electrocardiogram: atrial rhythms QRS complexes in 2:1 to 8:1 ratio
electrocardiogram: atrial rhythms qrs complexes in 2:1 to 8:1 ratio
ECG atrial rhythms QRS complexes in 2:1 to 8:1 ratio
ecg atrial rhythms qrs complexes in 2:1 to 8:1 ratio