Transvenous Left Atrial and Left Ventricular Pacing in Ebstein's Anomaly with Severe Interatrial Conduction Block

The implantation of permanent pacemakers in patients with congenital heart disease can be challenging. This report describes the complexity of pacemaker implantation in a patient with Ebstein's disease, tricuspid valve replacement, and right atrial abnormalities like severe intra- and interatrial conduction block that prevented dual chamber pacing from conventional sites. This case illustrates the promising possibility to circumvent the interatrial conduction block with single left atrial pacing instead of biatrial pacing which was not suitable here.     

Atrial Pacing: Efficacy and Safety

Atrial pacing has the advantages of simplicity, maintenance of AV synchrony, and economy. The major detraction has been the potential for deterioration of atrioventricular conduction. In this study, we followed 43 patients with sick sinus syndrome treated with atrial (AAI) pacing. Excellent initial implant parameters were obtained in all. Three early lead repositionings were required. Minor sensing and pacing problems could all otherwise be handled by reprogramming. FoIIow-up for a mean of 25 ± 20 months demonstrated excellent performance of the pacing systems. Pacing and sensing thresholds and lead impedance indicated excellent lead performance. There were no late lead failures. Nine patients have had mild deterioration in atrioventricular conduction and one of these had a change to DDD pacing at the time of elective battery change. All patients are asymptomatic. Thus, chronic atrial pacing in selected patients is safe and reliable with good chronic lead performance and low risk of subsequent conduction system disease.     

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.     

Evaluation of Asynchronous Left Ventricular Relaxation by Doppler Echocardiography During Ventricular Pacing with AV Synchrony (VDD): Comparison with Atrial Pacing (AAI)

The effect of right ventricular pacing on left ventricular relaxation was studied in 13 patients (age 62 ± 3 years), with the atrial sensing ventricular pacing mode (VDD). A control group of similar age (64 ± 4 years) consisted of 11 patients with atrial pacing (AAI). The timing of events was determined in both groups at similar R-R intervals (921 ± 77 ms vs 967 ± 37 ms). The loading conditions as estimated by peak systolic wall stress (afterload) and end-diastolic left ventricular dimensions (preload) were approximately the same in both groups. The ratio of late to early filling velocities were similar in both groups. Dominant changes were: increased preejection period (142 ± 13 ms vs 95 ± 15 ms); and higher velocities of isovolumic relaxation flow (60 ± 34 cm/s vs 25 ± 4 cm/s) in patients with ventricular pacing. The isovolumic relaxation time was longer in patients with VDD pacing (127 ± 14 ms vs 108 ± 12 ms). Anterior systolic interventricular septal motion (paradoxal motion) was recorded in nine patients with VDD pacing and in none of the patients with AAI pacing. Isovolumic relaxation flow was detected during atrial pacing in five (45%) patients and in 13 (100%) patients during atrial sensing ventricular pacing, indicating asynchronous left ventricular relaxation. This data shows that VDD pacing compared to atrial pacing resulted in an altered activation pattern of the left ventricle, associated with delayed onset, asynchronous contraction with interventricular septal motion abnormalities and prolonged asynchronous left ventricular relaxation with abnormal motion manifested by the presence of isovolumic relaxation flow.     

Atrial Pacing: Who do We Pace and What do We Expect? Experiences with 100 Atrial Pacemakers

The records of 100 patients with permanent atrial pacemakers implanted over a 7-year period were reviewed to assess the role and results of this mode of pacing. Indications for pacing were sick sinus syndrome in 91, carotid sinus hypersensitivity in 3, and use of an antitachycardia device in 6 patients. The mean follow-up period was 32.9 months. Symptomatic relief was good. Lead dislodgment occurred in 11 patients (usually in the first week). Threshold rises not amenable to reprogramming occurred in three patients and loss of sensing occurred in seven patients but only one required intervention. Overall, 21 patients required reoperation. The type of lead did not influence the need for reoperation that appeared to be related to the experience of the operator. Complete atrioventricular block occurred in three patients, two of whom had carotid sinus hypersensitivity and one had sick sinus syndrome. Chronic atrial fibrillation occurred in five patients, none of whom required revision of the pacemaker system. Atrial pacing is a satisfactory pacing mode in patients with sick sinus syndrome. Provided satisfactory atrioventricular conduction has been shown by incremental atrial pacing to at least 120 beats/min and carotid hypersensitivity is absent, progression to complete atrioventricular block is uncommon. Greater implanting skills are required for good results.     

