Immediate reinitiation of atrial tachyarrhythmias after spontaneous restoration of sinus rhythm in patients with an implanted monitoring device

Immediate reinitiation of atrial tachyarrhythmia (IRAT) has been observed after cardioversion. After spontaneous restoration of sinus rhythm (SR), incidence and characteristics of IRAT have not been described. Therefore, in patients with atrial tachyarrhythmias (ATs) and bradycardia, a pacemaker with dedicated memory functions was implanted. Devices were interrogated after 1 month and stored episodes of AT were analyzed: incidence of IRAT, duration and rate of the preceding episode, sinus rate before AT, coupling interval of atrial premature beats (APBs) initiating AT, and incidence of repetitive APBs. A potential association with IRAT was assessed for clinical characteristics. In 36 of 68 patients, stored electrograms confirmed correct detection of AT onset and termination in 545 episodes. IRAT was present in 212 (39%, 24 patients) episodes of AT. Episodes of AT preceding IRAT were longer than those before non-IRAT (156 vs 46 s, P < 0.001), and occurred during a higher atrial rate before onset of AT (cycle length 775 +/- 111 vs 856 +/- 133 ms, P < 0.001). The coupling interval of APBs initiating IRAT was shorter (502 +/- 83 vs 538 +/- 89 ms; P < 0.001) while the percentage of episodes with repetitive APBs before AT onset and the median atrial cycle length of the preceding AT were not different. On stepwise logistic regression analysis, none of the clinical factors evaluated independently predicted IRAT. In conclusion, IRAT is frequent after spontaneous restoration of SR. Changes of atrial electrophysiological properties promoting IRAT may already develop during AT of short duration.     

Usefulness of atrial pacing for prevention and termination of atrial tachyarrhythmias in a patient with persistent atrial fibrillation

Atrial pacing with dedicated algorithms for prevention and termination of atrial tachyarrhythmias is under clinical evaluation. A patient is described with persistent symptomatic AF. After cardioversion and implantation of a DDDRP pacemaker before planned AVN ablation, the patient was free of symptoms. Early after implant, one cardioversion of AF was necessary. Over the course of 12 months, only five episodes of atrial tachyarrhythmia occurred, all automatically pace terminated within 24 hours. Thus, selected patients with persistent AF may benefit from preventive atrial pacing since the tachyarrhythmia can organize intermittently to a degree sufficient for pace termination.     

Management of Atrial Tachyarrhythmias: Benefits of Pacemaker Diagnostics

FAUCHIER, L., et al.: Management of Atrial Tachyarrhythmias: Benefits of Pacemaker Diagnostics. The aim of this prospective multicenter study was to assess the clinical benefits of the Selection (Vitatron) pacemaker diagnostic functions (AF 1.0) in the management of AF. Forty patients (   71 ± 9  years   of age), with documented AF and conventional pacing indications, received a Selection. The AF 1.0 function of the pacemaker was programmed to document the AF burden, onset, daily distribution, duration, premature atrial beats before onset, and mode of onset of the last 12 episodes for AF episodes exceeding 180 beats/min. By comparing patients' symptoms records, patient conventional assessment at follow-up and AF 1.0 data, the investigators evaluated the usefulness of AF 1.0 in AF management at 3- and 6-month follow-ups. Usefulness was defined as a change in arrhythmia management prompted by the disclosure of AF 1.0 data. AF recurrences were recorded in 71% of the follow-ups with symptoms reported by patients in only 16%. Thirty-nine percent of therapeutic changes based on conventional assessment were confirmed by AF 1.0 data, and in 61% of instances, the initial changes were modified by AF 1.0 data. Changes included pacing parameters in 56% of cases, AF prevention with pacing algorithms in 37%, and medical treatment in 7%. All investigators indicated that AF 1.0 was useful in all patients. The AF 1.0 diagnostic functions offered a unique documentation of AF in asymptomatic patients, and allowed therapeutic adjustments impossible otherwise. (PACE 2003; 26[Pt. II]:233–238)     

