Conventional Holter Monitoring Research Articles

Comparison Between a Single-Lead ECG Garment Device and a Holter Monitor: A Signal Quality Assessment.

Wearable electronics are increasingly common and useful as health monitoring devices, many of which feature the ability to record a single-lead electrocardiogram (ECG). However, recording the ECG commonly requires the user to touch the device to complete the lead circuit, which prevents continuous data acquisition. An alternative approach to enable continuous monitoring without user initiation is to embed the leads in a garment. This study assessed ECG data obtained from the YouCare device (a novel sensorized garment) via comparison with a conventional Holter monitor. A cohort of thirty patients (age range: 20-82 years; 16 females and 14 males) were enrolled and monitored for twenty-four hours with both the YouCare device and a Holter monitor. ECG data from both devices were qualitatively assessed by a panel of three expert cardiologists and quantitatively analyzed using specialized software. Patients also responded to a survey about the comfort of the YouCare device as compared to the Holter monitor. The YouCare device was assessed to have 70% of its ECG signals as "Good", 12% as "Acceptable", and 18% as "Not Readable". The R-wave, independently recorded by the YouCare device and Holter monitor, were synchronized within measurement error during 99.4% of cardiac cycles. In addition, patients found the YouCare device more comfortable than the Holter monitor (comfortable 22 vs. 5 and uncomfortable 1 vs. 18, respectively). Therefore, the quality of ECG data collected from the garment-based device was comparable to a Holter monitor when the signal was sufficiently acquired, and the garment was also comfortable.

Evaluation of the Diagnostic Performance and Efficacy of Wearable Electrocardiogram Monitoring for Arrhythmia Detection after Cardiac Surgery.

Postoperative atrial fibrillation (A-fib) is a serious complication of cardiac surgery that is associated with increased mortality and morbidity. Traditional 24-hour Holter monitors have limitations, which have prompted the development of innovative wearable electrocardiogram (ECG) monitoring devices. This study assessed a patch-type wearable ECG device (MobiCARE-MC100) for monitoring A-fib in patients undergoing cardiac surgery and compared it with 24-hour Holter ECG monitoring. This was a single-center, prospective, investigator-initiated cohort study that included 39 patients who underwent cardiac surgery between July 2021 and June 2022. Patients underwent simultaneous monitoring with both conventional Holter and patchtype ECG devices for 24 hours. The Holter device was then removed, and patch-type monitoring continued for an additional 48 hours, to determine whether extended monitoring provided benefits in the detection of A-fib. This 72-hour ECG monitoring study included 39 patients, with an average age of 62.2 years, comprising 29 men (74.4%) and 10 women (25.6%). In the initial 24 hours, both monitoring techniques identified the same number of paroxysmal A-fib in 7 out of 39 patients. After 24 hours of monitoring, during the additional 48-hour assessment using the patch-type ECG device, an increase in A-fib burden (9%→38%) was observed in 1 patient. Most patients reported no significant discomfort while using the MobiCARE device. In patients who underwent cardiac surgery, the mobiCARE device demonstrated diagnostic accuracy comparable to that of the conventional Holter monitoring system.

Innovative primary care lead community palpitation management and investigation pathway

