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A thirty-three year old woman, known to have Kearns-Sayre syndrome for eight years, had an ECG pattern of right bundle branch block and left anterior fascicular block that evolved to complete atrioventricular block, leading her to a syncopal episode. A temporary pacemaker and a permanent one were installed. The patient has been asymptomatic so far.
AIMS: Implantation of single-lead VDD pacemakers is an established alternative to DDD pacing in patients with atrioventricular block. This study compares the long-term costs of both systems. METHODS AND RESULTS: Three hundred and sixty patients with atrioventricular block received VDD or DDD pacemakers in alternating order. Primary costs of implantation included: devices, leads and operation material, surgeons, nurses, medical technicians, and hospitalization. The mean cost of an uncomplicated DDD pacemaker implantation was defined as 1000 virtual cost-units (CU). Costs of pacemaker related complications or re-operations as well as upgrades from VDD to DDD devices were considered secondary costs and assessed during a mean follow-up period of 42+/-15 months. Pacing efficacy was assessed by event-free survival with maintained atrioventricular synchronized pacing mode. Costs of pacemaker devices were not different (639+/-26 CU in VDD vs 641+/-32 CU in DDD, ns). However, due to lower costs of lead hardware (102+/-10 CU in VDD vs 133+/-14 CU in DDD, P<0.001) and shorter implantation procedures (44.3+/-5.1 min vs 74.4+/-13.5 min, P<0.001), costs of an uncomplicated implantation were 8.9% lower in the VDD group (911+/-35 CU vs 1000+/-39 CU, P<0.001). A smaller complication rate in the VDD group led to a 16.1% reduction of secondary costs (26+/-17 CU year(-1)vs 31+/- 25 CU year(-1), P=0.024). Event-free survival did not differ between groups (83.4% in VDD vs 84.9% in DDD, ns). CONCLUSION: Use of single-lead VDD pacemakers achieves significant reduction of implantation and follow-up costs without loss of therapeutic efficacy compared to conventional DDD systems.
The natural history of patients who developed complete atrioventricular block after valvular heart surgery was investigated to determine the optimal timing for pacemaker implantation. Patients who developed complete atrioventricular block within 24 hours after operation, which then persisted for > 48 hours, were unlikely to recover; such patients could potentially undergo earlier pacemaker implantation if otherwise ready for discharge.
Twelve years after mediastinal irradiation for Hodgkin's disease, a 38-years old man developed an infra-hisian atrioventricular block with syncopes. The rarity of this complication of radiotherapy is emphasized. A review of the literature yielded only 6 cases of atrioventricular block associated with cobalt therapy; a pathological examination was performed in two of these patients and an electrophysiological study in two others.
A 65-year-old man with repeated chest discomfort and dizzy spells was transferred by an emergency car. On the way to hospital, his pulse was palpable as regular 4 to 5 beats followed by an unpalpable period of about 4 s. His electrocardiographic monitor showed that 4 to 5 sinus QRS complexes were followed by consecutive 3 to 4 blocked sinus P waves, which occurred repeatedly. When PP intervals gradually shortened during inspiration, sinus impulses were conducted to the ventricles, whereas when PP intervals lengthened during expiration, 3 to 4 sinus impulses were blocked in succession. An attempt was made to explain the mechanism for such apparent bradycardia-dependent atrioventricular block by using the concepts of periodic increases in vagal tone due to respiration and concealed electrotonic conduction of blocked impulses. Such a peculiar form of advanced second-degree atrioventricular block has never been reported before.
BACKGROUND: The incidence of perioperative bradyarrhythmias in patients with bifascicular or left bundle branch block (LBBB) and the influence of an additional first-degree atrioventricular (A-V) block has not been evaluated with 24-h Holter electrocardiographic monitoring. Therefore the authors assessed the rate of block progression and bradyarrhythmia in these patients. METHODS: Patients (n = 106) with asymptomatic bifascicular block or LBBB with or without an additional first-degree A-V block scheduled for surgery under general or regional anesthesia were enrolled prospectively. Three patients were excluded. Of the 103 remaining, 56 had a normal P-R interval and 47 had a prolonged one. Holter monitoring (CM2, CM5) was applied to each patient just before induction of anesthesia and was performed for 24 h. The primary endpoint of the study was the occurrence of block progression. As secondary endpoints, bradycardias < 40 beats/min with hemodynamic compromise (systolic blood pressure < 90 mmHg) or asystoles > 5 s were defined. RESULTS: Block progression to second-degree A-V block and consecutive cardiac arrest occurred in one case of LBBB without a prolonged P-R interval Severe bradyarrhythmias with hypotension developed in another eight patients: asystoles > 5 s occurred in two cases and six patients had bradycardias < 40/min. Pharmacotherapy was successful in these eight patients. There was no significant difference for severe bradyarrhythmias associated with hemodynamic compromise between patients with and without P-R prolongation (P = 1.00). CONCLUSIONS: In patients with chronic bifascicular block or LBBB, perioperative progression to complete heart block is rare. However, the rate of bradyarrhythmias with hemodynamic compromise proved to be relevant. Because an additional first-degree A-V block did not increase the incidence of severe bradyarrhythmias and pharmacotherapy by itself was successful in nearly all cases, routine prophylactic insertion of a temporary pacemaker in such patients should be questioned.
