Photo: Øystein Horgmo, UiO
Espen Bøe, MD, PhD, Researcher at Department of Cardiology, Oslo University Hospital, Cardiologist at Department of Cardiology, Akerhus University Hospital
Bøe completed his MD at University of Newcastle, Australia in 2005. After his internship at Haukeland University Hospital and a year in the Military, he worked in internal medicine at Akershus University Hospital before starting as a PhD student. Bøe has also taken a Master’s degree in health leadership, quality improvement and health economics at the University of Bergen. His research focuses on cardiac mechanics in LV dyssynchrony and ischemia.
Bøe successfully defended his PhD thesis "Evaluation of left ventricular function by pressure-volume and pressure-dimension analyses: Studies in myocardial ischemia and ventricular dyssynchrony" in June 2018. In this thesis, pressure-volume and pressure-dimension analyses, during ventricular pacing (experimentally) and myocardial ischemia (clinically), were used to investigate regional and global left ventricular (LV) function.
First, potential beneficial mechanisms of cardiac resynchronization therapy (CRT) and LV pacing in heart failure with narrow QRS were explored. LV pacing improved LV filling during baseline and heart failure with increased external constraint, however, systolic function was impaired by CRT and LV pacing due to pacing-induced dyssynchrony.
In a similar fashion, the acute effect of CRT on ventricular function during left bundle branch block was assessed using both load-dependent and load-independent parameters. CRT improved LV performance acutely by increasing ventricular efficiency demonstrated by unaltered or increased parameters of systolic function at a reduced preload. The reduction in preload attenuated CRT related improvements in conventional parameters of systolic function, which are used clinically.
Finally, in a clinical study, a non-invasive method of calculating regional myocardial work was compared to strain echocardiography at identifying acute coronary occlusion (ACO) in patients with non-ST-elevation acute coronary syndrome. The myocardial work index identified ACO with a higher sensitivity and specificity compared to strain. Further analysis showed that strain was sensitive to changes in load.
This research contributes to the understanding and assessment of CRT’s effect on cardiac function during normal and dyssynchronous electrical activation. Further, it shows that the myocardial work index was superior to current echocardiographic methods by accounting for the effect of load on myocardial shortening. The thesis demonstrates the ongoing need for experimental studies and pressure-volume analysis to understand current topics in cardiology.