Successful percutaneous extraction of an inadvertently placed left ventricular pacing lead.

A 74-year-old patient was referred for a rapidly increasing pacing threshold 9 months after DDD pacemaker implantation because of symptomatic total atrioventricular (AV) block. She had a history of hypertension, diabetes with micro-angiopathy and a recent transient ischaemic attack. The paced electrocardiogram on admission had a right bundle branch block pattern and 3-dimensional transoesophageal echocardiography demonstrated passage of the lead through an atrial septal defect with a left ventricular position in addition to moderate atherosclerosis of the ascending aorta. No thrombus could be detected on the lead. Percutaneous extraction is usually not recommended because of the risk of mobilization of thrombus material. However, the risk of stroke during removal using cardiopulmonary bypass in this patient was considerably increased because of the presence of multiple independent risk factors. Therefore, percutaneous extraction using a locking device was selected and performed without complications: follow-up was uneventful.     

Right ventricular enlargement mimicking electrocardiographic left ventricular pacing

Electrocardiographic right bundle branch block morphology during cardiac pacing is occasionally the result of accidental placement of pacemaker or defibrillator leads into the left ventricle. Inadvertent lead placement in the left heart is associated with a risk of systemic embolism. Previous authors have attempted to define safe (right ventricular origin) and unsafe (left ventricular origin) patterns of right bundle branch block during pacing. We report a case of a patient with severe dilated cardiomyopathy and a correctly positioned pacemaker-defibrillator lead in the right ventricular apex, who meets electrocardiographic criteria for lead implantation into the left ventricle.     

Safe right bundle branch block pattern during permanent right ventricular pacing

It is known that an electrocardiogram (ECG) after transvenous right ventricular (RV) pacing should yield left bundle branch block (LBBB) QRS patterns. When right bundle branch block (RBBB) pacing morphology appears in a patient with a permanent or temporary transvenous RV pacemaker, myocardial perforation or malposition of the pacing lead must be ruled out, even though the patient may be asymptomatic. We report a case of a 77-year-old man who underwent permanent transvenous VDD pacemaker implantation for symptomatic heart block. The postoperative ECG revealed a RBBB pacing configuration, but his chest X-ray and echocardiographic studies confirmed uncomplicated RV pacing. We review and discuss the literature concerning the differential diagnosis of such a safe RBBB ECG pattern.     

Malposition of transvenous pacing lead in the left ventricle

Transvenous pacemaker lead malposition in the left ventricle occurs rarely and requires a high index of suspicion for proper diagnosis. The case of a woman with unintentional lead placement in the left ventricle is presented. She had two episodes of transient neurologic deficits, possibly secondary to embolic events, and was started on oral anticoagulants. Chest x-ray and electrocardiogram (ECG) suggested pacemaker lead malposition and transesophageal echocardiography revealed sinus, venosus atrial septal defect. The lead was shown to cross the atrial septum and the mitral valve to the left ventricle. The malpositioned lead was successfully removed from the left ventricle at the time of surgical repair of the atrial septal defect. The potential value of 12-lead ECG, chest x-ray, posteroanterior and lateral views, and echocardiography in the diagnosis of pacemaker lead malposition are discussed and recommendations to avoid this complication at the time of pacemaker implant are outlined.     

Complete AV block in a heart catheter study using a Swan-Ganz catheter

A case of complete heart block during right heart Swan-Ganz balloon-tipped flow-directed catheterization in a patient with intermittent left bundle branch block after aortic valve replacement is reported. After entrance into the right ventricle with the catheter tip as well as after insertion of a temporary balloon-floated pacemaker electrode symptomatic complete heart block occurred. This case demonstrates that in a patient with intermittent left bundle branch block a complete AV block may occur and therefore the possibility of cardiopulmonary resuscitation and temporary pacing has to be taken in account.     

Unexpected malposition of a ventricular pacemaker electrode]

Ten years after mitral-valve replacement, a 69-year-old patient underwent VVI pacemaker implantation because of symptomatic bradyarrhythmia. Postoperatively, the electrocardiogram showed a right bundle branch pattern under ventricular stimulation while the threshold was optimal. Under fluoroscopy, we suspected a malposition of the electrode outside the right ventricle in the LAO and lateral view. This could not be verified by echocardiography, whereas contrast angiography of the right ventricle proved the extracavitary position of the electrode under the inferior wall of the left ventricle, probably in the middle cardiac vein. The electrode position was operatively corrected without complications. We discuss different ways of malposition and their detection by considering electrocardiographic configuration and fluoroscopy in LAO and lateral view.     

Two-dimensional echocardiography for the diagnosis of interventricular septum perforation by a temporary pacing catheter

This case study describes a patient with complete heart block inadvertently paced from the left ventricular posterior wall due to perforation of interventricular septum by a temporary pacing catheter. This is a rare but potentially fatal complication of pacing. The frontal chest radiograph neither identified abnormalities nor could determine the exact site of the catheter tip. The electrocardiogram revealed a right bundle branch block pattern. Echocardiography was performed immediately at bedside and the diagnosis was made. The temporary pacing catheter was removed without complications and, the next day, the patient underwent permanent pacemaker implantation. Given its noninvasiveness and availability, echocardiography is a highly effective means of assessing pacemaker complications such as catheter perforation.     

