Arrhythmia surveillance by transtelephonic monitoring: comparison with Holter monitoring in symptomatic ambulatory patients

Efficacy of diagnostic tools for detecting cardiac arrhythmias: systematic literature search

BACKGROUND/OBJECTIVES

Symptoms suggestive of cardiac arrhythmias are a challenge to the diagnosis. Physical examination and a 12-lead ECG are of limited value, as rhythm disturbances are frequently of a paroxysmal nature. New technologies facilitate a more accurate diagnosis. The objective of this study was to review the medical literature in an effort to define a guide to rational diagnostic testing.

METHODS

Primary studies on the use of a diagnostic tool in the evaluation of palpitations were searched in MEDLINE, and EMBASE with an additional reference check.

RESULTS

TWO TYPES OF STUDIES WERE FOUND: descriptive and experimental studies, which compared the yield of two or more devices or diagnostic strategies. Holter monitors seemed to have less diagnostic yield (33 to 35%) than event recorders. Automatically triggered recorders detect more arrhythmias (72 to 80%) than patient-triggered devices (17 to 75%). Implantable devices are used for prolonged monitoring periods in patients with infrequent symptoms or unexplained syncope.

CONCLUSION

The choice of the device depends on the characteristics of the symptoms and the patient. Due to methodological shortcomings of the included studies no evidence-based diagnostic strategy can be proposed. (Neth Heart J 2010;18:543-51.).

The real value of the transtelephonic ECG system in the clinical cardiological practice

A szerzők ismertetik a transztelefonos EKG-rendszer alapelveit és ennek alkalmazási lehetőségeit a kardiológiai klinikai gyakorlatban. A rendszer alapeleme a kisméretű felvevőegység, melynek révén tetszés szerinti telefonrendszeren keresztül lehet a jelet a fogadó- és irányítóközpontba küldeni. A rendszer használata előnyös heveny kardiológiai esetekben, angina pectoris szindrómában, szívritmuszavarokban és a kardiológiai gondozás keretében (rehabilitáció, pacemaker-ellenőrzés). Ismertetik a nemzetközi gyakorlat eddigi legfontosabb eredményeit és bemutatják a hazánkban működő rendszert.

Palpitations and cardiac awareness after heart transplantation

OBJECTIVE

The aim of this study was to examine the awareness of resting heartbeat in heart transplantation recipients, compare it with that found in other medical populations, and determine whether clinical characteristics are associated with accurate heartbeat awareness.

METHODS

Eligible patients underwent a research battery consisting of a heartbeat detection task and self-report questionnaires assessing cardiac symptoms, psychosocial variables, and cognitive function. The accurate awareness of resting heartbeat was determined by presenting the patients with auditory stimuli at each of six different delays following the R wave on the ECG. Patients then selected the tones that they thought coincided with the sensation they had of their heart beating. The patients' physicians rated their cardiac morbidity. The results were contrasted with comparable data obtained in previous work with other ambulatory medical populations.

RESULTS

Forty-one consecutive heart transplantation recipients who survived for at least 3 months after surgery were eligible. Thirty-four (82.9%) of them were studied and complete data were obtained on 26 (63.4%). Nine patients (34.6%) were reliably able to detect their resting heartbeat. When compared with the 17 patients who were not accurately aware of their heartbeat, the two groups did not differ significantly in cardiac morbidity, cognitive brain dysfunction, generalized psychiatric distress, depression, somatization, or hypochondriacal attitudes. A significantly higher proportion of heart transplantation recipients were accurately aware of their heartbeat than was found in a sample of general medical outpatients and in asymptomatic, nonpatient volunteers.

CONCLUSIONS

One-third of heart transplant recipients are accurately aware of resting heartbeat, despite the absence of cardiac innervation.

