Effect of Atrial Pacing on the Frequency of Tachycardia in Patients with Recurrent Junctional Tachycardia

In order to assess whether atrial pacing reduced the frequency of tachycardia in patients with recurrent junctional tachycardias, ten patients with recurrent junctional tachycardias with atrial Intertach antitachycardia pacemakers in situ were paced in a random order in atrial demand mode at 50 ppm (AAI 50), 80 ppm (AAI 80), and 100 ppm (AAI 100) for a period of up to 1 month. The numbers of tachycardias detected by the pacemaker over this period were recorded and compared with the number seen when unpaced (000). Correct arrhythmia detection by the pacemaker was confirmed by Holter monitoring. The number of tachycardias in 000 was 44.7 +/- 19.8 (mean +/- SEM). No significant reduction in tachycardia frequency was seen in any pacing mode. Back-up atrial pacing at 50 ppm tended to reduce the frequency of tachycardias (32.3 +/- 12.8 tachycardias; P = 0.06). The higher pacing rates increased the number of tachycardias (AAI 80; 57.1 +/- 24.6 tachycardias, P = 0.20: AAI 100; 81.8 +/- 30.2 tachycardias; P = 0.31). Symptoms increased with each pacing mode and palpitations were statistically more severe in AAI 100 mode. Four patients had disabling symptoms at this rate and had to drop out. Atrial back-up pacing may be of use in some patients with junctional tachycardia, but overdrive pacing is not helpful.     

Permanent Pacing in Patients with Univentricular Heart

Patients with one of several varieties of malformation designated as "univentricular hearts" may be especially challenging when permanent pacing is required. Our objective was to review our experience in this subset of patients that had undergone permanent pacing and thus determine the optimal approach. A retrospective chart review was done of 32 patients with some variety of "univentricular" malformation who had required permanent pacing at our institution. Although technically challenging, permanent pacing in this group of patients can be successful through several approaches. The various approaches, as well as consideration of the differences that exist between patients undergoing septation and those undergoing a Fontan procedure are discussed. Although long-term permanent pacing is possible in this group of patients, before pacing begins, a thorough understanding of the anatomy and prior surgical procedures is necessary. Use of a combined atrial transvenous and ventricular epicardial pacing system may work well for some patients. With the development of newer and more reliable coronary sinus leads, dual chamber transvenous pacing with ventricular stimulation via the coronary sinus could become the approach of choice in some patients with "univentricular hearts."     

Permanent Transvenous Atrial Pacing After Heart Surgery

Permanent transvenous atrial "J" leads were successfully implanted in 10 patients whose atrial appendages had been previously amputated during heart surgery. Early and late lead performance was satisfactory.     

Relationship Between Selected Overdrive Parameters and the Therapeutic Outcome and Tolerance of Atrial Overdrive Pacing

ATTUEL, P., et al. : Relationship Between Selected Overdrive Parameters and the Therapeutic Outcome and Tolerance of Atrial Overdrive Pacing. There is a paucity of information on the influence of selected overdrive parameters on the clinical efficacy and tolerance of atrial overdrive algorithms to suppress atrial tachyarrhythmias. Data from a completed clinical trial investigating a new DDD+ overdrive algorithm implemented in a permanent pacemaker were analyzed. One-hundred patients with standard pacing indications and atrial tachyarrhythmias were enrolled and followed for 6 months in DDD and 6 months in DDD+ mode in a randomized, crossover fashion. The overdrive step size was programmed at the discretion of the investigators between 4 and 12 beats/min, overdrive plateau length between 10 and 32 beats, and maximum overdrive rate between 100 and 160 beats/min. The effects of DDD+ versus DDD mode on burden and incidence of atrial tachyarrhythmias stored in the mode switch memory were examined as a function of the programmed overdrive parameters. An overdrive step size between 7 and 12 beats/min, and higher a maximum overdrive rate between 121 and 160 beats/min were slightly more effective than lower programmed values, though >500 randomized, crossover observations would have been necessary to verify statistical significance. Overdrive pacing related symptoms mandated early manual deactivation of overdrive pacing in 4.7% of 85 evaluated patients. Overdrive was disabled without testing tolerability of less aggressive overdrive values. There was no link between patient symptoms and programmed overdrive step size or overdrive plateau length values. (PACE 2003; 26[Pt. II]:257–263)     

Temporary Atrial Pacing in the Prevention of Postoperative Atrial Fibrillation

Background: Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting (CABG). Since its prevention with prophylactic drug therapy has limited success, alternative approaches are desirable. This study examined the efficacy of atrial or biatrial pacing, compared with no pacing, on the incidence of AF after isolated CABG.
Methods: From August 2002 to September 2004, 240 patients underwent CABG. After surgery, right and left atrial epicardial pacing wires were implanted for 72 hours of temporary pacing. Patients were randomly assigned to one of three groups: no pacing (control group), right atrial (RA), and biatrial (BiA) pacing. Cardiac rhythm was monitored continuously during intensive care, or daily on the ward. The primary endpoints of this study were an episode of AF occurring up to 72 hours after CABG and the risk factors correlated with this event.
Results: Atrial and BiA pacing significantly lowered the incidence (1.25% vs 25%, P = 0.001) of AF episodes, and were both correlated (odd ratio 0.038; 95% confidence interval 0.005–0.29) with a decrease in rates of postoperative AF. Multivariable analysis identified older age (odd ratio 1.074; 95% confidence interval 1.024–1.12) and no pacing as independent risk factors of postoperative AF.
Conclusions: Temporary right atrial or biatrial pacing after CABG significantly decreased the postoperative incidence of AF. Multivariable analysis identified older age and no pacing as predictors of AF occurrence .     

Left Atrial Size and Wall Motion in Patients with Permanent Ventricular and Atrial Pacing

KUBICA, J., ET AL.: Left Atrial Size and Wall Motion in Patients with Permanent Ventricular and Atrial Pacing. It is well known that during permanent ventricular pacing atrial arrhythmias and embolic complications occur much more frequently in comparison to permanent atrial or sequential pacing. He-modynamic disturbances caused by ventriculoatrial conduction (VAC) are thought to be responsible for those complications. The aim of this study was to compare the left atrial size and its wall motion in three groups of patients with sick sinus syndrome. Group 1: 58 patients with VVI pacing and VAC observed (22 males, 36 females, aged 31–86, mean 62.3). Group 2: 43 patients with primary AAI pacing (13 males, 30 females, aged 27–74, mean 57.8). Group 3: 13 patients with AAI or DDD replacing the primary VVI mode due to pacemaker syndrome and/or heart failure, all with VAC present during VVI pacing (7 males, 6 females, aged 26–80, mean 59.8). Two-dimensional/M-mode echocardiography was performed in all these patients. In group 1 mean diastolic as well as mean systolic atrial diameters were significantly greater (p < 0.005) and wall motion significantly smaller (p < 0.005) in comparison to the other groups. Left atrial wall motion amounted to only 7.4% of the mean diastolic diameter in this group. Mean left atrial diastolic and systolic diameters and wall motion in patients with pacemakers preserving atrioventricular synchrony (group 2 and group 3) were almost identical and wall motion amounted to about 22% of the diastolic diameter in both these groups. We conclude that ventriculoatrial conduction leads to significant enlargement of left atrium and to the atrial wall-motion decrease. This predisposes to arrhythmias and embolic complications. Changes in atrial size and performance seem to be reversible with restoration of the physiological atrioventricular synchrony.     

The Value of Transesophageal Atrial Pacing in Predicting the Efficacy of Antiarrhythmic Drugs in Patients with Paroxysmal Narrow QRS Complex Tachycardia

Transesophageal atrial pacing (TAP) is used in the diagnosis and treatment of paroxysmal narrow QRS complex tachycardia (NQT). The aim of this study was to assess the value of this technique in predicting the efficacy of antiarrhythmic therapy. The study group consisted of 30 consecutive patients with spontaneous NQT whose clinical tachycardia was inducible by TAP. Baseline TAP was performed off all antiarrhythmic medication and repeated during oral antiarrhythmic drug therapy. The pacing protocol consisted of three stages: a single extrastimulus introduced at progressively shorter coupling intervals during sinus rhythm, pacing at incremental rates to the point of second-degree AV block, and bursts of rapid pacing. On repeat stimulation while on oral antiarrhythmic therapy (37 pacing studies) NQT was still inducible in 12 cases. During the follow-up period ten patients developed a recurrence of NQT:nine cases out of 12 (75%), in whom NQT was inducible while on antiarrhythmic therapy, and one case out of 25 (4%), in whom NQT was not inducible (P less than 0.001). The sensitivity of TAP in predicting the outcome of the patients with NQT was 90%, and the specificity 89%. The negative predictive value of TAP (prediction of no recurrence of NQT) was 96%, and the positive predictive value (prediction of recurrence of NQT) was 75%. We conclude that TAP is a simple and accurate method for predicting the efficacy of antiarrhythmic treatment in patients with NQT.     