Alternating bundle branch block

Mechanisms postulated for alternating bundle branch block are incomplete-and cycle-length-dependent-block in both the right and left bundle branches. A patient with severe longstanding cardiac conduction disease who developed alternating bundle branch block during treatment for advanced ischemic heart disease and malignant ventricular arrhythmia is presented. In this patient alternation was induced by atrial premature beats as well as spontaneous and pacemaker induced premature ventricular beats. Right bundle branch block which followed a premature atrial beat resulted from the longer refractory period of the right bundle. The maintenance of right bundle branch block at long cycle lengths was presumed to be due to continuous retrograde reentry. This was terminated when a pause following a premature beat allowed functional recovery of the right bundle branch. This patient died suddenly at home with a functioning pacemaker, demonstrating the high risk of death from ventricular dysrhythmia in the post myocardial infarction patient with a new conduction defect.     

Delayed conduction in the bundle branches: A report of two cases in which the P-R interval increased with changes from left to right bundle branch block

Two cases are reported which, in the electrocardiogram, presented aberrations of the ventricular complexes of two types, suggestive of alternation of right and left bundle branch block. Changes from left to right bundle branch block were invariably accompanied by prolongation of the P-R interval; the increase measured 0.05 second or more. This fact suggested that what first appeared to be complete left bundle branch block was actually a delay of conduction in the left division of the bundle measuring 0.05 second. The delay in the left branch allowed the excitation, passed by the right bundle branch, to reach the left ventricle and to activate both chambers. At times, however, when the conduction in the right bundle branch failed, the left branch of the bundle took over the task of activating not only the left but also the right chamber. The delay of its conduction was then added to the A-V conduction time; causing a prolongation of the P-R interval by 0.05 second.     

Left bundle branch pacing from distal His‐bundle region by tricuspid valve annulus angiography

A 78‐year‐old man presenting with amaurosis was admitted to the outpatient clinic 1 week ago. His baseline electrocardiogram showed Mobitz type II atrioventricular block and right bundle branch block. The patient's heart rate from Holter was only 32 bpm and therefore the indication for pacemaker implantation.     

Failure to recognize a His bundle potential in complete atrioventricular block.

This report concerns a patient with complete heart block, in whom electrophysiological studies showed at times an escape rhythm with narrow QRS complexes preceded by His potentials with normal HV intervals (35--40 msec) and at other times an escape rhythm of similar rate, having wide QRS complexes of left bundle branch block configuration with no preceding His bundle activity. Complexes intermediate in width and configuration and preceded by His potentials with an HV interval inversely proportional to QRS width were also recorded. These observations are explained by a site of block proximal to the His bundle and competition between two pacemaker foci having similar discharge rates, one situated in the junctional region below the site of block and the other more distally in the right bundle branch or right ventricle. It is proposed that the combination of a proximal site of block and a distally situated dominant pacemaker may be a common reason for failure to record a His potential in patients with complete heart block.     

Positive T wave overshoot as a sign of ventricular enlargement

A consecutive series of 86 patients with an inverted T wave showing terminal positivity (overshoot) of a specific pattern in the resting electrocardiogram were studied. Patients with bundle branch block or electrocardiographic evidence of acute infarction and those taking digoxin or a similar drug were excluded. In 67 patients the heart was examined by echocardiography and in a further two by direct inspection. Sixty six of the 69 patients had an abnormal thickness of the left (or right) ventricle or a calculated left ventricular mass greater than 200 g. Seven of the patients examined by echocardiography had clinically pure ischaemic heart disease; all showed evidence of left ventricular enlargement. In only 39 of the 63 patients with anatomical evidence of left ventricular hypertrophy or dilatation did the electrocardiogram satisfy the standard voltage criterion of left ventricular hypertrophy. In the absence of acute infarction, bundle branch block, or digitalisation positive T wave overshoot of the pattern described is a sign of increased ventricular mass.     

Positive T wave overshoot as a sign of ventricular enlargement.

A consecutive series of 86 patients with an inverted T wave showing terminal positivity (overshoot) of a specific pattern in the resting electrocardiogram were studied. Patients with bundle branch block or electrocardiographic evidence of acute infarction and those taking digoxin or a similar drug were excluded. In 67 patients the heart was examined by echocardiography and in a further two by direct inspection. Sixty six of the 69 patients had an abnormal thickness of the left (or right) ventricle or a calculated left ventricular mass greater than 200 g. Seven of the patients examined by echocardiography had clinically pure ischaemic heart disease; all showed evidence of left ventricular enlargement. In only 39 of the 63 patients with anatomical evidence of left ventricular hypertrophy or dilatation did the electrocardiogram satisfy the standard voltage criterion of left ventricular hypertrophy. In the absence of acute infarction, bundle branch block, or digitalisation positive T wave overshoot of the pattern described is a sign of increased ventricular mass.     

