The objective of the work was to compare the use of two types of long-term ECG monitors in examinations of cardiac arrhythmias and to find out whether their yields differed significantly when patients with a history of palpitations and syncope are examined. Two recorders, King of Heart with manual operation of the ECG tracing were used and the R test with continuous recording of the ECG tracing. For statistical processing contingence tables were used. For examination by the King of Heart recorders 111 patients (40 men and 71 women) were indicated, average age 48 years (14 - 84 years). 108 patients were examined. Yield I (number of patients with complaints) - 89 %. Yield II (number of patients with pathological ECG) - 50 %. In indications for palpitation pathological findings were recorded in 52 % patients. In indication for syncope or presyncope pathological findings were recorded in 46 % patients. Yield II in these two groups does not differ significantly (p = 0.9). For examination with an R test recorders 74 patients (30 men and 44 women) were indicated with a mean age of 52 years (18 - 85). Yield I (number of patients with complaints) - 66 %. Yield II (number of patients with complaints and a pathological ECG) - 40 %. Yield III (total number of pathological ECG findings) - 79 %. Yield IV (number of patients without complaints with a pathological ECG) - 29 %. In indication on account of palpitation there were pathological findings in 69 % patients. In indication on account of syncope and presyncope pathological findings were recorded in 71% patients. Yieled II does not differ significantly in these sub-groups (p = 1.0). Statistical comparison of the yield of the two instruments: in the basic indication on account of palpitation the yield of these methods does not differ significantly (p = 0.09). In the basic indicati- on on account of syncope and presyncope the yield of the two methods does not differ significantly (p = 0.33). Conclusion: The yield of the two instruments for long-term Holter monitoring does not differ significantly, both can be recommended for examination of patients with suspected cardiac arrhythmias. The future belongs to instruments with continual ECG recording because of detection of asymptomatic arrhythmias.

        Key words: Cardiac arrhythmia - Holter monitoring - Pathological ECG - Palpitations - Syncope - Presyncope