Pacemaker Insertion



Pacemaker Insertion





Pacemakers are battery-operated generators that emit timed electrical signals, triggering contraction of the heart muscle and controlling the heart rate. Whether temporary or permanent, they’re used when the heart’s natural pacemaker fails to work properly.

Temporary pacemakers may be used in emergency situations—for example, when drug therapy fails to correct dangerous bradycardia or heart block, when the patient’s condition doesn’t permit implantation of a permanent pacemaker, or during open-heart surgery. They’re also used before a permanent pacemaker is implanted to observe pacing’s effects on cardiac function so that an optimum rate can be selected.

Permanent pacemakers are used when the heart’s natural pacemaker is irreversibly disrupted. Indications include symptomatic bradycardia, advanced symptomatic atrioventricular block, sick sinus syndrome, sinus arrest, sinoatrial block, and Stokes-Adams syndrome. Biventricular pacemakers are helpful in maintaining ventricular synchrony in patients with advanced heart failure.

The physician’s choice of a pacemaker depends on the patient’s underlying cardiac condition and electrocardiogram (ECG) findings. More than 300 types of pacemakers exist, and many of them are programmable to perform varied functions. They’re categorized according to their capabilities. (See Reviewing pacemaker codes.)


Procedure

Insertion or application of a temporary pacemaker varies, depending on the device. (See Types of temporary pacemakers, page 646.)

Although a permanent pacemaker can be implanted through a thoracotomy (which requires a general anesthetic), most are implanted using the transvenous endocardial approach. In this method, done under a local anesthetic, the patient is sedated and his chest or abdomen is prepared. Then the surgeon makes a 3″ to 4″(7.5- to 10-cm) incision in the selected site, inserts the electrode catheter through a vein, and uses fluoroscopy to guide it into the heart chamber appropriate for the type of pacemaker. After inserting the leads, he uses a pacing system analyzer to set the pulse generator to the proper stimulating and sensing thresholds, attaches the pulse generator to the leads, and then implants it into a pocket of muscle in the patient’s chest or abdominal wall. He uses nonabsorbable sutures to tie the connection, leaving extra lengths of leads coiled under the pulse generator to decrease tension on the leads and to simplify subsequent replacement of the pulse generator if necessary. He then closes the incision and applies a tight occlusive dressing.


Complications

Early complications include serous or bloody drainage from the insertion site, swelling, ecchymosis, incisional pain, and impaired mobility; less common complications include venous thrombosis, embolism, infection, pneumothorax, pectoral or diaphragmatic muscle stimulation from the pacemaker, arrhythmias, cardiac tamponade, heart failure, and abnormal pacemaker

operation with lead dislodgment. Late complications (up to several years) include failure to capture, failure to sense, firing loss, and pacemaker rejection.