Changes in ventricular depolarization in patients in sinus rhythm following closure of ventricular septal defect associated with atrioventricular discordance

Closing the ventricular septal defect in patients with atrioventricular discordance with sutures placed through the defect onto the morphologically right septal surface should avoid production of complete heart block. To discover whether this procedure otherwise affects conduction, standard electrocardiogram (ECG) were compared preoperatively and postoperatively in 11 such patients. Operation had lengthened the PR interval in one and shortened it in another. The QRS interval remained unchanged in 5 patients thought 2 of these showed minor changes in QRS configuration. Four patients showed QRS prolongation (increase greater than 20 msec) with delayed conduction towards the right ventricle and the initial QRS vector preserved, i.e., morphologically right bundle branch block. Two patients showed QRS prolongation with initial QRS vector alteration and delayed conduction towards the left ventricle, i.e., morphologically left bundle branch block. Repair through the morphologically left ventricle invariably caused bundle branch block. Repair through a right atriotomy caused bundle branch block in only 3 of 8 patients. Therefore closure of a ventricular septal defect by this method, particularly transatrially, need not affect conduction. Morphologically left ventriculotomy rarely if ever causes morphologically left bundle branch block. When present, morphologically right bundle branch block presumably results from interruption of the proximal right bundle.     

Transient unifascicular, bifasicular and trifascicular block: electrophysiologic correlations in a patient with rate-dependent left bundle branch block and transient right bundle branch block.

Correlations of the His to ventricular (H-V) conduction time were made with the surface electrocardiogram during normal intraventricular conduction, unifascicular block (right bundle branch block), bifascicular block (left bundle branch block) and trifascicular block (right and left bundle branch block) in a patient with rate-dependent left bundle branch block who had transient right bundle branch block during recording of the His bundle electrogram. The results provide a functional confirmation of the theory that a prolonged H-V time is a manifestation of trifascicular disease.     

Pathophysiology and management of syncope in Kearns-Sayre syndrome

A 20-year-old woman with known Kearns-Sayre syndrome was transferred to the emergency department due to syncopal episodes. The electrocardiogram on admission showed complete atrioventricular block. The diagnosis of mitochondrial encephalomyopathy was made when she was 14 years old. At the time of the initial diagnosis, she displayed a normal electrocardiogram pattern. At the age of 17, electrocardiogram recordings demonstrated right bundle branch block with left anterior fascicular block and a prolonged QTc interval of 485 milliseconds (Figure). She was taking coenzyme Q10, oral nicotinamide adenine dinucleotide (reduced), piribedil, amantadine, and primidone. Transthoracic echocardiography revealed normal wall motion of both ventricles and mitral valve prolapse without regurgitation. A permanent dual-chamber pacemaker was immediately implanted.     

Étude rétrospective monocentrique sur la prévalence et la signification du bloc de branche droit incomplet chez les jeunes sportifs de compétition en Tunisie

AimsFew studies have assessed the prevalence and significance of right bundle branch block in athletes. Aims of this study were to evaluate the prevalence of incomplete right bundle branch block and its correlation with the nature of sports practice and to compare the athlete with right bundle branch block and the one with a normal electrocardiogram.MethodsIt was a retrospective study of the electrocardiogram and echocardiography of competitive athletes recruited in the medical-sports center of SousseResultsA total of 554 athletes were included. Mean age was 16.1 ± 2.9 years and 69 % were male. The mean training duration was 5.8 hours per week. The prevalence of incomplete right bundle branch block was 13.9 % (77 cases). Endurance sports were practiced in 71.4 % of cases among subjects with right bundle branch block versus 55.4 % in the rest of the population (p < 0.001). The basal diameter of the right ventricle was larger in athletes with right bundle branch block compared to athletes without right bundle branch block: 28 ± 3.6 mm versus 24 ± 2.4 mm (p < 0.001).ConclusionsThe results of this study suggest that right bundle branch block is a marker of incomplete right ventricular remodeling. This remodeling represents a form of adaptation to sustained elevation of volumetric load observed mainly in endurance sports.     

Evaluation of a QRS scoring system for estimating myocardial infarct size. II. Correlation with quantitative anatomic findings for anterior infarcts

The ability of an independently developed QRS point score to estimate the size of infarcts predominantly within the anterior third of the left ventricle was evaluated by quantitative pathologic-electrocardiographic correlation. The study was limited to 21 patients with a single infarct documented by postmortem examination, for whom an appropriately timed standard 12 lead electrocardiogram was available that did not exhibit signs of left or right ventricular hypertrophy, left or right bundle branch block or anterior or posterior fascicular block. At necropsy the heart was cut into five to seven slices. The location and size of the infarct was quantitated by computer-assisted planimetry of the slices.The electrocardiogram of 19 (90 percent) of the patients exhibited either a Q wave or an R wave of no more than 20 ms in lead V₂. The infarct in the two patients without this electrocardiographic finding was small, occupying 2 and 3 percent of the left ventricle, respectively. The percent infarction of the left ventricle correlated with the QRS point score (r = 0.80). Thus in patients without complicating factors in the electrocardiogram and with a single infarct, the electrocardiogram provides a marker for infarction in the anterior third of the left ventricle and permits estimation of infarct size.