PRESENT AND FUTURE-ROLE OF AMBULATORY HOLTER MONITORING FOR ARRHYTHMIA RISK STRATIFICATION

Risk stratification for arrhythmogenic events and sudden death in pati ents with organic heart disease, particularly those with coronary hear t disease and a history of MI, continues to be one of the major tasks of clinical cardiologists, although advanced management strategies inc luding thrombolysis, acute PTCA and surgical intervention dramatically reduced the percentage of sudden deaths following acute MIs. Noninvas ive studies like resting and exercise EGG, echocardiography; signal av eraging, 24-hour EGG, and radionuclide studies, as well as invasive te chniques such as electrophysiologically programmed electrostimulation and coronary angiography, are being used routinely. Ambulatory Holter monitoring is an established noninvasive technique for risk stratifica tion. There is evidence showing that its predictive potential for arrh ythmogenic risks is enhanced, if more than one parameter is analyzed. Absence of ST segment changes and a normal HRV are the parameters sing ling out low-risk patients. The use of additional parameters which esc ape electrocardiographic recording, like ventricular function and myoc ardial ischemia, improve the accuracy of predicting arrhythmogenic eve nts. The most predictive combination of risk parameters is, however, s till poorly understood. Future research should define normal ranges of parameters recordable by H-ECG, solve technical problems of recording data and analyzing them. In addition, the accuracy of measuring QT du ration and documenting late potentials should be improved by more soph isticated methods. Rut it is unrealistic to expect that the QT interva l will become amenable to automatic analysis in all patients. A fully automatic QT analysis without visually checking the measuring points a t the tip and the end of the T wave for their consistency is hardly co nceivable. The documentation of late potentials; in turn, is limited b y artefacts caused by muscle contraction during physical activity. Cli nical aspects, e.g., the predictability of arrhythmogenic events in pa tients with cardiomyopathies and valvular disease, should be addressed . This will require studies combining the predictive potentials of rhy thmologic and hemodynamic data.