Mariëlle Kloosterman succesfully defended her PhD thesis on Atrial Fibrillation

On Monday the 23th of November 2020, Mariëlle Kloosterman successfully defended her thesis entitled “Characterization of Different Patient Populations with Atrial Fibrillation” in the Academy Building of the University of Groningen. Due to the COVID-19 pandemic a maximum of 20 persons could be present in the Aula. Three members of the opposition took part online and the thesis was live-streamed.

Mariëlle is currently doing her internal medicine rotations at the Martini Hospital in Groningen as part of her clinical cardiology training. She hopes to apply for a personal research grant in the near future.

Congratulations Mariëlle! We wish you good luck in your future endeavours!

Supervisors: Prof. dr. Isabelle van Gelder, Prof. dr. Michiel Rienstra and dr. Alexander Maass.

Opponents: Prof. dr. Rudolf de Boer, Prof. dr. Frans Rutten, Prof. dr. Karina Meijer, Prof. dr. Dirk Jan van Veldhuisen, Prof. dr. Adriaan Voors and Prof. dr. Jeff Healey

Mariëlle: ‘Thankfully my family, friends and colleagues who were not able to be physically present in the Aula were able to watch the entire process online. It was a special and lovely day.’

A short summary of her work

Atrial fibrillation (AF) encompasses so much more than just an irregular heart rhythm and is one of the major chronic conditions and challenges in modern cardiology. Mariëlle’s thesis aimed to better characterize some multifaceted aspects of AF and consisted of sub-analyses from several large (inter)national studies.

She showed that almost all patients with AF have less-established or borderline risk factors upon closer examination. She also showed that women have more accumulation of risk factors than men and experience a lower quality of life. Nevertheless, women achieved uniform benefit in terms of effectiveness in maintaining short-term sinus rhythm and increase in quality of life as men when they receive a succesfull AF catheter ablation. She further showed that an AF genetic risk score, based on 97 single nucleotide polymorphisms (SNPs) associated with AF in patients from European ancestry, was associated with AF prevalence in patients with heart failure. Analyses of biomarker profiles in heart failure patients with AF revealed that the presence of AF was associated with a homogeneously elevated cardiovascular risk marker profile in patients with heart failure with reduced ejection fraction, whereas in heart failure with preserved ejection fraction, the presence of AF was associated with a more scattered risk marker profile.

The findings of this thesis show that attempting to better characterize patient populations can provide valuable insights. The risks associated with AF are predominately influenced by clinical risk factors and these risk factors provide opportunities for tailored therapy. Combined with a sex-sensitive approach, that acknowledges and recognizes that differences exist in risk factor profiles and treatment provided to women and men, may allow clinicians to improve the health of the individual patient, as well as the overall patient population. Genetic risk scores, and blood biomarkers may provide the first step in understanding how, and in whom, AF develops.


Check her complete thesis here

Atrial Fibrillation Research Team