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Background Current guidelines suggest the use of atrial synchronous mode (VDD) pacemakers in patients with atrioventricular (AV) block and normal sinus node function. However VDD mode is being used much less than expected. The objectives of our study were to evaluate the efficacy of VDD pacing in long-term follow-up and to find risk factors for VDD loss. Methods We retrospectively evaluated all patients with VDD pacemakers who were implanted in our center between 1995 and 2007. Results During the study period, 123 consecutive patients with AV block (51% men, age 62 ± 17.8 years) received a VDD pacemaker. Mean follow up duration was 4.5 ± 3.2 years. At the last follow up visit, 21 patients (21.6%) lost their original VDD mode and were programmed to ventricular-based pacing (VVIR) (undersensing, 11; chronic AF, 7; SND, 3). In 28 patients, VDD mode was restored or maintained by increasing atrial sensitivity. No episodes of atrial oversensing were observed. In multivariate analysis history of paroxysmal AF (p = 0.007, odds ratio 36.6, 95% confidence interval 2.7–493.7) and p wave lower than 1 mv during the follow up (p = 0.021, odds ratio 7, 95% confidence interval 1.3–36.7), were found risk factors to VDD loss. Conclusions VDD pacing has good long-term performance. Absence of paroxysmal AF history predicts maintenance of VDD pacing mode. Taking into account that no atrial oversensing was observed, our recommendation is to increase atrial sensitivity when P wave amplitude declines to less than 1 mv. Copyright © 2010 Wiley Periodicals, Inc.

Transient hyperglycemia is common during acute myocardial infarction in non-diabetic patients and is associated with a worse outcome. There is limited data on the outcome of patients who undergo primary percutaneous coronary intervention and have transient hyperglycemia.Fasting plasma glucose was measured in 431 consecutive acute myocardial infarction patients who underwent primary percutaneous coronary interventions. Patients were classified into three groups: non-diabetics/non-hyperglycemic (NDNH, glucose126 mg/dL; n=224); non-diabetics/hyperglycemic (NDH, glucoseor = 126 mg/dL; n=119); and diabetics (n=88). Data were analyzed according to the different groups and according to exact glucose levels.In-hospital mortality was significantly lower in NDNH (1%) compared to NDH (8%) and diabetic (5%) patients (p=0.01). One-year cumulative mortality was highest (10%) in patients with NDH (p0.001). One year target lesion revascularization rates were identical in NDNH and NDH patients (6% vs. 8%) and higher in diabetic patients (19%, p=0.001). In a multivariate model, a striking increase in the risk of death (0.6%, p=0.05) and target lesion revascularization (2%, p0.0001) was found for every increment of 1 mg/dL in glucose level.Transient hyperglycemia in non-diabetic acute myocardial infarction patients who undergo primary percutaneous coronary interventions is associated with high one-year mortality. One year target lesion revascularization rates were significantly higher in diabetics compared to non-diabetics with normoglycemia or transient hyperglycemia.

Stents have revolutionized percutaneous coronary interventions (PCI), impacting on both acute and long-term results. However, despite improvements in stent design, stent deployment failure is not an unusual event. The aim of the present study was to assess the frequency and causes of stent deployment failure, as well as the outcome of these patients. Between 1997 and 2001, a total of 3,537 patients underwent stent-assisted PCI and delivery of 5,275 stents was attempted. In the majority of patients (118; 78.1%), stenting was performed as provisional; in the remaining 33 (21.8%) as a bailout procedure. A total of 175 (3.3%) stents in 151 (4.3%) patients failed. Failure to deliver the stent to the lesion site was the main cause in 139 patients (92%) and failure either to expand adequately the stent or premature disengagement of the stent from the balloon in only 12 patients (8%). Peripheral stent embolization occurred in 10 (0.3%) patients. Deployment of a different stent in place of the failed one was attempted in 122 patients and was successful in the majority (108; 88.5%). In-hospital major adverse cardiac events were observed in six patients (4%): three patients required emergency coronary artery bypass surgery, two had a myocardial infarction (MI), and one patient underwent urgent repeat coronary intervention. At a mean follow-up of 32.2 +/- 17.7 months, 22 major adverse cardiac event occurred in 17 patients (11.2%): 1 cardiac death, 3 patients had an MI, and 18 patients required target vessel revascularization. One-year event-free survival for the whole group was 91.2%. Patients with stent embolization did not have any major adverse cardiac or vascular events. Thus, the rate of stent deployment failure in our series was 3.3%, mainly due to failure to deliver the stent to the site. Another stent was successfully deployed in the majority of cases and these patients had favorable short- and long-term outcomes.