Determinants of persistent atrial fibrillation in patients with DDD pacemaker implantation

Occurrence of AF in a pacemaker implanted patient is a significant cause of morbidity and mortality. The aim of this study was to prospectively investigate the clinical, echocardiographic, and electrocardiographic determinants of persistent AF in patients with DDD pacemakers. A 101 consecutive patients were followed for an average of 19.8 +/- 11.8 months. Persistent AF was documented in 21 (20.8%) patients and 80 (79.2%) patients were in sinus or physiologically paced rhythm. In patients with persistent AF, previous AF attacks were observed more frequently (P < 0.03) and left atrial dimension was higher (3.5 +/- 0.6 vs 3.0 +/- 0.5 cm, P < 0.001). Average P maximum and P wave dispersion (PWD) values calculated in a 12-lead surface electrocardiogram were also found to be significantly higher in patients with persistent AF (P < 0.001). Cox regression analysis demonstrated that the presence of previous AF attacks (RR 8.95, P < 0.001), increased left atrial dimension (RR 2.1, P < 0.02), P maximum duration 120 ms (RR 6.1, P < 0.001), and PWD 40 ms (RR 12.2, P < 0.001) were associated with an increased risk of persistent AF. Cut-off points were 120 ms for P maximum and 40 ms for PWD. Sensitivity, specificity, and positive and negative predictive values were calculated as 76.2, 82.5, 53.3, and 92.9 for P maximum and as 85.7, 87.5, 64.3, and 95.9 for PWD, respectively. In patients with DDD pacemakers, previous AF attacks, increased left atrial dimension, P maximum value of 120 ms, and a PWD value of 40 ms were associated with a significantly increased risk of persistent AF. These patients must further be managed with other treatment modalities to prevent the development of persistent AF.     

The influence of symptoms and device detected atrial tachyarrhythmias on medical management: insights from A-HIRATE

BACKGROUND: The influence of symptoms and device-detected atrial tachyarrhythmias (AT) on the management of AT in a pacemaker population has not been well described. We report the influence of symptoms and device detected AT on pharmacological disease management. METHODS: Group 1 (n = 331) included patients without and Group 2 (n = 96) included patients with prior history of AT with an approved pacemaker indication. Dual chamber pacemakers, (kappa 700 or kappa 900, Medtronic, Minneapolis, MN, USA) were implanted. The impact of symptoms, AT burden, a history of AT, and time since implant on changes in the use of anticoagulation, beta-blockers, and antiarrhythmic drugs was analyzed. RESULTS: A total of 232 patients experienced at least one atrial high rate episode (AHRE). AT burden was higher in Group 2. Symptoms were reported by 154 patients in Group 1 and 47 patients in Group 2. Among patients experiencing AHRE, symptoms were reported in 17 patients in Group 1 (5.3%) and 22 patients in Group 2 (24.7%). Changes in antiarrhythmic drugs and anticoagulation were influenced by history of AT and AT burden, while changes in the use of beta-blockers were influenced by symptoms. The probability of a pharmacologic therapy change decreased with time since implant for all agents except coumadin. CONCLUSION: Pharmacologic AT therapy is differentially influenced by patient-reported symptoms of AT compared to device-detected asymptomatic AT. Anticoagulation and antiarrhythmic therapies are influenced by device detection of asymptomatic AT, whereas initiation of beta-blockers is more strongly influenced by symptoms.     

