Pacemaker troubleshooting: improved efficacy using a new diagnostic digital Holter recording system.

Asymptomatic dysfunction of cardiac pacing systems is not uncommonly detected using long-term ambulatory monitoring techniques. We report two patients with atrial and ventricular sensing abnormalities noted only on Holter monitoring. Multiple empirical attempts at pacemaker reprogramming based on deductive analysis of the pacing anomaly were unsuccessful. Through the use of a new digital recording system that allowed collection of surface electrocardiographic data, intracardiac electrograms, and Marker Channel data a correct diagnosis was made (pacing lead insulation failure). This new recording system has the advantage of significantly improving diagnostic sensitivity and resulting in cost savings.     

动态心电图对起搏器间歇性感知功能异常的诊断价值

目的 :探讨动态心电图检测对起搏器间歇性感知功能异常的诊断价值。方法 :采用MarquetteMars30 0 0动态心电图仪 ,对 36例 (4 9例次 )安装起搏器的患者进行随访 ,分析起搏、感知及与起搏器相关的心律失常。结果 :共检出起搏器间歇性感知功能异常 17例 (2 4例次 ) ,检出率为 4 7.2 % ,有 5例 (7例次 )合并两项感知异常。所有感知异常除 1例在常规心电图中检出外 ,其余 16例只在动态心电图中发现。检出与起搏器相关的心律失常 12例。根据动态心电图结果进行相应临床处理后 ,部分起搏器的感知功能异常消失。结论 :起搏器的感知功能异常多为间歇性的 ,动态心电图对间歇性感知异常的检出率较高 ,应是起搏器随访不可或缺的手段。     

Holter monitoring in dizziness and syncope.

Holter monitoring was used to detect the underlying mechanism among 53 patients referred for dizziness, fainting and/or syncope. The complaints were unexplained on clinical grounds in 38, suggestive of SSS in 11, and of pacemaker dysfunction in 4 patients who underwent pacemaker implantation for symptomatic A-V block. Occult dysrhythmias were revealed in 24 of 38 (61%) of the first group; the clinical impression of SSS was confirmed in 8 of 11 (72%) in the second, and ineffective pacing confirmed in 2 of 4 in the third group. Thus, the diagnosis was clarified in 34 of 53 (64%) of patients. It is concluded that Holter monitoring is most useful for detecting the underlying mechanism in the above mentioned conditions, especially in elderly subjects whose syncopal attacks remained unexplained despite routine cardiological and neurological examination. Holter monitoring should be carried out for at least 36 hours before ruling out dysrhythmias as a cause of dizziness and/or syncopal attacks.     

A Novel Mechanism of Failure to Detect Atrial Arrhythmias by Pacemakers and Implantable Cardioverter Defibrillators

Failed Atrial Arrhythmia Detection by Pacemakers and ICDs. A 64‐year‐old man with complete heart block, status post‐Medtronic dual chamber pacemaker insertion, failed ablation for atrial tachycardia at an outside institution. Despite persistent palpitations and known unsuccessful ablation, pacemaker interrogation revealed no evidence of atrial arrhythmias. At electrophysiology study, burst pacing from the high right atrium and distal coronary sinus at 370 ms revealed bidirectional 2:1 interatrial conduction block. Left atrial burst pacing at 260 ms induced an atrial tachycardia (cycle length 340 ms) with 2:1 left to right atrial block and right atrial activation at 680 ms. The tachycardia was localized to the lateral left atrial roof. A series of ablation lesions from left to right superior pulmonary vein terminated the tachycardia. Left to right interatrial conduction block is a mechanism for underdetection of atrial arrhythmias with implantable devices not previously described. As the extent of atrial ablation increases, the incidence of this mechanism of underdetection may increase. Though devices are often considered ideal for atrial arrhythmia detection and are used in multiple trials, detection failures can occur despite appropriate device function. This case underscores the need for electrocardiographic monitoring in addition to device‐based electrogram monitoring. (J Cardiovasc Electrophysiol, Vol. 21, pp. 325–328, March 2010)     

The Utility of Holter Monitoring Compared to Loop Recorders in the Evaluation of Syncope and Presyncope

