双腔起搏器最小心室化起搏与房室间期优化起搏对心功能影响的比较

目的观察双腔起搏器最小心室化起搏功能与最佳房室间期优化对减少心室起搏和心功能的影响。方法30例符合标准患者入选。随机分为最小心室化起搏组(RVP,n=16)和超声优化下最佳房室间期组(OAV,n=14)。首先,分别在术后1周和术后6个月进行随访,术后6个月两组交叉(RVP转OAV,OAV转RVP),并于术后1年再次随访。随访中评估右室起搏比例、6 min步行试验、纽约心功能分级、明尼苏达州心力衰竭患者生活质量问卷和左室射血分数等指标。结果术后6个月随访,RVP较OAV组的右室起搏比例明显降低(P0.05)。至术后1年随访时,OAV转RVP组的右室起搏比例较RVP转OAV组明显降低(P0.05)。交叉前后的自身比较显示起搏器RVP功能打开后能显著降低右室起搏比例(P0.05)。其他各项指标在两组间都无显著差异(P0.05)。结论两种优化方式对于患者短期心功能无明显影响,但RVP较OAV能明显减少右室起搏比例。     

Exercise performance and beta-adrenergic blockade in patients with complete heart block treated with ventricular inhibited pacing.

The effect of beta-adrenergic blockade (propranolol) on exercise performance was studied in 15 patients (12 men and 3 women, mean age 70 years) with complete heart block treated with a ventricular-inhibited pacemaker (VVI). In a double-blind procedure, the patients were randomly given either 0.1 mg/kg of propranolol or saline solution i.v. before a first exercise test and vice versa before a second test. The interval between the tests was 24 hours. Nine patients were in sinus rhythm, 4 patients had atrial flutter, and 2 others had atrial fibrillation. The exercise capacity was on an average 11% lower with propranolol than with placebo (p less than 0.001). The most marked reductions (20 and 33%) were found in the two patients with atrial fibrillation. The atrial rate in patients with sinus rhythm was significantly lower with propranolol than placebo both at rest (68 vs. 83 beats/min, p less than 0.001) and at maximal work load (91 vs. 141 beats/min, p less than 0.001). The present findings show that beta blockade has negative effects on exercise capacity in patients with complete heart block treated with VVI pacemakers. This finding should be considered in the selection of drug treatment in patients with fixed rate pacing and concomitant hypertension and/or ischemic heart disease.     

Selective increase of ventricular pacing threshold with complete exit block following DC cardioversion in a patient with a dual chamber pacemaker

We report the case of a 78-year old patient with a dual chamber pacemaker, who was admitted for cardioversion of atrial tachycardia. Transthoracic DC shock of 160 J was followed by transient loss of ventricular capture with complete exit-block and severe nodal bradycardia. Subsequent analysis of stimulation thresholds revealed a marked rise in the ventricular threshold only, whereas atrial threshold was unchanged. The selective dysfunction of ventricular capture is most likely caused by current-induced tissue damage at the electrode-endomyocardial interface by preferential shunting of high electrical energy into the ventricular lead as compared to the atrial lead. High output pacing prior to elective DC cardioversion is recommended to ensure consistent capture, particularly in pacemaker-dependent patients, and careful evaluation of pacemaker function after shock delivery should performed.     

Hemodynamic changes during ventricular pacing in patients with complete heart block and aortic and mitral valvular heart disease

Increasing the heart rate to near normal in patients with complete heart block (CHB) and slow ventricular rates may lead to greater improvement in ventricular function than when the heart rate is increased from normal to more rapid heart rates. Improvement in ventricular function is usually manifested by a decrease in left ventricular end-diastolic pressure (LVEDP) and volume and by an increase in contractility. In patients with both CHB and valvular heart disease improvement in ventricular function during pacing may be modified by the nature of the valvular disease.Hemodynamic data from six patients with both valvular heart disease and CHB were compared with those from ten patients with CHB and normal cardiac valves. Hemodynamic studies were performed at slow or idioventricular rates and again after increasing the heart rate to more nearly normal levels by ventricular pacing. When obstruction to left ventricular inflow (mitral stenosis) co-existed with CHB, increasing the heart rate resulted in a reduction of an elevated LVEDP to normal. This resulted in only a small increase in left atrial pressure in spite of a striking increase in the mean left atrial-ventricular gradient.When obstruction to left ventricular outflow prevailed (aortic stenosis), improvement in cardiac function was manifested mainly by a decrease in LVEDP and was accompanied by a decrease in left ventricular stroke work. When a large regurgitant volume (aortic insufficiency) was added to a ventricle which has enlarged subsequent to CHB, there was striking elevation in ventricular filling pressures which returned to more nearly normal levels when the heart rate was increased. This was accompanied by a reduction in regurgitant stroke volume in the patient in whom it was measured.Thus, an increase in heart rate may be especially beneficial to those patients with CHB who also have valvular lesions which contribute to an increase in LVEDP and end-diastolic volume. Careful hemodynamic evaluation is helpful in determining appropriate therapy in these patients.     

