Abnormalities of Conduction (Exclusive of Second- and Third-Degree Atrioventricular Block)

Abstract

In cases where the intervals are all prolonged, especially if an apparent bradycardia is present, it is necessary to find out whether the paper speed was set correctly, since recording the electrocardiogram (ECG) at a 50 mm/sec paper speed instead of the usual 25 mm/sec will cause apparent lengthening of the intervals. Abnormalities of conduction manifesting as alterations in the cardiac rhythm were discussed in Chapter 5. Alterations in the axis, which can also be caused by abnormalities of conduction, are discussed in this chapter.