Background: Holter monitoring is frequently used to assess patients with syncope, but rarely provides a diagnosis. Newer loop recorders provide the opportunity for prolonged electrocardiographic monitoring to enhance diagnostic yield. Methods: The results of 232 Holter monitors and 81 loop recordings performed for the investigation of syncope or presyncope were reviewed for indication, patient demographics, and presence and type of symptoms and/or arrhythmias. The results were classified as (1) symptom‐arrhythmia correlation, (2) clinically useful information (group 1 plus those excluding arrhythmic syncope, and those demonstrating asymptomatic serious arrhythmias) and (3) unhelpful (asymptomatic and no serious arrhythmias). Results: Loop recorders provided a symptom‐arrhythmia correlation in 11.1% of patients compared to only 0.4% in the Holter group (P < 0.0001). Clinically useful information was obtained in 54.3% of loop patients compared to 27.6% in the Holter group (P < 0.0001). Technical problems occurred in 0.4% of the Holter patients and in 3.7% of loop patients (P = 0.05). Classification was difficult in seven patients in the Holter group; two experienced symptoms during sinus rhythm but also had a serious asymptomatic arrhythmia, and five patients had 6–10 beats of asymptomatic ventricular tachycardia at a rate < 160 beats/min. Conclusion: Loop recording was well tolerated and superior to Holter monitoring in providing a symptom‐arrhythmia correlation or clinically useful information in patients with syncope and presyncope. An initial approach with a loop‐recording device should be employed in these patients.     

Langzeit-Elektrokardiographie

During the past almost 50 years Holter monitoring has become an established non-invasive diagnostic tool in clinical electrophysiology. It allows ECG recording independent of stationary monitoring facilities during daily life and, therefore, contains much information. In the beginning the main interest was directed towards quantitative and qualitative assessment of arrhythmias, their circadian behaviour, and the circadian behaviour of the heart rate. With advances in technology the analysis spectrum of Holter monitoring expanded, and it was used also for detection of silent myocardial ischaemia. New digital recorders and computers with large capacities made it possible to measure every single heart beat very accurately, which was a prerequisite for heart rate variability and QT-interval analysis, which provided new knowledge about the autonomic modulation of the heart rate and the circadian dynamicity of the QT interval, respectively. Beyond arrhythmia analysis Holter monitoring was increasingly used to assess prognosis in different cardiac conditions. It can also be valuable in assessing transient symptoms possibly related to arrhythmias or device dysfunction, which will not necessarily be revealed by simple device control.     

动态心电图在起搏器植入术后随访中的应用

目的:探讨动态心电图(DCG)评价起搏器功能状态的价值。方法:对93例起搏器植入术患者进行随访,分析起搏、感知及与起搏器相关的心律失常和症状。结果:起搏功能异常1例,检出感知异常28例,检出率为31．18％ (29／93),除1例感知异常及1例起搏异常在常规心电图中检出外,其余均在DCG中发现。根据检查结果进行起搏器程控调整和相应的临床处理后,28例中22例(78．6％)起搏及感知异常有不同程度改善或消失。结论:DCG监测对间歇性起搏及感知功能异常检出率较高,DCG是起搏器随访不可或缺的检查方法。     

Comparison of 24-hour Holter Monitoring with 14-day Novel Adhesive Patch Electrocardiographic Monitoring

Background

Cardiac arrhythmias are remarkably common and routinely go undiagnosed because they are often transient and asymptomatic. Effective diagnosis and treatment can substantially reduce the morbidity and mortality associated with cardiac arrhythmias. The Zio Patch (iRhythm Technologies, Inc, San Francisco, Calif) is a novel, single-lead electrocardiographic (ECG), lightweight, Food and Drug Administration–cleared, continuously recording ambulatory adhesive patch monitor suitable for detecting cardiac arrhythmias in patients referred for ambulatory ECG monitoring.

Methods

A total of 146 patients referred for evaluation of cardiac arrhythmia underwent simultaneous ambulatory ECG recording with a conventional 24-hour Holter monitor and a 14-day adhesive patch monitor. The primary outcome of the study was to compare the detection arrhythmia events over total wear time for both devices. Arrhythmia events were defined as detection of any 1 of 6 arrhythmias, including supraventricular tachycardia, atrial fibrillation/flutter, pause greater than 3 seconds, atrioventricular block, ventricular tachycardia, or polymorphic ventricular tachycardia/ventricular fibrillation. McNemar's tests were used to compare the matched pairs of data from the Holter and the adhesive patch monitor.