Clinical Observations with Long-term Atrial Pacing

Atrial pacing (AP), despite its beneficial hemodynamic and antiarrhythmic effect, is still an underused mode of stimulation. The main purpose of this study was to evaluate the long-term results of AP. Sixty four patients (pts) with sinus node disease (28 male and 36 female: mean age 54,2; range:44–88 years), 3,2% of the total implantation at our clinic were treated with AP between 1982–96. Criteria for atrial pacing were: no AV block in the history, no AV-block during carotid sinus massage, Wenckebach point > 130/min, left atrium <50mm, left ventricular EF >40%. The indication for pacing was predominant sinus bradycardia (SB) in 34 pts and tachycardia-bradycardia syndrome (TBS) in 30 pts. Pts with TBS were on antiarrhythmic treatment, while most pts with SB received no antiarrhythmic drugs. All the pts were checked up at every 3–6 month. Sixty-two pts were followed for 3–154 (mean: 67) months, two pts were lost for follow-up. Repeated lead dislodgment occurred in two pts, which made a pacing mode change necessary. Four pts died during the follow-up period for non-cardiac reasons. At the end of the follow-up period the data of 60 pts were available for evaluation (33 pts with SB, 27 pts with TBS). All the pts with SB were in sinus rhythm, and no patient developed AV block by the end of the follow-up period Seven out of 27 pts with TBS developed chronic atrial fibrillation, 3 out of them suffered a cerebral embolism; the remaining 20 pts were in sinus rhythm, and the number of paroxysmal attacks decreased significantly, which improved their quality of life significantly. Three pts in this group developed a temporary complete AV block, which regressed with decreasing the dosage of antiarrhythmic drugs. Atrial pacing is proved to be a safe and reliable treatment for sick sinus syndrome. Proper patient selection is crucial in preventing the development of AV conduction disturbance. Atrial stimulation had a satisfactory long-term antiarrhythmic effect in pts with sick sinus syndrome (SSS).     

Use of Atrial Pacing in a Young Population

Forty pediatric and young adult patients (1-20 years; mean, 11 years of age) had implantation of atrial demand (AAI) pacemakers over a 5.5 year period. Nineteen were implanted by epicardial technique and 21 transvenously. Standard lithium single chamber pulse generators and standard atrial leads were used. Operative stimulation thresholds were better for transvenous leads than for epicardial (0.75 volts vs. 1.5 volts at 0.5 ms) (p less than 0.05). Pulse width thresholds at a mean of 1.5 years were not significantly different (0.11 ms for transvenous vs. 0.18 for epicardial). No patient developed AV block. Eight patients (four epicardial and four endocardial) required reoperation during the mean 3.5 year follow-up--four because of lead problems and four because of persistent tachycardia. Of the six patients who received an automatic antitachycardia pacemaker, only one had persistent symptoms while seven of eight who received a standard unit continued to have symptoms. Twenty-eight of 29 symptomatic patients without tachycardia became asymptomatic. Atrial pacing appears to be a safe and effective therapy for children with sick sinus syndrome.     

