The maze III surgical procedure

AORN Journal, July, 2002 by Beverly Green

Home Study Program

THE MAZE III SURGICAL PROCEDURE

The article "The maze III surgical procedure" is the basis for this AORN Journal independent study. The behavioral objectives and examination for this program were prepared by Rebecca Holm, RN, MSN, CNOR, clinical editor, with consultation from Susan Bakewell, RN, MS, education program professional, Center for Perioperative Education.

A minimum score of 70% on the multiple-choice examination is necessary to cam 3 contact hours for this independent study. Participants receive feedback on incorrect answers. Each applicant who successfully completes this study will receive a certificate of completion. The deadline for submitting this study is July 31, 2005.

Send the completed application form, multiple-choice examination, learner evaluation, and appropriate fee to

AORN Customer Service c/o Home Study Program 2170 S Parker Rd, Suite 300 Denver, CO 80231-5711

or fax the information with a credit card number to (303) 750-3212.

BEHAVIORAL OBJECTIVES

After reading and studying the article on the maze III surgical procedure, the nurse will be able to

(1) explain the rationale for performing the maze III surgical procedure on the ideal surgical candidate,

(2) identify preoperative preparation specific to the patient undergoing the maze III procedure,

(3) describe cryosurgery,

(4) discuss the steps of the maze III surgical procedure, and

(5) describe the postoperative phase of a patient undergoing the maze III surgical procedure.

This program meets criteria for CNOR and CRNFA recertification, as well as other continuing education requirements.

In the healthy heart, electrical impulses travel one primary route through the heart; however, secondary routes are available should the primary route become obstructed by injury or disease. Abnormal heart rhythms, such as atrial fibrillation (A fib), can occur when electrical impulses travel via an aberrant pathway. The heart may convert to A fib without underlying heart disease, but the probability of A fib increases dramatically when cardiovascular disease is present. Atrial fibrillation also can occur in conjunction with noncardiovascular problems. (1)

After A fib becomes symptomatic, it typically is associated with significant morbidity related to reduced cardiac output. As the patient's cardiac output diminishes, blood pools in the atria, resulting in the formation of blood clots. Blood clots in the left atrium can dislodge and travel through the blood stream to the brain, resulting in stroke and even death. (2) Atrial fibrillation is the most common type of arrhythmia.

The maze procedure was designed to create a maze on the atria with multiple incisions that allow sinus rhythm to be conducted to the atrioventricular node without creating a reentry circuit. (3) The barriers force the electrical impulse to travel from the top of the heart to the bottom via only one major route. This procedure is designed to cause A fib to die out and not be transmitted to the ventricle. (4) Eliminating aberrant pathways prevents A fib and its potentially devastating effects.

ANATOMY AND PHYSIOLOGY

The heart is a muscle that functions primarily as a double-sided pump. The left side pumps oxygen-rich blood to all parts of the body. The right side of the heart pumps blood from the body back to the lungs to be reoxygenated. The heart has four chambers. The two upper chambers are the right and left atria. The two lower chambers are the right and left ventricles. The left ventricle is the strongest chamber of the heart. It ejects blood into the aorta (ie, the main supplier of oxygenated blood to the entire body). Heart valves (ie, aortic, mitral, tricuspid, pulmonary) that passively open and close to direct the flow of blood separate the upper and lower chambers and the aorta.

Electrical stimulation causes the heart muscles to contract or pump. During a normal heartbeat, an electrical impulse originating in the right atrium travels simultaneously to the left atrium and down the intra-atrial septum to the atrioventricular node. The impulse continues to travel down a common pathway splitting into the left and right bundle branches located in both ventricles. This cycle of electrical stimulation is known as normal sinus rhythm (NSR). In A fib, the tissue in the atria beats chaotically and ineffectively. Blood remains in the atria too long, sometimes causing the formation of blood clots, which may lead to a life-threatening stroke. (5)

Atrial fibrillation is thought to be the result of macro reentry in the atria (Figure 1). The maze procedure, therefore, is necessary to prevent possible reentry from occurring. (6) Macro reentry is defined as a storm of electrical energy that travels in spinning wavelets (ie, macro reentrant circuit) across both atria, causing these upper chambers to quiver or fibrillate 300 to 600 times per minute. (7)

[FIGURE 1 OMITTED]

SYMPTOMS AND TREATMENT OPTIONS

Medication, electrical cardioversion, ablation to remove or destroy the function of one or more electrical impulse centers in the heart, pacemaker implantation, or surgery are the usual treatment options for A fib. The surgeon identifies an individualized treatment course based on the patient's symptoms and his or her degree of disability. (8) After other treatment options are exhausted, the maze III surgical procedure is considered. The three major goals of treatment include: