Complications and malfunctions of electrical cardiac pacemakers

Pacemaker induced superior vena cava syndrome: a case report

Introduction

Pacemaker induced superior vena cava syndrome is an unusual complication of pacemaker implantation. Endothelial damage caused by repeated trauma from the lead is thought to be responsible for the stenosis. Malignancy has been historically the most common etiology. However, the increase in use of indwelling venous catheters and cardiac pacemaker has resulted in more patients with superior vena cava syndrome of benign etiology.

Case presentation

A 54-year-old female presented with recurrent spasm and swelling of the neck for the duration of two months. Pacemaker was implanted in 1997 for symptomatic third degree heart block. It was removed in 2007 due to recurrent infection at the lead site. Computed tomography of the chest and venogram were performed which showed stenosis at origin of the superior vena cava with some collateral circulation. She underwent angioplasty by the interventional radiology and is currently free of symptoms.

Conclusions

Our case highlights a relatively uncommon complication of pacemaker. As a primary care physician, one should be aware of this unusual complication of pacemaker. Superior vena cava syndrome should be suspected in patients with history of pacemaker insertion who present to the primary care physician with neck spasm or neck swelling. Primary care physicians should also be aware balloon angioplasty is a reasonable primary intervention in selected patient population.

Coronary artery fistula formation secondary to permanent pacemaker placement

We present the findings in two patients who apparently developed a coronary artery fistula as a complication of an endocardial pacing electrode. This complication may actually be occurring more frequently than recognized because the patient may be asymptomatic or minimally symptomatic and therefore not undergo a coronary angiogram. Awareness of this potentially serious complication is important and stresses the need for proper electrode placement without excess pressure on the tip.

Body surface isopotential mapping of permanent cardiac pacemaker spike amplitudes: a noninvasive method for detecting and localizing insulation failure

Cardiac pacing systems produce cardiac contractions by delivering electrical charges to the myocardium. Reliable cardiac pacing, and the longevity of pacemakers depends on the absence of electrical leaks. Electrical leaks often do not cause symptoms and if suspected, there are few methods which are able to identify their location and none suited to small or intermittent leaks. We surface mapped the pacemaker spike amplitudes over the pockets of 29 patients with unipolar pacemakers, several of which had suspected pacemaker leaks. For each patient, pacer voltage spikes were recorded with an optical ECG recorder from sixty-three positions on the skin over the pacemaker. The spike voltages were interpolated with a 2-D Fourier transform, contoured, and plotted by a computer. Electrical leaks were readily detected and their positions indicated by the resulting maps. The operative findings confirmed the map guided prediction in all six patients sent for pacemaker revision. Pacemaker spike amplitude surface mapping detects and locates pacing system insulation failures.

Spontaneous rotation of permanent pacemaker--a cause of muscle stimulation and myopotential inhibition

In 5 of 192 patients who received their first pacemaker during a 17-month period, severe pectoral muscle stimulation was caused by spontaneous rotation of the pacemaker in the pocket, so that the uncoated side faced backwards. All five patients were women with abundant, loose subcutaneous tissue which allowed increased mobility of the pacemaker. This causal mechanism of muscle stimulation seems to be related to the reduced size and the coating of modern pacemakers. Reprogramming of the pacemaker to a lower output solved the problem in three cases, but reoperation was necessary in two. These cases stress the need to secure the pacemaker to the fascia during implantation, particularly in patients at enhanced risk. For such patients, use of a pacemaker equipped with suture holes may be advisable.

Two-dimensional echocardiographic recognition of a pacing catheter perforation of the interventricular septum

A case of a pacing catheter perforation of the interventricular septum is presented here. The entire catheter length was visualized by two-dimensional real-time echocardiography utilizing the subcostal approach; the catheter was seen entering the left ventricle through the high interventricular septum.

An unusual cause of pacemaker current leakage causing muscle stimulation

Stimulation of skeletal muscle is a fairly common complication of permanent cardiac pacing. The usual cause is direct apposition of the anode of a unipolar pacemaker with muscle surrounding the pocket. Other causes include electrode insulation defects and electrode displacement. In this report we describe an unusual cause of muscle stimulation related to direct current leakage from the pacemaker.

Real-time, two-dimensional echocardiographic features of pacemaker perforation

Five patients (four adults and one child) with clinically suspected myocardial perforation by temporary transvenous pacemakers were studied by real-time, two-dimensional echocardiography. In three patients, the catheters were visualized passing through the right ventricular apical wall with the tip located outside the cardiac border. In one patient the catheter perforated the atrioventricular septum and entered the left ventricle with the tip lodged against the posterior wall. In another patient, the catheter had partially penetrated the ventricular septum near the apex. Pericardial effusion was observed in two patients, in one of whom it was localized to the site of perforation. No patient had evidence of cardiac tamponade. In four patients, the catheters were withdrawn under echocardiographic visualization and the catheter tips could be seen moving from the abnormal locations back into the right-heart chambers. Perforation was verified at autopsy in two patients, including one in whom the catheter was not withdrawn. Real-time, two-dimensional echocardiography appears to be valuable in the diagnosis of pacemaker perforation.

Ticket for admission: unexplained syncopal attacks in patients with cardiac pacemaker

A case of pacemaker syncope associated with cardiorespiratory arrest is reported. This patient was seen three times in emergency departments before finally being admitted for evaluation. Ventricular tachycardia due to pacemaker firing in the T-wave on electrocardiogram was observed. The patient was managed with cardioversion, temporary pacing and replacement of the generator and wire. The dislodgement of the pacemaker wire was confirmed at operation. Patients with pacemaker implants who present with unexplained syncopal attacks should be admitted to the hospital for monitoring, diagnostic work-up, and treatment.

