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Biomedical subjects

Jens Haarbo

Publications and source records attributed to Jens Haarbo.

8 recordsLinked to original sources
PubMed2006

Impact of implantable defibrillators and resynchronization therapy on outcome in patients with left ventricular dysfunction--a meta-analysis.

BACKGROUND: The clinical benefits of cardiac resynchronization therapy (CRT) and primary prophylactic implantable cardioverter defibrillator (ICD) in patients with left ventricular systolic dysfunction (LVSD) are debated. OBJECTIVE: To evaluate by a meta-analysis the effect of CRT and prophylactic ICD therapy in patients with LVSD. METHODS: Eligible trials evaluating the effect of CRT vs. no-CRT, ICD vs. no-ICD and adding ICD to CRT vs. no-ICD were selected and meta-analyzed. The outcomes were: all cause mortality, cardiac mortality, hospitalization for heart failure and change in exercise tolerance and New York Heart Association class. RESULTS: Implantation of CRT reduced all cause mortality odds ratio (OR) = 0.73 (0.60-0.89) p = 0.002 and hospitalization for heart failure OR = 0.60 (0.45, 0.80) p = 0.001, increased peak oxygen consumption by 1.77 (0.32-3.22) ml/kg/min p = 0.017 and improved New York Heart Association class by at least one class with OR = 1.52 (1.30, 1.77) p < 0.0001. Implantation of ICD reduced all-cause mortality OR = 0.75 (0.59-0.96) p = 0.025 and cardiac mortality OR = 0.63 (0.48, 0.82) p = 0.001. Adding ICD to CRT reduced all cause mortality OR = 0.69 (0.53-0.91) p = 0.008. CONCLUSION: Selective patients with LVSD benefit from CRT, ICD or both. Further investigations are necessary to clarify which patients benefit most from a single or combined device implantation.

Defibrillators, Implantable↗
PubMed2005

Phase 2 reentry in man.

BACKGROUND: Ventricular extrasystoles are characterized by a fixed coupling interval to the last QRST complex preceding it. OBJECTIVES: We hypothesized that this QRST complex differed from QRST complexes of other sinus beats not followed by ventricular extrasystoles. Further, we investigated whether phase 2 reentry, demonstrated in animal experiments to initiate ventricular extrasystoles, ventricular tachycardia, and ventricular fibrillation, also plays a role in humans. METHODS: We examined 18 patients with ventricular extrasystoles and/or ventricular tachycardia by signal averaging of the ECG (group A) or by single-beat analysis of intracardiac electrograms (group B). Group A consisted of six patients without structural heart disease and one patient with the Brugada syndrome. Six of the seven patients had right ventricular outflow tract ventricular extrasystoles. Group B consisted of 11 patients undergoing radiofrequency ablation. Eight of the 11 patients had right ventricular outflow tract extrasystoles. RESULTS: In six of the seven patients in group A, we demonstrated significant ST-elevation and/or T-wave changes in the sinus beat preceding ventricular extrasystoles compared with the second last sinus beat in one or more of the three orthogonal leads X, Y, and Z. In 9 of the 11 patients in group B, single-beat analysis of unipolar and bipolar electrograms recorded close to successful ablation sites demonstrated similar changes, that is, ST-elevation (median peak voltage gradient 150 muV, range 0-1,700) and T-wave changes in the sinus beat prior to ventricular ectopy. In addition, J-point elevation was demonstrated in several cases. In total, significant changes were demonstrated in 15 of the 18 patients studied (83%). CONCLUSION: J-point elevation, ST-elevation, and T-wave changes documented in the last sinus beat prior to ventricular extrasystoles are in agreement with phase 2 reentry, suggesting that this may be the responsible mechanism for ventricular extrasystoles and ventricular tachycardia/fibrillation. The phenomenon has been demonstrated in only animal experiments to date.

Adult↗
PubMed2004

Associated response in bone and lipids during hormone replacement therapy.

OBJECTIVE: In postmenopausal women, we investigated if the response in bone mineral density (BMD) was associated with the response in the atherogenic lipid profile during hormone replacement therapy. METHODS: We performed an exploratory, post-hoc analysis of data from a prospective double-blind placebo-controlled trial. Healthy postmenopausal women were randomised into five groups, each receiving different combinations of 17 beta-estradiol and gestodene or placebo. A total of 133 women completed the study. The study period was 3 years. The response in bone mass was expressed as the percentage change in BMD from baseline calculated by linear regression from semi-annual measurements. The change in lipid profile was evaluated as the average of three mid-cycle and end-cycle values in percentage from baseline in order to account for cyclic changes during sequential hormone therapy. RESULTS: A significant correlation between the increase in BMD of the spine and hip and forearm with the decrease in serum low density lipoprotein (LDL) and cholesterol was found. Additionally, the decrease in atherogenic lipids correlated significantly with the response in biochemical bone markers for resorption and formation. CONCLUSION: In conclusion, our study shows that it is the same women who have a favourable response in BMD as in the lipid-profile during hormone replacement therapy (HRT). The association is most likely driven by a common response in FSH to exogenous estradiol therapy. This indicates that common denominators for the response to HRT exist. Further studies are needed to explore and identify such predictors.