Respiratory-Dependent Atrial Pacing, Management of Sinus Node Disease

The effectiveness of respiratory-dependent atrial pacing (AAI-RD) was assessed in 23 patients (11 male, 12 female; 68 ± 10 years) with symptomatic isolated sinus node disease (SND). Follow-up was performed at 3 month intervals and included history taking, physical examination, ECG recording and 24-hour Holter monitoring. An incremental treadmill exercise test was performed in 21/23 patients before pacemaker implantation, in 23/23 patients after implantation (at least two tests with different programmed settings of respiratory rate/paced rate ratio); 21/23 patients underwent treadmill tests during both fixed rate 70 bpm and AAI-RD pacing. Physiological sensitivity of AAI-RD pacing was found excellent in 34 tests (85%) and fair in six (15%). Spontaneous heart rate was significantly higher after pacemaker implantation fbpm 115 ± 20 vs 98 ± 24, P < 0.001). In 10/21 patients paced rate was significantly higher during AAI-RD vs AAI pacing (131 ±9 vs 106 ± 16, P < 0.001) with better total work time (min 9.9 ± 4 AAI-RD vs 6.8 ± 2.6 AAI, P < 0.002), higher oxygen consumption at anaerobic threshold (ml/min 1137 ± 406 AAI-RD vs 882 ± 268 AAI-RD vs 5.5 ± 2.6 AAI, P - 0.001). No significant difference was found in 7/21 patients (overlap between spontaneous and paced rate during both AAI-RD and AAI programming); 4/21 patients did not reach anaerobic threshold owing to osteomuscular limitations. AV block was detected in 1/23 patients, Biorate circuital failure in 1/23, sporadic undersensing in 5/23, short and symptom-free myopotential inhibitions in 10/23. We concluded that AAI-RD pacing is a reliable, safe and useful modality in pacemaker management of isolated SNA, especially in patients with abnormal rate response to exercise.     

Atrial Pacing: Intracardiac Conduction Assessed by His Bundle Electrograms Acquired from the Permanent Atrial Electrode at Implantation

His bundle electrograms were recorded from conventional J-shaped atrial electrodes at implantation in twelve consecutive patients who had sinus node disorder. Five patients with impairment of atrioventricular conduction, received atrioventricuIar (DVI) pacemakers. His bundle recording by this method is simple and reliable, avoids the discomfort of the conventional technique, and represents a new application for the well established atrial "J" electrode.     

Prevention of Atrial Arrhythmias during DDD Pacing by Atrial Overdrive

We evaluated the effect of atrial overdrive on the incidence of atrial arrhythmias (AA) in 22 patients (67 ± 9 years. 7 women, 15 men) with Chorus 6234 DDD pacemakers. Atrial overdrive was defined as a programmed paced rate 10 ppm faster than the mean ventricular rate stored for the last 24-hour period in the pacemaker memory. The protocol consisted of three phases of 1 month each. Phase I: observation after discontinuation of antiarrhythmic therapy. Phase II: arrhythmia analysis using the pacemaker memory after programming the lower rate to 55 ppm. The fallback function and histogram data were used to document the number and maximal duration of AA episodes as well as the total AA time in a month. Phase III: atrial overdrive. The mean ventricular heart rate was 65 ± 4 beats/min before atrial overdrive versus 75 ± 5 with atrial overdrive (P = 0.02). At the end of phase II, all patients presented with AA episodes (mean number per patient: 42 ± 78 in one month). In phase III (with atrial overdrive), 14 (64.6%) patients had no recorded AA (group A). In the other eight patients with persistent AA episodes in phase III (group B), there was a significant reduction in the number of AA episodes (90 ± 106 in phase II vs 38 ± 87 in phase III; P = 0.01), their total duration (166 ± 115 in phase II vs 92 ± 134 hours in phase HI; P = 0.03) and their maximal duration (121 ± 103 in phase II vs 85 ± 89 min; P = 0.04). Our short-term data suggest tliat atrial overdrive prevents or reduces A A episodes and demonstrate the feasibility and need of long-term studies to determine whether this benefit is sustained.     