Trans-telephonic electrocardiographic monitoring--experience in India

A centre for trans-telephonic electrocardiographic monitoring (TTEM) was established at the Escorts Heart Institute in May 1996. We have reviewed our experience in the first 398 patients. There were 321 males (81%) and 77 females (19%); their age range was 1 month to 95 years. Sixty-five per cent of patients were from New Delhi, while the remainder were from other cities in India and abroad. As well as follow-up of patients after discharge, the system was used for the evaluation of chest pain, palpitation, chronic angina, arrhythmias, and pacemaker implants. Out of 664 symptomatic transmissions, 510 (77%) were for cardiac symptoms like chest pain (309), palpitation (90), uneasiness (61), dizziness (28) and breathlessness (22); the other 154 (23) were for non-cardiac symptoms like stitch pain and backache (51), typical chest pain (39), weakness and fever (45), and sweating (19). The majority of patients with chest pain (84%), palpitation (78%) and dizziness (75%) transmitted their electrocardiograms within one hour of the onset of the symptoms. Out of 664 symptomatic transmissions, 531 required either reassurance or drug-dose adjustment by telephone and 97 were called to the outpatient department on an elective basis. Immediate hospitalization was advised for 36 patients, for acute management of their symptoms. TTEM was useful in avoiding 628 unnecessary visits to the hospital, while 36 patients were immediately hospitalized for acute care.

The CB-12L: a new device for transtelephonic transmission of a 12-lead electrocardiogram

The value of transtelephonic transmission of ECG information is well established, and technological advances have continuously provided improved state-of-the-art equipment. Shahal Medical Services provides professional care to subscribers who call the medical center and describe their symptoms, whereupon therapeutic measures are decided upon. A new 12-lead patient controlled device for telephonically transmitting an ECG (GB-12L) has become available; the aim of this study was to evaluate its accuracy and practicability. Forty tracings (20 standard ECG tracings obtained under medical supervision in the physician's office and 20 by the patient in his home using the new CB-12L ECG device and transmitted by telephone to the center) from 20 subjects with various electrocardiographic pathologies were reviewed by 19 experienced physicians who were asked to interpret the results and identify the recording device. In 82% of the possibilities, the interpretation of the tracings was identical for both those recorded by the standard ECG recorder and the CB-12L ECG. An equal number of physicians could not identify the means by which device the tracings were taken. Proper placement of the electrodes did not prove to be a problem for the patient. Thus, the CB-12L ECG was found to be an easily operable and reliable tool which may be of value for early and prompt diagnosis of threatening cardiac situations in the prehospital setting.

Ambulatory patient-activated arrhythmia monitoring: comparison of a new wrist-applied monitor with a conventional precordial device

A wrist-applied transtelephonic device (WrTTD) and a precordial (PrTTD) patient-activated transtelephonic electrocardiographic (ECG) recorder were compared objectively (quality of ECG traces) and subjectively (device preference) in a prospective randomized crossover study of 24 patients. All underwent cardioversion for chronic atrial fibrillation and were then randomized to each device for 1 month. The ECG traces were sent weekly with additional traces if symptomatic. Self-administered questionnaires were completed after 1 month with each device, and the first five telemetered ECG traces for each patient were blindly assessed by two experienced cardiologists. Although the QRS complexes were smaller with the WrTTD (P < .001), the quality of the traces was similar. In particular, there was no significant difference in number of nondiagnostic traces, ability to detect atrial activity, degree of baseline fluctuation, or amount of artifact. Overall, patients preferred the PrTTD (P = .02). Patients found the PrTTD easier to use (P = .007) and were able to apply it more rapidly (P = .02). The quality of ECG traces obtained from the upper limbs by using a wrist-applied transtelephonic device was concluded to be comparable with those obtained by direct precordial application. In order to increase patient acceptability of the former, further improvements to simplify its operation are necessary.

Evaluation and outcomes of patients with palpitations

PURPOSE

To determine: (1) the etiologies of palpitations, (2) the usefulness of diagnostic tests in determining the etiologies of palpitations, and (3) the outcomes of patients with palpitations.

PATIENTS AND METHODS

One hundred and ninety consecutive patients presenting with a complaint of palpitations at a university medical center were enrolled in this prospective cohort study. Patients underwent a structured clinical interview and psychiatric screening. The charts were abstracted for results of the physical exam and tests ordered by the primary physician. Assignment of an etiology of palpitations was based on strict adherence to predetermined criteria and achieved by consensus of the two physician investigators. One-year follow-up was obtained in 96% of the patients.

