[Significance of electrocardiographic QRS width in patients with congestive heart failure: a marker for biventricular pacing].
OBJECTIVE
Biventricular pacing may be valuable for the treatment of patients with intractable heart failure, but how many patients in Japan would benefit from this type of therapy remains uncertain. This study investigated the incidence of intraventricular conduction delay in the electrocardiogram(ECG) as a marker of the need for biventricular pacing, as well as the underlying etiology of heart failure in patients admitted with congestive heart failure.


METHODS
Patients with heart failure admitted to the Tokai University Hospital from January 1990 to September 2000 were studied retrospectively. The distribution of age, sex and underlying diseases, and that of the rhythm and the QRS width in ECG recordings were analyzed. Patients with a QRS width of over 121 msec in the ECG were classified as the 'wide QRS' group.


RESULTS
Of a series of 1,200 consecutive patients with heart failure, 872 patients, 499 males and 373 females (mean age 67.9 +/- 13.9 years) were admitted to the hospital and 71 had 'wide QRS' by ECG. Among those in the 'wide QRS' group, 37% had ischemic heart disease and 14% had dilated cardiomyopathy. The widest QRS complexes were encountered in patients with dilated cardiomyopathy and the largest number of wide QRS complexes was encountered in patients with ischemic heart disease.


CONCLUSIONS
The most frequent causes of heart failure among patients considered suitable for biventricular pacing were ischemic heart disease and dilated cardiomyopathy, which is consistent with previous reports. Compared with the statistics reported from western countries, the incidence of ischemic heart disease and the incidence of intraventricular conduction delay were lower in Japanese patients with heart failure. The incidence of intraventricular conduction delay among patients with heart failure was 8.6%. Therefore, fewer patients need biventricular pacing in Japan than in western countries. Nevertheless, patients with heart failure resistant to other therapies might still benefit from this type of therapy.
D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications; D012189:Retrospective Studies; D016896:Treatment Outcome