Pacemaker Spike Research Articles

Influence of different electrode placement patterns on electromagnetic interference generated by Left Ventricular Assist Devices (LVADs) during electrocardiogram performance

Abstract Background Heart failure (HF), with an incidence of approximately 3/1000 person-years, often progresses to advanced stages where symptoms persist despite treatment. In such cases, mechanical circulatory assist devices, particularly left ventricular assist devices (LVADs) in ambulatory patients, enhance survival and quality of life. These LVADs generate electromagnetic interference, resulting in noise artefacts in conventional electrocardiograms (ECGs). The conventional ECG should be configured with a low-pass filter of 150 Hz and a high-pass filter of 0.05 Hz, as recommended by the American Heart Association/American College of Cardiology/Heart Rhythm Society. LVADs, such as the HeartMate 3 (Abbott®), typically operate at a rotational speed of 5000 to 6000 rpm, corresponding to oscillatory frequencies of 83.3 to 100 Hz. Objective To assess the impact of various surface electrode placement strategies and modifications to the low-pass filter on the electromagnetic interference produced by LVADs. Methods We conducted an observational study involving seven patients with HeartMate 3 adjusted to various rotational speeds (refer to Table 1). Three distinct electrode placement schemes (AHA, Mason Likar, and modified Torso) were employed for the frontal plane leads. The horizontal plane leads remained unmodified. Each patient underwent a total of 6 ECGs, corresponding to each of the aforementioned schemes. ECG recordings were performed using a high-pass filter set at 0.05 Hz and a low-pass filter set at 150 Hz. Additionally, a set of ECGs was obtained by modifying the low-pass filter to 40 Hz for further analysis. Results Figure 1 displays ECGs obtained from a male with a HeartMate 3 operating at 4600 rpm or 76.6 Hz. This device employs an algorithm to generate an "artificial pulse" by cyclically accelerating and decelerating the pump speed by 2000 rpm every 2 seconds, resulting in rotational speeds of 2600 rpm and 6600 rpm (43.3 Hz and 110 Hz, respectively). No specific placement scheme demonstrated consistent noise reduction across all cases, likely due to inter-individual variability resulting from factors such as the final position of the LVAD the rpm in each case, and the thoracic impedance of each patient. However, the modification of the low-pass filter to 40 Hz yielded a noteworthy improvement in noise reduction across all cases. In our limited sample, this adjustment did not pose issues for ECG interpretation. Nevertheless, it is essential to acknowledge that excessively low filter settings may not only eliminate noise but also potentially discard clinically relevant high-frequency signals (e.g., pacemaker spikes, large amplitude Rs, QRS notches). Conclusions Individualizing the electrode placement scheme is crucial for minimizing noise generated by LVADs. The adjustment of the low-pass filter to 40 Hz could generally prove beneficial in reducing artifact generation, despite the clinical limitations it may entail.

Limitations of Pacemaker Spike Detection in Capacitive ECGs via Deep Learning

Abstract Pacemaker spike detection is an important step in monitoring paced patients. Capacitive ECG facilitates unobtrusive monitoring of subjects during daily routines such as driving. Robust algorithms are required to deal with low signal quality and artifacts, e.g. by employing fusion of multiple signal channels. Due to the low signal-to-noise ratio of the measurement, there are limitations to detection accuracy compared to conventional ECG monitors. Especially low voltage stimulations such as bipolar pacemaker spikes are hard to detect. We present a convolutional network approach to improve on recent signal processing algorithms.We show a realistic evaluation of its performance using leave-one-subject-out cross validation (LOOCV), its dependence on the size of the receptive field, and an estimation of an upper performance bound.