Results

Over the total wear time of both devices, the adhesive patch monitor detected 96 arrhythmia events compared with 61 arrhythmia events by the Holter monitor (P < .001).

Conclusions

Over the total wear time of both devices, the adhesive patch monitor detected more events than the Holter monitor. Prolonged duration monitoring for detection of arrhythmia events using single-lead, less-obtrusive, adhesive-patch monitoring platforms could replace conventional Holter monitoring in patients referred for ambulatory ECG monitoring.     

Efficacy of three-channel ambulatory electrocardiographic monitoring for the detection of myocardial ischemia.

The recognition of silent myocardial ischemia (SMI) has been demonstrated to have important clinical relevance. Two-channel ambulatory (Holter) electrocardiographic recording is a commonly utilized method for detecting transient electrocardiographic ST segment changes representative of SMI. It has been suggested that the analysis of two channels alone may not adequately detect SMI. We therefore evaluated the diagnostic yield of three channels using a three-channel electrocardiographic monitoring device in 46 consecutive patients (age 61 +/- 9 years) undergoing percutaneous transluminal coronary angioplasty of an isolated single-vessel stenosis. Modified bipolar chest leads V2, V5, and AVF (CM-V2, CM-V5, and CS-AVF) were utilized for analysis. The percent detection of ST segment changes from various combinations of two-lead recordings were compared to the total three leads, and an absolute transient ST segment shift (STSS) of greater than or equal to 1 mm during balloon inflation was considered as evidence of myocardial ischemia. One patient was excluded because of the need for ventricular pacing during balloon inflation. A total of 33 of 45 patients had STSS in all three leads (percent detection = 73%), while 32 (71%) had STSS in the two-lead grouping with the highest diagnostic yield (CM-V2/CM-V5; p = ns). Of the various two-lead combinations studied, leads CM-V2 and CM-V5 provided the best lead set overall for the detection of ischemic STSS. Three-channel ambulatory electrocardiographic recording only marginally improves upon the detection of ischemia when compared with standard (CM-V2/CM-V5 or CM-V5/CS-AVF) two-channel ambulatory electrocardiographic recordings.     

Pacing for adult patients with left atrial isomerism: efficacy and technical considerations.

AIM: Left atrial isomerism (LAI) is an uncommon congenital heart disease, which is combined with a range of intracardiac abnormalities. Atrial arrhythmia is common in LAI. We hypothesized that permanent pacing will decrease arrhythmia recurrence in adult patients with LAI. METHODS AND RESULTS: Patients with LAI and permanent pacing were identified from the Royal Brompton Adult Congenital Heart Database. Hospital records were reviewed, and patients' current status was assessed with clinic reviews including standard and Holter ECGs, and transthoracic echocardiograms. Four patients who underwent permanent pacing at the age of 27.5+/-11.7 years fulfilled inclusion criteria, namely permanent pacing in the setting of LAI. All 4 had sick sinus syndrome-with sustained supraventricular arrhythmia in 3-requiring several hospitalizations for arrhythmia management prior to pacing. All 4 patients remained free of clinical arrhythmia and hospital admission at a mean follow-up of 67.0+/-59.5 months from pacing. The latest ECG revealed paced rhythm in all. NYHA functional class remained stable. There were no pacemaker related complications at implantation or during follow-up. CONCLUSION: Adults with LAI benefit from pacemaker implantation, which reduces recurrence of supraventricular tachycardia and maintains atrioventricular synchrony. Future studies need to determine the preferred pacemaker mode and optimal timing for pacing.     