Effects of continuous and triggered atrial overdrive pacing on paroxysmal atrial fibrillation in pacemaker patients

Background: The aim of the study was to compare the effects of different pacing strategies to prevent paroxysmal atrial fibrillation (AF): triggered atrial overdrive pacing versus the combination of triggered and continuous overdrive pacing.
Methods : Patients with an indication for dual-chamber pacing (Selection 9000, Prevent AF; Vitatron B.V., Arnhem, the Netherlands) and a history of paroxysmal AF were randomized to triggered atrial pacing (three pacing functions, "triggered group": PAC Suppression™, Post-PAC Response™, and Post-Exercise Response™) or to the combination of continuous (Pace Conditioning™) and triggered atrial pacing (four pacing functions, "combined group"). After 3 months, there was a crossover to the other pacemaker setting.
Results : In 171 enrolled patients, the median AF burden of the combined group was with 2.1% versus 0.1% in the triggered group (P = 0.014). Fewer AF episodes were observed in the triggered (median: 7) than in the combined group (median: 116; P = 0.016). The combined group had more frequent atrial pacing (median 97%) than the triggered group with 85% (P < 0.001), but ventricular pacing was not significantly different with 95% and 96% in the combined and triggered group, respectively. After the crossover, the AF burden increased in the triggered group to 0.3% and decreased in the combined group to 0.4%.
Conclusions : Triggered atrial pacing functions alone resulted in a low AF burden. The additional activation of continuous atrial overdrive pacing increased the percentage of atrial pacing, but had no beneficial effects on the prevention of paroxysmal AF.     

Impact of Dual Chamber Pacing on the Incidence of Atrial and Ventricular Tachyarrhythmias in Recipients of Implantable Cardioverter Defibrillators

Recent observations suggest that frequent dual-chamber pacing in recipients of implantable cardioverter defibrillators (ICD) may adversely influence clinical outcomes. This prospective, multicenter study examined the relationship between the frequency of atrial (%AP) and ventricular pacing (%VP) and the incidence of atrial (AT) and/or ventricular tachyarrhythmias (VT) in a standard ICD population. A total of 141 consecutive patients with primary and secondary ICD indications were studied. Continuous arrhythmia detection with a dual-chamber ICD revealed paroxysmal AT in 60 (43%) and VT in 72 (51%) patients within 6 months of device implantation. Far-field oversensing of ventricular signals occurred in 13% of all "atrial tachy response" mode switches. Without adjustment for covariates, a higher %AP was associated with an increased incidence of AT (P < 0.05). However, this association remained only weakly significant after adjustment for covariates using a multivariate model. High New York heart failure functional classes correlated significantly with AT (P = 0.02) and VT (P = 0.007). Rate-modulated pacing, programmed in 1/3 of patients, correlated with occurrence of AT (P = 0.006), but not with occurrence of VT. With respect to dual-chamber pacing, a %AP ≥ 48% combined with a %VP > 40% was associated with an increased probability for VT. In conclusion, AT and VT occurred frequently within 6 months after dual-chamber ICD implantation. High rates of DDD/R stimulation were associated with a trend toward higher incidence of AT, VT, or both.     

心房颤动射频消融术中出现规律性快速性房性心律失常的预测因素

目的：分析心房颤动（简称房颤）经导管射频消融术中出现心房扑动、房性心动过速等规律性快速性房性心律失常（RATs）的预测因素。方法：首次行经导管射频消融治疗的497例房颤患者（阵发性房颤333例,持续性和（或）永久性房颤164例）在三维标测系统及环状标测电极导管指导下行经导管射频消融治疗（包括环肺静脉电隔离、线性消融和（或）碎裂电位消融）。术中记录RATs的发生情况,并分析RATs的可能影响因素。结果：术中共有163例患者[32．8％;阵发性房颤92例,持续性和（或）永久性房颤71例]出现195种RATs,持续性和（或）永久性房颤术中RATs的发生率显著高于阵发性房颤（43．3％比27．6％,P〈0．001）。单因素分析发现心脏外科术后（P〈0．001）、术前有RATs（P=0．010）、持续性和（或）永久性房颤（P〈0．001）、左房内径增大（P〈0．001）、左室射血分数降低（P=0．018）是房颤术中出现RATs的影响因素。Logistic多因素回归分析发现心脏外科术后[优势比（0R）=8．14,95％可信区间（CI）：I．69～39．1,P=0．0093、术前有RATsEOR=2．15,95％CI：1．35～3．42,P=0．001]、持续性和（或）永久性房颤[0R=1．71,95％CI：1．06～2．76,P=0．029]、左房内径[0R=1．04,95％CI：1．01～1．08,P=0．025]是术中出现RATs的独立预测因素。结论：房颤射频消融术中常出现RATs,心脏外科术后、术前有RATs、持续性和（或）永久性房颤、左房内径是术中出现RATs的独立预测因素。     

Characterization of atrial fibrillation in man: studies following open heart surgery.