Abstract Funding Acknowledgements Type of funding sources: None. Background Palpitations are a common reason for General Practitioner (GP) appointment in primary care and a frequent reason for cardiology referral. In the region where this project was performed, this translated to approximately 24,000 primary care and out of hours consultations in 2021 alone. Purpose The purpose of this pilot was to evaluate a pathway for palpitations diagnosis and management in primary care. The proposed pathway was designed to avoid unnecessary referrals to secondary care, to shorten the waiting time to diagnosis for patients and to cut down visits to A&E and out of hours service in primary care. Method The pathway, which was piloted at a federation for 30,000 patients, was based on a community cardiology approach, where a GP with Special interest in cardiology could offer the service for the wider community. The pathway began with an initial clinical evaluation comprising medical history, physical examination, and a standard 12-lead ECG. After ruling out of any red flags and otherwise deemed appropriate to continue to be assessed with the proposed diagnostic method, the patients were provided with a handheld ECG device for intermittent 30 seconds ECG registration at home. During a four-week investigation period the patients would record their ECG when experiencing symptoms. The primary care team remotely monitored the traces which were received on a cloud-based system with AI capabilities, and if pathology was recorded, patient was contacted and informed of management plan. If after four weeks no pathology was found, patients received a discharge consultation for reassurance and final report was generated. Results During the 24-month pilot we screened the total of 191 patients. Out of the patients screened 24 (13%) were diagnosed with atrial fibrillation, 92 (48%) were diagnosed with benign ectopics as the cause of their palpitations. Two rare occurrences of a life threatening broad complex tachycardias were also detected, both of which ended up needing defib implantation. Table 1. further presents the results by diagnosis for rest of the patients. Conclusions The results from the pilot indicated a reduction in GP / out of hours consultations by 50% and over 90% reduction in referral to secondary care for Holter monitoring by implementing an easy-to-use handheld ECG as part of the community led palpitation pathway. The results further implied that a district-wide implementation could lead to at least 120 new AF diagnosis in our project district per year, having a knock-on benefit of stroke reduction and cost economic impact in the society by reducing anxiety, lost employment hours and increasing productivity. Another key outcome seen is the reassurance value of conducting symptomatic palpitation monitoring to reassure patients, majority of whom had either normal sinus rhythm or benign ventricular ectopics and had failed to be satisfied with conventional Holter monitoring in the past.

Diagnostic yield of a portable electrocardiographic device versus 24-hours conventional holter monitoring in the diagnosis of arrhythmic events

Abstract Funding Acknowledgements Type of funding sources: None. Background The study of palpitations, presyncope or dizziness constitutes an important part of the cardiology consultations. These symptoms are nonspecific most of times, and with the usual diagnostic tools (24-hour Holter mainly) it is difficult to reach an accurate diagnosis, since episodes occur erratically once or a few times a month. The Kardia® electrocardiographic monitoring device is a diagnostic tool that allows the patient to self-perform ECG based on symptoms and send it for later review and interpretation by a cardiologist. Purpose We compared the diagnostic yield of the conventional 24-hour Holter monitor versus the Kardia® device in patients undergoing a cardiology study. Methods We conducted a prospective cohort study in 36 patients referred to the cardiology consultation due to palpitations or presyncope. In all of them, a 24-hour Holter was carried out, according to the usual protocol, and then a KardiaMobile® 6L device was given for a month. They received training to perform an ECG (six limb leads) and use the mobile application. The quantitative variables are expressed as means and standard deviation and the qualitative values as percentages. Results The study included 36 patients, of which 66.7% were women and 33.3% men, mean age of 44.2±14.3 years. The most frequent clinical symptom was palpitations (88.9%). Regarding the 24-hour Holter, only 22.2% of patients felt the symptoms for which they consulted during the day they wore it. Only in 19.4% the etiological diagnosis was reached through this method. Regarding the KardiaMobile® device, 72.2% of patients presented symptoms during the month of follow-up. Through the records obtained with this device, the diagnosis was reached in 52.8% of the cases, taking into account that if the patient reported having symptoms at the time the ECG was performed, if the ECG was normal, it was considered a diagnostic success, since the non-cardiological cause of the symptom was demonstrated. The diagnosis implied a therapeutic approach in 30.6% of cases: antiarrhythmic drugs were started in 8 patients, and 4 electrophysiological studies were indicated: in 3 patients for AVRNT ablation and in 1 patient for sustained ventricular tachycardias. Table1 shows a summary of the results. Conclusion Despite the limited number of patients, in our study, the 30-day recording with portable KardiaMobile® monitoring system showed statistically significant superiority (p <0.05) compared to the conventional 24-hour Holter monitor in the etiological diagnosis of palpitations and dizziness in a selected group of patients. It must be borne in mind that this is a relatively young population and the study needs to be extended to a larger number of patients to generalize these conclusions. The main limitation of the KardiaMobile® device is that it requires minimal skills in terms of using a smartphone, so this tool is not extensible to any patient profile.

Clinical Implications of Atrial Fibrillation Detection Using Wearable Devices in Patients With Cryptogenic Stroke (CANDLE-AF) Trial: Design and Rationale.