A temporary external DDD pacing unit

A device for temporary external DDD pacing was developed using a modified permanent pulse generator, and temporary atrial and ventricular electrode catheters were inserted pervenously. The atrial lead was a J type and the ventricular lead had a remote anode in the superior vena cava. With a special clamp and appropriate connectors the permanent DDD pulse generator provided unipolar external DDD pacing. The device was evaluated in 13 patients to control bradyarrhythmias or for overdrive pacing in an attempt to control tachyarrhythmias. Nine patients were ambulatory; all had continuous electrocardiographic monitoring. The device was used for 1 to 12 days (mean 4.9). Eight patients benefited from temporary DDD pacing and 7 had permanent DDD pacemakers implanted. In 1 patient, atrial fibrillation developed, 2 patients had brief episodes of ventricular lead displacement and another required reprogramming because of loss of ventricular capture. Results suggest that the device is applicable for a clinical trial of DDD pacing before possible permanent implantation when attempting to improve cardiac output or control arrhythmias.     

Value of Holter monitoring in assessing cardiac arrhythmias in symptomatic patients.

Holter electrocardiographic monitoring in 55 symptomatic patients with syncope, palpitations or dizziness uncovered significant arrhythmias in 30 patients (55 percent). By providing an observation period of at least 24 hours including a period of sleep, the procedure aided detection and diagnosis in both symptomatic and asymptomatic patients of transient arrhythmias or conduction abnormalities not documented by routine electrocardiograms. Bradyarrhythmias accounted for the majority of arrhythmias recorded in 21 or 30 symptomatic patients (70 percent); 15 had sinus bradycardia (35 to 55 beats/min) alone and 6 also had long episodes of sinus arrest of up to 5 seconds. Two had sinus bradycardia with periods of atrioventricular block with Wenckebach phenomenon. Five patients had a tachycardia-bradycardia syndrome; three had other episodic arrhythmias and one had pacemaker failure. In 15 (60 percent) of the 25 patients without arrhythmias, monitoring did not document the cause of symptoms. Holter monitoring is of considerable value in assessing the efficacy and adequacy of drug treatment, especially in patients with known heart disease, and in detecting pacemaker malfunction. However, very long periods of monitoring may be needed to make a diagnosis in those with only sporadic symptoms.     

Pacing and sensing disturbances in patients with DDD pacemakers in the early period after implantation

OBJECTIVES: We sought to determine the usefulness of ambulatory 24-hour Holter monitoring in detecting asymptomatic pacemaker (PM) malfunction episodes in patients with dual-chamber pacemakers whose pacing and sensing parameters were proper, as seen in routine post-implantation follow-ups.This aspect has not been widely discussed so far. METHODS AND RESULTS: Ambulatory 24-hour Holter recordings [HM] were performed in 100 patients with DDD pacemakers one day after the implantation. Only asymptomatic patients with proper pacing and sensing parameters (assessed on PM telemetry on the first day post-implantation) were enrolled in the study. The following parameters were assessed: failure to pace, failure to sense (both oversensing and undersensing episodes) as well as the percentage of all PM disturbances. Despite proper sensing and pacing parameters, HM revealed PM disturbances in 23% of the patients.Atrial undersensing episodes were found in 12 patients and failure to capture in I patient. T wave oversensing was the most common ventricular channel disorder (9 patients). Malfunction episodes occurred sporadically, leading to pauses of up to 1.6 s or temporary bradycardia, which were, nevertheless, not accompanied by clinical symptoms. No ventricular pacing disturbances were found. CONCLUSION: Asymptomatic pacemaker dysfunction may be observed in nearly 25% of patients with proper DDD parameters after implantation.Thus, ambulatory HM during the early post-implantation period may be a useful tool to detect the need to reprogramme PM parameters.     

Oversensing during ventricular pacing in patients with a third-generation implantable cardioverter-defibrillator