The nature of localized atrial activation during atrial fibrillation was characterized in 34 patients following open heart surgery. Bipolar atrial electrograms (AEG) recorded in each patient with atrial fibrillation exhibited a myriad of sizes, shapes, polarities, amplitudes, and beat-to-beat intervals. On the basis of the AEG morphology and the nature of its baseline, we have classified the recordings into four Types. Type I was characterized by discrete AEG complexes separated by an isoelectric baseline free of perturbation, Type II by discrete AEG complexes but with perturbations of the baseline between complexes, Type III by AEGs which failed to demonstrate either discrete complexes or isoelectric intervals, and Type IV in which AEGs of Type III alternated with periods characteristic of Type I and/or Type II. In 22 patients, the AEGs were recorded a second time, and in 11 of these patients the type of atrial fibrillation changed between the first and second recording period. An atrial flutter-fibrillation pattern in the ECG was associated with a relatively ordered atrial activation pattern and a relatively slow atrial rate. Human atrial fibrillation is not an electrophysiologically homogeneous process when compared among different patients or ad seriatim in the same patient.     

Value of pacemaker atrial diagnostic data in patients with paroxysmal atrial fibrillation: an opportunity to improve rates of warfarin utilization

Atrial diagnostic data within implantable devices provide an opportunity to assess the frequency and quantity of atrial fibrillation (AF) episodes (AF burden) and its impact on appropriate warfarin anticoagulation. Cardiologists were given clinical scenarios to review with different types of pacemaker diagnostic data in an elderly patient with risk factors for stroke. AF specific data was associated with increased warfarin utilization, but only at intermediate rates. Potential reasons and clinical implications are discussed.     

Incidence and rate characteristics of atrial tachyarrhythmias in patients with a dual chamber defibrillator

Atrial tachyarrhythmias play an important role in the treatment of patients with malignant ventricular tachyarrhythmias not only with respect to inappropriate discharges but also to left ventricular function and stroke risk. A combined dual chamber defibrillator provides separate therapies for atrial and ventricular tachyarrhythmias. To assess the incidence of atrial tachyarrhythmias in patients with this dual chamber implantable defibrillator, 40 patients with ventricular tachyarrhythmias and concomitant atrial tachyarrhythmias and/or AV conduction disturbances were included in a prospective study. During a mean follow-up of 25 +/- 11 months, 26 of 40 patients had a total of 1,430 recurrences of atrial tachyarrhythmias. The vast majority of the atrial tachyarrhythmias with regular atrial cycles had a mean median atrial cycle length of 235 +/- 37 ms and a mean duration of 34 +/- 144 minutes. Atrial tachyarrhythmias with irregular atrial cycles exhibited a median atrial cycle length of 198 +/- 31 ms and had a mean duration of 246 +/- 1,264 minutes. In addition, 67% of 375 tachyarrhythmias, in which the median ventricular cycle length during the ongoing episode could be documented, had a ventricular rate <100 beats/min. Continuous atrial arrhythmia detection with a dual chamber ICD reveals a high incidence of atrial tachyarrhythmias with a predominantly short duration of paroxysmal recurrences <1 hour in the vast majority of episodes.     

