granuloma. The second man had active granulomatous cardiac infiltration, according to a gallium scintigram. The first man recovered after receiving immunosuppression, heart-failure medication, and an implantable defibrillator; the second received the same plus radio-frequency catheter ablation, but experienced serious heart failure. The woman was being treated for pulmonary sarcoidosis but complained of progressive cardiac symptoms. She recovered after receiving heart-failure medication, immunosuppression, and a biventricular pacemaker. Sarcoidosis is a multi-system granulomatous disorder of unknown aetiology with cardiac involvement in 20 to 30% of patients, resulting in severe morbidity and mortality. With the help ofgadolinium MRI and positron emission tomography (PET), these conditions can be detected at an earlier stage, which allows for improved evaluation of the efficacy of available therapies. The use of resynchronisation therapy and implantable defibrillators has improved the prognosis of patients with cardiac sarcoidosis.

Cardiomyopathies↗
PubMed2005

End-diastolic myofiber stress and ejection strain increase with ventricular volume overload--Serial in-vivo analyses in dogs with complete atrioventricular block.

BACKGROUND: Myocardial stress and strain are considered primary mechanical stimuli for hypertrophic remodeling. Their values and significance in the intact beating heart during chronic overload remain poorly characterized. METHODS AND RESULTS: Left-ventricular (LV) dimensions (echocardiography) and pressure (invasive) were simultaneously recorded in anesthetized dogs at sinus rhythm (SR), acute and 1, 2, 6, 12 weeks of atrioventricular block (AVB), leading to structural, electrical and contractile remodeling. Mechanical load of the myocardium was quantified as myofiber stress (sigma(f)), being force along myofiber orientation per cross-sectional area, and natural myofiber strain (e(f)), being change in natural logarithm of myofiber length (l) divided by its reference length: e(f) = ln(l/l(ref)). Time courses of sigma(f) and e(f) were calculated from LV pressure and dimensions, using a validated mathematical model of cardiac mechanics. End-diastolic sigmaf increased from 2.0 +/- 0.1 kPa at SR to 3.4 +/- 0.3 kPa at acute AVB, remaining elevated for > 6 weeks. Systolic sigma(f) was not affected by AVB. Ejection strain rose instantly upon AVB, reaching a maximum at 2 weeks: 0.24 +/- 0.02 vs. 0.10 +/- 0.01 at SR. The increase of myofiber stroke work (sigma(f)-e(f) loop area) from 3.1 +/- 0.3 at SR to 6.0 +/- 0.5 kJ/m(3)/beat at 1 week AVB was attributed mainly to an increase of strain during ejection. Stroke work and ejection strain remained elevated up to 12 weeks. The rate of LV-mass increase was maximal (2.2 +/- 0.4 g/day) at 1 week AVB. CONCLUSIONS: Serial mechanical phenotyping is feasible in the intact anesthetized dog with chronic ventricular overload. Our new approach yields values of mechanical load that are comparable to those found in isolated myocardium by others. In chronic AVB, both end-diastolic myofiber stress and ejection strain are increased. Early increases of both parameters coincide with peak hypertrophic growth, suggesting their important role for mechanotransduction. Peak systolic sigmaf is likely not important for hypertrophy in this model, since it does not change throughout the experiment.

Animals↗
PubMed2005

Radiofrequency ablation of atrial arrhythmias after previous open-heart surgery.

AIM: To report the results of ablation of atrial arrhythmias (AA) after previous open-heart surgery. METHODS: Nineteen patients [50+/-11 years, 11 women] underwent ablation of symptomatic AAs after previous open-heart surgery. In 11 patients mapping was performed using conventional multielectrode catheters. In the other eight patients CARTO electro-anatomical mapping system was used to supplement conventional mapping. RESULTS: After conventional mapping, 10/11 patients (91%) were found to have typical atrial flutter (AFL). The cavotricuspid isthmus was successfully ablated in these 10 patients. CARTO combined with conventional mapping showed that 7 of 8 patients had one macro-reentry right atrial circuit. The remaining patient had two focal atrial tachycardias. CARTO-guided ablation was successful in all eight patients (100%). After follow-up of 12+/-11 months, 2/18 patients (11%) had recurrence of either the same (n=1) or a new (n=1) AA. CONCLUSIONS: AAs after previous open-heart surgery can be ablated successfully (>90%) with a low recurrence rate (11%) at 1-year follow-up. Typical AFL was found frequently (14/19 patients, 72%). This could be ablated successfully, often, after conventional mapping alone. CARTO helps to uncover peri-scar reentry and guide the ablation by creating a line of block connecting the scar to another landmark (unconventional isthmus).

Atrial Flutter↗
PubMed2004

[The practice guideline 'atrial fibrillation' from the Dutch College of General Practitioners; a response from the perspective of cardiology].