Indications for Pacing in Patients with Congenital Heart Disease

Background: Advances in pacing technology have increased indications for antibradycardia pacing and new indications have appeared for treatment of atrial tachycardia and cardiac failure in patients with congenital heart disease (CHD).
Methods and Results: Implantation of a pacemaker is mandatory for symptomatic children with complete atrio-ventricular block (CAVB). In asymptomatic neonates and infants, prophylactic pacing is indicated when the ventricular rhythm is <55 beats per minute (bpm) or 70 bpm in case of significant cardiac malformations. Beyond one year of age, PM implantation is recommended in children with an average heart rate <50 bpm or long pauses on 24-hour recordings. Post-operative block that persists 7 days after cardiac surgery is a class I indication for pacing. Postoperative heart block may also be transient, but patients with residual conduction abnormalities and a long HV interval have a high risk of late sudden death and should be paced. After cardiac surgery, atrial pacing may also be considered, in patients with severe sinus bradycardia and symptoms, or in those requiring antiarrhythmic drugs for tachy-bradycardia syndrome; in case of failure of antiarrhythmic drugs, antitachycardia atrial pacing now appears to be safe and efficacious. Finally, cardiac resynchronization therapy may apply to children with congenital heart block and cardiomyopathy, as well as to the population with CHD. Methods and results are described in the section dedicated to resynchronization.
Conclusion: Cardiac pacing indications have extended beyond prevention of sudden death and pacemaker implantation is now indicated to improve quality of life of patients with CHD and as a bridge to cardiac transplantation.     

Paired Ventricular Pacing: An Alternative Therapy for Postoperative Junctional Ectopic Tachycardia in Congenital Heart Disease

Junctional ectopic tachycardia (JET) is one of the most life-threatening postoperative arrhythmias in children with congenital heart disease, and medical management is difficult. Paired ventricular pacing (PVP) may provide a safe alternative mode of management. We evaluated the safety and efficacy of PVP for the management of postoperative JET in patients with congenital heart disease. A retrospective collection of data was done from 1981-1995. PVP was successfully tried in five postoperative patients (age range: 37 days to 22 years, median: 10 months). Onset of JET was 3-60 hours (mean +/- SD, 19 +/- 23 hours) postoperatively. The maximal JET rate was 261 +/- 39 beats/min. PVP was used as the first line of management in three patients and was successful in all patients. It resulted in an instantaneous increase in blood pressure from 66 +/- 9 to 94 +/- 15 mmHg (42% increase) and was required for 12 +/- 14 hours (range 2-36 hours). No complications were noted. Therefore, in our experience, this is a safe alternative modality for the control of postoperative JET.     

Successful Treatment of Congenital Atrial Flutter with Antitachycardia Pacing

Congential atrial flutter is a condition that rarely requires chronic pharmacological therapy. An unusual case of congenital atrial flutter is described which was resistant to medical therapy, yet responded well to antitachycardia pacing. While most experience with antitachycardia pacing in pediatrics has been with the postoperative congenital heart patient, patients such as the one described with unscarred atria may prove to be the most suitable pediatric candidates for this pacing modality.     

Bedside Termination of Sustained Ventricular Tachycardia by Transesophageal Atrial Pacing

Transesophageal atrial pacing was used to terminate hemodynamically stable sustained monomorphic ventricular tachycardia in two patients. The procedure was performed at the bedside, no anesthesia was required, there were no complications, and one of the patients went home after the procedure was performed. This method should be considered prior to using direct current cardioversion in patients with hemodynamically stable sustained monomorphic ventricular tachycardia.     

Acute Effects of Different Atrial Pacing Sites in Patients with Atrial Fibrillation: Comparison of Single Site and Biatrial Pacing