Predictors and clinical impact of atrial fibrillation after pacemaker implantation in elderly patients treated with dual chamber versus ventricular pacing

The Pacemaker Selection in the Elderly (PASE) trial was a prospective, multicenter, single blind, randomized comparison of single chamber, rate adaptive, ventricular pacing (VVIR) with dual chamber, rate adaptive pacing (DDDR) in 407 patients aged > or =65 years(mean 76 +/- 7 years, 60% male)with standard bradycardia indications for dual chamber pacemaker implantation. The incidence, predictors, and clinical consequences of atrial fibrillation (AF) developing after pacemaker implantation in the PASE trial were studied prospectively. During a median follow-up of 18 months, AF developed in 73 (18%) patients. Kaplan-Meier estimated cumulative incidences of AF in patients with sinus node dysfunction (n=176) at 18 months were 28% in the VVIR and 16% in the DDDR groups (P=0.08). After adjustment for other clinical variables using a Cox multivariate regression model, randomization to VVIR compared with DDDR pacing mode among patients with sinus node dysfunction was independently associated with a 2.6-fold increased relative risk (RR) of developing AF after pacemaker implantation (P=0.01). Other independent clinical risk factors for development of postimplant AF included a preimplant history of hypertension (P=0.02) or supraventricular tachyarrhythmias(P<0.04). Patients who developed AF had similar health related quality of life scores and cardiovascular functional status after 18 months of pacing as patients who remained free of AF. The RR of death, stroke, or heart failure hospitalization was not increased in patients who developed AF. Thus, in the elderly patients with sinus node dysfunction requiring permanent pacing, DDDR pacing mode protected against the development of AF. However, development of AF after pacemaker implantation in this population was not associated with a significant impact on quality-of-life, functional status, or other clinical endpoints during 18 months of follow-up.     

Incidence of Atrial Fibrillation in Patients with Different Mode of Pacing. Long-term Follow-up

We evaluated the incidence of atrial fibrillation in 189 patients (92males, 97females, mean age 75 ± 12yrs, range 41–100yrs) with pacemaker, during a mean follow-up of 5.5yrs (range 1–24yrs). The indications for implant were: complete AV block (115pts), second degree Möbilz 2 AV block (51pts). bifascicular block (5pts). sick sinus syndrome (14pts), symptomatic bradycardia (4pts). The mode of stimulation considered were VVI (105pt), VVI rate responsive (21pts), single lead VDD (43pts), DDD (20pts). The occurrence of retrograde VA conduction in patients with VVI or VVI rate responsive pacing was also evaluated. Atrial fibrillation occurred in 40 pts (21%). The highest incidence was evidenced in patients with sick sinus syndrome (9pts, 64%), and in patients with VVI stimulation (28pts, 27%). On the contrary, the lowest incidence was found in single lead VDD stimulation (4pts, 9%). The patients with dual chamber pacing showed a relatively high incidence of the arrhythmia (5pts, 25%). Atrial fibrillation occurred in 9 out of 32 patients with retrograde VA conduction, and in 22 out of 94 patients without retrograde conduction (28% versus 23%, p=NS). In conclusion, it is confirmed that patients with sick sinus syndrome are at high risk for atrial fibrillation. Single lead VDD stimulation seems to be the better mode of pacing in preventing atrial fibrillation, while dual chamber pacing showed minor efficacy. The presence of retrograde VA conduction could not predict the occurrence of the arrhythmia.     

Pseudotermination of intermittent atrial fibrillation by a pacemaker algorithm: antitachycardia pacing without capture miscounted as successful termination of fibrillation episodes

A patient is described with intermittent AF and an implanted pacemaker which provides preventive pacing and overdrive stimulation designated to terminate atrial arrhythmias. The case highlights the possibility of false estimation of therapeutic efficacy and possible proarrhythmic effect of this therapeutic modality.     