Haemodynamic advantage with single chamber rate responsive pacemakers over dual chamber pacemakers during exercise in chronotropic incompetence.

Sequential cardiac chamber activation and chronotropic response are amongst the important determinants of cardiac performance. This study compared VVIR mode with DDD and VVI mode to assess the contribution of these two factors in the determination of cardiac performance during exercise. Ten patients with a mean age of 68 +/- 5 years were studied during 1988-90, who had complete heart block and sinus node dysfunction with a mean LV ejection fraction of 51.5 +/- 6.25%. Five patients had DDD pacemakers and the rest had VVIR pacemakers. Patients were exercised first in VVI mode followed by either DDD or VVIR mode. Exercise duration, maximum rate pressure product, exercise capacity and cardiac output were measured with graded treadmill test in Bruce protocol. There was remarkable increase in the exercise duration (P < 0.001) and the maximum rate pressure product (P < 0.001) in patients with VVIR as compared to DDD and VVI mode. In DDD mode, as compared to VVI mode, this increase was less remarkable, though statistically significant (P < 0.005). Therefore, it is concluded that patients with chronotropic incompetence as well as complete heart block do better during dynamic exercise when they have VVIR mode compared to VVI or DDD mode.     

Double blind crossover comparison of the effects of dual chamber pacing (DDD) and ventricular rate adaptive (VVIR) pacing on neuroendocrine variables, exercise performance, and symptoms in complete heart block.

OBJECTIVE--To compare the effects of dual chamber pacing (DDD) and ventricular rate adaptive pacing (activity sensing) (VVIR) in patients with complete heart block. DESIGN--Double blind crossover comparison with one month in each pacing mode. PATIENTS--10 consecutive patients aged 23-74 presenting with complete anterograde atrioventricular block at rest and on exercise and with an intact atrial rate response received Synergyst I (Medtronic) pacemakers. MAIN OUTCOME MEASURES--Symptom scores, maximal exercise performance on a treadmill, and the plasma concentrations of atrial natriuretic peptide, adrenaline, and noradrenaline. RESULTS--No significant differences were identified between pacing modes in symptom scores for dyspnoea, fatigue, and mood disturbance; exercise time; and maximal oxygen consumption. One patient with intact ventriculoatrial conduction developed pacemaker syndrome during VVIR pacing. Resting plasma concentrations of atrial natriuretic peptide were raised in complete heart block and were restored to normal by DDD pacing but not by VVIR pacing. Resting plasma catecholamine concentrations were normal in complete heart block and in both pacing modes. During exercise the increase in the concentrations of all three hormones was similar in both pacing modes. CONCLUSIONS--In patients with complete anterograde and retrograde atrioventricular block, symptoms and maximal exercise performance were no better during DDD than during VVIR pacing.     

Double blind crossover comparison of the effects of dual chamber pacing (DDD) and ventricular rate adaptive (VVIR) pacing on neuroendocrine variables, exercise performance, and symptoms in complete heart block.