Published data regarding stenting very small arteries are still limited. The BiodivYsio stent is a new stent coated with phosphorylcholine, a biocompatible molecule designed to reduce the formation of thrombus and potentially the risk of restenosis. The feasibility, safety, and efficacy of implantation of the 2.0 mm coated coronary stent were prospectively studied. We studied 97 patients from three centers who underwent elective, urgent, or bailout implantation of 106 BiodivYsio mini-stents (2.0 mm) in 101 lesions. Forty percent of lesions had unfavorable characteristics (type B2 or C) and 16% had thrombus and/or chronic total occlusion. Successful stent deployment was achieved in 100/101 lesions (99%). MLD increased from 0.49 ± 0.31 mm to 1.89 ± 0.41 mm and diameter stenosis decreased from 89% ± 7% to 5.6% ± 6%. Small vessel stenting was the only procedure in 71% patients. There was one acute stent thrombosis case. During 6-month follow-up, none died, one had MI, and one was referred to CABG due to nontarget lesion progression. Angiographic restenosis that required target lesion revascularization was performed in 8/18 that had catheterization due to chest pain or significant ischemia. Most patients improved in their clinical symptoms. The rate of major adverse cardiac events was 4.1% at 30-day and 10.3% at 6-month follow-up. This initial clinical experience indicates that the implantation of 2.0 mm stents coated with phosphorylcholine appears to be safe and efficacious in the treatment of complex coronary lesions and is associated with low target vessel revascularization rate in spite of the very small vessel diameter. Cathet Cardiovasc Intervent 2002;55:303–308. © 2002 Wiley-Liss, Inc.

Results from previous trials have shown conflicting results from local delivery of thrombolytic agents to diminish thrombus burden before intervention in native coronary arteries and saphenous vein grafts. We described a patient with an acute coronary syndrome who was treated for 24 hours with systemic tirofiban (Aggrastat®), a glycoprotein IIb/IIIa inhibitor, for the treatment of a degenerated saphenous vein graft with a TIMI grade 4 thrombus (large-sized thrombus). Angiographic evaluation 48 hours later revealed complete resolution of the thrombus with normal coronary blood flow. (Int J Cardiovasc Intervent 2003; 5: 92-94)

Implantation of permanent pacemakers in children and adolescents is possible but usually is limited to single chamber generators. The natural growth of these patients may require physiological pacing, but until recently two leads were required for this type of pacing. The single pass lead VDD pacing mode makes possible physiological pacing by using only one lead, for both atrial sensing and ventricular sensing and pacing. The feasibility of VDD pacing using endocardial lead was evaluated in 16 children and adolescents with congenital or postsurgical atrioventricular block. Their mean age was 7.9 +/- 4.9 years (range 1-16 years) and the smallest patient's weight was 8.2 kg. In all the patients, a single pass pacing lead with atrial sensing rings and bipolar ventricular pacing and sensing capability was implanted through the left or right subclavian vein. The pacemaker generator was implanted in a rectopectoral position. The mean atrial electrogram during the implantation was 4.2 +/- 2.1 mV and 2.6 +/- 1.9 mV after a mean of 1 week. The ventricular pacing threshold was 0.5 +/- 0.2 V; the ventricular pacing impedance was 560 +/- 95 omega; and the ventricular electrogram amplitude was 9.9 +/- 2.1 mV. This is a first report to demonstrate the feasibility of atrial synchronous ventricular endocardial pacing using a single pass lead in a relatively large group of children and adolescents.

This paper describes an approach to the treatment of exposed pacemaker generator and electrode. Local infection is controlled by the administration of systemic antibiotics and topical antibacterial solutions. Because the generator and lead are enveloped by an inert synthetic coating, it is possible to eradicate an infection without their removal if it is due to a weak opportunist pathogen fully sensitive to antibiotics. Thereafter, subcapsular relocation of the exposed generator or vertical-to-horizontal transposition of the exteriorised lead is carried out. These surgical interventions are designed to overcome the vertical force which tends to cause the extrusion of the pacing hardware.

(2003). Spontaneous healing of long, catheter-induced right coronary artery dissection. International Journal of Cardiovascular Interventions: Vol. 5, No. 4, pp. 211-211.

