This patient should undergo inpatient cardiac monitoring because of his clinical history and presentation consistent with cardiogenic syncope. His loss of consciousness was abrupt, without prodrome except for palpitations, and occurred while seated, all of which are characteristics consistent with the presentation of cardiogenic syncope. Additionally, he is at high risk for ischemic cardiac disease based on his risk factors, including hypertension, hyperlipidemia, diabetes mellitus, tobacco use, and left bundle branch block noted on electrocardiogram. Cardiac syncope is associated with a high mortality rate (1-year mortality rate of 18%-33%), whereas the risk for negative outcomes with most other causes of syncope is markedly lower. Therefore, patients with syncope of possible cardiac etiology, such as this one, should be admitted to the hospital for further monitoring and evaluation.

Several risk stratification tools are available to assist in making admission decisions in patients with syncope. The Risk Stratification of Syncope in the Emergency Department (ROSE) index is a validated tool that identifies specific independent predictors for severe outcomes at 1 month (myocardial infarction, life-threatening arrhythmia, pulmonary embolism, stroke, intracranial or subarachnoid hemorrhage, or pacemaker insertion). These predictors are elevated B-type natriuretic peptide concentration (≥300 pg/mL), bradycardia (≤50 beats/minute), fecal occult blood in patients with suspected gastrointestinal bleeding, anemia (hemoglobin level ≤9 g/dL [90 g/L]), chest pain, electrocardiogram with Q waves (not in lead III), and oxygen saturation less than 94% on ambient air. Other high risk factors include age greater than 65 years; abnormal ECG; history of heart failure, ischemic heart disease, or ventricular arrhythmias; or lack of warning signs or symptoms. In patients with these clinical findings, many of which are present in this patient, inpatient monitoring and evaluation are recommended.

As this patient with a history suggestive of cardiac syncope is at high risk for adverse events, outpatient evaluation with event monitoring would not be appropriate.

Implantable loop recorders are best reserved for patients with unexplained recurrent syncope, which is not present in this patient. Inpatient monitoring and further cardiac evaluation for ischemia are the most appropriate next steps in management.

Criteria for pacemaker insertion in a patient with syncope include symptomatic bradycardia or asystolic pauses. This patient currently only has mild bradycardia, which would not be the cause of his syncope, and a pacemaker is not indicated at this time. He should be monitored for further decline in heart rate and symptoms or for the development of advanced-degree block and other symptomatic arrhythmias. This should initially take place in the inpatient setting.