OBJECTIVE--To compare the effects of dual chamber pacing (DDD) and ventricular rate adaptive pacing (activity sensing) (VVIR) in patients with complete heart block. DESIGN--Double blind crossover comparison with one month in each pacing mode. PATIENTS--10 consecutive patients aged 23-74 presenting with complete anterograde atrioventricular block at rest and on exercise and with an intact atrial rate response received Synergyst I (Medtronic) pacemakers. MAIN OUTCOME MEASURES--Symptom scores, maximal exercise performance on a treadmill, and the plasma concentrations of atrial natriuretic peptide, adrenaline, and noradrenaline. RESULTS--No significant differences were identified between pacing modes in symptom scores for dyspnoea, fatigue, and mood disturbance; exercise time; and maximal oxygen consumption. One patient with intact ventriculoatrial conduction developed pacemaker syndrome during VVIR pacing. Resting plasma concentrations of atrial natriuretic peptide were raised in complete heart block and were restored to normal by DDD pacing but not by VVIR pacing. Resting plasma catecholamine concentrations were normal in complete heart block and in both pacing modes. During exercise the increase in the concentrations of all three hormones was similar in both pacing modes. CONCLUSIONS--In patients with complete anterograde and retrograde atrioventricular block, symptoms and maximal exercise performance were no better during DDD than during VVIR pacing.     

右室心尖部和高位室间隔起搏对完全性房室传导阻滞患者心功能的影响

目的评价右室心尖部(RVA)起搏和高位右室间隔(HRVS)起搏对完全房室传导阻滞(CAVB)患者心功能的影响。方法 118例因CAVB植入起搏器的患者,其中52例为RVA起搏(RVA组),66例为HRVS起搏(HRVS组)。分别对术前、术后6个月及术后1年、2年的左室射血分数(LVEF)和2年内因心力衰竭住院人数进行随访观察。结果所有患者均完成1年随访,101例完成2年随访。术后6个月和1年时两组LVEF比较无差别(0.55±0.08vs0.55±0.08,P=0.926;0.54±0.09vs0.55±0.07,P=0.407),但是对于术前LVEF(0.50者,术后1年时LVEF两组有差别(0.40±0.04vs0.44±0.04,P=0.01)。术后2年,HRVS组优于RVA组(0.51±0.10vs0.55±0.06,P=0.01)。2年内,RVA组因心力衰竭住院人数多于HRVS组[31.1%(14/45)vs12.5%(7/56),P=0.02]。结论 HRVS起搏对CAVB患者心功能的长期影响低于RVA起搏。     

Dual chamber rate responsive pacing and chronotropic insufficiency. Comparison of double and respiratory sensors

Late responsive DDD pacemakers are the most technically advanced devices presently available. These pacemakers are particularly useful in patients with chronotropic insufficiency when the sinus node is incapable of accelerating during exercise. The latest pacemakers have two sensors to reproduce optimal physiological sinus acceleration. The aim of this study was to analyse the performances of a new rate responsive pacemaker with a double activity and respiratory sensor, the interaction of which is automatically controlled by a sophisticated algorithm, in 12 patients (8 men and 4 women) with a mean age of 75 +/- 7 years. Analysis was based on the performance of the sensors used singly or in association: during three exercise stress tests with measurement of the VO2 max; during everyday activities using the data archived by the pacemaker and the answers to a simplified questionnaire on quality of life. The results showed that during exercise stress testing with measurement of VO2 max, the best performances were obtained with the double sensor or the respiratory sensor compared with the activity sensor alone, suggesting that these two sensors are more effective in intense exercise. This tendency was also observed in the analysis of the memory bank of the pacemaker which showed that the total duration of the faster heart rates was greater with the two sensors. On the other hand, the quality of life was not significantly different, whichever sensor was studied. Longer scale trials are necessary to appreciate the real value of these new double sensor pacing devices and to identify the best indications for their usage.     

Single chamber ventricular compared with dual chamber pacing: a review

Since its introduction in the 1950s, the cardiac pacemaker has become increasingly sophisticated in an attempt to mimic normal cardiac physiology. Rapidly evolving pacing technology has seen pacemakers evolve from crude, fixed-rate, single chamber ventricular devices to dual chamber rate-adaptive units. While there is indirect evidence that supports the use of dual chamber pacing in the vast majority of patients, it is still unclear whether these newer, more expensive devices afford a significant morbidity and mortality benefit over single-chamber, ventricular, rate-adaptive pacemakers. A review of three large, randomized trials failed to demonstrate a clear benefit of dual chamber or atrial-based pacing over single chamber ventricular pacing for the majority of cardiovascular outcomes (heart failure, stroke and mortality), with the possible exception of atrial fibrillation. Information is also needed on the potential protective effects of atrial-based pacing over dual chamber pacing in elderly patients with sinus node dysfunction. Longer follow-up periods may be necessary to determine whether there are any mortality benefits associated with dual chamber pacing. Additional confirmation of benefits of dual chamber pacing may be provided by other ongoing prospective trials.     

