A normal QRS complex is less than or equal to 0.12 seconds. A wide QRS can be indicative of a pacemaker, a bundle branch block, a premature ventricular complex (PVC), or ventricular tachycardia. Deciphering which arrhythmia is happening would depend on reading the whole ECG strip. Answer and...
(2) Perez MV1, Mahaffey KW1, Hedlin H1, et. al. Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation. N Engl J Med. 2019 Nov 14;381(20):1909-1917. doi:10.1056/NEJMoa1901183. (3) Farzam K, Richards JR. Premature Ventricular Contraction (PVC) [Updated 2019 Jun 29...