Dual-chamber Pacemaker Implantation Research Articles

Early mobilization after pacemaker implantation

There are no international guidelines indicating how long a patient should stay strictly in bed after pacemaker implantation. In the present study, we tested a new protocol concerning the mobilization of patients 3 h after receiving a single or a dual-chamber pacemaker. Consecutive patients who underwent single or dual-chamber pacemaker implantation were randomized to a 3 or 24 h immobilization protocol. Only bipolar passive fixation leads were computed. After the implant, an elastic bandage was put on the homolateral shoulder of all patients for 24 h. A complete clinical and electronic follow-up was performed before discharge and repeated 2 months later. End-points considered were the displacement of the lead, high pacing thresholds (> 3.5 V/0.4 ms at the discharge or > 2.5 V/0.4 ms at the 2-month follow-up), sensing defects not corrigible by programming and clinical complications of the pocket One hundred and thirty-four patients were included in the study: 57 in group A (mobilization after 3 h) and 77 in group B (24 h). In group A, one haematoma and two displacements occurred in three patients. In group B, we registered one haematoma, one subclavian vein thrombosis, three displacements and three high stimulation thresholds. No statistical differences were observed between the end-points of group A versus B. The present study shows that an early mobilization protocol is feasible because no statistical differences resulted from the two groups of study as regards clinical outcome, complications and electronic measurements of the implanted devices, which have been followed up for 2 months.

Does treatment with ACE inhibitors or angiotensin II receptor antagonists prevent atrial fibrillation after dual chamber pacemaker implantation?

A retrospective observational study was performed to test the hypothesis that a lower incidence of atrial fibrillation (AF) would be observed in patients treated with either angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor antagonists (AIIRAs) than those without these drugs, 1-year following implantation of a dual chamber pacemaker for all indications. One hundred and sixty consecutive patients who underwent implantation of a dual chamber pacemaker between January and August 2002 were identified and their case notes were retrospectively analysed. The primary endpoint was the presence of persistent AF (confirmed by 12-lead ECG recorded from the visit to the pacemaker clinic) at 12-month follow-up. Overall, 8% patients developed new onset persistent AF at 1-year follow-up. The incidence of AF at 1-year was 4% in patients treated with ACE inhibitors, 8% in patients taking AIIRAs or 5% on either drug. Although a trend towards a higher incidence of AF was observed at 1-year (10%) in patients not receiving either of these drugs, this was not statistically significant (P = 0.21, drug vs. no drug). The incidence of AF in patients with a previous history of paroxysmal AF or cardioversion was significantly higher (23%) than those patients without (5%), P < 0.0001. An odds ratio (95% CI) of 7.9 (2.3-27.8) was obtained. To confirm these interesting initial results and to investigate this important relationship further, larger prospective randomised controlled studies are required.

Far‐Field R‐Wave Reduction with a Novel Lead Design: Experimental and Human Results

The purpose of this study was to examine a bipolar screw-in lead (NL), specially designed to reduce unwanted far-field R-wave (FFRW) signal detection in an acute human setting. The results were compared with animal experiments. The newly designed lead with a center-to-center distance between the anode and cathode electrodes of 3.23 mm, corresponding to an inter-electrode spacing of 1.1 mm was implanted in nine canines with a follow-up of 6 months. Sensing of P waves, FFRW signals, pacing threshold, and impedance was measured at regular intervals. As a result of the positive outcome with the animal study, an acute human experiment was performed. In patients scheduled for conventional dual chamber pacemaker implantation, the NL was compared to a Tendril Model 1388T bipolar screw-in lead (St. Jude Medical, CRMD, Sylmar, CA). Utilizing a tip-to-ring distance of 1.1 mm, the optimum P wave to FFRW ratio was found in animal experiments. In the acute human tests in 15 patients, the mean P-wave voltage of the 1388T lead of 3.30 +/- 1.54 mV was slightly larger than that of the NL, at 2.55 +/- 1.11 mV, but did not differ significantly (P = 0.13). The FFRW voltage of the 1388T lead was 0.62 +/- 0.37 mV and was significantly greater from that of the NL, at 0.10 +/- 0.08 mV (P < 0.0001). Pacing thresholds and pacing impedances were comparable. Animal testing results were reproducible in the acute human test setting. The lead reduced the paced FFRW signal amplitudes significantly, allowing for high atrial sensitivity settings but without sensing the FFRW. A robust P-wave signal could be retained.