Objectives. The purpose of this study was to identify the causes of oversensing during ventricular pacing in patients with a thirdgeneration implantable cardioverter-defibrillator.Background. Third-generation implantable cardioverterdefibrillators have the capability for bradycardia pacing as well as antitachycardia pacing and defibrillation. With the Ventritex Cadence Tiered Therapy Defibrillator System, the pulse generator sensitivity is increased during bradycardia pacing to prevent undersensing of an arrhythmia with small amplitude signals.Methods. Records from 85 consecutive patients who underwent implantation of a Cadence device for treatment of ventricular tachyarrhythmias were reviewed.Results. Four patients required continuous pacing for bradyarrhythmias. In three of these patients, ventricular pacing was accomplished using the bradycardia pacing feature of the Cadence device. All three experienced spurious device discharges or had aborted shocks for oversensing. Analysis of real-time and stored electrograms revealed intermittent high frequency, large amplitude noise in two patients and oversensing of maximally gained R and T waves in the remaining patient. No evidence of lead fracture was found in any patient. The problem was solved by implantation of a separate permanent pacemaker in two patients and was partially solved by reprogramming of the device in the remaining patient.Conclusions. Although the Cadence implantable cardioverterdefibrillator has the capability for ventricular pacing in patients with bradyarrhythmias, certain features of its automatic gain control circuit limit its utility in this instance. Oversensing occurs commonly, leading to device discharges or aborted shocks. Implantation of a separate permanent pacemaker may be required in patients who have a Cadence device for tachyarrhythmia control and who also need pacing for bradycardia.     

Evaluation of pacemaker telemetry as a diagnostic feature for detecting atrial tachyarrhythmias in patients with sick sinus syndrome.

AIM: The aim of the present study was to validate pacemaker telemetry as a diagnostic feature for detecting atrial tachyarrhythmias (AT) during pacemaker treatment in patients with sick sinus syndrome (SSS). METHODS AND RESULTS: Patients with SSS and bradytachy syndrome (n = 28, 20 women), mean age 71 +/- 10.3 years, were included. The patients were treated with AAIR (n = 14) or DDDR pacing. At a routine follow-up visit pacemaker telemetry was reset and the patients underwent Holter recording for at least 24 h. Episodes of atrial fibrillation (AF) during Holter recording were compared with episodes of AT detected by the pacemaker. Only episodes of AF lasting for at least 1 min during Holter recording were registered. AT detected by the pacemaker telemetry was defined as: an atrial high rate episode with a rate of > or = 220 bpm for > or = 5 min, atrial sensing with a rate of > or = 170 bpm in > or = 5% of total counted beats, mode-switching in > or = 5% of total time recorded or a mode-switching episode of > or = 5 min. Twenty-eight Holter recordings (mean duration 31.5 h, range 20-72 h) were used for evaluation. Ten patients had one or more episodes of AF lasting at least 1 min on their Holter recordings. Nine of these patients had AT detected by their pacemaker telemetry according to our criteria. None of the patients had AT detected by the pacemaker telemetry and not by the Holter recording. The specificity and sensitivity for detection of AT recorded by the pacemaker telemetry in this study was 100% and 90%, respectively. The false-positive rate was 0%. CONCLUSION: Pacemaker telemetry was found to be a reliable tool for detecting AT in patients with SSS.     

Arrhythmia in patients with a DDD bicameral pacemaker

Dual chamber pacemakers, with coordinate atrial and ventricular sensing and stimulation (DDD), even if allowing "physiological" pacing, exhibited new and complicated arrhythmic manifestations, whose real frequency is still unascertained. In 65 patients (mean age 68 +/- 12 years), implanted with a DDD multiprogrammable device (15 pts. Medtronic Versatrax 7000 A, 50 pts. Pacesetter AFP 283), we carried out a 24 hours Holter monitoring while pacemaker was programmed with standard parameters. In a subset of 15 patients Holter monitoring was performed before and after pacemaker implantation. We evidenced: a) atrial sensing and/or pacing malfunction in 3 patients (4.5%); b) pacer-unrelated arrhythmias in 49 patients (75%): atrial extra beats 35 patients (54%), ventricular extra beats 23 patients (35%), non-sustained ventricular tachycardias 10 patients (15%), atrial tachyarrhythmias 8 patients (12%); c) supraventricular arrhythmias with PM-mediated high rate ventricular pacing in 12 patients (18%); d) PM induced and sustained endless loop tachycardias in 31 patients (47%); e) arrhythmias depending on over-sensing in 11 patients (17%): myopotential interferences 9 patients (14%), cross-talk ventricular pacing inhibition 2 patients (3%). The prevalence of ventricular arrhythmias was not different before and after the pacemaker implantation. The prevalence of atrial extrasystoles (53% versus 40%) and atrial tachyarrhythmias (26% versus 6%) decreased after the pacemaker implantation. Aimed reprogramming with progressive extension of atrial refractory period (from 250 to 400 msec and DDX) achieved disappearance of PM-endless loop tachycardias in 95%. Use of multi-programmability lowered the incidence and symptoms of most PM-related arrhythmias. Drug therapy was of choice in clinical arrhythmias unrelated to pacer.     