BackgroundAlthough many electrocardiography wearable devices have been released recently for the detection of atrial fibrillation (AF), there are few studies reporting prospective data for wearable devices compared to the strategy of the existing guidelines in the detection of atrial fibrillation (AF) after cryptogenic stroke. A tiny single-patch monitor is more convenient than a conventional Holter monitor recording device and, therefore, longer duration of monitoring may be acceptable.Methods and DesignThe CANDLE-AF study is a multicenter, prospective, randomized controlled trial. Patients with transient ischemic attack or ischemic stroke without any history of AF will be enrolled. The superiority of the 72-h single-patch monitor to standard strategy and non-inferiority of the 72-h single-patch monitor to an event-recorder-type device will be investigated. Single-patch monitor arm will repeat monitoring at 1, 3, 6, and 12 months, event-recorder-type arm will repeat monitoring twice daily for 12 months. The enrollment goal is a total of 600 patients, and the primary outcome is the detection of AF which continues at least 30 s during study period. The secondary outcome is the rate of changes from antiplatelet to anticoagulant and major adverse cardiac and cerebrovascular events within 1 year.ConclusionsThe results of CANDLE-AF will clarify the role of a single-lead patch ECG for the early detection of AF in patients with acute ischemic stroke. In addition, the secondary outcome will be analyzed to determine whether more sensitive AF detection can affect the prognosis and if further device development is meaningful. (cris.nih.go.kr KCT0005592).

Cardiac Ambulatory Monitoring: New Wireless Device Validated Against Conventional Holter Monitoring in a Case Series.

Background: Cardiac arrhythmias are very common but underdiagnosed due to their transient and asymptomatic nature. An optimization of arrhythmia detection would permit to better treat patients and could substantially reduce morbidity and mortality. The SmartCardia ScaAI wireless patch is a novel CE IIa approved, single-lead electrocardiographic (ECG) ambulatory monitor designed for cardiac arrhythmias detection.Hypothesis: The accuracy of the new SmartCardia wireless patch to detect arrhythmias is comparable to the conventional Holter monitoring.Methods: Patients referred for a suspicion of arrhythmia between February and March 2020 were included in the trial. Simultaneous ambulatory ECG were recorded using a conventional 24-h Holter and the SmartCardia. The primary endpoint was the detection of cardiac arrhythmias over the total wear time of the devices, defined as premature atrial contraction (PAC), supraventricular tachycardia ≥3 beats, premature ventricular contraction (PVC), and ventricular tachycardia ≥3 beats. Conduction abnormalities, pause ≥2 s and atrioventricular block (AVB), were also tracked. McNemar's test was used to compare the matched pairs of data from both devices.Results: A total of 40 patients were included in the trial. Over the total wear time, there was no significant difference between the devices for ventricular and supraventricular arrhythmias detection. Pauses and AVB were equally identified by the two devices in three patients.Conclusion: Over the total wear time, the SmartCardia device showed an accuracy to detect arrhythmia similar to the 24-h Holter monitoring: single-lead, adhesive-patch monitoring might become an interesting alternative to the conventional Holter monitoring.

Economic evaluation of extended electrocardiogram monitoring for atrial fibrillation in patients with cryptogenic stroke.

