When performing gynecologic surgery on patients with pacemakers, it is preferable to place the electrocautery unit ground plate on the leg to minimize interference by preventing the pacemaker generator from sitting within the electrocautery circuit and to maximize distance from the pacemaker device. If possible, use of bipolar cautery devices are recommended rather than monopolar devices. In patients with a demand pacemaker in place, the pacemaker should be converted preoperatively to the fixed-rate (or asynchronous) mode. Although this can be accomplished oftentimes by placing a magnet over the pacemaker, it may be better to reprogram the pacemaker preoperatively and then again postoperatively. Patients should be monitored continuously intraoperatively with both telemetry and continuous pulse oximeter. Close coordination with anesthesia and cardiology is imperative. Patients with an implantable cardioverter defibrillator device should have their device programmed off prior to surgery and reprogrammed postoperatively (155).
Surgery is not contraindicated in patients with bundle branch blocks or hemiblocks (204). Peri-operative mortality rates are not increased by bundle-branch block. Complete heart block rarely develops during noncardiac surgical procedures in patients with conduction system disease. The presence of a left bundle-branch block may indicate the presence of aortic stenosis, which can increase surgical mortality if it is severe.
Valvular Heart Disease Although there are many forms of valvular heart disease, two types—aortic and mitral stenosis—primarily are associated with significantly increased operative risk (205). Patients with significant aortic stenosis appear to be at greatest risk, which is increased in the presence of atrial fibrillation, congestive heart failure, or coronary artery disease. Significant stenosis of aortic or mitral valves should be repaired before elective gynecologic surgery (176).
Severe valvular heart disease usually is evident during physical exertion. Common findings in such patients are listed in Table 22.18. The classic history presented by patients with severe aortic stenosis includes exercise dyspnea, angina, and syncope, whereas symptoms of mitral stenosis are paroxysmal and effort dyspnea, hemoptysis, and orthopnea. Most patients have a remote history of rheumatic fever. Severe stenosis of either valve is considered to be a valvular area of less than 1 cm2, and diagnosis can be confirmed by echocardiography or cardiac catheterization.
Patients with valvular abnormalities are subdivided by the American Heart Association into risk groups for the development of subacute bacterial endocarditis following surgery. Patients in the highest risk groups should receive prophylactic antibiotics immediately preoperatively to prevent subacute bacterial endocarditis (Table 22.8). As defined by the American Heart Association, only patients with prosthetic cardiac valves, congenital heart disease, and cardiac transplantation who develop cardiac valvulopathy should receive perioperative endocarditis prophylaxis (76). All other patients do not require antibiotics for subacute bacterial endocarditis prophylaxis. Routine prophylaxis for GI or GU procedures is not recommended. Only in cases of a known infection of the GI or GU tract should antibiotics coverage for enterococcus with amoxicillin or ampicillin or vancomycin be provided.
Patients with aortic and mitral stenosis tolerate sinus tachycardia and other tachyarrhythmias poorly. In patients with aortic stenosis, sufficient levels of digitalis should be provided to correct preoperative tachyarrhythmias, and propranolol may be used to control sinus tachycardia. Patients with mitral valve stenosis often have atrial fibrillation and, if present, digitalis should be used to reduce rapid ventricular response.