PO-626-01 PERFORMANCE AND ACCURACY OF A SMART WATCH SINGLE-LEAD ECG: A PILOT STUDY

Prior studies have evaluated the accuracy of the Apple Watch single-lead ECG for the detection of atrial fibrillation and other arrhythmias. However, no study to date has analyzed the watch ECG morphology and interval characteristics compared to a standard 12 lead ECG, important in assessing patients on medications and for physician overreads. To analyze the characteristics of single-lead ECGs collected by an Apple Watch compared to a clinical 12 lead ECG. All Mayo Clinic ECG lab patients >18 years old were invited to participate in this study. Participants underwent a 30 second single-lead ECG recording with an Apple Watch Series 5 in a seated position within 5 minutes of 12 lead ECG (12 L). The collected ECGs were manually interpreted by physician staff. PR, QRS, QT intervals were manually calculated, and RR interval determined by computer. Seventy-four patients were included with 12 L ECG and Apple Watch ECG pairs. The cohort was 44.6% female (N=33) and 91.6% white (N=68) with an average age of 59.2. Six patients were in atrial fibrillation at the time of recording and six patients had pacemakers. The average differences between 12 L ECG and Apple Watch ECG intervals (in milliseconds) were: PR 23.3 ±18; QRS 18.9 ±16.3; QT 22 ±17.3; RR 79 ±70. Bland-Altman plots were created to visualize interval variation (Figure 1). Eleven patients were excluded from PR interval analysis as P waves were unable to be identified due to absence (i.e. atrial fibrillation) or other conditions (significant AV block, sinus bradycardia, low P amplitude in L I). Apple Watch ECG result interpretation was complicated by 1) aberrant inflection points before and after QRS complexes, 2) attenuation of P waves, 3) disappearance of pacemaker spikes and 4) significant artifact from a patient’s tremor (Figure 2). Apple Watch ECG processing can result in peri-QRS artifact, P-wave amplitude reduction, and pacemaker spike elimination. The Apple Watch single-lead ECG appeared most reliable in determining the QT interval and least reliable in determining the PR interval (Figure 1). The findings suggest that different processing or access to raw, unfiltered Apple Watch data may facilitate expert over-reads of these signals when applied for medical use.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

A case of post-COVID-19 mucormycosis with permanent pacemaker posted for functional endoscopic sinus surgery: Anaesthetic challenges.

