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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our preliminary experience with dual-chamber DDD pacemakers is reported. Technological innovations of the device, atrio-ventricular electrode stability and sequential stimulation have contributed to improve the conditions of patients previously submitted to VVI pacemaker implantation. Primary indications for DDD pacemaker implantation in our series included 7 patients with complete atrio-ventricular (A-V) block, 3 with Mobitz type II second-degree A-V block and 2 with sick sinus syndrome. In six of the 12 patients (50%) additional indications included: ventricular tachycardia in 4 patients, atrial fibrillation in one and pacemaker syndrome in one. Other cardiac conditions were diagnosed: dilated cardiomyopathy in 3 patients, ischemic heart disease in 2 patients, valvular heart disease in 2 patients, congenital heart disease in 1 patient and hypertrophic cardiomyopathy in one patient. The implanted pacemakers were: 5 Genesis, 4 Ultra CPI and 3 Versatrax. J-shaped atrial electrodes were used in 8 patients and in 4 instances a screw-in electrode was employed. Improvement of hemodynamic function was achieved by frequent follow up and reprogramming of DDD pacemaker in every patient. While 4 patients died with progressive deterioration of cardiac function, eight patients survived with adequate sequential stimulation. We conclude that DDD pacemakers are reliable and afford symptomatic relief in a broad spectrum of patients.
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PMID:[DDD dual chamber pacemakers. Initial experience]. 134 19

Permanent cardiac pacing is now easily feasible in children and even in small infants, but the long-term results of this procedure are not well known. We analyzed our experience to determine the morbidity of pacing in children. Over the past 10 years, 47 pediatric patients (pts) required pacemaker implantation in our institution. The mean age was 8.3 +/- 4 years (1 day-17 years) and mean body weight was 23 +/- 14 Kg (2.2-60 Kg). 25 pts had heart disease. 40 children had an A-V block (congenital in 22 cases, post-operative in 17 pts, and secondary to a systemic disease in 1 case); 7 pts had a sick sinus syndrome, primitive in 4 and postoperative in 3 cases. The first pacemaker implantation was epicardial in 17 and transvenous in 30 pts. The pacing was single-chamber in 45 pts (VVI 32, VVIr 7, AAI 5, AAIr 1) and dual-chamber in 2 pts (DDD 1, VDD 1). Two newborns, both with a congenital A-V block and severe heart failure, died in the first hours after epicardial pacing. Two other children, both with congenital heart disease, died during follow-up, but the death was not pacemaker-related. Finally, two children were lost to follow-up. The mean follow-up of the 41 remaining pts was 5.2 +/- 3.5 years (4 months-10 years). Twelve children (29%) required 19 implant revisions and the causes were: lead fracture (26%), rising stimulation threshold (26%), growth problems (21%), erosion and/or pocket infection (21%). Revisions were more common in epicardial (52%) than in endocardial (22%) implantation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Complications and sequelae of cardiac electrostimulation in children. Our experience with 47 children]. 142 83

We have attempted to optimize cardiac performance in patients with congenital heart disease requiring artificial pacing by using pacemakers capable of both sensing and pacing both the atrium and the ventricle (DDD). We reviewed our results with 88 patients receiving DDD devices to determine the safety and dependability of these devices in children. Age ranged from 1 hour to 25 years. Endocardial leads were used in 68 patients, whereas epicardial leads were used in 20 patients. Previous cardiac procedures had been done in 30 patients. There were nine deaths but none due to pacemaker malfunction. Endocardial leads functioned better than epicardial leads. Ninety-eight percent of patients with endocardial leads and 62% of patients with epicardial leads were maintained in the DDD mode. Complications were infrequent and all were corrected without long-term sequelae. The DDD mode may offer considerable benefits to children who require artificial pacing. Our data allow us to conclude that most children can be paced safely and dependably in the DDD mode.
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PMID:Atrioventricular pacing in congenital heart disease. 151 May 15

The coexistence of bradycardia and a tachyarrhythmia may preclude effective pharmacologic treatment of 1 arrhythmia without paradoxic aggravation of the other. This study evaluated the potential relation between the 2 types of arrhythmias and the effect of conventional modes and rates of pacing for bradycardia on the frequency of the associated tachyarrhythmias. Twenty-one young patients, aged 2 to 19 (mean 11) years with congenital heart disease and a tachyarrhythmia occurring in the setting of chronic bradycardia were studied. The effects of pacing were evaluated by comparison of the number of episodes of clinical tachycardia during the 12-month intervals before and after pacemaker implantation. During these intervals, antiarrhythmic drug therapy was not altered. Patients were analyzed as independent groups, based on the type of tachyarrhythmia: supraventricular (n = 5), atrial flutter (n = 9) and ventricular (n = 7). The modes of chronic pacing were AAI (n = 4), DDD (n = 6) and VVI (n = 11). The prevention of bradycardia by pacing was associated with a significant decrease in the frequency of supraventricular (p = 0.008) and ventricular (p = 0.02) tachyarrhythmias. However, the frequency of atrial flutter was not altered. Prevention of tachycardia was more frequently associated with the AAI and DDD modes of pacing compared to VVI (p = 0.08). Pacing represents an effective therapy for certain tachyarrhythmias associated with chronic bradycardia, although critical modes may be required.
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PMID:Bradycardia-mediated tachyarrhythmias in congenital heart disease and responses to chronic pacing at physiologic rates. 230 88