Timely identification of occult atrial fibrillation following cryptogenic stroke facilitates consideration of oral anticoagulation therapy. Extended electrocardiography monitoring beyond 24 to 48 h Holter monitoring improves atrial fibrillation detection rates, yet uncertainty remains due to upfront costs and the projected long-term benefit. We sought to determine the cost-effectiveness of three electrocardiography monitoring strategies in detecting atrial fibrillation after cryptogenic stroke. A decision-analytic Markov model was used to project the costs and outcomes of three different electrocardiography monitoring strategies (i.e. 30-day electrocardiography monitoring, three-year implantable loop recorder monitoring, and conventional Holter monitoring) in acute stroke survivors without previously documented atrial fibrillation. The lifetime discounted costs and quality-adjusted life years were $206,385 and 7.77 quality-adjusted life years for conventional monitoring, $207,080 and 7.79 quality-adjusted life years for 30-day extended electrocardiography monitoring, and $210,728 and 7.88 quality-adjusted life years for the implantable loop recorder strategy. Additional quality-adjusted life years could be attained at a more favorable incremental cost per quality-adjusted life year with the implantable loop recorder strategy, compared with the 30-day electrocardiography monitoring strategy, thereby eliminating the 30-day strategy by extended dominance. The implantable loop recorder strategy was associated with an incremental cost per quality-adjusted life year gained of $40,796 compared with conventional monitoring. One-way sensitivity analyses indicated that the model was most sensitive to the rate of recurrent ischemic stroke. An implantable loop recorder strategy for detection of occult atrial fibrillation in patients with cryptogenic stroke is more economically attractive than 30-day electrocardiography monitoring compared to conventional monitoring and is associated with a cost per quality-adjusted life year gained in the range of other publicly funded therapies. The value proposition is improved when considering patients at the highest risk of recurrent ischemic stroke. However, the implantable loop recorder strategy is associated with increased health care costs, and the opportunity cost of wide scale implementation must be considered.

Cost-Effectiveness of Extended Electrocardiogram Monitoring for Atrial Fibrillation After Stroke: A Systematic Review.

Management of cryptogenic stroke involves the identification of modifiable risk factors, such as atrial fibrillation (AF). Extended rhythm monitoring increases AF detection rates but at an increased device cost compared with conventional Holter monitoring. The objective of the study was to identify and synthesize the existing literature on the cost-effectiveness of prolonged rhythm monitoring devices for AF detection in cryptogenic stroke. We conducted a systematic review of available economic evaluations of prolonged ECG monitoring for AF detection following cryptogenic stroke compared with standard care. Of the 530 unique citations, 8 studies assessed the cost-utility of prolonged ECG monitoring compared with standard care following cryptogenic stroke. The prolonged ECG monitoring strategies included 7-day ambulatory monitoring, 30-day external loop recorders or intermittent ECG monitoring, and implantable loop recorders. The majority of cost-utility analyses reported incremental cost-effectiveness ratios below $50 000 per QALY gained; and two studies reported a cost-savings. There is limited economic literature on the cost-effectiveness of extended ECG monitoring devices for detection of atrial fibrillation in cryptogenic stroke. In patients with cryptogenic stroke, extended ECG monitoring for AF detection may be economically attractive when traditional willingness-to-pay thresholds are adopted. However, there was substantial variation in the reported ICERs. The direct comparison of cost-effectiveness across technologies is limited by heterogeneity in modeling assumptions.

NOVEL INVESTIGATIVE TOOLS IN PATIENTS WITH SUSPECTED INHERITED HEART RHYTHM DISORDERS

Patients with inherited heart rhythm disorders (IHRD) attend regional specialty clinics to undergo a series of cardiac investigations, including ECG, Holter monitor, and exercise tests. Cardiac patch monitors may help reduce the burden of hospital-based testing and extend the ability to capture ambient arrhythmias, changes in heart rate with daily activities and physiologic exercise. We compared home-based patch monitoring to conventional Holter monitoring and exercise testing. Patients assessed at St. Paul’s Hospital from the BC Inherited Arrhythmia Clinic (catchment 4.6 million persons) underwent single ECG lead patch monitoring for seven days (Icentia CardioSTAT device) in a prospective feasibility study, compared to conventional testing modalities. Corrected QT intervals were measured and calculated according to Bazett’s formula. 39 patients underwent seven-day patch monitoring (median age 44 years (range 15-70), 61% male). In a follow-up interview, 76% of patients expressed satisfaction and preferred the device over Holter monitor. The median duration of monitoring was 7.0 days (range 2.0-7.3), with 12% noise during the first 24-hours (median 176 minutes, range 25min-12h). All but one patient was in sinus rhythm throughout (one patient with known atrial fibrillation). The median HR, PAC and PVC burden, and supraventricular and ventricular runs are reported, with strong correlations in all variables between monitoring modalities, except for PVC burden and supraventricular runs (Table). Patch monitors demonstrated variability in ectopic burden over seven days (PACs: 114±451 over 24-hours vs. 161±527 over seven days; PVCs: 388±942 over 24-hours vs. 428±972 over seven days). Compared to the median PAC and PVC burden over seven days, Holter monitoring under- or overestimated ectopy by over 20% in 84% of cases (PAC variation: median 7%, range -100 to +43,000%; PVC variation: median 33%, range -100 to +867%). Corrected QT intervals correlated across monitoring modalities at rest (Figure, Pearson Correlation 0.781 and 0.776), but demonstrated poor correlation at peak heart rate compared to exercise testing (Pearson Correlation 0.098 and 0.161). Most patients (82%) did not reach 85% of the age-predicted maximum heart rate on the patch monitor. The cardiac patch monitor is a reliable option in the diagnostic work-up of patients with suspected IHRD, with basic measurements consistent with other devices. The burden of PACs and PVCs varies significantly day-to-day, and prolonged monitoring may provide for more reliable quantification and improved arrhythmia detection in patients with suspected IHRD. QTc measurements were reproducible at rest, but correlation at peak heart rates was poor and requires further investigation.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Loop Recorder Implantation: Keeping up with the Guidelines with a Single-Centre Experience