Pacing of the Atria in Sick Sinus Syndrome Trial: Preventive Strategies for Atrial Fibrillation

SPITZER, S.G., et al .: Pacing of the Atria in Sick Sinus Syndrome Trial: Preventive Strategies for Atrial Fibrillation. This study examines the effects of various atrial lead positions in physiological pacing on the incidence of AF in patients with sick sinus syndrome. The lead is implanted in the RA free wall, in the RA appendage, near the coronary sinus ostium (CSO) or, in dual site RA pacing, in the appendage and the CSO. Since CSO and dual site right atrial pacing aim at modifying the pathological substrate, pacing of two-thirds of all cardiac cycles is attempted by adapting the basic rate and the rate response option. The results of this study are expected to assist in the development of guidelines for the placement of atrial pacing leads in sick sinus syndrome. (PACE 2003; 26[Pt. II]:268–271)     

Is Chronic Atrial Stimulation a Reliable Method for Single Chamber Pacing in Sick Sinus Syndrome?

To evaluate the feasibility of chronic atrial pacing (AAI) in sick sinus syndrome (SSS), 22 patients (pts) with bradytachycardia syndrome (BTS) and 17 patients with only bradyarrhythmias (BA) were studied on the incidence of supraventricular tachycardias (SVT) and occurring AV block. A scoring system based on symptoms of SVT was developed (grade 0–5). All patients had proven normal AV conduction before PM implantation. In the BTS-group, nine patients (41%) had symptomatic SVT at the end of follow-up (mean 53 months), despite drug therapy. These patients had a high SVT score on entry (mean 3.2). High degree AV block occurred in three patients. Although in the BA-group SVT arose in six patients (35%), there was only one symptomatic patient at the end of follow-up (mean 36 months). In this group, only one patient developed high degree AV block. Atrial stimulation should be considered as a reliable therapy in patients with SSS and low SVT score before PM implantation when normal AV conduction is present.     

Chronic Ventricular Pacing with Ventriculoatrial Conduction Versus Atrial Pacing in Three Patients with Symptomatic Sinus Bradycardia

Three patients with symptomatic sinus bradycardia due to sick sinus syndrome were treated with permanent ventricular pacing for periods rang-ing from 2.5 to 4 years. All three patients had ventriculo-atrial conduction on routine electrocardiography. Although ventricular pacing was effective, they complained of fatigue, lightheadedness, and near syncope. Hemodynamic studies revealed the presence of regular cannon waves in the right atrium as well as in the pulmonary artery wedge pressure curves. Temporary atrial pacing resulted in disappearance of the cannon waves and a significant rise in cardiac output (32–48%). After narmal atrio-ventricular conduction was confirmed by rapid atrial stimulation and His bun-dle electrocardiography, the pacing mode was changed to permanent atrial pacing on demand. The effort tolerance of the patients marked by improved, and the previ-ously mentioned symptoms disappeared. Control hemodynamic studies 9 to 12 months affer impiantation of the atrial demand pacemaker showed that the im-provement in cardiac performance was maintained.     

Permanent Left Atrial Pacing with a Specifically Designed Coronary Sinus Lead

This article reports the original use of a specifically designed coronary sinus (CS) lead for permanent left atrial (LA) pacing. The device is characterized by its distal end shape featuring a double 45° angulation. which ensures very close contact with the CS upper wall. The device was successfully implanted in 39 out of 40 patients (97.5%). The tip electrode was eventually positioned in the distal CS in 9 patients, in the middle CS in 21 patients, and close to the ostium in the proximal CS in 9 patients. The mean acute pacing threshold voltage was 0.9 ± 0.5 V with a mean impedance of 578 ± 144 Ω as measured in unipolar distal configuration at 0.5 ms pulse width (PW). The mean A wave amplitude was 3.5 ± 2.1 mV. Early lead dislodgment occurred only once (3%) when the tip electrode was placed in the distal or middle CS, but more often (4/9 cases) when it was placed in the proximal CS. After a mean follow-up duration of 14 ± 8.5 months, 35 of the 39 successfully implanted leads (89.7%) were still functional in terms of LA pacing and sensing. The mean chronic pacing threshold voltage was 1.5 ± 0.8 V and the mean A wave amplitude was 2.7 ± 1.6 mV. There were no lead related complications. In conclusion, the device proved to be safe and highly effective for permanent LA pacing, provided the distal tip could be positioned in the distal or middle part of the CS.     