A 75-year-old male underwent cardiac catheterization for frequent ventricular premature contractions and reduced left ventricular function. ECG on admission showed complete right bundle branch block (RBBB) and left anterior hemiblock. Right heart catheterization was performed uneventfully, but complete atrioventricular block (CAVB) occurred suddenly when a pig-tail catheter was inserted into the left ventricle. Electrophysiological study identified this CAVB as HV block, and demonstrated HV prolongation in sinus rhythm. The coronary angiogram revealed no obstructive lesion or spasm with ergonovine. The reproducibility of the CAVB was demonstrated. The final CAVB developed and persisted for more than one week, requiring the implantation of a permanent pacemaker (DDD). Complete atrioventricular block induced during left heart catheterization is very rare. Pre-existing RBBB with left anterior or posterior hemiblock and reduced left ventricular function may be common factors in patients with this condition. Emergency pacing equipment should always be on-line when left heart catheterization is conducted in such patients.
A 4-month-old girl with a ventricular septal defect underwent cardiac surgery. During the operation, complete atrioventricular block (CAVB) occurred, but on postoperative day 16 it converted to normal sinus rhythm with persistent complete right bundle branch block and left anterior hemiblock. Fourteen years after the operation, second-degree atrioventricular block was detected, but her general condition was good. Fifteen years after the operation, CAVB occurred. The intracardiac electrophysiologic recording revealed A-H and H-V block. A permanent pacemaker was implanted, and following the implantation she completely recovered.
A patient with a history of multiple syncopal episodes had electrocardiographic findings of Wenckebach type of second degree atrioventricular block and left bundle branch block. He was thought to have intermittent complete heart block. His bundle recordings demonstrated the unusual occurrence of Mobitz type I block localized to the ventricular specialized conduction system. Based on the findings of this case and those of previous case reports, it is recommended that electrophysiologic studies should be performed on all patients with Mobitz type I atrioventricular block who also have bundle branch block.
Cardiac contusion may cause disorders of impulse formation and propagation in the specific conduction system. Transient complete atrioventricular block following a nonpenetrating chest trauma is a rare complication.We describe the case of a patient who presented a transient complete atrioventricular block, and later a transient right bundle branch block and a left anterior hemiblock, following a nonpenetrating chest trauma due to a car accident. The difficulty for diagnosing myocardial contusion is pointed out, and the usefulness of the electrophysiological study for detecting baseline conduction system disorders is discussed.
A prospective comparison of physiologic response to single-rate ventricular and dual-chamber atrioventricular pacing was conducted in 14 pediatric patients (age 1 to 24 years, median 14) with symptomatic nonsurgical second- or third-degree atrioventricular block. All patients were studied acutely during cardiac catheterization before and after 1 hour of both pacing modes. Following pacemaker implant, eight patients were reevaluated after 1 month of each mode with symptom questionnaire, resting ECG, resting echocardiogram, and Doppler cardiac output measurement at rest and at peak treadmill exercise. Cardiac outputs (mean +/- standard error) increased acutely (n = 14) with both ventricular (32 +/- 12%) and dual-chamber (39 +/- 10%) pacing over intrinsic rhythm values (p less than 0.01 in both). During chronic pacing (n = 8), symptoms were reported only with the ventricular mode. Dual-chamber synchronous pacing was associated with improved mean resting shortening fraction and cardiac output, slower mean resting sinus rate (89 +/- 5 compared to 73 +/- 4 bpm (p less than 0.02), and a 23% increase in mean excerise cardiac output (4.2 +/- 0.4 compared to 3.4 +/- 0.3 L/min/m2) compared to single-rate ventricular pacing. Exercise-induced dysrhythmias occurred only with ventricular pacing. This study demonstrates that pediatric patients with nonsurgical atrioventricular block can compensate for loss of atrioventricular synchrony at rest but exhibit improved cardiac function with chronic dual-chamber atrioventricular compared to single-rate ventricular pacing.
We report here a case of Duchenne muscular dystrophy (DMD) who underwent pacemaker implantation for complete atrioventricular block. This 30 year-old male had the deletion of exon 45-52 in the dystrophin gene and complained of palpitation and precordial oppression. Because his electrocardiogram showed complete atrioventricular block, a permanent pacemaker was implanted. He has been doing well for 15 months after implantation. There have been few reports about pacemaker implantation for patients with DMD. As these patients survive longer by mechanical ventilation with chest respirators or nasal intermittent positive pressure ventilators, an increasing number of cases may require pacemaker implantation.