Persistent atrial fibrillation is associated with a poor prognosis in patients with atrioventricular block and dual-chamber pacemaker

Background : The prognostic significance of development of persistent atrial fibrillation (AF) in patients with atrioventricular (AV) block and dual chamber (DDD) pacemakers has not been separately investigated. We sought to determine whether persistent AF influences clinical outcome in these patients. Methods: Three hundred‐eight consecutive patients with second‐ or third‐degree AV block and implanted a DDD pacemaker were followed for 36 ± 20 months and retrospectively divided into two groups. Thirty‐four patients who developed persistent AF formed persistent AF group, and 278 patients who remained free of this arrhythmia control group. Clinical and outcome data of the two groups were compared. The primary outcome was cardiovascular death. Results: The primary outcome occurred more often among the patients in the persistent AF group (6.8% per year) than among those in the control group (2.9% per year; P = 0.028). This difference was primarily because of higher rate of heart failure‐related deaths in the persistent AF group (P = 0.009). Secondary outcomes, hospitalization for heart failure and paroxysmal AF episode ≥5 minutes, occurred also more often among the patients in the persistent AF group (P = 0.008 and P < 0.001, respectively), although the risk of nonfatal stroke was similar in both groups (P = 0.628). Conclusion: In patients with second‐ or third‐degree AV block and DDD pacemaker, the development of persistent AF is associated with an increased risk of cardiovascular death and heart failure. (PACE 2012; 35:695–702)     

Is the Atrial High Rate Episode Diagnostic Feature Reliahle in Detecting Paroxysmal Episodes of Atrial Tachyarrhythmias?

The atrial high rate episode diagnostic in The Thera® pacemaker reports frequency, duration, and date/time of atrial tachyarrbytbmias according to programmed criteria. The aim of The study was to validate The atrial high rate episode diagnostic feature. Episodes of atrial fibrillation recorded by Holter monitoring were compared to episodes detected by the pacemaker. Eorty five ambulatory (Holter) recordings were used for evaluation. Thirty of 45 ambulatory (Holter) recordings showed sinus rhythm. On 4 of these 30 ambulatory (Holter) recordings, The Thera® detected 12 episodes of atrial tachyarrbythmias as false-positives (sinus rhythm was detected as atrial tacbyarrbytbmia). The main reason was far-field R and T wave oversensing. On 15 of 45 ambulatory (Holter) recordings, 125 episodes of atrial tachyarrhytbmias were recorded. Ninety-three of these events also were detected by the pacemaker, while for 32 events the Thera® reported sinus rhythm. The main reason was that the episodes were of too short duration. Therefore, the Thera® (programmed with detection rate 160 beats/min, detection beats 40, termination beats 10) was unable to detect atrial tachycardias. Software simulation of The diagnostic algorithm under several programming settings using the digitized Holter files demonstrated highly reliable detection of atrial tachyarrhythmias (sensitivity 98%, specificity 100%) when programmed as follows: detection rate 220 beats/min, detection beats 10, termination beats 20. It can be concluded that Thera®'s high rate episode monitor is a reliable tool for detection of a trial tachyarrhythmias, if programmed as recommended.     

Mechanism of decrease in the atrial potential after implantation of a single-lead VDD pacemaker: atrial histological changes after implantation of a VDD pacemaker lead in dogs

The single-lead VDD pacemaker system (VDDPS) enables atrial synchronous ventricular pacing with only one lead in patients with an atrioventricular block. There are some cases in which the atrial potential decreases after implantation of a VDDPS, making physiological pacing difficult. The mechanism of this decrease has not been elucidated yet. To elucidate the possible relationship between the decrease of the atrial potential after implantation of a VDDPS and histopathological changes of the atrium. We implanted a VDDPS from the jugular vein under anesthesia in 10 adult dogs. The tip of the pacing lead was fixed in the right ventricular apex of the heart under fluoroscopic guidance. Then, the lead was ligated and fixed to the jugular vein at a point where a favorable atrial potential was obtained. The end of the lead was passed from the neck to the back subcutaneously; then pulled outside and fixed there to measure the atrial potential. The atrial potential was measured using a pacing system analyzer under anesthesia on days 3 (n = 9) and 7 (n = 8), as well as on weeks 2 (n = 6), 3 (n = 4), and 4 (n = 3), after the implantation. The heart was removed from the dogs on day 3 (n = 2), day 7 (n = 2), week 2 (n = 2), and week 4 (n = 4) to examine the atrial histological findings. The atrial potential was 2.7 +/- 0.7 mV at the time of the implantation, 1.7 +/- 1.1 mV (P < 0.05) on day 3, and 1.7 +/- 0.7 mV on week 4 after the implantation. Macroscopically, the pacemaker lead was covered with thrombus, and adhered to the atrial wall in 80% of animals. Microscopically, the endocardium was hypertrophic due to fibrous tissue; besides RBC extravasation, inflammatory cells infiltration and degeneration of myocardial cells, were observed under the endocardium. Inflammatory changes developed in the atrial wall after implantation of the VDDPS, and this seemed to be one of the mechanisms for the decrease of the atrial potential of the VDDPS.     