The aim of this prospective study is comparing long-term prognosis in patients implanted with a VVI pacemaker (group A) with those implanted with a sequential pacing device, AAI or DDD, (group B). Both groups of 45 patients each, were comparable as regards to age, sex, pacing indications, underlying heart disease, and technical conditions of implantation and were followed-up over 55 months. Atrial arrhythmias (A.A.) incidence was higher in group A: 24.4% than group B: 8.8% (P less than 0.05). Arterial embolisms (A.E.) occurred in group A patients only. Worsening or occurrence of exercise limitation was more frequent in group A: 35.6% as compared to group B: 13.3% (P less than 0.05) and deaths related to these complications, occurred in seven cases in group A versus four cases in group B. In group A, all patients who experienced a worsening or occurrence of an A.A. or an A.E., had a ventriculoatrial conduction (VAC). No statistical difference was observed in worsening or occurrence of exercise limitation between patients with VAC and those without VAC: nine (42.8%) and seven (29.2%) but they respectively experienced at least one complication in 16 cases (76.2%) and seven cases (29.2%) (P less than 0.01). In conclusion, long-term prognosis in patients implanted with VVI pacing as compared to patients implanted with sequential pacing is poorer. The presence of VAC in patients treated with permanent VVI pacing is a major factor for complications and deaths related to A.E. and cardiac failure. Thus VVI pacing should be avoided in patients with VAC.
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PMID:Long-term follow-up of patients treated with VVI pacing and sequential pacing with special reference to VA retrograde conduction. 246 68

This is a retrospective study of 16 children with congenital complete atrioventricular block (CAVB) who were fitted with a pacemaker in infancy. All were neonates admitted at the age of 1 to 9 days for bradycardia; 3 had a cardiopathy. In 8 children a permanent pacemaker was implanted in the first two days of life on account of a heart rate slower than 50 beats/min, accompanied with threatening symptoms (heart failure or syncopes) in 4 cases. In 6 children the pacemaker was implanted at the age of 2 to 3 months; in spite of reassuring electrocardiograms, 5 of them were readmitted in an emergency for heart failure or syncope with slow heart rate; the 6th patient had disorders of ventricular excitability. Finally, 2 asymptomatic infants underwent pacing: one at 20 days for bundle branch block, the other at 6 months for slow phase abnormalities. Pacing was epicardial in all patients, the chamber being positioned in the space that separates the kidney from the parietal peritoneum. Ventricular synchronous pacing (VVI) was applied in 14 cases and atrioventricular pacing (DDD) in the two most recent cases. Two children died post-operatively, due to inadequate attachment of the electrode resulting in loss of ventricular capture in one case, and to extensive left atrial thrombosis in the other case. Two children died at a later stage of severe respiratory pathology. The 12 survivors were followed up for a mean period of 3.7 +/- 3.1 years. Three pacemakers were replaced: one at 28 months for infection, the others at 3 and 6 years respectively for running down of the batteries.2 +
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PMID:[Artificial cardiac stimulation in the newborn infant with complete congenital atrioventricular block. Study of 16 cases]. 250 99

In dual chamber pacing, an improvement of exercise capacity is expected when the atrial refractory period is shortened, because the 2/1 point is increased. This objective can be achieved by greatly reducing atrioventricular delay (AVD) on exercise. Are such variations (up to 100-120 ms) detrimental from a haemodynamic standpoint? This study was performed to analyse this particular aspect of DDD pacing. Three DDD pacing modes, differing by their AVDs (fixed 200 ms AVD, fixed 150 ms AVD, and rate-adapted AVD) were tested in random order, with a haemodynamic protocol including ten patients with chronic atrio-ventricular (A-V) block. For the rate-adapted AVD pacing mode, AVD was reduced by 20 ms every 10 beats min-1 increment (from 220 ms at 90 beats min-1 to 100 ms at 150 beats min-1). Pacing rate was increased from 90 to 150 beats min-1 by increments of 10 beats min-1 every 5 min. Cardiac performance was significantly improved with the rate-adapted AVD above the two fixed AVDs, despite a large AVD variation. When AVD was rate adapted, cardiac index, stroke volume index and left ventricular systolic work index were generally higher and pulmonary capillary wedge pressure, pulmonary arterial pressure and systemic vascular resistances were generally lower, especially at 120, 130 and 140 beats min-1. Comparing the two fixed AVDs, 200 AVD improved cardiac function more at lower heart rates, whereas 150 AVD improved cardiac function more at higher heart rates. Despite its limitations, this study demonstrates that the potential benefits of reducing AVD with increasing heart rates should be twofold in dual chamber pacing: (a) haemodynamic, optimizing cardiac performance on exercise for all heart rates, especially in cases of organic heart disease; (b) electrophysiologic, permitting a sufficiently rapid maximal tracking rate in cases with long post-ventricular atrial refractory periods, allowing a satisfactory level of exercise.
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PMID:Haemodynamic benefit of a rate-adapted A-V delay in dual chamber pacing. 276 75