Morbidity and Mortality of Patients with Sinus Node Disease: Comparative Effects of Atrial and Ventricular Pacing

ZANINI, R., ET AL.: Morbidity and Mortality of Patients with Sinus Node Disease: Comparative Effects of Atrial and Ventricular Pacing. In patients with sinus node disease (SND), VVI pacing seems an inappropriate method of cardiac stimulation because of its potential adverse hemodynamic and arrhythmic effects. AAI-DDD pacing, preferred because of lower morbidity, may also determine a higher survival rate. We examined retrospectively two groups of patients with SND. Stimulated respectively with VVI pacing (group 1 = 57 patients) and AAI pacing (group 2 = 53 patients). The mean duration of the follow-up interval was 40.1 months for group 1 and 45 months for group 2. Ten patients (17.5%) in the VVI group and five (9.4%) in the AAI died. During the follow-up, in the VVI group three patients developed congestive heart failure and ten developed chronic atrial fibrillation, whereas only one case of heart failure and two with atrial fibrillation have been recorded in the AAI group. Moreover, four patients had embolic complications in group 1. Five patients (9.4%) with AAI pacing were converted to sequential pacing due to the occurrence of second-degree heart block. The statistical analysis was developed by the X² test for the comparison of the proportion of the events (atrial fibrillation, congestive heart failure, embolic accidents) in the two groups: a significantly higher morbidity (p < 0.01) was recorded in the AAI group. Survival is also higher in AAI patients, but the survival rate difference, calculated using the Mantel-Cox method, is not statistically significant. The findings of our study show that in SND the superiority of AAI pacing over VVI is statistically significant as far as morbidity is concerned, and we have also noticed an evident but not statistically significant superiority regarding mortality.     

Hemodynamic Findings During Sinus Rhythm, Atrial and AV Sequential Pacing Compared to Ventricular Pacing In a Dog Model

The hemodynamic responses of atrial lAF], atrioventricu-lar sequential (AVP) and ventricuJar pacing (VP) were compared to sinus rhythm (SfiJ in seventeen anesthetized dogs with intact AV conduction. The atrium and/or ventricle were paced at fixed rates above the control sinus rate. An AV interval shorter than normal conduction was selected to capture the ventricle. The changes of pulmonary capillary wedge pressure (PCWP, mmHg). mean aortic pressure (MAP, mmHg), cardiac output (CO, L/min), systemic vascular resistance (SVR, dynes/s/cm⁻⁵), left ventricular stroke work index (SWI) and mean systolic ejection rate (MSER, ml/s) during sinus rhythm, atrial pacing and atrio-ventricular sequential pacing (expressed in percentages of the individual values during ventricular pacing) were:
The importance of atrial systole for cardiac performance was clearly demonstrated in dogs with normally compliant hearts. In both atrial and atrioventricular sequential pacing compared to ventricular pacing there was a reduction of pulmonary capillary wedge pressure (PCWP) (p < 0.01) and systemic vascular resistance (SVR) (p < 0.01) despite an increase in cardiac output (CO). The lesser mean systolic ejection rate (MSER) found during atrioventricular sequential pacing compared to sinus rhythm and atrial pacing may be explained by the abnormal ventricular depolarization in this pacing mode; nevertheless, the mean systolic ejection rate was still greater than that found during ventricular pacing (p < 0.05).     

Variability of Left Atrial Bloodflow Predicts Intolerance of Ventricular Demand Pacing and May Cause Pacemaker Syndrome

Variability of left and right atrial and left ventncular bloodflow was studied using transthoracic and transesophageal Doppler echocardiography and related to pacemaker mode preference during everyday activity. Bloodflow variability was less at all sites during dual chamber pacing compared to single chamber pacing. However, in patients suffering from pacemaker syndrome and whom prefer DDDR pacing, significantly increased variability of left atrial antegrade (but not retrograde) bloodflow during VVIR pacing compared to DDDR pacing was noted, which was not evident in patients tolerating VVIR mode pacing. This effect was not detected at any other site and suggests that adverse left atrial hemodynamics may result in intolerence to VVI/R mode pacing and might cause pacemaker syndrome.     