Method of atrioventricular programming in atrial flutter in patients with biventricular pacemaker

BACKGROUND: Atrial flutter is a common cause of exacerbation of congestive heart failure (CHF). Typically, during atrial tachycardia, pacemakers, both dual and biventricular, are programmed to ignore atrial tracking. Virtually all current pacemakers and defibrillators use a programmable mode switch algorithm to switch between atrial tracking modes (DDD, DDDR) to nontracking modes (DDIR, DDI, VVI) during episodes of atrial tachycardia. METHODS: In this report, we describe a novel method of atrioventricular (AV) pacemaker programming in four patients with atrial flutter and CHF who remained symptomatic postbiventricular pacemaker implantation. All patients had chronic atrial flutter upon interrogation; adjustment of AV delay and postventricular atrial refractory period (PVARP) was performed to enable sensing of every second to fourth atrial flutter beat by the atrial lead. Mode switch was turned "OFF" in all points, and lower and upper rate limits were set to 50 and 100 bpm. Once sequential early and late diastolic filling was seen on mitral inflow pulsed-wave (PW) Doppler, further adjustment of AV delay and PVARP was performed until the highest and broadest atrial velocity occurred on mitral inflow PW Doppler. RESULTS: All patients developed improvement in aortic ejection duration and peak ejection velocity during AV optimization. Repeat ECG in these patients at 8 months, 7 days, 2 days, and 2 months postoptimization showed no change in P and QRS relationship. All patients developed improvement in CHF symptoms postbiv pacemaker optimization. CONCLUSION: In symptomatic patients with CHF and stable atrial flutter who have a biventricular pacemaker, atrial mechanical contribution to cardiac output can be achieved by adjusting PVARP and AV delay during echo-guided pacemaker programming.     

肺静脉前庭隔离联合左心房线性及碎裂电位消融治疗持续性心房颤动的临床研究

目的探讨肺静脉前庭隔离联合线性及碎裂电位消融治疗持续性心房颤动（房颤）的有效性与安全性。方法共45例持续性房颤患者入选本研究（其中长时程持续性房颤28例）,男性32例,女性13例,年龄（58.8±9.0）岁,病程（23.3±22.4）个月。消融步骤是先行肺静脉前庭隔离,后行线性消融,最后行心房碎裂电位消融。术后所有患者均给予服用培哚普利4 mg/d和抗心律失常药物3个月。甲状腺功能异常者,给予普罗帕酮450 mg/d,共3个月;术前未用胺碘酮者,术后即刻静点胺碘酮1 mg/min,6 h后减量为0.5 mg/min维持42 h,同时口服0.6 g/d连续1周,继之0.4 g/d连续1周,以后0.2 g/d,共3个月;术前口服胺碘酮患者,术后继续口服,0.2 g/d,共3个月。结果消融术中有9例房颤终止,2例先转变为三尖瓣峡部依赖性心房扑动,峡部消融后转为窦性心律（窦律）;3例转为房性心动过速（房速）,最早激动点或者关键峡部消融后转复为窦律;其余患者均行电复律转复为窦律。平均随访（18.2±9.2）个月,共12例患者发作房性心律失常;复发房颤3例,房速9例。结论持续性房颤患者,肺静脉前庭隔离联合左房线性及碎裂电位消融能够破坏更多的维持机制,是治疗持续性房颤的安全、有效的方法。