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Atrial tachyarrhythmias are the most common cardiac arrhythmias affecting millions of people worldwide. We investigated the detection and invasive ablation treatment of these heart rhythm disturbances and present the results in this thesis. In Part I, we validated an automated photoplethysmography atrial fibrillation (AF) detection algorithm. We found that this algorithm had excellent test characteristics to detect AF by omitting uncertain rhythm outcomes, with a corresponding sensitivity of 98.1% (95% CI 93.4 – 99.8) and specificity of 98.1% (95% CI 93.2 – 99.8%). In part II, we present the long-term outcome of cryoballoon ablation in patients with persistent AF, the efficacy of non-pulmonary vein (PV) target ablation in patients undergoing repeat AF ablation, and the additional value of mini electrodes in cavotricuspid isthmus ablation. The most important findings are i) 3.7 years after cryoballoon ablation, a substantial number of patients had an AF relapse. However, 80% of the patients improved in AF-related symptoms, and patients scored a high quality of life. ii) Non-PV target ablation did not improve arrhythmia free survival and was associated with a higher AT recurrence incidence. iii) The use of mini-electrodes in cavotricuspid isthmus ablation had additional value in only a small number of patients. In Part III of this thesis, we describe the safety outcomes of AF ablation using data from the Netherlands Heart Registration. The registered complication incidence of AF ablation was 3.6% and 30-day mortality was only 0.05%. We found that females had an increased risk of developing a cardiac tamponade, vascular complication, and phrenic nerve palsy.

Molaren van acht soorten grote herbivoren (reuzenhert Megaloceros giganteus, edelhert Cervus elaphus, rendier Rangifer tarandus, eland Alces alces, steppewisent Bison priscus, muskusos Ovibos moschatus, wolharige neushoorn Coelodonta antiquitatis en bosneushoorn Stephanorhinus kirchbergensis) werden ex situ verzameld uit opgebaggerde pleistocene en Holocene zandafzettingen uit de Noordzee en uit Nederlandse vindplaatsen in het binnenland. In de plooien van vele molaren bevonden zich gekauwde plantenresten en daarbij ook microfossielen. We determineerden pollen (stuifmeel) en sporen en interpreteren op basis hiervan voedselkeuzes en de mogelijke effecten op de pollenspectra als een deel van het bloeiseizoen vertegenwoordigd is. We bediscussiëren ook de effecten van de veranderende vegetatiesamenstelling in relatie tot het klimaat en de ouderdom van de molaren. Verschillende factoren hebben bijgedragen aan de samenstelling van het pollen. Toch geven de pollenspectra een beeld van de vegetatie en kunnen we de voedselkeuze en de ouderdom afleiden en krijgen we een beeld van de landschapstypen, van subarctische open gebieden tot interglaciaal bos. Ecologische en statistische analyses van de resultaten laten verschillen zien tussen de voedselkeuze van, en de beschikbaarheid van plantensoorten voor de verschillende zoogdiersoorten. Deze bijdrage is gebaseerd op een artikel dat eerder in Quaternary Science Reviews verscheen. -- Molars of eight large herbivore species (Megaloceros giganteus, Cervus elaphus, Rangifer tarandus, Alces alces, Bison priscus, Ovibos moschatus, Coelodonta antiquitatis and Stephanorhinus kirchbergensis) were collected ex situ from Pleistocene and Holocene sands dredged in the North Sea, and from Dutch inland sites. Folds in many molars contained compacted masticated plant remains, and also microfossils. We identified pollen, spores, and non-pollen palynomorphs and on this basis interpret food preferences, represented flowering seasons, or parts of flowering seasons. We also discuss effects of changing vegetation composition in relation to climate and age of the molars, based on the pollen spectra. Various confounding factors have contributed to the recorded pollen composition, but nevertheless the pollen spectra show valuable aspects of vegetation composition, food choice, age, and landscapes, from subarctic open areas to interglacial forest. Ecological and statistical analysis of the results shows dietary differences between the mammal species analyzed. This contribution is based on a paper that appeared in Quaternary Science Reviews.

The molar of a giant deer, Megaloceros giganteus (Blumenbach, 1799), was discovered in sandy deposits of the North Sea, about 10 km west of the present shoreline of the Netherlands. Compacted masticated plant remains were preserved in the molar's deep folds. A palaeoecological analysis of these plant remains shows the complete dominance of pollen from Artemisia (sage) and other Asteraceae Tubuliflorae (Compositae), indicating that the animal foraged in a steppe environment, and may have preferred to eat Artemisia, which contain a high level of nutrients such as calcium and phosphorous components, which are important for antler building. Radiocarbon dating indicates that the plant remains are of mid‐Weichselian age [38 570 (+300, −290) 14C a BP, Greenland Interstadial‐11]. This is the first study of the food choice of M. giganteus based on palaeoecological evidence. We hypothesize about links between the extirpation of M. giganteus at the onset of the Holocene in North‐West Europe and the transition from a landscape with highly dynamic geomorphological processes and consequently prevalence of immature and nutrient‐rich soils, to a less dynamic landscape with stable, leached and acidifying soils, and the decline of Artemisia and other calciphilous plants.

Humans colonized the Balearic Islands 5-4. ka ago. They arrived in a uniquely adapted ecosystem with the Balearic mountain goat Myotragus balearicus (Bovidae, Antilopinae, Caprini) as the only large mammal. This mammal went extinct rapidly after human arrival. Several hypotheses have been proposed to explain the extinction of M. balearicus. For the present study ancient DNA analysis (Sanger sequencing, Roche-454, Ion Torrent), and pollen and macrofossil analyses were performed on preserved coprolites from M. balearicus, providing information on its diet and paleo-environment. The information retrieved shows that M. balearicus was heavily dependent on the Balearic box species Buxus balearica during at least part of the year, and that it was most probably a browser. Hindcast ecological niche modelling of B. balearica shows that local distribution of this plant species was affected by climate changes. This suggests that the extinction of M. balearicus can be related to the decline and regional extinction of a plant species that formed a major component of its diet. The vegetation change is thought to be caused by increased aridity occurring throughout the Mediterranean. Previous hypotheses relating the extinction of M. balearicus directly to the arrival of humans on the islands must therefore be adjusted.

Grommets or not? This reviews the indications for grommets.

Tijdens de ijstijden van het Pleistoceen lag de Noordzee droog. Het leek wel een koude, droge Serengeti. In dit rijk geïllustreerde boek komen de dieren voorbij die in de verschillende perioden op de Noordzeebodem leefden. De auteurs verzamelden hun botten op de visafslag of haalden ze hoogstpersoonlijk van de zeebodem omhoog. Ze bestudeerden de bijbehorende stuifmeelkorrels om het landschap te reconstrueren, ze dateerden de vondsten met radioactief koolstof en ze zochten en vonden sporen van menselijke bewoning. Deze Kleine Encyclopedie is daarmee haast een reportage uit de eerste hand over het leven in het Pleistoceen.