It has been reported that a trial single site or biatrial pacing can suppress the occurrence of AF. However, its mechanism remains unclear. The study population included 32 patients with AF (n = 20: AF group), or without paroxysmal AF (n = 12: control group). The mechanism and efficacy of atrial pacing were investigated by electrophysiological studies to determine which was more effective for suppressing AF induction; single site pacing of the right atrial appendage (RAA) or distal coronary sinus (CS-d), or biatrial (simultaneous BAA and CS-d) pacing. In the AF group, AF inducibility was significantly higher with BAA extrastimulus during RAA (12/20; P < 0.0001) or biatrial paced drive (7/20; P < 0.01) than during CS-d paced drive (0/20). In the control group, AF was not induced at any site paced. In the AF group, the conduction delay and other parameters of atrial vulnerability significantly improved during CS-d paced drive. The atrial recovery time (ART) at RAA and CS-d was measured during each basic pacing mode. ART was defined as the sum of the activation time and refractory period, and the difference between ARTs at RAA and CS-d was calculated as the ART difference (ARTD). The ARTD was significantly longer during BAA pacing in the AF group than in control group (155.0 +/- 32.8 vs 128.8 +/- 32.9 ms, P < 0.05). In the AFgroup, ARTDs during biatrial (52.0 +/- 24.2 ms) and CS-d pacing (51.7 +/- 26.0 ms) were significantly shorter than ARTD during RAA pacing. The CS-d paced drive was more effective for suppressing AF induction than biatrial or RAA paced drive by alleviating conduction delay. CS-d and biatrial pacing significantly reduced ARTD compared with RAA pacing.     

Extraction of Chronic Pacing Lead and Angioplasty for Complete Superior Baffle Obstruction in Complex Congenital Heart Disease

Laser lead extraction in adult patients with congenital heart disease is safe and effective. Baffle angioplasty for obstruction in patients with a Mustard procedure is well established. We describe a unique combined interventional and electrophysiological approach on a patient with superior baffle obstruction. This technique utilized the channel created after extracting the chronic pacing lead to cross the obstruction and stent angioplasty of the superior baffle.     

Radiofrequency Ablation of Intraatrial Reentrant Tachycardia after Surgery for Congenital Heart Disease

Intraatrial reentry tachycardia is a common cause of both morbidity and mortality after surgery for a variety of congenital heart defects. Despite an armamentarium of arrhythmia management tools, including drug therapy, antibradycardia, and antitachycardia pacing, and catheter ablation, management of these arrhythmias remains a challenge. This report briefly reviews the problem, assesses the current successes and failures of radiofrequency catheter ablation for treating it, and discusses a number of ongoing developments that may improve both early and late outcome.     

Chronic Rapid Atrial Pacing to Maintain Atrial Fibrillation: Use to Permit Control of Ventricular Rate in Order to Treat Tachycardia Induced Cardiomyopathy

LR was a patient, followed over a 16-year period, who presented with an atrial tachycardia which was initially intermittent, but became incessant. Neither the atrial tachycardia nor the associated rapid ventricular response rate could be treated successfully with available drug therapy, resulting in a dilated cardiomyopathy and New York Heart Association (NYHA) class III-IV congestive heart failure. Acute induction of atrial fibrillation with rapid atrial pacing demonstrated that the associated ventricular rate could be satisfactorily slowed with digitalis therapy. Initially, short bursts from an implanted, radiofrequency controlled, patient activated pacemaker programmed to a rate of 600 bpm and connected to a permanent endocardial atrial J lead successfully interrupted the tachycardia and precipitated atrial fibrillation. Over a period of 3 months, this therapy changed the patient's heart failure to NYHA class II status. Subsequently, precipitation of atrial fibrillation with this technique failed, resulting in return to NYHA class III-IV congestive heart failure. Therefore, a custom-designed, high rate, rate-programmable pacemaker was implanted to pace the atria rapidly and continuously to maintain atrial fibrillation. A pacing rate of 375 bpm plus digoxin slowed the ventricular rate to 70-80 bpm, with stabilization of the congestive heart failure to NYHA class II. The pacemaker generator was replaced 6 months later, and after another 5 months, pacing was discontinued. The patient's subsequent rhythm remained stable atrial fibrillation with clinically successful control of both the ventricular rate and heart failure (NYHA class II) until the patient's death 72 months later. This unique case demonstrates another form of chronic therapy which, in selected cases, can be used for the long term control of rapid ventricular response rates to supraventricular arrhythmia.     

Permanent Cardiac Pacing After Open-heart Surgery: Acquired Heart Disease

Retrospective review of 5,942 patients who underwent open-heart surgery for acquired heart disease revealed that 123 patients (2.1%) required permanent cardiac pacing postoperatively; 4.6% of these underwent predominantly valvular surgery and 0.6% had coronary bypass. The most important factors appeared to be: 1) preoperative evidence of a conduction disorder; 2) advanced patient age; 3) dense calcium in the aortic annulus; 4) valvular surgery and, especially, tricuspid valve surgery; and 5) poor myocardial protection. Postoperative permanent pacing had a considerable impact on patient morbidity from maintenance operations; most complications were lead-related problems.