Thesis defence in the University of Oulu

Doctoral Candidate

M.D. Henri Terho

Faculty and research unit

University of Oulu Graduate School, Faculty of Medicine, Medical Research Center Oulu, Internal Medicine

Field of study

Clinical Medicine

Date and time of the thesis defence

15.11.2019 12:00

Place of the thesis defence

Topic of the dissertation

Sydänsähkökäyrän riskitekijät sydänperäisille tapahtumille keski-ikäisessä väestössä

Opponent

Professor Pekka Raatikainen, Helsinki University Hospital, Cardiac Unit, Meilahti, Helsinki

Custos

Professor emeritus Heikki Huikuri, Oulun yliopistollinen sairaala, internal medicine

Abnormal ECG findings are associated with adverse cardiac events in middle-aged population

Aim of this thesis was to study abnormal electrocardiographic (ECG) findings for cardiac events in middle-aged population. Material used in this study consisted of almost 11 000 ECG recordings gathered in 1960s’ and 1970s’. The follow-up was 30±11 years.

The QRS-complex represents electrical function of cardiac ventricles. First study of this thesis focused on fragmentation of the QRS-complex (fQRS), which in general in thought of being a sing of damage in the heart muscle. The results suggested that subjects with fQRS had increased risk of cardiac death due to ischemia (impaired oxygen supply of the heart muscle) and arrhythmia. The risk was present in those subjects who had underlying cardiac disease and fQRS in leads concerning left ventricle (lateral leads).

The aim of the second and third study was to evaluate other abnormal ECG findings to cardiac events in subjects with a known cardiac disease. In the second study subjects with abnormal ECG had moderately elevated risk of cardiac death after 10- and 30 years of follow-up. Abnormal ECG did not increase the risk of hospitalization. According to the results of the third publication, the risk of sudden arrhythmic death was almost 3-fold in subjects with ≥2 abnormal ECG findings compared to those with normal ECG.

Cardiovascular diseases are still one of the most common causes of death even though prevention of cardiac diseases has improved markedly in the past decades. The prevention of sudden arrhythmic death remains challenging. As the main finding of this thesis, ECG provides valuable information of the cardiac function, thus is important part of clinical examination. Future studies should focus on evaluation of different ECG abnormalities in risk prediction for cardiac events and cumulative risk of these abnormalities should be noticed.

Dissertation

Last updated: 8.11.2019