Biomarkers↗
PubMed2004

Impact of premature atrial contractions in atrial fibrillation.

In spite of the increasing knowledge about paroxysmal atrial fibrillation (PAF), details on mode of initiation in unselected patients are scarce. This paper focuses on trigger mechanisms of spontaneous onset of AF in consecutive patients with PAF. One hundred eight consecutive patients with two or more ECG documented AF episodes within the previous year had a 24-hours Holter recording performed. All AF episodes (n = 157) were reviewed and, within the last 10 beats prior to AF initiation. PP intervals were measured on 25 mm/s paper printouts and premature atrial contractions (PACs) were counted. Additionally, randomly selected coupling intervals (PP') for PACs not triggering AF were measured and compared to AF triggering intervals and to PP' intervals from healthy controls. PACs preceded all AF episodes. AF initiation displayed a wide variety in terms of PP coupling intervals and number of PACs prior to initiation within and between subjects. In episodes with PACs within the last 10 beats prior to initiation, we observed a long-short PP sequence at the time of initiation. Mean PP' interval (+/- SE) for AF triggering PACs was 403 +/- 9 ms, significantly shorter, P < 0.0001, than PP' for nontriggering PACs (584 +/- 8 ms) and PACs in healthy controls (589 +/- 6 ms). However, a large proportion of nontriggering PACs had short PP' coupling intervals without triggering AF. These observations highlight the importance of other factors than the trigger per se, such as the arrhythmogenic substrate, and suggest that therapeutic maneuvers aimed at curing PAF should target these as well as the trigger mechanisms.

Aged↗
PubMed2003

[Out-of-hospital cardiac arrest. Mechanisms and treatment with automated external defibrillator].

In Denmark, approximately 4500 persons suffer yearly from an out-of-hospital cardiac arrest with mortality close to 100%. The principal arrhythmia is ventricular fibrillation, which can only be treated effectively with prompt external defibrillation. Automatic external defibrillators (AED) are small, portable, easily operated devices. They have documented high specificity and sensitivity. Moreover, biphasic automatic external defibrillators are at least as effective as traditional monophasic defibrillators. Survival rates with good neurological status as high as 60% have been reported. Better survival of out-of-hospital cardiac arrest victims requires, however, improvements throughout the chain of survival, not only more automatic external defibrillators. Therefore, the health care system has to discuss thoroughly and solve important questions regarding organisation, logistics, education, and legal aspects in order to improve survival for out-of-hospital cardiac arrest victims.

Automation↗
PubMed2003

Paroxysmal atrial fibrillation: ectopic atrial activity and prevalence of severely symptomatic patients.

Catheter ablation is a promising approach in severely symptomatic patients with paroxysmal atrial fibrillation (PAF). Until this time it has only been performed in highly selected patients with weekly episodes and frequent premature atrial contractions (PACs). The aim of the present study was to estimate the prevalence of severely symptomatic patients with PAF and to evaluate the significance of PACs. The files of 7,447 consecutive patients were screened and 1,357 PAF patients identified. Holter recordings were performed in 108 patients with >/=2 spontaneous AF episodes. Despite antiarrhythmic treatment, 6.5% (1.8-11.1%) had a history of weekly PAF episodes. 29.2% of patients and 10% of healthy, age-matched controls had more than 700 PACs. The number of PACs was inversely related to the reported numbers of previous episodes and directly related to age and size of left atrium. We estimate that about 6.5% of patients with PAF are severely symptomatic and might benefit from catheter ablation. Our data suggest that the number of PACs should not be used as a selection criterion for catheter ablation. Frequent PACs are seen in a substantial proportion of elderly healthy individuals.

Adult↗
PubMed2003

Lack of difference among progestins on the anti-atherogenic effect of ethinyl estradiol: a rabbit study.

BACKGROUND: Progestins in combination with estrogen are believed to have different effects on the cardiovascular system. The aim of this study was to investigate the influence of different oral contraceptive formulations on the development of experimental atherosclerosis and vascular reactivity. METHODS: A total of 160 sexually mature rabbits were ovariectomized and randomly assigned to equally large groups: (i) a cholesterol-rich diet (320 mg/day), either given alone (placebo), or together with (ii) ethinyl estradiol (EE 70 micro g/day, oral), (iii) desogestrel (DSG 525 micro g/day, oral), (iv) gestodene (GSD 262.5 micro g/day, oral), (v) levonorgestrel (LNG 525 micro g/day, oral), (vi) EE + DSG, (vii) EE + LNG, or (viii) EE + GSD. After 31 weeks of treatment, aortic accumulation of cholesterol and vascular vasoreactivity (in vitro) were determined. RESULTS: Progestins alone did not reduce the accumulation of cholesterol. EE alone or in combination with a progestin reduced the accumulation of cholesterol relative to placebo (P < 0.0001). Isolated vessels from EE-treated animals relaxed significantly more to physiological concentrations of acetylcholine than did placebo (P < 0.001), whereas vessels treated with EE plus a progestin showed an intermediate response. CONCLUSION: The progestins investigated can be combined with EE without attenuating the anti-atherogenic effect of EE.

Animals↗