RESULTS

An etiology of palpitations was determined in 84% of the patients. The etiology of palpitations was cardiac in 43%, psychiatric in 31%, miscellaneous in 10%, and unknown in 16%. Forty percent of the etiologies could be determined with the history and physical examination, an electrocardiogram, and/or laboratory data. The 1-year mortality rate was 1.6% (95% confidence interval [CI] 0% to 3.4%) and the 1-year stroke rate was 1.1% (95% CI 0% to 2.6%). Within the first year, 75% of the patients experienced recurrent palpitations. At 1-year follow-up, 89% reported that their health was the same or improved compared to that at enrollment, 19% reported that their work performance was impaired, 12% reported that workdays were missed, and 33% reported accomplishing less than usual work at home.

CONCLUSIONS

The etiology of palpitations can often be diagnosed with a simple initial evaluation. Psychiatric illness accounts for the etiology in nearly one third of all patients. The short-term prognosis of patients with palpitations is excellent with low rates of death and stroke at 1 year, but there is a high rate of recurrence of symptoms and a moderate impact on productivity.

Approach to the patient with palpitations

Palpitations are a common complaint present in up to 16% of outpatients. They are nonspecific and in only 15% of patients do they correlate with a cardiac arrhythmia. The significance of palpitations is related to the presence or absence of underlying cardiac disease, the clinical setting in which palpitations occur, and the characteristics and severity of symptoms. This article presents a concise approach to the evaluation of the ambulatory patient with palpitations.

Evaluation of the reliability of ST segment monitoring by transtelephonic electrocardiogram transmission

INTRODUCTION

Transtelephonic electrocardiographic transmission is a diagnostic technique which has been systematically applied in recent years, mainly for the detection of arrhythmias or pacemaker malfunction. The purpose of this study was to assess the efficacy of this method in the recording and transmission of ST segment and T wave changes.

METHOD

A Bruce protocol exercise stress test was carried out in 47 consecutive patients (39 males, eight females, age 53.1 +/- 11.5 years) with suspected coronary artery disease (CAD). At the same time, a transtelephonic ECG system, with a 2-min memory and the capability for 16.5 days continuous recording, was used to transmit the ECG (modified leads II and V5).

RESULTS

A positive ST segment shift was observed in 19 patients (40.4%) during the exercise test. The transtelephonic system recorded this change in 18 of these patients but missed the anteroseptal ST segment depression (V2-V4) in one patient (sensitivity 94.7%). All of the 23 patients with no ST segment changes during the exercise test had a negative transtelephonic ECG transmission (specificity 100%). The width of the ST depression recorded from modified lead II on the transtelephonic recording was not significantly different from that of the 12-lead ECG. The same was true for modified lead V5.

CONCLUSION

Transtelephonic ECG transmission in patients with suspected CAD can significantly contribute to the investigation of this problem, since the method has high sensitivity and specificity. The capacity for continuous recording and the memory of the device make possible the monitoring of high risk patients for a good length of time.

The accuracy of symptom reporting by patients complaining of palpitations

PURPOSE

To examine the relationship between patients' reports of palpitations and documented arrhythmias.

PATIENTS AND METHODS

Consecutive patients complaining of palpitations and referred for 24-hour ambulatory electrocardiographic monitoring were studied using self-report questionnaires and a structured diagnostic interview. Electrocardiographic results were subsequently analyzed in conjunction with symptom diaries. Positive predictive value was used to estimate the likelihood that a reported symptom coincided with a documented arrhythmia. Sensitivity was calculated as a measure of the likelihood that an arrhythmia would be detected and reported as a symptom.

RESULTS

Positive predictive value was inversely related to somatization, hypochondriacal attitudes, and psychiatric symptoms. It was not related to chronicity of palpitations, previously diagnosed heart disease, more extensive medical care utilization, or clinically significant arrhythmias. Patients were generally insensitive to their arrhythmias, failing to note the vast majority.

CONCLUSIONS

Somatizing and hypochondriacal patients are not more sensitive to or accurately aware of subtle changes in cardiac activity, but rather may be expressing a response bias toward reporting somatic and psychologic distress in general. Apparently, patients do not learn to discriminate and detect cardiac activity more accurately as a result of having more medical care or suffering longer with their symptoms.

