title: Ambulatory cardiac arrhythmias in relation to mild hypokalaemia and prognosis in community dwelling middle-aged and elderly subjects.
abstract: Severe hypokalaemia can aggravate arrhythmia tendency and prognosis, but less is known about risk of mild hypokalaemia, which is a frequent finding. We examined the associations between mild hypokalaemia and ambulatory cardiac arrhythmias and their prognosis.
  
  
  
  Subjects from the cohort of the 'Copenhagen Holter Study' (n = 671), with no history of manifest cardiovascular (CV) disease or stroke, were studied. All had laboratory tests and 48-h ambulatory electrocardiogram (ECG) recording. The median follow-up was 6.3 years. p-Potassium was inversely associated with frequency of premature ventricular complexes (PVCs) especially in combination with diuretic treatment (r = -0.22, P = 0.015). Hypokalaemia was not associated with supraventricular arrhythmias. Subjects at lowest quintile of p-potassium (mean 3.42, range 2.7-3.6 mmol/L) were defined as hypokalaemic. Cardiovascular mortality was higher in the hypokalaemic group (hazard ratio and 95% confidence intervals: 2.62 (1.11-6.18) after relevant adjustments). Hypokalaemia in combination with excessive PVC worsened the prognosis synergistically; event rates: 83 per 1000 patient-year in subjects with both abnormalities, 10 and 15 per 1000 patient-year in those with one abnormality, and 3 per 1000 patient-year in subjects with no abnormality. One variable combining hypokalaemia with excessive supraventricular arrhythmias gave similar results in univariate analysis, but not after multivariate adjustments.
  
  
  
  In middle-aged and elderly subjects with no manifest heart disease, mild hypokalaemia is associated with increased rate of ventricular but not supraventricular arrhythmias. Hypokalaemia interacts synergistically with increased ventricular ectopy to increase the risk of adverse events.
authors: Department of Cardiology, Copenhagen University Hospital of Bispebjerg, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark nickm@dadlnet.dk.
authors: Nick
authors: N
authors: Mattsson
authors: Department of Cardiology, Copenhagen University Hospital of Rigshospitalet, Copenhagen, Denmark.
authors: Golnaz
authors: G
authors: Sadjadieh
authors: Department of Cardiology, Copenhagen University Hospital of Bispebjerg, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark.
authors: Preman
authors: P
authors: Kumarathurai
authors: Department of Cardiology, Copenhagen University Hospital of Bispebjerg, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark.
authors: Olav Wendelboe
authors: OW
authors: Nielsen
authors: Department of Cardiology, Copenhagen University Hospital of Rigshospitalet, Copenhagen, Denmark.
authors: Lars
authors: L
authors: Køber
authors: Department of Cardiology, Copenhagen University Hospital of Bispebjerg, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark.
authors: Ahmad
authors: A
authors: Sajadieh
mesh_terms: D000367:Age Factors; D000368:Aged; D018880:Atrial Premature Complexes / Q000209:etiology / Q000401:mortality / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D003718:Denmark; D018572:Disease-Free Survival; D004232:Diuretics / Q000627:therapeutic use; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D007008:Hypokalemia / Q000097:blood / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy / Q000401:mortality; D057187:Independent Living; D053208:Kaplan-Meier Estimate; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011188:Potassium / Q000097:blood; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012307:Risk Factors; D012720:Severity of Illness Index; D013617:Tachycardia, Supraventricular / Q000209:etiology / Q000401:mortality / Q000503:physiopathology; D013997:Time Factors; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology
chemical_list: D015415:Biomarkers; D004232:Diuretics; D011188:Potassium
keywords: Arrhythmias; Atrial premature complexes; Hypokalaemia; Mortality; Ventricular premature complexes