Benefits of dual chamber pacing in sick sinus syndrome

The effects of DDD (fully automatic) and VVI (ventricular demand) pacing modes on exercise tolerance, symptom diary cards, and Holter monitoring were investigated in a randomised double blind crossover study of 16 patients who had had DDD pacemakers implanted because of frequent syncope. Eight patients presented with sick sinus syndrome and, with one exception, retrograde atrioventricular conduction and eight age and sex matched patients presented with 2:1 or complete atrioventricular block. Maximal symptom limited exercise in those with atrioventricular block was significantly higher after one month of DDD pacing than after VVI pacing. In those with sick sinus syndrome, however, maximal effort tolerance was not significantly different for the two pacing modes. In all but one patient with sick sinus syndrome sinus rhythm developed during exercise in VVI pacing. For both VVI and DDD modes maximal atrial rates were significantly lower in those with sick sinus syndrome. Palpitation and general wellbeing were significantly improved during DDD pacing in the eight patients with sick sinus syndrome. Shortness of breath was improved by DDD pacing in the eight patients with atrioventricular block but not in those with sick sinus syndrome. Holter monitoring showed that sick sinus syndrome patients remained in paced rhythm, either DDD or VVI, for most of the 24 hour period. DDD pacing was better than VVI pacing in sick sinus syndrome with retrograde atrioventricular conduction. Despite their ability to show sinus rhythm and inhibit their pacemakers on exercise patients with sick sinus syndrome are just as likely to have symptomatic benefit from DDD pacing as patients with atrioventricular block.     

Benefits of dual chamber pacing in sick sinus syndrome.

The effects of DDD (fully automatic) and VVI (ventricular demand) pacing modes on exercise tolerance, symptom diary cards, and Holter monitoring were investigated in a randomised double blind crossover study of 16 patients who had had DDD pacemakers implanted because of frequent syncope. Eight patients presented with sick sinus syndrome and, with one exception, retrograde atrioventricular conduction and eight age and sex matched patients presented with 2:1 or complete atrioventricular block. Maximal symptom limited exercise in those with atrioventricular block was significantly higher after one month of DDD pacing than after VVI pacing. In those with sick sinus syndrome, however, maximal effort tolerance was not significantly different for the two pacing modes. In all but one patient with sick sinus syndrome sinus rhythm developed during exercise in VVI pacing. For both VVI and DDD modes maximal atrial rates were significantly lower in those with sick sinus syndrome. Palpitation and general wellbeing were significantly improved during DDD pacing in the eight patients with sick sinus syndrome. Shortness of breath was improved by DDD pacing in the eight patients with atrioventricular block but not in those with sick sinus syndrome. Holter monitoring showed that sick sinus syndrome patients remained in paced rhythm, either DDD or VVI, for most of the 24 hour period. DDD pacing was better than VVI pacing in sick sinus syndrome with retrograde atrioventricular conduction. Despite their ability to show sinus rhythm and inhibit their pacemakers on exercise patients with sick sinus syndrome are just as likely to have symptomatic benefit from DDD pacing as patients with atrioventricular block.     

Cost benefit analysis of single and dual chamber pacing for sick sinus syndrome and atrioventricular block: An economic sensitivity analysis of the literature

The benefits of dual (DDD) over single chamber pacing (VVI)have been demonstrated in haemodynamics, exercise capacity,quality of life and reduced complications in atrioventncularblock and sick sinus syndrome. The literature was reviewed to provide complication rates fordual and VV1 pacing. Cost calculations were based on UnitedKingdom 1991 prices. Over a 10-year period, a computer modelcalculated the incidence and prevalence of atrial fibrillation,stroke, permanent disability, heart failure and mortality insix patient categories: sick sinus syndrome paced VVI, sicksinus syndrome upgraded to DDD, sick sinus syndrome paced DDDfrom outset, atrioventricular block paced VYI and those upgradedto DDD and atrio ventricular block paced initially DDD. Calculationswere based on intention to treat. The 10 year survival with DDD vs YVI pacing was 71% vs 57% insick sinus syndrome and 61% vs 51%, respectively, in atrioventricularblock. In both indications the prevalence of heart failure inthe 10 year survivors was 600 lower with DDD pacing. In sicksinus syndrome patients paced VVI, 36% had severe disabilitywhile only 8% experienced this with DDD pacing. For atrioventricularblock the figures were, respectively, 22% vs 3%. The differencein 10 year cumulative cost between VVI and DDD is 13 times thepurchase price of a VVI pulse generator for sick sinus syndromeand 7 times for atrioventricular block. In the third year afterimplantation the cumulative costs of DDD were lower than forVVI for both indications. Dual chamber pacing for both indications, sick sinus syn dromeand atrioventricular block, is both clinically and cost effective.     