Ambulatory arrhythmia screening in symptomatic children and young adults: comparative effectiveness of Holter and telephone event recordings

Effective initial identification of potential cardiac arrhythmias in symptomatic children is difficult due to the infrequency, brief duration, and vague nature of subjective complaints in the young. Although both telephone event and Holter monitoring are used for this purpose, no comparative studies of the initial screening efficacy of either have been performed. A total of 202 consecutive symptomatic children (age 11 days to 26 years, mean 10.2 years) were evaluated for potential cardiac arrhythmias with either 24-h Holter (97 patients) or telephone event (105 patients) recorders and grouped according to the presence or absence of congenital heart defects, normal or abnormal resting electrocardiogram (ECG), and presence or absence of cardiac surgery. The results showed 30% of all recordings (61% event; 14% Holter) failed to substantiate any arrhythmias in spite of subjective symptoms. Event recordings showed a better correlation of sensed symptoms with arrhythmias (32%) compared to Holters (5%) (p < 0.01) with 73% of Holter recordings performed during both asymptomatic and arrhythmia-free 24-h periods. Holter monitoring was more effective in detecting nonsensed and asymptomatic events (8% versus 0.5%, (p < 0.01), among high-risk children. This study demonstrates that although both monitoring devices are applicable to children, each has inherent limitations and usefulness. These must be considered in choosing either device to permit their most optimal and cost-effective application.

Optimum duration of transtelephonic ECG monitoring when used for transient symptomatic event detection

Transtelephonic electrocardiographic monitoring (TTM) has been used for postpacemaker follow-up study, postmyocardial infarction monitoring, and transient symptomatic event detection (TSED). For postpacemaker follow-up study, TTM is continued indefinitely. For postmyocardial infarction monitoring, TTM is continued for 1 year or more. For TSED, the appropriate duration for TTM has not yet been adequately assessed. Accordingly, the authors determined the yield, by week, of TTM for TSED. Five thousand fifty-two patients who made 20,590 calls were analyzed for this investigation. Ninety-five percent of patients making symptomatic calls or making a call in which an arrhythmia was documented did so within 5 weeks. Shorter periods would sacrifice yield, longer periods may not be cost-effective.

Diagnostic utility of memory equipped transtelephonic monitors

The diagnostic utility of memory-equipped transtelephonic electrocardiographic monitors was evaluated in a series of 31 patients referred for evaluation of unexplained syncope (16), presyncope (8), or palpitations (7). Previous nondiagnostic workups included 4 +/- 1 days (mean +/- standard error of the mean) of 24-hour Holter and/or in-hospital telemetric monitoring per patient. The duration of monitoring averaged 31 +/- 2 days per patient. Electrocardiographic recordings were made during a typical symptom episode in 9 of 31 (29%) patients, including 0 of 16 with syncope, 3 of 8 (37%) with presyncope, and 6 of 7 (86%) with palpitations (p less than .001). The probability of recording typical symptoms was strongly influenced by their previous frequency. Potentially causal arrhythmias were documented in 5 of 7 (71%) patients with palpitations, but in none of the other symptom subgroups (p less than .001). Monitoring led to changes in therapy in only two patients. During followup of 9 +/- 1 months, symptoms continued in 4 of 16 (25%) with syncope, 7 of 8 (87%) with presyncope, and 7 of 7 (100%) with palpitations (p = .001). The diagnostic utility of these devices thus appears to be low in patients with previously unexplained syncope or presyncope. The yield was high in those monitored for palpitations, which may be in part attributable to the greater frequency of symptoms observed in this group.

Transtelephonic monitoring: documentation of transient cardiac rhythm disturbances

Symptoms suggestive of a transient disturbance in cardiac rhythm often prompt a patient to seek medical help. Transtelephonic monitoring (TTM) can document the rhythm at the exact time that the patient is experiencing clinical symptoms. Our experience with TTM from 1979 to 1983 involved 526 patients who had one or more of the following symptoms: near-syncope (in 121), light-headedness (in 248), intermittent palpitations (in 281), and tachycardia (in 321). Patients suspected of having a life-threatening arrhythmia after the initial history, physical examination, and laboratory testing were excluded from this study. Of the 526 patients, 259 transmitted with the TTM device during a typical symptomatic episode; 186 had an arrhythmia identified, and 73 had a normal cardiac rhythm. The mean duration (+/- SD) from receipt of the TTM system until the first transmission was 48 +/- 80 days. The most frequent diagnoses at transmission were supraventricular tachycardia (in 80 patients) and sinus tachycardia (in 46). This study showed that TTM is effective in documenting infrequent arrhythmias and in establishing the temporal relationship between clinical symptoms and the patient's heart rhythm. TTM is a useful, practical, and efficient addition to more conventional means of electrocardiographic monitoring for patients with non-life-threatening arrhythmias.