Validation of Dual‐Chamber Pacemaker Diagnostic Data Using Dual‐Channel Stored Electrograms

Pacemaker diagnostic counters are used to guide device programming and patient management. However, these data are susceptible to inappropriate classification of events. The aim of this multicenter study was to evaluate pacemaker diagnostic data using stored intracardiac electrograms (EGMs). The study included 351 patients (191 males, aged 71 +/- 10 years) with standard indications for dual-chamber pacemaker implantation. EGM triggers were atrial tachycardia (AT), ventricular tachycardia (VT), sudden bradycardia response (SBR), and pacemaker-mediated tachycardia (PMT). For this study, the devices could store up to 5 EGMs of 8s each (with marker annotation and onset recording). After 3 months, the EGMs were analyzed and classified as "confirmed" if the EGM validated the trigger and as "false positive" if the EGM showed an event different from the trigger. Of the 1,003 EGMs available, the triggers were AT in 640 EGMs, VT in 76, SBR in 105, and PMT in 178 EGMs. Four EGMs were triggered by magnet application. The trigger was confirmed in 614 EGMs (62%): 62% of AT episodes, 18% of VT episodes, 100% of SBR episodes, and 54% of PMT episodes. In 385 cases (45%), the EGMs revealed false-positive events due to far-field sensing (39%), noise and myopotential sensing (26%), sinus tachycardias (21%), double counting (9%), exit block (4%), and undersensing (1%). This large-scale study of stored EGMs revealed their value in validating diagnostic counter data. Therapeutic decisions should not be based on diagnostic counters alone; they should be validated by sophisticated tools like stored EGMs.

Accidental Transarterial Implantation of Dual Chamber Pacemaker Leads in the Left Ventricle and the Right Coronary Artery

Implantation of permanent pacemaker systems is associated with a low rate of complications. The case of a 72-year-old woman is described who suffered from a cluster of complications related to permanent pacemaker implantation. Besides major bleeding, requiring transfusion and pneumothorax, malposition of both pacemaker leads in the arterial system occurred, with the atrial lead screwed into the right coronary artery, with subsequent occlusion of the vessel and the ventricle lead placed in the left ventricle.

Pneumopericardium and Pneumothorax After Permanent Pacemaker Implantation

We present a patient with chronic obstructive pulmonary disease who developed discomfort 2 days after dual-chamber pacemaker implantation via the left cephalic vein approach. The pacer was placed with active-fixation leads without obvious complications. A computed tomography (CT) scan taken in the emergency room showed right pneumothorax and associated pneumopericardium without pneumomediastinum. A three-dimensional reconstruction of CT images confirmed the atrial lead protruding into the pleural space. This lead likely ruptured a bulla causing a pneumothorax followed by pneumopericardium through a pleuro-pericardial communication. Chest tube placement relieved both pneumothorax and pneumopericardium without the need for atrial lead extraction.

A 60-year-old man with chest pain following pacemaker implantation

A 60-year-old man with variant angina was taking verapamil to prevent coronary spasm. Symptomatic second-degree atrioventricular block developed, and he required implantation of a permanent dual-chamber pacemaker. However, during the implantation procedure, repeated attempts to penetrate the left

Outcome of Right Ventricular Bifocal Pacing in Patients with Permanent Atrial Fibrillation and Severe Dilated Cardiomiopathy Due to Chagas Disease: Three Years of Follow-up