In 55 patients with coronary artery disease (n = 37), cardiomyopathy (n = 12), or myocarditis (n = 6) and programmable ventricular or dual-chamber atrioventricular (AV) demand pacemakers, left ventricular (LV) performance was studied by gated radionuclide ventriculography during pacing (60 or 70 to 120 bpm). Twenty-three patients were followed over 4 to 6 months. In 16 patients the findings in ventricular (VVI) and dual-chamber AV (DDD) pacing were compared. In all patients end-diastolic volume (EDV) decreased and cardiac output increased when the pacing rate was changed from 60 or 70 to 120 bpm. For instance, in the patient group with VVI pacemakers, EDV decreased by 7.53% +/- 3.5% (p less than 0.01) and cardiac output increased by 53.5% +/- 19.4% (p less than 0.01). The results were independent of the underlying heart disease. After 4 to 6 months, a reduction of both cardiac output and ejection fraction was found in 6 of the 23 patients. As compared to VVI pacing, a significantly higher cardiac output (2% to 16%) was derived from DDD pacing. The results indicate the dependence of LV performance on the pacing rate and the benefit of DDD pacing. Since gated radionuclide ventriculography provides the means to determine the effect of different pacing modes on LV performance, an optimal pacing mode may be found for each individual.
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PMID:Evaluation of left ventricular performance by radionuclide ventriculography in patients with atrioventricular versus ventricular demand pacemakers. 672 May 21

The prevalence of chronotropic incompetence in patients with sinus node disease (SND) is not well defined. To assess this, we evaluated 18 patients (7 men, 11 women; mean age: 64 +/- 11) with SND and permanent pacemakers (AAI/DDD) with Holter monitoring and treadmill stress test. Only 2 patients received active cardiac drugs (1, L-dopa an 1 propafenone). The treadmill tests results were compared with a control group of 15 men and 18 women (mean age: 66 +/- 5, p = NS) without organic heart disease. During ambulatory activity all pacemaker patients increased their own cardiac rate to a value higher than the programmed basic pacemaker rate. In 8 patients the maximal rate attained was over 100/min (mean 95 +/- 19/min). The maximal rate during treadmill test in pacemaker patients was 131 +/- 25 (control group 138 +/- 14, p = NS). Exercise tolerance in METs was similar in pacemaker patients (5.2 +/- 2.6) and in controls (5.8 +/- 1.2) (p = NS). Two pacemaker patients (12%) didn't reach 100/min during stress test. Most patients with SND and permanent pacemakers (AAI/DDD) are able to increase cardiac rate during exercise. Rate responsive pacing (AAIR/DDDR) should be limited to a minority of patients with true chronotropic incompetence.
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PMID:[Chronotropic competence in patients with the sick sinus syndrome wearing AAI or DDD pacemakers]. 831 99

Based on a retrospective study, we report the clinical and electrophysiological characteristics of 62 cases of effort-induced atrio-ventricular block (AVB). The diagnosis of effort-induced AVB was established by stress test and/or Holter ECG. This series consisted of 18 women and 44 men with a mean age of 64 +/- 13 years. AVB presented in the form of poor adaptation to effort in 41 patients (66%), fainting and/or presyncope suggestive of Stokes-Adams attacks in 20 patients (32%), associated with poor adaptation to effort, except in 5 patients. 48 patients (77%) did not have any underlying heart disease. The ECG was normal in 25 patients (40%) or abnormal, demonstrating a 1st degree AVB and/or an intraventricular conduction disorder. On electrophysiological investigation, the AVB was type II (Mobitz II) in 48 patients (77%), generally 2/1. The block was infranodal, either in or below the His bundle, in 56 patients (90%). When it was situated above the His bundle, it was organic and degenerative, situated at the AV node, at the node-His junction, or even proximally in the His bundle. Effort-induced AVB implies DDD atrioventricular stimulation. The presence of this anomaly should be investigated in patients with poor adaptation to effort, but also when the clinical picture is dominated by Stokes-Adam attacks.
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PMID:[Effort-induced atrioventricular block. Apropos of 62 cases]. 874 58


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