We followed 120 patients 4-14 yr after permanent pacemaker implantation for high-grade atrioventricular block to assess the effect of sex, age at implantation, date of implantation and various chronic co-existent illnesses on survival. The overall survival rates were 91% at 1 yr, 63% at 5 yr and 41% at 10 yr. Patients with congestive heart failure demonstrated the lowest survival rates of all cohorts studied. Survival rates of patients with congestive heart failure were significantly lower than survival rates of patients without congestive heart failure and were also significantly lower than those of patients with conduction system disease only. Similarly, patients with coronary heart disease demonstrated significantly lower survival rates than both patients without coronary heart disease and patients with conduction system disease only. The presence of hypertension, valvular heart disease, diabetes mellitus or cerebral infarction influenced survival less adversely than congestive heart failure or coronary heart disease. Survival decreased progressively with increasing age; however, the differences were not significant. Sex and date of implantation had no apparent effect on survival. Thus, coronary heart disease and the presence of congestive heart failure appear to be the major determinants of survival following permanent pacemaker implantation for high-grade atrioventricular block.
A 40 year-old woman with acute myelogenous leukemia developed an advanced atrioventricular block and pericardial effusion. On autopsy, pericardial effusion without pericarditis and mononuclear cell infiltration in His bundle were found. Focal infiltration of His bundle by leukemic cells was suggested as the cause of the atrioventricular block.
An 89-year-old man with chronic glaucoma received hourly pilocarpine eye drops for seven hours, when he developed third-degree atrioventricular block with a slow idioventricular escape rate. After discontinuing the pilocarpine, the atrioventricular block gradually disappeared. The site of pilocarpine-related block was most likely within the His-Purkinje system.
One patient with complete atrioventricular heart block and another with high-degree atrioventricular block, complicated by "torsade de pointes" are presented. Both patients were symptomatic. One had a syncopal episode and the other presented with signs and symptoms of congestive heart failure. The electrocardiographic phenomena of torsade de pointes was repeatedly recorded. No other known predisposing factors for torsade de pointes were identified. The use of right ventricular endocardial pacing suppressed the paroxysms in both patients.
The aims of this study were to develop a suitable model to study proarrhythmic potential using isolated rabbit hearts with atrioventricular block and to examine the proarrhythmic potential of several drugs using this model. With a normal K/Mg solution (K+=5.7 mM and Mg2+=1 mM), d,l-sotalol (10 and 30 microM), a class III antiarrhythmic drug, prolonged ventricular repolarization, such as QT intervals and monophasic action potential duration, and induced early after-depolarization and polymorphic ventricular tachyarrhythmia. Cisapride (0.1 and 0.3 microM), a 5-HT4 receptor agonist, also prolonged the ventricular repolarization, and induced early after-depolarization. With a low K/Mg solution (K+=1.5 mM and Mg2+=0.35 mM), d,l-sotalol at 30 microM and cisapride at 0.3 microM more potently prolonged the ventricular repolarization than with a normal K/Mg solution. Furthermore, the incidence of polymorphic ventricular tachyarrhythmia caused by cisapride at 0.3 microM with a low K/Mg solution was higher than that with a normal K/Mg solution. Mosapride citrate, another 5-HT4 receptor agonist, at 10 microM prolonged the ventricular repolarization and induced early after-depolarization with a low K/Mg solution, whereas the drug at 1 and 3 microM did not affect any of the parameters examined. Des-4-fluorobenzyl-mosapride, a metabolite of mosapride citrate, at 10 microM slightly prolonged the ventricular repolarization without inducing early after-depolarization or ventricular tachyarrhythmia. These results suggest that mosapride citrate and des-4-fluorobenzyl-mosapride have much less proarrhythmic potential than cisapride and that isolated rabbit heart with atrioventricular block, perfused with a low K/Mg solution, is a suitable model for predicting the proarrhythmic potential of drugs.
OBJECTIVE: To look at the presentation, treatment and outcome of patients who developed atrioventricular block after transcatheter closure of a perimembranous ventricular septal defect (PMVSD) with the Amplatzer PMVSD device. SETTING: Three tertiary referral centres for paediatric cardiology in two countries. RESULTS: All three patients presented within 10 days of the procedure. All three patients were treated with intravenous steroids. A permanent pacemaker was inserted in all patients but no pacemaker required activation after two months. CONCLUSION: Complete atrioventricular block occurring in the weeks after device occlusion of a PMVSD appears to resolve quickly. Continued involvement in multicentre device databases is required to monitor safety.