Sudden cardiac death, cardiac mortality, and morbidity in women. Electrocardiographic risk markers.

Cardiovascular disease is the leading cause of death worldwide both in women and in men. Majority of cardiac deaths are sudden and unexpected. Sudden cardiac death is often the first manifestation of cardiac disease. Coronary artery disease is the most common cause of sudden cardiac death. The erroneous perception that coronary artery disease would be men's disease is still strong even though most of the patients with coronary artery disease are elderly women. Especially among women, sudden cardiac death is often the first manifestation of the coronary artery disease. Recently, increasing interest has aroused in the field of use of the electrocardiogram as a risk stratification tool, yet studies taking account the gender differences are sparse.

In this thesis dissertation, the prognostic value of abnormalities in electrocardiogram for sudden cardiac death, cardiac death and cardiac morbidity was studied in women with different risk profiles. Five different study populations were exploited containing overall 25,482 electrocardiograms: one included sudden cardiac death victims undergone medico-legal autopsies in Northern Finland from 1998 to 2017, one patients with coronary artery disease and three others were vast general population based populations collected by Finnish Institute of Health and Welfare during 1966 - 2001.

The results of this thesis dissertation showed that cardiac death, sudden cardiac death and hospitalization for heart failure are more difficult to predict solely based on electrocardiogram in women than in men. Regardless of the adverse outcome, women had more often normal electrocardiogram compared to men. Also, the prevalence of electrocardiographic abnormalities tend to be lower in women. Only electrocardiographic sign of left ventricular hypertrophy was more typical finding in pre-mortem electrocardiogram of female sudden cardiac death victims compared to male victims, and it also had a greater prognostic value for cardiac death in women than in men in other study populations. Electrocardiographic sign of left ventricular hypertrophy was also the only prognostic electrocardiographic abnormality in women predicting hospitalization for heart failure, and it was not prognostic for heart failure hospitalization in men.

In addition, gender differences in etiology of sudden cardiac death were found. Non-ischemic sudden cardiac death was more common in women, and especially the role of primary myocardial fibrosis as a cause of death was pronounced. Results of this thesis dissertation contribute to a growing understanding of the different electrocardiographic risk profiles of men and women. Early identification of cardiac diseases is essential to improve the prognosis of the patients and to prevent sudden cardiac deaths. Search for novel risk factors continues to be an important research area.