Several studies have shown that heart failure may benefit from cardiac resynchronization therapy (CRT). Studies have demonstrated a beneficial effect of right ventricular (RV) bifocal pacing, using two leads at different positions, in similar patient populations. The aim was to evaluate this approach in Chagas disease patients who developed both severe dilated cardiomiopathy and chronic atrial fibrillation. The study included 30 patients with a mean age of 52 +/- 6 years (16 male), who had atrioventricular block at functional class II or IV (NYHA). Patients underwent endocardial dual-chamber pacemaker implantation with two RV leads-one placed near the RV outflow tract and the other in the apex. Patients were examined by echocardiography, 24-hour Holter, and New York Heart Association (NYHA) class determination before and 3, 6, 12, 18, 24, and 36 months after CRT. Compared to the baseline, the left ventricular ejection fraction increased in the first month of CRT, the left ventricular end diastolic diameter decreased, all patients were downgraded to NYHA class I or II, and the incidence of ventricular arrhythmias decreased. However, these could not be maintained and worsened after 6 months CRT. There was a mortality rate of 43.3% during the first year, and only 23.3% of patients remained alive after 3 years. They underwent an electrophysiological study, which revealed complex arrhythmias justifying implantable cardioverter defibrillator (ICD) in six out of seven patients. The favorable effects of RV bifocal pacing could not be maintained beyond the first 6 months, likely due to the ventricular arrhythmias. Therefore, CRT combined with ICD from the outset may be recommended for this patient group.

Hypertrophic cardiomyopathy: state‐of‐the‐art review, with focus on the management of outflow obstruction

Significant advances in our understanding and management of hypertrophic cardiomyopathy have been made in the last decade, as the complex genetics and phenotype-genotype correlations that characterize the disease are gradually unravelled. The well-described clinical heterogeneity of hypertrophic cardiomyopathy is now understood to be based on profound genetic variability, with at least 10 genes and over 150 mutations implicated. Several new therapeutic tools have entered clinical practice. The implantable cardioverter-defibrillator is now strongly indicated in those at high risk of sudden arrhythmic death. Our ability to abort sudden death in this subgroup has placed added emphasis on risk stratification in newly diagnosed patients. New procedures have also been developed for the relief of outflow obstruction in patients with refractory symptoms and a significant subaortic outflow gradient. Although not as efficacious as the 'gold-standard' surgical myectomy-myotomy, dual-chamber pacemaker implantation can be of modest benefit in select patients. Percutaneous transluminal septal myocardial ablation is an emerging catheter-based procedure for the relief of left ventricular outflow obstruction. Long-term follow-up data are still awaited. However, intermediate-term results suggest equivalent efficacy to surgical myectomy-myotomy.

Permanent pacemakers: should straightened atrial leads be repositioned?

The aim of this study was to assess if atrial leads whose "J" configuration has straightened significantly on the postprocedural chest X ray should be repositioned. Between January 1996 and December 1997, 445 patients underwent dual chamber pacemaker implantation at the Papworth Hospital. Postprocedural chest X rays were available in 410 of these. The degree of straightening of the tip of the atrial lead was assessed from the lateral chest X ray and was graded as mild (-10 to +10 degrees from the horizontal), moderate (+10 to +30 degrees), or severe (> or = +30 degrees). Patients were followed with regard to atrial sensing and pacing characteristics, lead displacements, and lead revisions. Fifty-two (12%) patients had some degree of straightening (graded mild, moderate, severe) of the atrial lead on the postprocedure chest X ray (passive fixation in 48, active 4). Of these, 12 patients underwent next day lead repositioning, 5 of whom had abnormalities of pacing and/or sensing parameters. Seven patients therefore underwent repositioning of the atrial lead despite normal pacing parameters in view of lead straightening alone. Of the 12 patients who underwent repositioning, 3 still had lead straightening after the second procedure. The cohort for follow-up consisted of 43 patients (24 [56%] men, age 69 +/- 11 years at the time of implant) who were left with significant atrial lead straightening but adequate atrial parameters. Straightening was mild in 26 patients, moderate in 10, and severe in 7 patients. At implant the P wave amplitude was 4.8 +/- 2.4 mV. Follow-up was for 4.8 +/- 2.1 years, a total of 178 patient years. At final follow-up, the P wave amplitude was 2.7 +/- 1.3 (P < 0.05 vs implant). Censoring events occurred in 16 cases, comprising 11 deaths (none suspected to be pacemaker or lead related), 3 cases of persistent atrial fibrillation, 1 system extraction for infection, and 1 lead extraction for erosion. There were no cases of inadequate atrial lead sensing or pacing in the remaining patients. Irrespective of the degree of lead straightening on the postoperative lateral chest X ray, atrial leads should not be repositioned unless there are abnormalities of pacing or sensing parameters.