右室间隔起搏与心尖部起搏对完全性房室传导阻滞患者心功能影响的比较

目的:初步探讨右室间隔起搏(RVSP)和右室心尖部起搏( RVAP)对完全房室传导阻滞( CAVB) 患者心功能的影响。方法:87例因CAVB植入起搏器的患者, 其中45例行RVSP术(RVSP组)，42例行RVAP术(RVAP组)，分别对术前及术后6、12和18个月，患者的QRS波时限、左室舒张末内径（LVEDD）、 左室射血分数（LVEF）、每搏量（SV）、心脏指数（CI）、加速度指数（ACI）进行检查比较。结果:所有患者均完成12个月随访, 79例完成18个月随访。术后RVAP组QRS波时限较RVSP组明显增宽(P<0.05)，术后12个月RVAP组LVEF、SV、ACI均较RVSP组明显降低(P<0.05)，术后18个月RVAP组LVEDD较RVSP组明显增大(P<0.05)，RVAP组CI均较RVSP组降低，但尚未达到显著性差异。结论:RVSP较RVAP有利于CAVB患者心功能的保护。     

Effect of right ventricular pacing in patients with complete left bundle branch block

The relation between left ventricular electromechanical delay and the acute hemodynamic effect of right ventricular pacing was studied in heart failure patients with and without complete left bundle branch block. Whereas right ventricular pacing provided a shorter electromechanical delay that correlated with an improvement in left ventricular function in patients with left bundle branch block, the converse was observed in patients without left bundle branch block.     

Effect of ventricular extrasystoles on idioventricular rhythm in patients with complete heart block.

Idioventricular rate, QRS width, site of block and responses to premature ventricular stimulation were studied in 23 patients with chronic complete heart block in an attempt to distinguish patients liable to syncopal attacks. Seven patients were asymptomatic, five gave a history of presyncope and 11 of syncope. Although the mean idioventricular rate of the nine patients in the narrow QRS group (39.7 per min) was significantly faster than that of the 14 patients in the wide QRS group (35.3 per min; P less than 0.05), the rate did not distinguish symptomatic patients within either the narrow or the wide QRS groups. His bundle studies of the site of block and the effect of single and paired right ventricular stimulation upon idioventricular rhythm were also unhelpful. The response of the return cycle to increasingly premature ventricular extrasystoles, however, proved more complex than was anticipated.     

双腔起搏对Ⅲ°房室传导阻滞患者心房率的影响

目的探讨永久双腔起搏治疗对Ⅲ°房室传导阻滞患者心房率的影响。方法回顾性选择2015年6月～2018年6月山西省人民医院心内科成功实施永久起搏器置入术的Ⅲ°房室传导阻滞患者46例,所有患者术前以及术后连续3d进行静息标准十二导联心电图检查。记录每份心电图P波以及QRS波频率,并将每日P波以及QRS波频率进行对比。同时记录并分析每例患者的一般情况,包括性别、年龄、合并的基础疾病等。结果 46例Ⅲ°房室传导阻滞患者中,术前窦性P波频率60～88(73.4±6.2)次/min,室性逸搏频率30～50(41.9±5.6)次/min。术后第1天在未用任何抗心律失常药物基础上,窦性P波频率降至60～80(66.7±4.8)次/min,较术前明显降低,差异有统计学意义(P0.01)。术后第2天以及第3天窦性P波频率仍有下降趋势,分别为60～72(65.6±3.7)次/min,60～71(64.8±3.1)次/min,但速度已放缓,仍较术前明显降低,差异有统计学意义(P0.01)。结论双腔起搏可改善Ⅲ°房室传导阻滞患者心功能,降低心房率。     