Clinical efficacy of permanent cardiac pacing in patients with bradysystolic forms of disturbances of cardiac rhythm and conduction

From 1996 to 2002 primary implantations of pacing systems because of bradysystolic disturbances of cardiac rhythm and conduction had been carried out in 311 patients. Indications were disturbances of atrioventricular conduction in 168 and sick sinus syndrome in 143 patients. According to type of permanent pacing patients were divided into 3 groups: with single-chamber ventricular on demand pacing (VVI, n=215), with single-chamber atrial pacing (AAI, n=39), and with dual-chamber pacing (DDD, n=57). As characteristics illustrating long term clinical results of permanent pacing we used development of the pacemaker syndrome; development of permanent atrial fibrillation; risk of thromboembolic complications and strokes; progression of heart failure; total, cardiovascular mortality and their structure; 7 year survival.     

病态窦房结综合征患者房室传导功能分析

为了解病态窦房结综合征患者的房室传导功能,用食管电生理检查观察窦房结功能正常者86例、窦房结功能低下者40例和病态窦房结综合征者109例的房室传导功能.结果显示:3组的文氏型阻滞点、2:1阻滞点差异无显著意义(P>0.05).将窦房结功能障碍者的窦房结恢复时间与文氏型阻滞点、2:1阻滞点作相关分析,结果均无相关性(P>0.05).认为病态窦房结综合征发生房室传导阻滞的概率较低,植入起搏器前应作食管心房调搏检查房室传导系统功能.     

Our experience using continuous atrial stimulation in sick sinus syndrome

Temporary atrial pacing (AAI) was applied in 31 patients with sick sinus syndrome (S.S.S.), including 20 with tachycardia-bradycardia syndrome (t.b.s.). In all patients before pacemaker implantation atrioventricular conduction was estimated using rapid left atrial, transoseophegeal stimulation assuming Wenckebach's point over 120 imp./min to be a physiological one. In all cases, but one ventricular electrodes were implanted and connected with multiprogrammable pacemakers (MP). Follow-up time ranged from 3 to 38 months (mean 18,4). Electrode dislodgment was not observed. In 9 persons sensing disorders were observed but thanks to programming the pacemaker sensitivity they could be resolved almost in all of them. Second degree Mobitz type I a-v block occurred in 3 patients during a long-term follow-up. In one of them changing the pacing mode to VVI was necessary. In persons with tachycardia-bradycardia syndrome cardiac pacing together with pharmacologic therapy allowed to almost eliminate tachycardia attacks. Authors positively estimated AAI pacing mode.     

Pacemaker syndrome and retrograde ventriculoatrial conduction

19 cases of pacemaker syndrome were observed in 121 patients implanted with VVI pacemakers. The main manifestations of pacemaker syndrome were dizziness, lightheadedness, fatigue, hypotension and congestive cardiac failure after permanent ventricular pacing. The incidence of pacemaker syndrome was 20% in patients with sick sinus syndrome and 13.2% with A-V block. Pacemaker ECG showed retrograde ventriculoatrial conduction in 25 of 121 cases. Among these patients, 14 (56%) had pacemaker syndrome, while only 5 of 96 cases without ventriculoatrial conduction had this syndrome, so the incidence of the two groups were quite different, P less than 0.0001. The frequency of ventriculoatrial conduction in patients with sick sinus syndrome was higher than in patients with A-V block (16/45 vs 9/76, P less than 0.05). The electrophysiologic study were performed in 17 cases before PM implantation. 3 cases had 170-190 ms ventriculoatrial 1:1 conduction. Retrograde ventriculoatrial conduction in pacemaker ECG were present during ventricular pacing in all of them.     

