The fragmented wide QRS---another important electrocardiographic sign

It is increasingly recognized that not all bundle branch blocks are alike. Designations such as complicated and uncomplicated bundle branch blocks have recently been suggested. A recent paper in Circulation: Arrhythmia and Electrophysiology reports that the finding of greater than 2 notches in the R or S wave of a wide QRS is of prognostic import:

f-wQRS was defined by the presence of greater than 2 notches on the R wave or the S wave and had to be present in greater than or equal to 2 contiguous inferior (II, III, aVF), lateral (I, aVL, V₆) or anterior (V₁ to V₅) leads. ECG analyses of 879 patients (age, 66.7±11.4 years; male, 97%; mean follow-up, 29±18 months) with bundle branch block (n=310), premature ventricular complex (n=301), and pQRS (n=268) revealed f-wQRS in 415 (47.2%) patients. Myocardial scar was present in 440 (50%) patients. The sensitivity, specificity, positive predictive value, and negative predictive value of f-wQRS for myocardial scar were 86.8%, 92.5%, 92.0%, and 87.5%, respectively. The sensitivity and specificity for diagnosing myocardial scar were 88.6% and 94.4%, 81.4% and 88.4%, and 89.8% and 95.7% for f-bundle branch block, f-premature ventricular complex, and f-pQRS, respectively. f-wQRS was associated with mortality after adjusting for age, ejection fraction, and diabetes (P=0.017).

In addition to bundle branch block, paced ventricular complexes and ventricular ectopic beats lend themselves to this analysis.