A patient in their 70s was referred to the emergency department for worsening shortness of breath, chest tightness, and episodes of palpitations. The patient’s medical history was remarkable for hypertension and kidney insufficiency. Initial evaluation revealed a heart rate of 53 beats/min, blood pressure of 221/85 mm Hg. Laboratory test results revealed that the patient’s B-type natriuretic peptide level was 838.6 pg/mL (normal level, <300 pg/mL). The initial 12-lead electrocardiogram (ECG) is presented in the Figure, A. Transthoracic echocardiography showed left atrial enlargement (52 mm), normal left ventricular wall thickness, and mild pulmonary hypertension.
Questions: What are the noteworthy findings on the patient’s initial ECG? What is the clinical significance?