The pacemaker syndrome: old and new causes

The pacemaker syndrome refers to symptoms and signs in the pacemaker patient caused by inadequate timing of atrial and ventricular contractions. The lack of normal atrioventricular synchrony may result in decreased cardiac output and venous "cannon A waves." A sudden increase in atrial pressure at the onset of asynchrony may elicit a systemic hypotensive reflex response. A wide range of symptoms can be observed. The pacemaker syndrome is encountered in a significant number of patients with ventricular (VVI) pacemakers, mostly when 1:1 retrograde ventriculoatrial conduction is present. The risk of occurrence of the pacemaker syndrome is minimized if pacemaker systems are used which restore or maintain the normal atrioventricular contraction sequence. Hence, in sinus node disease, atrial stimulation with or without ventricular stimulation should be employed, while in high-grade atrioventricular block dual-chamber pacing is recommended. The pacemaker syndrome is not restricted to the VVI stimulation mode. It can be seen, though rarely, in atrial and dual-chamber pacing, and an awareness of these new causes is necessary. An established pacemaker syndrome can often be counteracted by adjusting the pulse generator function.     

Dual chamber pacing: how many patients remain in DDD mode over the long term?

OBJECTIVE--DDD pacing is better than VVI pacing in complete heart block and sick sinus syndrome but is more expensive and demanding. In addition, some patients have to be programmed out of DDD mode and this may have an important impact on the cost-effectiveness of DDD pacing. The purpose of this study was to determine how many patients remain in DDD mode over the long term (up to 10 years). DESIGN--A retrospective analysis of the outcome over 10 years of consecutive patients who had their pacemakers programmed initially in DDD mode. SETTING--A district general hospital. PATIENTS--249 patients with DDD pacemakers. Sixty two patients (24.9%) had predominantly sick sinus syndrome and 180 (72.3%) had predominantly atrioventricular conduction disease. Mean (range) complete follow up for this group of patients was 32 months (1-10 years). RESULTS--Cumulative survival of DDD mode was 83.5% at 60 months. Atrial fibrillation was the commonest reason for abandonment of DDD pacing. Atrial fibrillation developed in 30 patients (12%), with atrial flutter in three (1.2%). Loss of atrial sensing or pacing, pacemaker mediated tachycardia, and various other reasons accounted for reprogramming out of DDD mode in eight patients (3.2%). Overall, an atrial pacing mode was maintained in 91% and VVI pacing was needed in only 9%. CONCLUSIONS--With careful use of programming facilities and appropriate secondary intervention, most patients with dual chamber pacemakers can be maintained successfully in DDD or an alternative atrial pacing mode until elective replacement, although atrial arrhythmia remains a significant problem. There are no good reasons, other than cost, for not using dual chamber pacing routinely as suggested by recent guidelines and this policy can be achieved successfully in a district general hospital pacing centre.     

