Describe and interpret this ECG.
Atrial = 240 min-1
Ventricular = 80 min-1
Atrial flutter with variable 3:1 and 4:1 blockade
Duration = 80 ms
Duration = 160 ms
Morphology = normal
Duration = 112 ms
Axis = 77°
R wave progression:
LV Hypertrophy [Sokolow; SV1 + (RV5 or RV6) > 35mm) or RI + SIII > 25mm]?
RV Hypertrophy [R/S ratio V5 or V6 < 1 or R/S ratio V1 > 1 or S1S2S3 pattern]?
Interpretation: There is atrial flutter with variable 3:1 and 4:1 blockade. The atrial rate is slower than anticipated (240 min-1 rather than 300 min-1). This implies that the patient is likely to be on rate control medications (β-blockers, CCBs, Class III anti-arrhythmics).