RESUMEN
Twenty-five patients on chronic HD were screened with Holter electrocardiogram [ECG] monitoring for arrhythmias. Serum electrolyte levels and ST segment changes during Holter monitoring were studied to evaluate their possible role in the genesis of arrhythmias. Fourteen patients showed ST segment depression diagnostic of myocardial ischemia during the last two hours of HD which disappeared after dialysis and ten of them had arrhythmias. Serum K was significantly decreased to subnormal level at the end than at the start of HD and was also significantly decreased in patients with arrhythmias than those without at the end of HD. Serum Ca was significantly increased at the end than at the start of HD. Serum Mg levels were above normal through the whole HD period. Serum Na levels were within normal through the whole HD period. The levels of Mg and Na showed insignificant differences when measured at the end and at the start of HD. Echocardiographic study demonstrated increased left ventricular mass index in eight patients, all were hypertensives, five of them had PVBs. None of the studied patients had impairment of left ventricular systolic or diastolic functions