中老年起博器植入患者的动态心电图分析

目的探讨动态心电图（DCG）监测对起搏器起搏及感知功能异常的诊断价值。方法采用美国惠普43400B型DCG分析系统,对95例年龄在50岁以上植入起搏器的患者进行随访,分析起搏、感知功能及与起搏器相关的心律失常并与常规心电图对照。结果共检出起搏器功能障碍23例,其中间歇性起搏功能障碍2例（占2%）,间歇性感知功能障碍21例（占22%）。检出与起搏器相关的心律失常17例（18%）。而常规心电图仅发现感知功能障碍2例。两种检查方式在检测间歇性感知功能障碍及与起搏器相关的心律失常方面存在显著性差异（P<0.01）。检出起搏功能异常的差异性未达到显著水平。DCG对3种类型（AAI、VVI、DDD）之间感知功能异常检出率无显著性差异。根据DCG结果,进行临床相应处理后,起搏器的起搏及部分感知功能障碍消失,相关心律失常引起的临床症状逐渐消失。结论起搏器的起搏、感知功能障碍及与起搏器相关的心律失常多为间歇性发生,DCG对其检出率较高,并可系统了解起博器工作状态及各种心律失常,是对起博器随访的重要手段之一。     

Interactions Between Pacing and Arrhythmia Detection Algorithms in the Dual Chamber Implantable Cardioverter Defibrillator

Dual chamber implantable cardioverter defibrillator (ICD) combines the possibility to detect and treat ventricular and atrial arrhythmias with the possibility of modern heart stimulation techniques. Advanced pacing algorithms together with extended arrhythmia detection capabilities can give rise to new types of device–device interactions. Some of the possible interactions are illustrated by four cases documented in four models of dual chamber ICDs. Functioning of new features in dual chamber devices is influenced by the fact that the pacemaker is not a separate device but a part of the ICD system and that both are being used in a patient with arrhythmia. Programming measures are suggested to optimize use of new pacing algorithms while maintaining correct arrhythmia detection.     

Long-term follow-up of patients treated with the QT interval sensing rate-responsive pacemaker

Thirty-seven patients (mean age 70 years) with QT-interval sensing (TX) rate-responsive pacemakers were followed for a mean of 27 months. This pacemaker measures the QT interval of the paced beat and, if the QT shortens, the pacing rate increases according to a programmed relationship, the 'slope'. With TX pacing the heart rate was 56% and the exercise tolerance 15% higher than with fixed-rate ventricular-inhibited (VVI) pacing during exercise. Holter ECG monitoring showed a physiological rate variability. Six patients (16%) have died during follow-up, and programming to the VVI mode was necessary in six patients (16%). The remaining patients were alive with a subjectively adequate TX function at the end of follow-up. Including the five patients who were on TX pacing at the time of death, satisfactory TX pacing was obtained in 84% of the patients. Although the TX pacemaker has been reliable and provides an adequate rate response during exercise, complaints of worsening angina pectoris and the somewhat complicated programming of the device are problems with the current models.     

动态心电图监测老年冠心病无症状心肌缺血的意义

目的:探讨24小时动态心电图(Holter)对老年冠心病患者无症状心肌缺血(SMI)的检出情况。方法:回顾分析我院门诊及住院336例老年冠心病患者的临床情况和Holter资料。结果:(1)常规心电图检出心肌缺血106例(31.55％),Holter检出心肌缺血220例(65.48％);SMI发生率为69.09％,有症状心肌缺血发生率为30.91％;(2)SMI发作有明显生物节律,以清晨6-12时发作频率最高;(3)SMI发作时心率减慢的比例明显低于有症状心肌缺血的(P<0.005);(4)SMI的心律失常检出率为93.4％。结论:Holter可早期发现老年人的无症状心肌缺血,有重要价值。