Asymptomatic telephone ECG transmissions as an outpatient surveillance system of ventricular arrhythmias: relationship to quantitative ambulatory ECG recordings

Although ambulatory ECG recordings provide quantitative information in the follow-up of patients with ventricular arrhythmias, they are performed infrequently, potentially missing serious arrhythmias in the unmonitored periods. Telephone ECG systems offer "real-time" ECG information, theoretically functioning as an arrhythmia surveillance system. Thus we incorporated frequent telephone ECG transmissions in two antiarrhythmic drug protocols. The first investigation was designed to show the relationship of telephone and ambulatory ECGs in patients with frequent ventricular tachycardia (VT). The second protocol selected patients with "nonlife-threatening" frequent premature ventricular complexes (PVCs) in whom a second placebo period was instituted to simulate the clinical situation of asymptomatic arrhythmia increase. In both drug trials there was a strong linear relationship between the log-transformed PVC counts of telephone ECG and concomitant PVC, couplet, and VT frequencies on ambulatory ECG. In the VT population, greater than or equal to 1 PVC on telephone ECG reflected the presence of VT on ambulatory ECG (sensitivity 87%; specificity 77%). In the second study, telephone ECG transmissions with PVCs on three consecutive transmissions reflected the change from less than or equal to 10 PVCs/hour to greater than or equal to 40 PVCs/hour on ambulatory ECG within 48 hours. These data support the concept that daily surveillance by means of telephone ECG provides arrhythmia information of qualitative clinical relevance.

The impact of transtelephonic documentation of arrhythmia on morbidity and mortality rate in sudden death survivors

A post hospital follow-up system based on predetermined antiarrhythmic strategies and telephone transmitters used to record ECGs was helpful in managing post hospital course and improved survival in patients with a history of out-of-hospital sudden death. All patients underwent therapy guided by serial electrophysiologic testing. Of the 47 patients, 19 used the telephone transmitter system and 28 did not. During follow-up, residual symptomatic and silent ventricular arrhythmia was documented in 78% of patients using telephone transmitters. Ventricular tachycardia was transmitted in six patients--all survived. During an average 15-month follow-up, 1 of 19 patients using the telephone transmitter system died vs 12 deaths among the 28 patients who did not use the system (p less than 0.005). These results were independent of ejection fraction, presence of congestive heart failure, amiodarone therapy, and the outcome on electrophysiologic therapy. Thus, patients with a history of out-of-hospital sudden death, discharged following electrophysiologic guided therapy, require repeated antiarrhythmic dose titration for side effects or residual ventricular arrhythmia. Prompt diagnosis and treatment of potentially fatal arrhythmia is crucial and feasible, especially with regular ECG checks through telephone transmission.

Usefulness of transtelephonic documentation of the electrocardiogram during sporadic symptoms suggestive of cardiac arrhythmias

One hundred patients with sporadically occurring symptoms suggesting cardiac arrhythmias were evaluated with the aid of a transtelephonic electrocardiographic recording device (Cardiomemo). In 83 patients, 124 episodes with symptoms were documented and a correlation with electrocardiographic findings could be established. Forty of these patients (48%) had a cardiac arrhythmia and 43 (52%) had a normal heart rhythm. It appears that, for the assessment of sporadically occurring symptoms, transtelephonic electrocardiographic recording is a valuable supplement to 24-hour ambulatory electrocardiographic monitoring.

