Serum K+, Ca+ and Na+ should be checked as should thyroid function tests to rule out hypothyroidism.
Sinoatrial arrest laboratory findings
Torsades de pointes laboratory findings
Pacemaker syndrome laboratory findings
ST elevation myocardial infarction laboratory findings
Confusion echocardiography or ultrasound
Pulseless ventricular tachycardia laboratory findings
Cyanosis electrocardiogram
Atrial fibrillation laboratory findings