Sir, The important perioperative challenges during surgical debridement for post-coronavirus disease (COVID)-19 rhino-orbital-cerebral mucormycosis include difficult airway, uncontrolled diabetes mellitus (DM), side effects of amphotericin B (AmB), presence of other comorbidities and post-COVID-19 systemic abnormalities including a decline in respiratory function.[1] We report the successful management of a patient with post-COVID-19 mucormycosis with a permanent pacemaker in situ posted for functional endoscopic sinus surgery (FESS) under general anaesthesia. A 70-year-old male with post-COVID-19 mucormycosis came with complaints of right-sided facial swelling and pain with nasal blockage. The patient when admitted for COVID-19 was given tablets favipiravir and prednisolone and discharged after 15 days. He had a history of syncopal attacks and was diagnosed as having a heart block 8 years back for which a permanent pacemaker had been inserted [Figure 1]. He was a known case of DM and hypertension, with a blood sugar of 490 mg/dL and urine ketones positive on admission, and was started on insulin to control the blood sugar. The airway examination showed Mallampati classification (MPC) grade 3 with a thyromental distance of 6.5 cm. Oedema and pain present on the maxillary and orbital regions limited the mouth opening. A preoperative arterial blood gas (ABG) analysis showed PaO2 60 mmHg, PaCO2 34 mmHg, and pH 7.4 and six-zone involvement on chest radiograph. The baseline oxygen saturation (SpO2) was 91% (room air) and the baseline heart rate was 70/min and regular. The electrocardiogram (ECG) showed ventricular pacing with wide QRS complexes [Figure 2]. The echocardiography showed degenerative changes with fair left ventricular systolic function (ejection fraction of 60%). The pacemaker was identified as VITATRON A20A1SR (mode VVIR) which was reprogrammed to asynchronous V000 mode prior to surgery. The defibrillator, transcutaneous pacing and crash cart trolley were kept ready. After pre-oxygenation, the patient was induced with intravenous fentanyl 50 μg, thiopentone 250 mg and rocuronium and tracheal intubation were facilitated with a C-MAC video laryngoscope. The patient was maintained on oxygen, nitrous oxide, isoflurane and vecuronium. He was extubated at the end of the procedure and shifted to the post-anaesthesia care unit. The pacemaker was programmed to its initial mode after surgery. The COVID-19 mucormycosis patients with a pacemaker in situ pose several challenges for an anaesthesiologist. Diabetic nephropathy, renal toxicity and electrolyte imbalance associated with inj. AmB are major concerns besides preoperative hypokalaemia, fever and hypotension.[2] Perioperative blood pressure, urine output, renal function and serum electrolyte monitoring is mandatory.Figure 1: Chest radiograph showing six zone involvement and a ventricular pacing systemFigure 2: Pacemaker spike precedes each QRS complex with LBBB, discordant ST segment and T waves- consistent with right ventricular pacingSupraglottic oedema, fungal debris in the oropharyngeal region and palatal perforation can lead to difficult mask ventilation and endotracheal intubation.[3] In our patient, the thyromental distance was less, the MPC was grade 3 and the mouth opening was restricted leading to an anticipated difficult airway. Hence, a C-MAC videolaryngoscope was used. Post-COVID-19 pulmonary fibrosis leads to breathlessness, dyspnoea, cough, fatigue, limited exercise tolerance and an abnormal ABG picture (low PaO2, high PaCO2, low SpO2).[4] The patient on preoperative oxygen therapy can desaturate during the laryngoscopy for which adequate pre-oxygenation and minimum time for laryngoscopy and intubation is the key. Hypoxaemia and hypercapnia can increase the pacing threshold, and thus, lead to the failure of the pacemaker to capture. Mucormycosis may exist with diabetic ketoacidosis and further treatment with AmB can lead to renal toxicity, acid-base and electrolyte disturbances (hypokalaemia, hyperkalaemia, hypomagnesemia) and hypovolaemia, which may precipitate arrhythmias. These conditions can cause perioperative interference with the pacemaker function leading to failure to capture and pacemaker dysfunction.[5] In addition, FESS is in proximity to the pacemaker and requires the use of cautery leading to electromagnetic interference.[6] Similarly, the microdebrider can lead to artefacts in the ECG mimicking ventricular tachycardia and even asystole. Hence, we converted the pacemaker to an asynchronous mode; nonetheless, pacemaker failure in the synchronous and asynchronous modes has been noted leading to hypotension, arrhythmias or cardiac arrest. Thus, a post-COVID-19 case of mucormycosis with suboptimal lung function, compromised airway, uncontrolled diabetes and an artificial cardiac pacemaker, posted for FESS was managed successfully with vigilant perioperative monitoring under general anaesthesia. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Car Seats with Capacitive ECG Electrodes Can Detect Cardiac Pacemaker Spikes

The capacitive electrocardiograph (cECG) has been tested for several measurement scenarios, including hospital beds, car seats and chairs since it was first proposed. The inferior signal quality of the cECG compared to the gold standard ECG guides the ongoing research in the direction of out-of-hospital applications, where unobtrusiveness is sought and high-level diagnostic signal quality is not essential. This study aims to expand the application range of cECG not in terms of the measurement scenario but in the profile of the subjects by including subjects with implanted cardiac pacemakers. Within this study, 20 patients with cardiac pacemakers were recruited during their clinical device follow-up and cECG measurements were conducted using a seat equipped with integrated cECG electrodes. The multichannel cECG recordings of active unipolar and bipolar pacemaker stimulation were analyzed offline and evaluated in terms of scores using a pacemaker spike detection algorithm. scores from 3652 pacing events, varying from 0.62 to 0.78, are presented with influencing parameters in the algorithm and the comparison of cECG channels. By tuning the parameters of the algorithm, different ranges of scores were found as 0.32 to 0.49 and 0.78 to 0.88 for bipolar and unipolar stimulations, respectively. For the first time, this study shows the feasibility of a cECG system allowing health monitoring in daily use on subjects wearing cardiac pacemakers.