Detection of arrhythmia: limited usefulness of patient activated recording devices

The findings of 24 hour ambulatory electrocardiography and monitoring with the Cardiomemo, a device recording 32 seconds of electrocardiogram during symptoms, were compared in 20 patients with symptoms suggestive of arrhythmia. Ambulatory electrocardiography showed arrhythmia in seven patients, extrasystoles in six, and normal findings in seven. Nine patients failed to transmit any Cardiomemo recordings, and the Cardiomemo failed to show ventricular and supraventricular tachycardia. It did not show any appreciable arrhythmia in the seven patients with normal 24 hour electrocardiograms. The Cardiomemo does not offer any important advantages over ambulatory electrocardiography, and its relative cheapness is outweighed by the limited number of patients who can use the device in one year. It can, however, reassure anxious patients of the absence of arrhythmia during symptoms.

Transtelephonic electrocardiographic monitoring: reliability in detecting the ischemic ST segment response during exercise

The ECG detection of ST segment depression during maximal treadmill exercise has diagnostic and prognostic significance in coronary artery disease. This study of 200 consecutive patients undergoing Bruce exercise testing for chest pain documents the ability of a transtelephonic ECG system, capable of storing segments of ECG memory during exercise, to reliably record ST segment depression detected during simultaneous exercise testing (sensitivity 79%; specificity 99.6%). Of the three transtelephonic ECG systems tested, the modified precordial V5 snap-on lead most accurately reflected ST segment amplitude and morphology with no "false positives" (specificity 100%) and few "false negatives" (sensitivity 78%). Therefore, this system is a potentially important clinical tool for accurately and conveniently monitoring coronary patients during exercise outside the hospital (e.g., following myocardial infarction) as well as for providing useful clinical information for ambulatory patients with undiagnosed sporadic chest pain.

[Value of ECG-telephone transmission in determining symptomatic heart-rhythm disorders]

The ECG-telephone-transmission (TTM) was used to record an ECG-strip during a typical symptomatic period in patients complaining of symptoms possibly caused by arrhythmias (palpitations, dizziness, paroxysm tachycardia, pulse irregularities; angina and dyspnea only if other reasons could be excluded). Patients complaining of syncope only were not admitted, because of the inability to make a telephone call successfully during such a symptomatic period. The ECG was transmitted to the CCU using a frequency modulation technique. In 60% of 196 patients an ECG-TTM could be achieved during a typical symptomatic period, whereas arrhythmias as cause for the symptoms could be excluded in 51 patients (26%). The remaining 66 patients (34%) demonstrated various arrhythmias ranging from simple SVPB and PVC to total AV-block and sustained VT. TTM, an easy-to-perform and cost-effective method allowed a successful ECG registration during a symptomatic period in almost two-thirds of symptomatic patients. In these patients arrhythmias could be verified or excluded as cause of the symptoms.

Transtelephonic monitoring in pediatric patients with clinically suspected arrhythmias

Evaluation of patients with symptoms suggestive of cardiac arrhythmias is difficult using standard studies if the episodes are infrequent and have a short duration. Transtelephonic electrocardiographic recorders were provided for 41 patients with suspected arrhythmic episodes. None had previously documented arrhythmia. There were 18 males and 23 females (age range 14 months to 19 years; mean 10.9 years). The interval prior to a diagnostic transmission was 0.5 to 8 months (mean 2.5 months). Twenty-one of 41 patients (51%) provided transmissions during a typical episode, nine of which were abnormal. Paroxysmal supraventricular tachycardia was found in eight patients and unsuspected intermittent complete heart block in one patient. The remaining 12 patients had normal sinus rhythm. Twenty patients did not transmit because episodes either were too brief or did not recur. Transtelephonic monitoring was effective in the diagnosis of certain arrhythmias that are infrequent and short in duration. Normal transmitted electrocardiograms during a typical symptomatic episode excluded cardiac arrhythmias.

Electrocardiogram recording by telephone in antiarrhythmic drug trials

The purpose of this study was to evaluate ECG recording by telephone as a research tool for documenting the cardiac rhythm during symptoms of paroxysmal atrial tachycardia. Eleven patients were enrolled in the study during the first year. They transmitted 34 rhythm strips during symptoms, 17 of which showed paroxysmal atrial tachycardia; only one of the 34 was uninterpretable. Three patients thought they were having paroxysmal atrial tachycardia when their rhythm strips showed that they were having sinus tachycardia. Patient compliance and satisfaction with our follow-up system were high. Our study supports the use of ECG recording by telephone as an excellent tool to document arrhythmias in patients enrolled in clinical trials.