Long-term follow-up after cardiac pacing in bradyarrhythmias

Fifty-nine patients aged 39-80 years underwent implantation of a cardiac pacemaker and were followed for up to 9 years (average duration of pacing 39 months). Atrioventricular conduction disturbances (complete atrioventricular block, 2 : 1 atrioventricular block, bifascicular block, and atrial fibrillation with slow ventricular rate) were present in 49 patients and sick sinus syndrome (sinus arrest or sino-atrial block, and bradycardia-tachycardia syndrome) in 10. Pacing was required because of Adams-Stokes attacks in 41 patients, 2 of whom also had congestive heart failure. It was required in 6 because of frequent dizziness, in 10 because of congestive heart failure, and in 2 because of low cardiac output. The symptomatic improvement after cardiac pacing was well recognized in most of our patients, and 32 (54 percent) of the 59 patients pursued normal physical and daily activity. Although the efficacy of pacemaker therapy was of limited value in some patients with congestive heart failure or underlying or coexisting diseases, the beneficial effects following pacemaker implantation were: (1) abolishment of transient neurologic symptoms such as Adams-Stokes attack, (2) relief from a constant fear of a recurrence of an Adams-Stokes attack or sudden cardiac death, and (3) improvement in restricted physical activity due to low cardiac output. Thus, we conclude that pacemaker implantation in most patients with bradyarrhythmias is beneficial not only for the treatment of the acute problem but also because it prolongs life and greatly enhances its quality. However, in spite of the beneficial effects after pacemaker implantation, we still observe a number of complications connected with the use of a permanent pacemaker. Therefore, our policy is to implant a permanent pacemaker following the execution of sufficient studies of the bradyarrhythmia and the etiology of symptoms, and then under taking long-term follow-up of the patients.     

Pacemakers: normal function

AV sequential pacemakers are particularly useful in patients who have developed "pacemaker syndrome" with single-chambered ventricular demand units, since the normal atrioventricular relationship is then restored. Fully automatic pacemakers are indicated for patients with AV block, with or without sinus node dysfunction, or with moderate sick sinus syndrome and AV nodal or His-Purkinje disease, with at least some ability to increase atrial rate with exercise.     

Comparison of first- and second-generation leadless pacemakers in patients with sinus rhythm and complete atrioventricular block

Introduction

The efficacy and safety of leadless cardiac pacemakers (LPMs) as an alternative to conventional transvenous cardiac pacing have been largely reported. The first generation of the Micra^TM transcatheter pacing system (VR; Medtronic) was able to provide single-chamber VVI(R) pacing mode only, with a potential risk of pacemaker syndrome in sinus rhythm patients. A second-generation system (AV) now provides atrioventricular synchrony through atrial mechanical (Am) sensing capability (VDD mode).

Objective

We sought to compare VR and AV systems in sinus rhythm patients with chronic ventricular pacing (Vp) for complete atrioventricular block.

Methods

All consecutive patients implanted with an LPM in our department for complete atrioventricular block were retrospectively screened. Patients with atrial fibrillation, sinus dysfunction, or Vp burden <20% at 1 month postimplantation were excluded. Patients were systematically followed with a visit at 1 month, and then at least once a year.

Results

A total of 93 patients—45 VR (2015–2020) and 48 AV (2020–2021)—were included. VR and AV patients had similar baseline characteristics, except for VR patients being older (80 ± 8 vs. 77 ± 9 years, p = 0.049). The mean Vp burden was 77% in the VR and 82% in the AV group (p = 0.38). In AV patients, the median AV synchronous beats rate was 78%, with 65% having a >66% rate. An E/A ratio <1.2 as measured on echocardiography was the only independent predictor of accurate atrial mechanical tracking (p = 0.01). One-year survival rate was similar in both groups. Five patients in the VR and 0 in the AV group eventually developed pacemaker syndrome within 1 year post-implantation (p = 0.02).

Conclusion

In sinus rhythm patients with chronic Vp for complete atrioventricular block implanted with an LPM, the atrial mechanical sensing algorithm allowed significant atrioventricular synchrony in most patients and was associated with no occurrence of—otherwise rare—pacemaker syndrome.     

右心室流出道间隔部起搏对左心室功能的影响

目的比较右心室流出道间隔部(RVOT)起搏与右心室心尖部(RVA)起搏的血流动力学差异;评估RVOT起搏技术的可行性与安全性。方法选择有永久起搏器置入适应证的患者75例。根据术者建议和患者意愿分为RVOT组(40例)和RVA组(35例)。所有房室传导阻滞及病窦综合征合并一度房室传导阻滞患者采用双腔起搏双腔感知触发抑制型起搏模式,心房颤动伴长间歇患者采用抑制型心室按需起搏模式。比较2组的血流动力学差异。结果 RVOT组的QRS波宽度较RVA组缩窄(23.2±28.7)ms,差异有统计学意义(P<0.01)。与RVA组比较,RVOT组LVEF、左心室短轴缩短率明显升高,左心室舒张末容积明显下降(P<0.05,P<0.01)。与术前比较,RVA组LVEF、左心室短轴缩短率明显下降,左心室舒张末容积明显升高,差异有统计学意义(P<0.01)。结论利用螺旋电极进行RVOT起搏可行且较为安全。RVOT起搏的血流动力学参数优于RVA。     