Stroke is the most important complication of atrial fibrillation. The new practice guideline 'Atrial fibrillation' from the Dutch College of General Practitioners strongly advocates active detection of atrial fibrillation and antithrombotic treatment guided by stroke-risk stratification in order to decrease the risk of stroke. The stratification scheme it proposes skips age as a parameter. Instead, the general practitioners propose exclusive use of clinical risk factors such as previous stroke, hypertension, heart failure, coronary artery disease and diabetes. The practice guideline advocates abandoning rhythm control unless the patient is symptomatic and physically fit. The guideline also advocates referral to a cardiologist of a physically fit patient who is younger than the arbitrary age of 65 years. In summary, the new guideline is timely and appears after many new studies have provided important evidence for the optimal diagnosis and treatment of this frequent type of arrhythmia. This guideline will contribute significantly, not only to the improvement of daily clinical practice but also to scientific research. Both electrocardiography and echocardiography can be expected to play a larger role in the future in the patient with atrial fibrillation who is first seen by the general practitioner.

Anticoagulants↗
PubMed2004

Radiofrequency ablation of atrial fibrillation.

UNLABELLED: Twenty-five patients (16 males, mean age 46 years) underwent radiofrequency ablation because of either paroxysmal (13 patients) or persistent atrial fibrillation (12 patients). Ablation aimed at earliest activation of spontaneous and catheter-induced repetitive ectopy in left and right atria and appendages, and pulmonary veins. Catheter-induced repetitive ectopy was defined as acute onset of a burst of rapid atrial premature beats on touching the wall, sustained irritability while at the spot and acute termination of rapid activity upon release of the catheter. Post-ablation patients received antiarrhythmic drugs to prevent tachycardias, thereby allowing reversal of atrial remodeling. RESULTS: Lone atrial fibrillation was present in 19 patients, 4 patients had hypertension and 2 patients coronary artery disease with preserved left ventricular function. The median duration of the history of atrial fibrillation was 4 years (range 1-14 years) and the median number of antiarrhythmic drug failures 5 (range 1-6). Ablation was successful, i.e. no recurrences of atrial fibrillation with or without antiarrhythmic drugs in eight patients (32%) during a median follow-up of 28 months (range 18-52). The median number of foci was 3 (range 2-6) and 2 (range 1-7) in the successfully and unsuccessfully treated patients, respectively. Minor complications occurred in three patients. CONCLUSIONS: Radiofrequency ablation of atrial fibrillation aiming at spontaneous and catheter-induced repetitive ectopy is a safe procedure. However, it is only successful in one third of the patients. Further investigations are warranted to identify the ideal patient, as well as to develop better ablation strategies.

Anti-Arrhythmia Agents↗
PubMed2004

Cardiac involvement of Churg Strauss syndrome demonstrated by magnetic resonance imaging.

Churg Strauss syndrome (CSS) may lead to cardiac involvement in up to 60% of patients. The myocardium, coronary vasculature, valves and pericardium may be affected. This results in significant morbidity and mortality, accounting for 48% of deaths due to CSS. Cardiac magnetic resonance imaging (CMR) is used to evaluate cardiac structure and function, and is able to evaluate myocardial perfusion and delineate scar tissue. We are the first to demonstrate these features in a 53-year-old CSS patient who presented with palpitations and atypical chest pains, and was found to have myocardial perfusion defects and scar tissue, most likely secondary to vasculitis of the small myocardial vasculature and myocardial infiltration.

Churg-Strauss Syndrome↗
PubMed2002

Microalbuminuria is related to marked end organ damage in previously untreated, elderly hypertensive patients.

We wondered whether, in an elderly hypertensive population in a primary prevention setting, free from diabetes mellitus and clinical atherosclerosis, differences between end organ damage and microalbuminuria (MA) could be found using a lower level of urinary albumin excretion than that of classically defined MA. From a population survey of 173 previously untreated hypertensive patients (4x blood pressure systolic > or = 160 and < or = 220 mmHg, and/or diastolic > or = 95 and < or = 115 mmHg), mean age 67 +/- 4 years, were screened for MA (defined as albumin excretion between 20 and 300 mg/24 h). End organ damage was determined by B-mode ultrasound scanning of carotid and femoral arteries and echocardiography. Out of 173 hypertensives, 14 showed MA (8%). These hypertensives had a significantly higher intima media thickness (IMT; 1.01 +/- 0.21 vs 0.88 +/- 0.6 mm, p < 0.05) and increased left ventricular mass index (118 +/- 31 vs 103 +/- 22 g/m2, p < 0.05) than hypertensives without MA. Linear regression analysis showed that MA, age, male gender and diastolic blood pressure were independently related to IMT, while systolic blood pressure, male gender and body mass index were independently related to left ventricular mass. Even using lower levels of urinary albumin excretion rate, patients with MA had significantly higher IMT and increased left ventricular mass. Moreover, MA was independently related to IMT in these elderly hypertensives. These results suggest that the threshold value for MA should be reconsidered in hypertension.

Aged↗