Comparison of Resting Hemodynamic Indices and Exercise Performance During Atrial Synchronized and Asynchronous Ventricular Pacing

Resting hemodynamic indices and exercise tolerance were measured during atrial synchronized (VAT) and asynchronous ventricular pacing (VOO) in 35 patients with implanted pacemakers which could be externally programmed to function in either pacing mode. Cardiac output and mean systemic arterial pressure were significantly greater during VAT pacing (VAT: 4.5 ± 1.21 /min, 115 ± 28 mmHg; VOO: 3.7 ± 0.8 1/min 105 ± 25 mmHg respectively), although there was no difference in pulmonary artery end-diastolic pressure. Maximal exercise performance was assessed using the Bruce protocol in both pacing modes. Neither the patient nor the supervising physician was aware of the preselected pacing mode; a second physician monitored the electrocardiogram and blood pressure but influenced the point of exercise termination only if a potentially dangerous arrhythmia or hypotension occured. Blood pressure responses were superior and atrial rates lower during VAT pacing, In all but five patients, exercise tolerance was improved by VAT pacing. This amounted to 33 percent or more in 23/35 patients. This improvement was shown to be maintained in the 20 patients who had repeat exercise tests several weeks later. Ventricular arrhythmias, hypotension, and lightheadedness frequently complicated exercise during asynchronous pacing but occurred rarely with atrial synchronized pacing. Resting hemodynamic indices did not predict the extent of improvement gained by physiological pacing.     

Balloon‐Facilitated Delivery of a Left Ventricular Pacing Lead

While modern implant tools have contributed greatly to the success of cardiac resynchronization therapy, technical challenges remain. A common problem is the inability to advance left ventricular pacing leads into branch veins that are tortuous or arise at steep angles. In these cases, advancement of the lead causes it to buckle and prolapse into the coronary sinus or great cardiac vein. Lead prolapsed can be avoided by employing a balloon to temporarily obstruct the coronary sinus or great cardiac vein just upstream from the branch vein. The balloon redirects the force of advancement laterally into the branch vein, facilitating delivery. (PACE 2013; 36:e31–e34)     

Long-term Stability of Endocardial Left Ventricular Pacing Leads Placed via the Coronary Sinus

Background: Left ventricular endocardial pacing leads placed via the coronary sinus (CS) are increasingly implanted to achieve cardiac resynchronization therapy (CRT); however, the long-term stability of these leads is unknown. We sought to determine the implant success and long-term stability of CS leads in our single center experience.
Methods: All consecutive patients who underwent CRT via implantation of the CS lead between January 1999 and December 2005 were included. Pacing thresholds at implant and during long-term follow-up were reviewed and the rate of acute (within 24 hours of implant) and chronic (>24 hours) lead failure was determined.
Results: A total of 512 patients (mean age 68 ± 12 years; 409 [80%] male) underwent CRT device implantation and were included. The CS lead implantation was successful on the initial implantation in 487 patients (95%) and subsequently successful in six patients (24%) in whom initial attempts were unsuccessful. Acute lead failure occurred in 25 patients (5.1%) and was most commonly due to persistent extra-cardiac stimulation. The rate of chronic lead failure was 4% in the first year and remained stable during long-term follow-up. The CS lead pacing thresholds remained stable with only minimal increase (1.42 ± 0.85 V/0.42 ± 0.25 ms vs 1.51 ± 1.05 V/0.47 ± 0.29 ms; P = 0.04).
Conclusions: Placement of a left ventricular pacing lead via the CS is feasible and safe in the vast majority of patients. Once placed, the CS leads remain stable with excellent pacing thresholds over the longer term.     