双腔起搏器植入术后对三度房室传导阻滞患者左心房功能的影响

目的：应用应变率成像（SRI）技术评价右室流出道起搏对于三度房室传导阻滞患者左心房功能的影响。方法：分别于双腔起搏器植入术前、术后1个月和术后3个月应用SRI技术对20例三度房室传导阻滞患者左心房功能进行评价。结果：与术前比较,术后1月左心房收缩期前容积[（30．17±2．92）ml比（27．66±3．25）ml]、最大容积[（47．00±2．94）ml比（44．25±3．15）ml]、最小容积[（18．27±3．02）ml比（16．14±2．54）ml]明显减小（P均〈0．05）,心室收缩期左心房峰值应变率（SRS）[（3．82±0．28）S-1比（3．58±0．32）S-1]降低,心室舒张晚期左心房峰值应变率FSRa,（-2．49±0．29）S-1比（-2．72±0．31）S-1]和心室舒张早期左心房峰值应变率[-SRc,（-3．11±0．28）S-1比（-3．32±0．27）S-1]升高,术后3月,上述指标变化更为显著（P〈0．01）;术后3月主动排空分数[（25．78±9．00）％比（49．39±9．33）％]和被动排空分数[（35．77±5．40）％比（41．46±7．44）％]、左室射血分数[（62．85±3．27）％比（65．75±2．87）％]明显升高（P〈0．05～〈0．01）;与术前相比,术后3个月左室射血分数的变化率与SRa的变化率呈显著的正相关（r=0．522,P〈0．05）。结论：双腔起搏器植入术后可影响三度房室传导阻滞患者的左心房的功能,表现为管道和辅泵功能增加,储器功能下降。     

Transoesophageal left ventricular pacing in heart failure patients with permanent right ventricular pacing.

BACKGROUND: Previous studies of biventricular (BV) pacing for treatment of heart failure (HF) patients with left bundle branch block (LBBB) evaluated responders to BV pacing with acute transvenous left ventricular (LV) pacing and arterial pulse pressure (PP). The aim of this study was to assess transoesophageal LV pacing in evaluation of the haemodynamic response with a view to upgrading responders from permanent right ventricular (RV) pacing to BV pacing. METHODS AND RESULTS: Ten HF patients (age 62+/-8 years; one female, nine males) in NYHA III, LV ejection fraction 24+/-9% and permanent RV pacing by means of an implanted pacemaker or ICD were tested using transoesophageal LV pacing and PP. Permanently RV-paced HF patients were analysed with transoesophageal atrial sensed LV pacing in VAT mode with a different AV delay (n = 6) and with transoesophageal LV pacing in V00 mode during atrial fibrillation (n = 4). In five responders, PP was higher during transoesophageal LV pacing than PP during RV pacing (74+/-42 versus 57+/-31 mmHg, P = 0.015). Responders were upgraded by means of an LV lead via the coronary sinus in the posterior (n = 1) or posterolateral (n = 4) walls and after attaining a high LV pacing threshold with an epicardial LV lead on the anterior (n = 1) or anterolateral (n = 1) walls. NYHA class improved from 3 to 2+/-0.3 (P = 0.003) during 204+/-120 days follow-up and cardiac output increased from 4.4+/-1.5 to 5.6+/-1.7 l/min (P = 0.027) when comparing BV pacing and optimal AV delay with RV pacing. In five nonresponders, PP was not higher during transoesophageal LV pacing than during RV pacing. CONCLUSION: Transoesophageal LV pacing may be a useful technique to detect responders to BV pacing in permanently RV-paced HF patients.     

Randomised crossover trial of rate responsive Activitrax and conventional fixed rate ventricular pacing.

Atrial tracking pacemakers may improve exercise capacity and symptoms because they maintain atrioventricular synchrony and preserve the physiological response of heart rate to exercise. A rate responsive pacemaker which reacts to physical activity may be effective in patients with sinus node disease who are unsuitable for VDD pacing. At least three months after implant a double blind randomised short and long term crossover study was performed in ten patients with complete heart block: block was present at rest and during exercise on a modified Bruce protocol. Symptoms were assessed on a visual analogue scale and exercise capacity (maximal oxygen consumption and anaerobic threshold) was measured during rate responsive (peak rate 125/min) and conventional fixed rate (VVI) pacing (70/min). One month after randomisation treadmill exercise was performed. The mode was then changed to the other pacing mode and exercise was repeated three hours later. After another month the process was repeated but in the reverse order. During long term assessment there was subjective improvement in the sensation of breathlessness with rate responsive pacing. During short term assessment maximal oxygen consumption increased and the benefit was maintained during long term rate responsive compared with long term VVI pacing; oxygen consumption at the anaerobic threshold was similarly improved. Activity detecting rate responsive pacing is better than fixed rate ventricular pacing in patients with complete atrioventricular block.