The “Better” Answer

The “Better” Answer

Derivation and validation of the Montreal prehospital ST-elevation myocardial infarction activation rule

BackgroundPrehospital ECGs (phECGs) are the main screening tool used by paramedics to identify ST elevation myocardial infarction (STEMI). In the absence of telemetry or personnel trained in ECG interpretation, paramedics must rely on computerized interpretation of phECGs, which suffer from an elevated false-positive (FP) rate, impairing reliable early activation of reperfusion centers by Emergency Medical Services. ObjectiveDevelop a clinical prediction rule to reduce the frequency of FPs for STEMI in prehospital patients. MethodsThis was a retrospective analysis of prehospital patients with a computer interpretation of ‘***ACUTE MI***’ on phECG. We used logistic regression analysis to identify the independent variables for derivation of the rule. Once derived, we validated the rule on a distinct cohort of consecutive phECGs. ResultsAmong the 654 cases in the derivation cohort, 46.2% were FP STEMIs. Four elements emerged as independent FP predictors: HR ≥ 120, no ongoing chest pain, no interpretable ST-segments in a lead, and presence of baseline wander or pacemaker spikes. In the derivation cohort this rule decreased FPs to 15.1% of the total cohort, while labelling 13.8% of STEMI cases as false-negatives (FNs). In the validation cohort (386 phECGs, 41.7% FPs), the rule decreased FPs down to 8.0%, while 25.9% were FN. ConclusionUse of computer interpretation alone leads to a high STEMI FP rate. A clinical prediction rule based upon four elements available to paramedics can substantially lower the proportion of FPs. This clinical prediction rule should be incorporated into the decision for prehospital activation of the cardiac catheterization laboratory.

Lightning-induced pacing system malfunction: a case report.

BackgroundAtmospheric electrical discharge is an extremely powerful natural phenomenon which can have dangerous and lethal effects on the human body. However, there is no evidence to indicate whether and, if so, to what extent the electric current travelling through the body can affect proper pacemaker function.Case summaryAn 80-year-old patient admitted to emergency department after being struck by a lightning bolt while riding a bike. The patient had a DDD pacemaker implanted 4 years prior to the incident. The ECG on admission depicted pacemaker spikes and native sinus rhythm at 50–60 b.p.m. On the 3rd day after admission the patient developed recurrent pacing-induced tachycardia. Pacemaker interrogation showed high pacing thresholds (failure to pace in the atrial channel). When the patient’s condition stabilized she was transferred to the tertiary hospital for transcutaneous lead extraction. The extracted pacing system was sent to Biotronik for thorough evaluation.DiscussionInjuries due to a lightning strike are considered a rare occurrence but being struck by lightning with a pacemaker or an ICD is even less common. In the present case, the cause of cardiac arrhythmia was most probably electrical burn at the endocardial-electrode interface and a sudden elevation of the pacing threshold leading to transient pacing failure in both PM channels. To the best of our knowledge, in this case presentation we first described permanent lightning-induced pacemaker dysfunction.

Quantification of the influence of 0.67 Hz high-pass monitoring filters on the magnitude of the spatial ventricular gradient

A 67 year old female with diabetes mellitus type 2, chronic kidney disease, ischemic cardiomyopathy, status post biventricular implantable cardioverter-defibrillator presented to the Heart Failure clinic for routine follow up with a tachycardia with alternating pacemaker spikes.

A low-pass filter of 300 Hz improved the detection of pacemaker spike on remote and bedside electrocardiogram.