Introduction: Implantable loop recorders (ILR) have a retrospective memory which continuously records the patient's ECG. Patients with infrequent short duration symptoms are unlikely to be diagnosed by conventional Holter monitoring. ILR devices have become smaller and simpler to implant, allowing for improved arrhythmia detection rates. However, the most recent guidelines for ILR devices were last updated in 2009. Methods: The aim of this audit was to review the indications and outcomes for ILR devices at the Lyell McEwin Hospital. 88 consecutive ILR devices inserted from May 2014 – July 2015 and case notes were retrospectively reviewed. Follow-up was 18 - 32 months. Results: 88 ILRs were implanted with the indications of syncope (n = 43), palpitations (n = 27), stroke (n = 7), pre-syncope (n = 2), bradycardia (n = 2), hypertrophic cardiomyopathy (n = 1) and unknown indication (n = 6). 41% (n = 36) of patients received a diagnosis as a result of the ILR. 21% (n = 19) had an indication for device therapy. 9% (n = 8) were treated with an electrophysiological ablation, and 10% (n = 9) were treated medically. 86% (n = 31) of ‘diagnostic’ ILRs were inserted for investigation of either ‘syncope’ or ‘palpitations’. 59% (n = 52) of patients did not have an arrhythmia identified. 20% (n = 11) of these had the ILR removed. 41% (n = 36) are having on-going follow-up, and 6% (n = 4) were lost to follow-up. 92% of these patients (n = 48) had no recurrent symptoms after the ILR was inserted. Discussion: With improved availability of ILR devices, the diagnostic yield still compares favourably with previous pooled data when utilising the current ILR insertion guidelines.

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

BackgroundCardiac 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. MethodsA 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. ResultsOver 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). ConclusionsOver 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.

A Wearable ECG Acquisition System With Compact Planar-Fashionable Circuit Board-Based Shirt

A wearable electrocardiogram (ECG) acquisition system implemented with planar-fashionable circuit board (P-FCB)-based shirt is presented. The proposed system removes cumbersome wires from conventional Holter monitor system for convenience. Dry electrodes screen-printed directly on fabric enables long-term monitoring without skin irritation. The ECG monitoring shirt exploits a monitoring chip with a group of electrodes around the body, and both the electrodes and the interconnection are implemented using P-FCB to enhance wearability and to lower production cost. The characteristics of P-FCB electrode are shown, and the prototype hardware is implemented to successfully verify the proposed concept.

Indications for the use of diagnostic implantable and external ECG loop recorders

