Risk Factors of Ventricular Fibrillation in Chronic Heart Disease

Overview

The objective was to describe in subjects with spontaneous ventricular fibrillation (VF), after ruling out acute heart disease, some conditions for the development of this arrhythmia (pathophysiological, epidemiological, occupational, motor and chronobiological factors).The authors included in the investigated group 46 patients (39 men and 7 women), age bracket 24 to 78 years (mean age 59±12 years) with spontaneous VF without acute heart disease, who did not die within three months after this tachyarrhythmia. 39 subjects suffered according to selective coronarography from ischaemic heart disease. The authors investigated in all patients the presence of the main risk factors of ischaemic heart disease (hyperlipidaemia, smoking, hypertension, diabetes) and alcohol consumption. They evaluated the physical activity during work incl. emotional stress, the frequency of VF in relation to season, calendar month and circadian rhythms. They recorded the potassium blood level (effect of potassium depleting diuretics), the use of beta-blockers of the sympathetic nerve.In the group subjects with at least one risk factor of ischaemic heart disease predominated (94 %). Chronic ethylism was revealed in one case. Moderate physical activity during work was recorded in 26 % subjects with VF (as a rule associated with emotional stress). The greatest danger of tachyarrhythmia was observed during the winter period (33 %), as to months, in August (8 subjects) and as to the time of the day, between 6 and 12 a.m. (70 %). At the age above 65 years tachyarrhythmias predominated during winter and as to months in January. As to motor activities before the arrhythamias most freqeuntly a sedentary position was recorded (33 %). Beta-blockers of the sympathetic nerve were taken by 20 % of the patients. Reduced kalaemia was described by the authors in 15 % subjects (in all instances in subjects who took potassium-depleting diuretics).The authors emphasize the importance of elimination of risk factors of ischaemic heart disease incl. reduction of emotional stress at work for the prevention of VF. VF develops most frequently between 6 and 8 a.m., in winter with the subject in a sedentary position. Beta-blockers of the sympathetic nerve do not always protect the patient from arrhythmias. When diuretics are administered it is important to monitor the serum potassium level.

Key words:
arrhythmia -⁠ beta-blockers -⁠ circadian rhythm -⁠ diuretics -⁠ epidemiology -⁠ plotassium -⁠ ventricular fibrillation -⁠ monthly variation -⁠ sudden cardiac death.