A Method for Permanent Transvenous Left Ventricular Pacing

LV-based pacing has recently been reported to be of benefit in patients with severe cardiac failure and left bundle branch block. LV permanent pacing has been reported using epicardial leads but the surgical mortality is excessive. A transvenous approach is now favored. In this regard, cannulation of the coronary sinus and of one of its tributaries using only the permanent electrode is feasible but technically challenging. We describe a "long guiding sheath" method using catheterization, and a long radiopaque and peelable sheath. Once the coronaiy sinus is cannulated with the electrophysiological catheter, the long sheath is advanced to the mid-part of the coronary sinus. The permanent pacing electrode is then placed through the sheath and into a tributary of the coronary sinus. This method has been attempted in 10 patients and was successful in 8, with an average lead insertion time of 21 ± 5.5 minutes and an average fluoroscopic time of 11 ± 5.5 minutes. In conclusion, although transvenous left ventricular pacing remains a challenge, the "long guiding sheath" approach appears to facilitate this procedure with both a high success rate and an acceptable procedure time.     

Microvolt T-Wave Alternans During Atrial and Ventricular Pacing

Introduction: Assessment of microvolt T-wave alternans (MTWA) by the spectral analysis (SA) method requires the heart rate to be stable within a certain range. This can be achieved by ventricular pacing (VP). We compared MTWA during short-term VP versus atrial pacing (AP).
Methods: Patients presenting for evaluation of risk of sudden cardiac death underwent an invasive electrophysiologic study. The concordance of results of MTWA-VP with MTWA-AP was evaluated, as well as the specificity, sensitivity, negative, and positive predictive values of MTWA-VP versus MTWA-AP. The maximum recorded amplitude of MTWA (MValt) in concordant positive results, as well as noise levels in all, were compared in both pacing modes.
Results: We studied 42 consecutive patients, of whom 31 completed both tests (32 by AP, 40 by VP). Compared to AP, VP—MTWA SA had a sensitivity of 93%, specificity of 71%, negative predictive value of 92%, and positive predictive value of 72%. The results were concordant in 25 patients (80%, κ= 0.62, P < 0.001). The noise level was significantly higher during VP than AP (1.4 ± 0.8 vs 1± 0.8, P< 0.01), and there was a trend toward a higher amplitude of TWA by VP (10.7 ± 5.3 vs 7.8 ± 3.9, P = 0.058).
Conclusions: MTWA SA is more likely to be completed during VP than AP. Overall there was concordance between both tests. VP generates higher amplitudes and noise, and a higher percentage of nonnegative results.     

Long-Term Experience with a Preshaped Left Ventricular Pacing Lead

OLLITRAULT, J., et al. : Long-Term Experience with a Preshaped Left Ventricular Pacing Lead. This study describes a long-term experience with a new LV pacing lead. The study population consisted of 62 patients (85% men,   71 ± 10   years old) with advanced dilated cardiomyopathy, in NYHA Class III or IV despite optimal drug therapy, and a QRS duration >150 ms. Patients in sinus rhythm were implanted with a triple chamber pacemaker to maintain atrioventricular synchrony. A dual chamber pacemaker was implanted in patients in atrial fibrillation for biventricular pacing only. A clinical evaluation and interrogation of the resynchronization pacemaker were performed at implant, at 1 week (W1), one (M1), four (M4), and seven (M7) months after implantation. A longer follow-up (2 years) is available for patients implanted at the authors institution. LV measurements were pacing threshold at 0.5-ms pulse duration and pacing impedance. R wave amplitude (mV) was measured at the time of implantation only. The system was successfully implanted in 86% of patients with the latest design of the lead. Mean R wave amplitude at implant was   15 ± 7 mV   and mean pacing impedance was   1054 ± 254 Ω   . Between implant   (n = 38)   and M7   (n = 15)   , pacing threshold rose from   0.73 ± 0.54   to   1.57 ± 0.60 V (P < 0.001)   . In conclusion, the situs lead was successfully implanted in a high percentage of patients. In addition, low pacing threshold and high impedance measured during follow-up are consistent with a low pacing current drain, ensuring a durable pulse generator longevity. (PACE 2003; 26[Pt. II]:185–188)