Preoperative evaluation of patients with electrocardiographic conduction defects.

Prophylactic pacemakers should be recommended for all preoperative patients with second- and third-degree heart block, regardless of whether the block is in the AV node or the trifascicular conduction system. Symptomatic patients with potential for trifascicular block should also have a transvenous pacemaker. Those without symptoms should be monitored during anesthesia and the postoperative recovery period.

Septicemia in patients with an endocardial pacemaker.

The records of 1,235 consecutive patients treated with long-term pacing by the endocardial route between 1964 and 1977 were analyzed to determine the incidence, mechanism, course and treatment of septicemia. Septicemia developed in 12 patients (1 percent), and Staphylococcus aureus was isolated from the blood culture in 10. All patients were treated with the usual prolonged course of bactericidal drugs. Treatment was successful in only two of the seven patients whose endocardial pacing system was left in place; in three of the seven the septicemia recurred, necessitating removal of the endocardial system, and two of these patients died. In the remaining four patients the endocardial wire was promptly withdrawn, with use of a thoracotomy when necessary, and an epicardial system inserted; all of these patients survived. This is the treatment of choice.

Permanent pacemaker implantation in the absence of a right superior vena cava. A case report.

In a patient with syncope and sinus bradycardia the left superior vena cava drained into the right atrium via the coronary sinus. He underwent permanent transvenous pacemaker implantation via the tortuous left superior vena-caval route, and has continued to show normal pacing over an 18-month follow-up period. The problem of pre-operative recognition and the optimum means of permanent and temporary pacing in this condition are discussed.

A biologic model of parasystole.

The electrotonic interactions of a parasystolic pacemaker with ventricular responses to the normal pacemaker across an area of depressed excitability were simulated in a model consisting of strands of canine Purkinje fibers mounted in a sucrose gap preparation. Experiments were conducted to study the patterns of ectopic activity that result from entrainment of the "ectopic" pacemaker (EP) on one side of the sucrose gap by evoked responses (sn) on the other side of the gap. When one-way conduction ("entrance block") was established, manipulations of the SN frequency and of the impedance between the two outer chambers resulted in periods of silence, concealed or manifest bigeminy, trigeminy and quadrigeminy, and periods of more complex patterns of group beating as the entrainment ratios changed. The results confirm the predictions of the previously described mathematical model that these patterns depend on the magnitude of the electrotonic influence of SN on the EP cycle length and also on the ratio of the intrinsic frequencies. These studies should help to distinguish between reentrant and parasystolic mechanisms in clinical arrhythmias.

Cardiac pacemaker insertion: a study of the anaesthetic and postoperative complications.

One hundred and three patients undergoing pacing procedures have been studied, the majority requiring the insertion of an epicardial system under general anaesthesia. The main findings were of an elderly group of patients with a high incidence of associated disease, who suffered predominantly from pulmonary and renal complications. Methods of reducing these complications, particularly in relation to general anaesthesia are discussed.

Development of carcinoma of the breast at the site of an implanted pacemaker in two patients.

We report here on two female patients who had permanent pacemakers implanted in their chests and who developed carcinoma of the breast subsequently. An association is suspected between the breast cancer and the pacemaker, which is implanted in an area which borders with the mammary gland or is even right within it. This suspicion led us lately to change in female patients the site of the subcutaneous pocket for the implantation of the pacemaker to a position higher in the chest than before. Moreover, we advocate frequent breast examinations in all female patients with implanted pacemakers.

Electroconvulsive therapy in patients with pacemakers.

A patient with an R-wave inhibited permanent pacemaker required electroconvulsive therapy (ECT). Possible interference by this therapy with pacer functioning through external interference or internal interference by inhibitory myopotentials was eliminated by temporary conversion to fixed rate pacing before ECT.

The wayward pacemaker electrode.

Complications from the use of permanent cardiac pacemakers are frequent and manifold. The most common complications associated with pacemaker electrodes, both endocardial and myocardial, as well as their prevention and treatment are discussed. Also described is a new technique of inserting a myocardial electrode without formal thoracotomy.

Single lead for permanent physiological cardiac pacing.

A method of achieving permanent pacing by the use of a single bipolar transvenous lead is described, the atrial and ventricular electrodes being located on the same lead 14--17 cm apart. The new leads have been implanted successfully in two patients.

A simple method for exposing the external jugular vein for placement of a permanent transvenous pacing catheter electode.

A method is presented for cannulating the external jugular vein and implanting a pacemaker through one incision. No increase in morbidity over the conventional methods has been demonstrated. This technique is an attractive alternative to the standard emthods in use.