The inability of cardiac pacemakers to selectively reject retrograde P waves limits the usefulness of dual-chamber pacemakers (because of the possibility of endless loop tachycardias) and of antitachycardia devices which use a dual-chamber sensing algorithm. In order to determine selective sensing parameters, amplitude, slew rate, and configuration of antegrade and retrograde atrial electrograms were measured in 34 patients undergoing dual-chamber pacemaker implant—31 with unipolar and three with bipolar units. All antegrade and retrograde pairs were measurably different. All 34 cases had measurable antegrade/retrograde amplitude differences; 30 of the unipolar cases (96.8%) and all bipolar cases displayed antegrade/retrograde amplitude differences of at least 0.25 mV. Thirty of the unipolar cases (96.8%) and two bipolar cases had measurable slew rate differences. Conflguration differed in 14 of 31 (45.2%) of unipolar and in two bipolar cases. A combined criterion with 0.25 mV sensitivity steps (available in at least two presently avallable pacemakers) and 0.5 V/sec slew rate gradations (through the use of externally programmable filters) would allow the discrimination of retrograde from antegrade depolarizations in all 34 cases. With the use of amplitude and slew rate differences, it is therefore possible to reject retrograde P waves while sensing antegrade P waves with current technology.

A 3-beat episode of ventricular arrhythmia was recorded in a patient with an AV universal (DDD) pacemaker. This arrhythmia mimicked "endless loop" tachycardia (ELT) because it appeared following a ventricular premature contraction (VPC), its rate approached the preset upper-rate limit and the regular P waves disappeared during the episode. However, as retrograde conduction was absent ELT could not exist. The mechanism of this arrhythmia was based on a combination of interference by VPC of the regular sequence of QRS complexes produced by P wave and the pacemaker commitment to maintain an upper rate limit by prolongation of the programmed pacemaker AV delay.

Amiodarone is an antiarrhythmic agent with high iodine content. Ten patients treated with amiodarone developed thyrotoxicosis. I131 uptakes were negligible, and TT3 levels low in relation to TT4 levels, and sometimes even normal. Cessation of amiodarone caused thyroid functions to return to normal in one to five months, unrelated to propylthiouracil treatment. Eight of the patients had normal thyroid glands on radioscan or palpation. All patients tested had normal TRH tests. Thyrotoxicosis is a relatively common complication of amiodarone treatment, probably caused by its high iodine content. It is possible in apparently normal thyroid glands, suggesting failure of the homeostatic mechanisms controlling thyroid synthesis and release in these patients. Amiodarone is very efficient in controlling tachyarrhythmias and angina pectoris, situations in which thyrotoxicosis is dangerous. Thyroid function tests should therefore be drawn periodically, and the complication considered whenever tachyarrhythmias worsen on treatment with amiodarone.

The follow-up of 80 patients above the age of 70 years with implanted pacemakers is described. These patients were the most advanced in age from a total group of 150 with implanted pacemakers. Their ages ranged from 70 to 87 years, with an average of 75.4 years; 50 were male and 30 were female. An epicardial electrode was implanted in 13 patients and an endocardial electrode in 67. The pacemaker was implanted in 76 patients for symptomatic atrioventricular block and in four patients for sick-sinus syndrome. Two patients (2.5 per cent) died during the postoperative period and 19 patients within a period of 3 months to 6 years after the implantation. The survival rates were: 1 year, 90.0 per cent; 2 years, 82.1 per cent; 3 years, 74.1 per cent; 4 years, 67.2 per cent; 5 years, 58.3 percent. These survival rates were surprisingly similar, for the first 3 years of follow-up, to those of our and others' previous studies, which included all age groups. The survival rates in the most advanced age groups decreased in comparison only in fourth and fifth years after the implantation. There was no evidence of new episodes of myocardial infarction among this group of patients during the follow-up period. We conclude that even in patients of the most advanced age groups the implantation of an endocardial pacemaker significantly prolongs life, improves its quality, and this at a low operative risk.

A model 7000 pacemaker in the DVI mode emitted two stimuli, the first stimulating the right ventricle and the second 110 ms later. The atrial lead was found in the right ventricular outflow tract. The QRS complex produced by the atrial lead fell after the blanking period, and "committed" the ventricular stimulus 110 ms after the "atrial." Intracardiac electrography during the original implant would have enabled proper atrial lead position.

A 65-year-old man with Behçet's disease developed transient complete A-V block with syncope. An attempt to implant a permanent transvenous endocardial electrode failed owing to obstructions in the subclavian, innominate, and superior vena cava veins demonstrated by angiography. Sutureless epicardial electrodes were successfully implanted through a subxyphoid approach. Obstruction in the great veins is a common feature in patients with Behçet's disease. We suggest that patients with this disorder, who require a permanent pacemaker, should be investigated by angiography prior to implant to rule out obstruction in the upper great veins.