T axis and cardiac events in elderly people

Abstract

Jan Kors and colleagues' data on T-axis changes (Aug 22, p 601)1Kors AJ de Bruyne MC Hoes AW et al.T axis as an indicator of risk of cardiac events in elderly people.Lancet. 1998; 352: 601-605Summary Full Text Full Text PDF PubMed Scopus (152) Google Scholar certainly challenge received thought on the reliability of the T-wave as a single prognostic and diagnostic tool. 75 years ago, when it was first appreciated that T-wave changes could indicate the presence of cardiac ischaemia, Wilson and Finch2Wilson FN Finch R The effect of drinking iced water upon the form of the T deflection of the electrocardiogram.Heart. 1923; 10: 275-278Google Scholar showed that swallowed iced water could produce similar changes; these researchers correlated their observations with work in animals in which local cooling of the left ventricle caused identical T-wave changes. After these findings, Frank Wilson was hesitant to attribute isolated T-wave abnormalities to cardiac disease. Robert Grant was equally cautious when he translated Wilson's seminal vectorcardiographic studies into electrocardiographic terms,3Grant RP Clinical electrocardiography. The spatial vector approach. McGraw-Hill, New York1957Google Scholar and pointed out the potential importance of non-cardiac factors that could change T-vector magnitude rather than direction.The practising cardiologist, however, is uncertain what these vectorial changes mean in the conventional surface electrocardiogram: what did Kors and colleagues see and how could they translate their findings into the practical statements that Grant made part of electrocardiographic language? Without this information how can cardiologists and other physicians assess and use the results from the Rotterdam study, because they are familiar with comments like that of Fisch, that “non diagnostic ST-segment and T-wave changes are the most common ECG (electrocardiogram) abnormality and account for about 50% of the abnormal tracings recorded in a general hospital population and in 2·4% of all cardiograms”.4Fisch C Electrocardiography.in: Braunwald E Heart disease. A textbook of cardiovascular medicine (5th edition). WB Saunders Co, Philadelphia1997: 108-151Google ScholarFisch then emphasises the fact that “an isolated T-wave change must be interpreted with caution and must always be correlated with all available clinical and laboratory information. Misinterpretation of the significance of a T-wave abnormality is the most common cause of ‘iatrogenic ECG heart disease’.” How can we be guided successfully and distinguish those at risk of cardiac events from those at risk from unwise deductions? Jan Kors and colleagues' data on T-axis changes (Aug 22, p 601)1Kors AJ de Bruyne MC Hoes AW et al.T axis as an indicator of risk of cardiac events in elderly people.Lancet. 1998; 352: 601-605Summary Full Text Full Text PDF PubMed Scopus (152) Google Scholar certainly challenge received thought on the reliability of the T-wave as a single prognostic and diagnostic tool. 75 years ago, when it was first appreciated that T-wave changes could indicate the presence of cardiac ischaemia, Wilson and Finch2Wilson FN Finch R The effect of drinking iced water upon the form of the T deflection of the electrocardiogram.Heart. 1923; 10: 275-278Google Scholar showed that swallowed iced water could produce similar changes; these researchers correlated their observations with work in animals in which local cooling of the left ventricle caused identical T-wave changes. After these findings, Frank Wilson was hesitant to attribute isolated T-wave abnormalities to cardiac disease. Robert Grant was equally cautious when he translated Wilson's seminal vectorcardiographic studies into electrocardiographic terms,3Grant RP Clinical electrocardiography. The spatial vector approach. McGraw-Hill, New York1957Google Scholar and pointed out the potential importance of non-cardiac factors that could change T-vector magnitude rather than direction. The practising cardiologist, however, is uncertain what these vectorial changes mean in the conventional surface electrocardiogram: what did Kors and colleagues see and how could they translate their findings into the practical statements that Grant made part of electrocardiographic language? Without this information how can cardiologists and other physicians assess and use the results from the Rotterdam study, because they are familiar with comments like that of Fisch, that “non diagnostic ST-segment and T-wave changes are the most common ECG (electrocardiogram) abnormality and account for about 50% of the abnormal tracings recorded in a general hospital population and in 2·4% of all cardiograms”.4Fisch C Electrocardiography.in: Braunwald E Heart disease. A textbook of cardiovascular medicine (5th edition). WB Saunders Co, Philadelphia1997: 108-151Google Scholar Fisch then emphasises the fact that “an isolated T-wave change must be interpreted with caution and must always be correlated with all available clinical and laboratory information. Misinterpretation of the significance of a T-wave abnormality is the most common cause of ‘iatrogenic ECG heart disease’.” How can we be guided successfully and distinguish those at risk of cardiac events from those at risk from unwise deductions?