Complications arising after implantation of DDD pacemakers: the MOST experience

The purpose of this study was to characterize the incidence, time course, frequency, and spectrum of acute and chronic complications arising from dual-chamber pacemaker implantation. This information may serve as a benchmark when comparing complication rates for dual-chamber pacemaker implantation with those for biventricular pacemaker implantation.

Effective long-term left atrial pacing using regular screw-in leads implanted within the coronary sinus.

Passive-fixation leads positioned inside the coronary sinus (CS) have been found to be effective in LA pacing and sensing, but their use is limited by a high incidence of early and late dislodgment. Since anatomic studies have shown that the proximal part of the CS is surrounded by a relatively thick musculature, the feasibility, safety, and efficacy of acute and chronic coronary sinus pacing via regular screw-in leads positioned within the first centimeters of the CS were evaluated as compared to passive-fixation leads. Thirty-three patients (21 men, age 62 +/- 10 years) underwent dual chamber pacemaker implantation with LA pacing obtained via passive-fixation leads (7 patients) or regular screw-in leads (26 patients). The former approach was prematurely abandoned because of a high rate of acute and late lead dislodgment (42%). The chronic pacing threshold was 1.7 +/- 1.0 V at 0.67-ms pulse width and 1.47 +/- 1.3 V at 0.5-ms pulse width for passive- and active-fixation leads, respectively. In the CS active-fixation lead group, no postoperative pericardial effusion, CS lead dislodgment, nor diaphragmatic stimulation were observed. In this last group, steroid eluting leads (14 patients) have a statistically lower pacing threshold than noneluting steroid leads (12 patients) (0.88 +/- 0.23 vs 2.29 +/- 1.68 V, P = 0.011) at long-term follow-up. The use of regular screw-in leads implanted within the CS allows effective and safe long-term LA pacing without risk of dislodgment.

Transvenous Dual Chamber Pacemaker Implantation via a Persistent Left Superior Vena Cava

A 73-year-old patient underwent dual chamber pacemaker implantation because of symptomatic second-degree heart block. During implantation, persistence of the left superior vena cava was observed. A passive fixation right ventricular lead and an active fixation right atrial lead were used with satisfactory long-term pacing and sensing result.

Dual chamber pacemaker implantation during atrial fibrillation in patients with PAF

Dual chamber pacemaker implantation during atrial fibrillation in patients with PAF

Dual chamber pacemaker implantation during atrial fibrillation in patients with PAF

Dual chamber pacemaker implantation during atrial fibrillation in patients with PAF

Dual-chamber pacemaker implantation via the cephalic vein in healthy equids.

The purpose of the present study was to develop a feasible and safe technique for dual-chamber pacemaker implantation in healthy horses. Implantation was performed in a standing, tranquilized horse and in ponies. Atrial and ventricular leads were transvenously inserted through the cephalic vein, and a subcutaneous pacemaker pocket was created between the lateral pectoral groove and the manubrium sterni in 6 equids. Positioning of each lead was guided by echocardiography and by measuring the electrical characteristics of the lead. The implantation procedure lasted about 4 hours in each animal and was well tolerated. In all animals, dual-chamber pacemaker function was obtained, and these results remained good throughout the follow-up period. At the time of implantation, atrial and ventricular sensing were between 2.1 and 7.2 mV and 7.8 and 16.8 mV, respectively, and atrial and ventricular pacing thresholds at 0.5 millisecond varied from 0.5 to 0.7 V and from 0.3 to 1.0 V, respectively. Six months after the implantation, sensing values varied from 2 to 10 mV for the atrial lead and from 2 to 16 mV for the ventricular lead, while pacing thresholds at 0.5 millisecond varied from less than 0.5 to 2.5 V for the right atrium and from less than 0.5 to 5.0 V for the right ventricle. Atrial lead dislodgment occurred in 2 animals, requiring insertion of a new lead. Ventricular lead dislodgment was not observed.

