In the absence of an AMI, temporary transvenous pacing should be considered in any patient presenting with acute symptomatic bradyarrhythmia refractory to medical therapy until the offending cause is withdrawn (e.g., beta-blocker, calcium channel blocker, digoxin) and appropriate evaluation for structural or ischemic heart disease and the need for permanent pacing is completed. Other clinical situations where temporary transvenous pacing should be considered include advanced AV block associated with Lyme carditis. Given the reversible nature of bradyarrhthmias in Lyme disease, temporary rather than permanent pacing should be considered if needed. Temporary transvenous pacing is also used after the removal of an infected permanent pacemaker in patients who are deemed pacemaker dependent. A temporary pacermaker is placed until the infection is treated with intravenous antibiotics, after which it is replaced with a new permanent pacer. Similarly, temporary transvenous pacing may be indicated in patients with acute endocarditis (especially with aortic valve involvement) who show signs of conduction disturbance (advanced AV block or new bundle branch block). In addition, prophylactic transvenous pacing should be considered during right heart catheterization or right ventricular endomyocardial biopsy in patients with existing left bundle branch block, given the associated risk of traumatic right bundle branch block during the procedure leading to completer heart block.