Intracardiac electrocardiography during permanent pacemaker implantation: predictors of cardiac perforation

Intracardiac electrograms from 50 successive patients undergoing permanent pacemaker implantation have been analyzed. There were 29 male and 21 female patients aged 14 to 93 years (mean age 68.4 years). The electrograms were obtained using methods that simulated the wave form that would be detected by unipolar cardiac pacemakers. Three types of electrographic patterns were identified: qR pattern with a q/R ratio of less than 1 (type I): QR pattern with a Q/R ratio between 1 and 4.4 (type II); and Qr pattern with a Q/r ratio between 12 and 15 (type III). A type I pattern was seen in 29 patients (58 percent), type II in 18 (36 percent) and type III in 3 patients (6 percent). The duration of the follow-up period ranged from 3 weeks to 20 months (mean 9.7 months); three patients were lost to follow-up study. There were four deaths apparently unrelated to the pacemaker. Recognizable problems (either pacing or sensing failure) occurred in one patient (6 percent) with a type II pattern, in two patients (66.7 percent) with a type III pattern and in no patient with a type I pattern. On the basis of these data it is suggested that at the time of pacemaker implantation, intracardiac electrograms with a type I pattern indicating good pacing thresholds and sensing should be sought. If type II wave forms occur with good pacing thresholds and sensing then the electrode could probably be left in position. The incidence of a type III pattern is rare; when it does occur it is greatly suggestive of myocardial perforation. When this pattern is seen, the pacemaker catheter must be repositioned.

Superior vena caval stenosis: a complication of transvenous endocardial pacing

Superior vena caval obstruction is a rare complication of transvenous endocardial pacing and is usually the result of thrombus formation round the pacing electrode (Kosowsky and Barr, 1972). We report a case of superior vena caval obstruction without thrombus formation secondary to localised stenosis at the site of the proximal cut end of a retracted endocardial electrode. This complication of transvenous pacing electrodes has not been described previously.

Dislodgment of pacemaker electrode simulating focal motor seizure

The unusual finding of dislocation of the electrode of a pacemaker in a patient caused repetitive twitching of the right leg. Initial confusion with focal motor seizure resulted in the administration of antiepileptic medication. Malposition of the electrode was confirmed by appropriate roentgenographic studies, and subsequent repositioning terminated the episode.

The diagnosis of right ventricular perforation by an endocardial pacemaker electrode

The diagnosis of right ventricular perforation by an endocardial pacemaker electrode should be suspected when failure of pacing occurs without electrode displacement. Although a number of changes occur on the standard electrocardiogram (ECG), none of these are diagnostic. The intracardiac electrogram performed during electrode withdrawal is not only diagnostic of perforation but can also aid in electrode positioning. Two case reports highlight these changes in the intracardiac electrogram. The first case also illustrates that, with electrode perforation, the ability to sense the intrinsic intracardiac electrical activity may be retained.

Pacemaker-induced endocardial friction rub

Two patients had a typical sounding cardiac friction rub after placement of a temporary transvenous pacemaker. Absence of myocardial perforation was documented in one patient during thoracotomy for placement of an epicardial electrode and in the other with an electrogram recorded from the pacemaker as it was being withdrawn. The rubs disappeared during pacemaker removal. These cases are believed to represent endocardial friction rubs resulting from contact of the pacing wire with the endocardium.

Cardiac pathology of transvenous pacemakers in dogs

Transvenous right ventricular pacemaker catheters were implanted in 18 mongrel dogs for periods of 2 to 18 months (average 4.9 months). Heart block was produced in 15 of these dogs by injection of 37 per cent formaldehyde into the interatrial septum. In the other three dogs which served as controls, no heart block was produced and no electrical stimulation was applied to the implanted catheters. After the animals had been put to death, gross and microscopic examination of the hearts revealed four categories of morphological changes: (1) connective tissue sheath formation around the catheters, (2) endocardial papillary thickening, (3) interatrial septal changes, and (4) myocardial damage. Changes 1, 2, and 4 occurred in one or more intracardiac locations in all 18 dogs. Change 3 occurred only in the 15 dogs in which heart block was produced. The most striking histologic findings were areas of cartilagenous metaplasia in endocardium an underlying myocardium and areas of marked cellular proliferation of the endocardial cells both in the endothelium and underlying stroma. Chronic implantation of transvenous intracardiac pacemaker catheters in dogs consistently produces morphologic changes which may interfere with cardiac and pacemaker function and may hinder attempts to remove nonfunctional or unneeded catheter electrodes. The changes observed appear to be related to the presence of foreign material per se and not external electrical stimulation of the heart.

Probable postcardiotomy syndrome following implantation of a transvenous pacemaker: report of the first case

The syndrome of fever and pericarditis is reported following implantation of a transvenous pacemaker in a 72-year-old man. The pacemaker was placed for prophylactic reasons (i.e., presence of bifascicular block). The syndrome resolved spontaneously after over four weeks of fever and a pericardial friction rub. Perforation of the right ventricle, although not recognized in this patient, is a complication which occurs with passage of a transvenous pacemaker. There was no other antecedent events to explain the syndrome such as myocardial infarction or trauma to the chest.

Demand pacemaker malfunction due to abnormal sensing. Report of two cases

Two cases with external demand pacemakers are presented because of abnormal prolongation in the pacing interval. In both cases, pacemaker inhibition was caused by signals which were not recorded by the conventional surface electrocardiograms. In one case, inhibition was related to a partial lead fracture which generated a voltage transient in the region of the T wave. In the other case, inhibition was caused by current emitted from a faulty pacemaker unit. In both cases precise localization of the problem was possible by simple bedside recordings and measurements.