Permanent Pacing from a Left Ventricular Vein in a Patient with Persistent Left and Absent Right Superior Vena Cava

Persistent left superior vena cava with coexisting absent right superior vena cava is rare with less than 150 cases in the literature. Various techniques for pacemaker implantation have been described in this situation. We report a 40-year-old man with sinus and atrioventricular nodal dysfunction who underwent dual chamber pacemaker implantation. We elected to implant the ventricular electrode down a left ventricular branch of the coronary sinus and the lead is stable at 4-month follow-up.

Clinical characteristics of patients intolerant to VVIR pacing

The incidence and clinical predictors of the development of intolerance to VVIR pacing have not been extensively studied in prospective long-term randomized trials comparing different pacing modes. The frequency and clinical factors predicting intolerance to ventricular pacing are controversial. The Pacemaker Selection in the Elderly (PASE) Trial enrolled 407 patients aged ≥65 years in a 30-month, single-blind, randomized, controlled comparison of quality of life and clinical outcomes with ventricular pacing and dual-chamber pacing in patients undergoing dual-chamber pacemaker implantation for standard clinically accepted indications. We reviewed the clinical, hemodynamic, and electrophysiologic variables at the time of pacemaker implantation in 204 patients enrolled in the PASE trial and randomized to the VVIR mode, some of whom subsequently required crossover (reprogramming) to DDDR pacing. During a median follow-up of 555 days, 53 patients (26%) crossed over from VVIR to DDDR pacing. A decrease in systolic blood pressure during ventricular pacing at the time of pacemaker implantation (p = 0.001), use of β blockers at the time of randomization (p = 0.01), and nonischemic cardiomyopathy (p = 0.04) were the only variables that predicted crossover in the Cox multivariate regression model. After reprogramming to the dual-chamber mode, patients showed improvement in all aspects of quality of life, with significant improvements in physical and emotional role. The high incidence of crossover from VVIR to DDDR pacing along with significant improvements in quality of life after crossover to DDDR pacing strongly favors dual-chamber pacing compared with single-chamber ventricular pacing in elderly patients requiring permanent pacing.

Right Pneumothorax Resulting From an Endocardial Screw-In Atrial Lead

Right pneumothorax complicated by an endocardial atrial lead has never been reported. Herein, we report on a small-build 79-year-old Taiwanese woman who suffered from complete AV block and underwent dual-chamber permanent pacemaker implantation. An active fixation screw-in atrial lead was chosen. The procedure was complicated by right pneumothorax associated with atrial perforation. Since simple measurements of the implantation parameters could not be used to predict the occurrence of perforation, great caution should be taken in to avoid overscrewing the atrial lead, and in scrutinizing the penetration depth of the helix of the lead under fluoroscopy.

Study Group on Ablate and Pace Therapy for Paroxysmal Atrial Fibrillation

Part 1. Indications for ablate and pace treatment: evidence of eYcacy 1. Prospective, randomized study of AV ablation and mode-switching, dual-chamber pacemaker implantation medical therapy in drug-resistant PAF — Michele Brignole, MD (Lavagna, Italy) 2. Prospective, randomized study of AV ablation and mode-switching, dual-chamber pacemaker implantation using two diVerent algorithms vs drug therapy in patients with PAF — Howard Marshall, MD (Birmingham, U.K.) 3. Experience with the North American Ablate and Pace Registry — Mark Wood, MD (Richmond, Virginia, U.S.A.)