ECG loop recorders have a retrospective (loop) memory which continuously records and deletes the patient's ECG. They include a patient-activation function that allows the patient to activate ECG storage as a result of symptoms and an auto-activation feature that allows the capture of arrhythmic events without relying on patient compliance or perception of symptoms. Loop recorder devices can be both implantable (ILR) and external (ELR). Table 1 summarizes the characteristics of the most common diagnostic loop recorders. The retrospective memory differentiates loop recorders from prospective-only event recorders. While event recorders have some usefulness in patients with intermittent palpitations, they have no indication to detect syncope. View this table: Table 1 Most common implantable and external loop recorders Knowledge of what occurs during a spontaneous event is the ideal gold standard for evaluation. Patients with infrequent short-duration transient symptoms, recurring over weeks or months, are unlikely to be diagnosed by conventional Holter monitoring, since the likelihood of symptom-ECG correlation is very low. Consideration should be given to patient-activated event recording in such patients, but this technique has important limitations that might prevent a successful ECG recording of the event, especially for those with syncope, as it implies the activation of recording by the patients once the patient has already recovered consciousness. In such circumstances, consideration should be given to implantable and external ECG loop recorders. It is likely that loop recorders will become increasingly important, and their use will increasingly be appropriate instead of, or before, many current conventional investigations. This early loop recorder approach implies, on the one hand, the need for careful initial risk stratification in order to exclude from such a strategy patients with potential life-threatening conditions that require immediate hospitalization or intensive evaluation and treatment. On the other hand, as a general rule ECG loop recorders are indicated only when there is …

Feasibility of an implantable arrhythmia monitor.

Conventional Holter monitoring is of limited benefit in patients with infrequent symptoms suspected to be related to arrhythmia. A small recorder implanted subcutaneously might obviate many limitations of conventional monitoring. To determine the feasibility of obtaining adequate electrocardiographic signals from such a device, a prototype was temporarily implanted in 17 patients undergoing pacemaker implantation. The prototype contained four disc-shaped titanium electrodes, 0.21 inches in diameter embedded in epoxy. The four electrodes were in a square configuration spaced 0.72 inches center to center and were placed face down in a subcutaneous pocket in the left pectoral region. Bipolar recordings were made from a horizontal pair, a vertical pair, and both diagonal paris of electrodes (interelectrode distance 1.02 inches) and recorded on electromagnetic tape after filtering at 0.5-250 Hz. The mean peak-to-peak amplitude in each configuration was determined over a five-beat interval. Clear recordings were obtained from all 17 patients with recognizable P, QRS, and T waves. The amplitude of the signals obtained from the diagonal pairs of electrodes (175 +/- 51 and 170 +/- 54 microV) were greater than obtained from either the vertical pair (142 +/- 62 microV, P = 0.08 compared to diagonal electrodes) or the horizontal pair of electrodes (105 +/- 54 microV, P < 0.01). The maximum amplitude recorded from any configuration was 189 +/- 54 microV. In six patients the device was also tested with the electrodes face up in the subcutaneous pocket.(ABSTRACT TRUNCATED AT 250 WORDS)

A new method for recording a three-lead electrocardiogram using a two-channel Holter system.

A technique for recording a three-lead electrocardiogram (ECG) without increasing the number of channels and electrodes in a commercially available two-channel Holter recorder was devised. On channel 1, a V5-like lead (CM5 lead) was recorded for 24 consecutive hours. On channel 2, the device could switch continuously between a V2-like lead (CM2 lead) and a II- or III- or a VF-like lead (CMf lead) every 30 sec. Fifty eight patients with angina pectoris were studied using this new device. There were 2 patients with variant angina pectoris, one of whom showed ST elevation in the CM2 lead coupled with ST depression in the CMf lead and the other ST elevation in the CMf lead coupled with ST depression in the CM2 lead. The number of patients having ST depression confined to the CM5 lead only, CM2 lead only and CMf lead only was 17, 2 and 3, respectively. In 41 patients, 127 transient episodes of ischemic type ST changes were observed during daily activity. Only 35 (28%) of these episodes were associated with anginal symptoms and the remaining 92 episodes occurred unrelated to such symptoms. Accordingly, 3-lead Holter monitoring using this device is useful, particularly for the detection of variant angina, and makes it less likely for asymptomatic ischemic ST changes to be overlooked as compared to the 2-lead conventional Holter monitoring system.

A clinical evaluation of an improved Holter monitoring technique for artificial pacemaker function.

This paper discusses shortcomings of conventional Holter monitoring in paced patients and describes a new technique which permits reliable detection of intermittent pacemaker malfunction and counts pacemaker activity during the recording period. Evaluation of the system of 64 consecutive patients revealed 15 with unsuspected episodic pacemaker dysfunction.