Implications of marked fatty infiltration around and in the atrophic atrioventricular node in elderly patients with permanent pacemaker implantation for symptomatic sick sinus syndrome

The present study undertook an extensive analysis of the histopathological findings of the atrioventricular conduction system in 14 elderly patients treated with permanent pacemakers for sick sinus syndrome (SSS). Special attention was given to the lowest Wenckebach block points of atrioventricular conduction during rapid atrial pacing, and ventricular rate or duration of ventricular pause during chronic atrial fibrillation. An electrophysiological study (EPS) was conducted under sinus rhythm in 13 patients and under junctional escape rhythm in 1 patient. Three of the 14 cases showed a lower Wenckebach block point of 130 beats/min or less. Two of these 3 cases showed excessive fatty infiltration around the atrionodal junction area and into the atrophic atrioventricular node (AVN) itself. Of the 6 patients who had chronic atrial fibrillation after pacemaker implantation, 2 cases showed a slow ventricular response of less than 60 beats/min and/or a long ventricular pause of 3.3 s. One of the 2 cases showed a lower Wenckebach block point of 130 beats/min at the time of EPS. The other, who later progressed to idiopathic atriomegaly, also showed marked fatty infiltration around the AVN. This fatty lesion was closely associated with diffuse disruption of the muscular fibers connecting the atrophic AVN with the atrium. In addition, most of the remaining cases also had an atrophic AVN. In conclusion, a sparse or absent atrionodal connection and an atrophic AVN due to excessive fatty infiltration in the atrionodal transitional area should be investigated in atrioventricular conduction disturbances in the elderly with SSS.     

心律失常的起搏治疗

为探讨永久性人工心脏起搏器及埋藏式心内自动除颤器(ICD)纠治重症缓慢性及快速性心律失常的临床疗效、心律失常类型与起搏模式的关系,对我院植入永久性人工心脏起搏器及ICD的102例患者进行回顾性分析.结果53例病态窦房结综合征患者植入DDD或VVI,48例房室传导阻滞植入DDD、VDDR或VVI,1例室性心动过速、心室颤动、反复心脏停搏患者植入ICD后临床症状均明显改善或消失.提示植入合适的永久性人工心脏起搏器及ICD,对重症缓慢性心律失常及致死性快速性心律失常能起到良好治疗作用.     

The Activitrax rate responsive pacemaker system

Bipolar Medtronic Activitrax rate responsive pacemakers were implanted in 31 patients for ventricular (28) or atrial (3) pacing. Mean follow-up was 16 months (range 10 to 26). Twenty pacemakers were implanted after catheter ablation of the His bundle, 7 for sick sinus syndrome. 1 for atrioventricular block and 3 for sick sinus syndrome with atrioventricular block. A rate response value was selected that gave a pacing rate of about 100 pulses/min during walking. Of the 31 patients, all had 24-hour ambulatory electrocardiographic monitoring with diary, 11 walked a 20-minute circuit, including a flight of stairs, and 20 had a treadmill exercise test. In 9 patients the pacing rate could be compared with the underlying sinus rate during exercise and was seen to match it very closely. In 12 patients the pacing rate during car driving was found to be similar to the sinus rate of 5 volunteers under similar conditions (mean minimum and maximum rate was 80 and 99 pulses/min, respectively). No pacing-induced arrhythmias were seen during ambulatory electrocardiographic monitoring. At high pacing rates slightly irregular pacing intervals were sometimes observed, which was due to polarization sensing. Sporadically, 1 pacing interval shortened to the upper rate value, because of a known and now resolved timing anomaly. Neither anomaly was of clinical consequence and the first could be resolved by reprogramming.(ABSTRACT TRUNCATED AT 250 WORDS)     

Natural history of sinus node disease treated with atrial pacing in 213 patients: implications for selection of stimulation mode.

