37. Ectopic atrial rhythm, rate 82, otherwise normal ECG.
P-waves in leads I, II, and aVF are inverted suggesting an ectopic origin of the atrial beats.
The normal PR-interval (0·16 seconds) implies that the origin is in the atrium rather than in
the AV junction.
40. • When the ECG rhythm is a narrow-complex regular
tachycardia,
• the differential diagnosis includes ST, SVT, and
atrial flutter.
• In this case, there is a 1:1 relationship between the
P-waves and the QRS complexes, thus confirming
the diagnosis of ST.