ABSTRACT
BACKGROUND: Recently, cardiac resynchronization therapy, by using biventricular pacemakers, has become implemented in the treatment of patients with severe heart failure. However, using the classical inclusion criteria, 30 % of patients treated with resynchronization do not improve symptoms or activity level. Phase analysis of radionuclide ventriculography gives information about pattern of ventricular contraction and may detect dyssynchrony. The method may therefore be used to select patients with dyssynctrony to resynchronization therapy. In this study we have investigated the amount of dyssynchrony, by using phase analysis of radionuclide ventriculography, in men and women as a function of left ventricular ejection fraction. MATERIAL AND METHODS: The study is based on 1 266 radionuclide ventriculographies performed at Section of Nuclear Medicine, University Hospital North-Norway, during 1998 - 2006. The relationship between left ventricular ejection fraction and number of patients with ventricular dyssynchrony was investigated. 90 patients with no known heart problems were considered as reference values for synchrony data. RESULTS: The phase analysis showed that 35 % of the women and 34 % of the men with left ventricular ejection fraction below 35 % had both inter- and intra-ventricular dyssynchrony. INTERPRETATION: Today's criteria for including patients to resynchonizing therapy are not good enough. Phase analysis of radionuclide ventriculography of patients with left ventricular ejection fraction below 35 % shows that one third of the patients have both inter- and intra- ventricular dyssynchrony. These patients might be responders to resynchronization therapy.
