[Myocardial infarction and nocturnal hypoxaemia].
BACKGROUND
There is an increased risk of cardiovascular morbidity and mortality in patients with nocturnal intermittent hypoxaemia.


OBJECTIVE
The aim of this study was to evalute the influence of nocturnal hypoxaemia on ventricular arrhythmias and myocardial ischaemia in patients with myocardial infarction (MI).


METHODS
We studied 77 patients (55.8 +/- 7.9 years) with MI free of complications, chronic pulmonary diseases, abnormal awake blood gases tension. All patients underwent overnight pulse oximetry and 24-hour electrocardiography. Patients were divided into two groups according to nocturnal hypoxaemia. Total number of ventricular premature complex (VPC); maximal VPC/h; incidence of VPC Lown class > 2 and occurrence of ST-segment depression were analysed for nocturnal (10 PM to 6 AM), daytime (6 AM to 22 PM) periods and for the entire 24 hours.


RESULTS
Both groups were similar in age, gender, standard risk factors, myocardial infarction size and did not differ in VPC during the analysed periods. The number of nocturnal maximal VPC/h was insignificantly greater in group 1 (with hypoxaemia) compared to group 2 (without hypoxaemia), (p = 0.084). Maximal VPC/h did not differ significantly either for daytime or for 24 hours among the groups. Nocturnal VPC Lown > 2 were significantly more frequent in group 1 (25% vs 0%, p = 0.002). The incidence of VPC Lown > 2 was similar during the daytime, and during 24 hrs in both groups. Occurrence of ST-segment depression did not differ between groups 1 and 2.


CONCLUSIONS
Nocturnal hypoxaemia was associated with complex nocturnal ventricular arrhythmias in patients with MI.
Pencić
Biljana
B
Dekleva
Milica
M
Celić
Vera
V
Rasić
Zorica
Z
D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology*; D017286:Polysomnography; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000175:diagnosis