OBJECTIVES. This study was designed to analyze the incidence and determinants of complications and long-term survival in sinus node disease treated with atrial pacing. BACKGROUND. Knowledge of the natural history of sinus node disease treated with different pacing modes is imperfect, and controversy exists regarding the optimal pacemaker therapy. METHODS. A consecutive series of 213 patients with sinus node disease initially treated with atrial pacing was studied for a median follow-up period of 60 months. The end points studied were permanent atrial fibrillation, high grade atrioventricular (AV) block, P wave undersensing, pacing mode change, reoperation and death. Several prognostic factors were evaluated statistically and the survival rate was compared with that of a matched general population. RESULTS. The incidence rate of permanent atrial fibrillation during follow-up was 7% (1.4%/year). The risk of this arrhythmia increased substantially with age greater than or equal to 70 years at pacemaker implantation. Only 2 of the 15 patients who developed permanent atrial fibrillation required ventricular pacing. High grade AV block occurred in 8.5% (1.8%/year) and its incidence was much greater in patients with complete bundle branch block or bifascicular block (35%) than in patients without such conduction disturbances (6%). A change to ventricular or dual-chamber stimulation was necessary in 14% of all patients, primarily because of early lead dislodgment or high grade AV block. Surgical intervention with maintenance of atrial pacing was required in 7% of patients. The survival rates of 97% at 1 year, 89% at 5 years and 72% at 10 years did not differ significantly from those of a matched general population. CONCLUSIONS. In sinus node disease, atrial pacing can be successfully applied during long-term follow-up. Patients with complete bundle branch or bifascicular block in addition to sinus node disease should initially receive a dual-chamber pacemaker, but routine application of dual-chamber stimulation does not appear to be warranted.     

Unique Interaction Between an Atrial Single-Chamber Pacemaker and a Ventricular Defibrillator

A well described interaction between an antibradycardia pacemaker and a ventricular defibrillator is sensing of pacemaker stimuli by the ventricular defibrillator. This report describes an interaction between an atrial demand pacemaker and a ventricular defibrillator that resulted in ventricular asystole and polymorphic ventricular tachycardia. In this case, the ventricular defibrillator sensed atrial pacing stimuli when complete atrioventricular block with a slow ventricular escape rate developed. Defibrillator-based ventricular demand pacing was inhibited, resulting in prolonged periods of ventricular asystole, polymorphic ventricular tachycardia, and multiple defibrillator shocks. Ventricular defibrillator sensing of atrial pacemaker stimuli in the setting of complete atrioventricular block and ventricular asystole cannot be simulated during defibrillator implantation when atrioventricular conduction is intact. Therefore, a pacemaker programmed to atrial demand pacing in a patient with a ventricular defibrillator can result in inappropriate inhibition of ventricular pacing in the setting of complete heart block. Furthermore, this interaction can be avoided with a dual-chamber pacing ventricular defibrillator.     

Pacing for sinus node disease: A therapeutic rationale

Symptomatic sinus node disease is a common indication for permanent pacemaker implantation. Single-chamber ventricular (VVI) pacing, single-chamber atrial (AAI) stimulation, and dual-chamber (DDD or DDI) systems are used to a varying extent at different implanting centers. Hemodynamic and clinical studies relevant to the choice of pacing mode in these patients are reviewed. The data currently available strongly support the use of pacing systems providing atrial stimulation. The choice between single-chamber atrial or dual-chamber pacing can be based on the relative importance assigned to a number of factors: Hemodynamic aspects, the risk of ventricular lead problems, cost, and complexity aspects favor AAI pacing, whereas patients with a substantial risk of developing atrioventricular block should receive a DDD or DDI unit.