Background:The current upper-frequency cutoff of 150 Hz sometimes causes loss of pacemaker spike and misdiagnosis. We hypothesized that low-pass filter (LPF) other than 150 Hz could improve the detection of pacemaker spike. This study aimed to examine the effect of different LPF on pacemaker spike detection in remote and bedside electrocardiogram (ECG).Methods:Patients with permanent pacemaker implantation were included during routine follow-up. Standard 12-lead ECGs at 6 different upper-frequency cutoff (40, 100, 150, 200, 300, and 400 Hz) were collected. All ECGs were then transmitted to the remote clinic center. Ventricular and atrial pacing were analyzed by 2 independent medical practitioners.Results:A total of 88 patients’ ECGs were analyzed (mean age 73.8 ± 10.2 years and 85 with dual-chamber pacemakers). About 75.3% (64/85) of patients were diagnosed as atrial pacing by pacemaker programming. Among 6 different upper-frequency cutoff, the 300 Hz turned out to perform best in detecting atrial-paced spike (area under the curve [AUC] = 0.73, 95% confidence interval [CI]: 0.61–0.84 vs. 0.56, 95% CI: 0.61–0.84 at 150 Hz; P = 0.002) on bedside ECGs. Using programming as the golden standard, the 300 Hz LPF has a sensitivity of 59.4%, specificity of 85.7%, positive predictive value of 92.7% and negative predictive value of 40.9% on bedside ECGs. As for the ventricular pacing, the 300 Hz LPF also had a higher accuracy (AUC = 0.93; 95% CI = 0.84–1.00) than that at 150 Hz (AUC = 0.86; 95% CI: 0.77–0.94; P < 0.001) in detecting ventricular-paced spike on bedside ECGs. The results of remote ECGs were similar with bedside ECGs.Conclusions:A filter of 300 Hz cutoff may be recommended for ECG spike detection. With the recommended parameter, remote ECG can perform as well as bedside ECG.

Tachycardia with alternating pacemaker spikes: Is it pacemaker malfunction?

A 67 year old female with diabetes mellitus type 2, chronic kidney disease, ischemic cardiomyopathy, status post biventricular implantable cardioverter-defibrillator presented to the Heart Failure clinic for routine follow up with a tachycardia with alternating pacemaker spikes.

A Contactless Sensor for Pacemaker Pulse Detection: Design Hints and Performance Assessment.

Continuous monitoring of pacemaker activity can provide valuable information to improve patients’ follow-up. Concise information is stored in some types of pacemakers, whereas ECG can provide more detailed information, but requires electrodes and cannot be used for continuous monitoring. This study highlights the possibility of a continuous monitoring of pacemaker pulses by sensing magnetic field variations due to the current pulses. This can be achieved by means of a sensor coil positioned near the patient’s thorax without any need for physical contact. A simplified model of coil response to pacemaker pulses is presented in this paper, along with circuits suitable for pulse detection. In vitro tests were carried out using real pacemakers immersed in saline solution; experimental data were used to assess the accuracy of the model and to evaluate the sensor performance. It was found that the coil signal amplitude decreases with increasing distance from the pacemaker lead wire. The sensor was able to easily perform pacemaker spike detection up to a distance of 12 cm from the pacemaker leads. The stimulation rate can be measured in real time with high accuracy. Since any electromagnetic pulse triggers the same coil response, EMI may corrupt sensor measurements and thus should be discriminated.

Critical Care Nurses Cannot "Phone It In".

Critical Care Nurses Cannot "Phone It In".

Late Twiddler’s Syndrome in a Nigerian on a Demand Pacemaker

A 75 year old woman with unipolar ventricular pacemaker presented with cough, difficulty breathing and dizziness. An initial electrocardiogram (ECG) showed atrial fibrillation, incomplete right bundle branch block with no pacemaker spikes. The chest radiograph revealed twisting of the leads at various points. She was managed conservatively with anti-failure drugs and monthly ECG. The pacemaker could not be interrogated due to logistic reasons. However, the ECG during the 8th month of follow-up showed pacemaker spikes and complete left bundle branch block pattern suggestive of spontaneous return of pacemaker function.

Taquicardias de complejo QRS ancho precedidas de espiga de marcapasos

The differential diagnosis and therapeutic management of wide QRS tachycardia preceded by pacemaker spike is presented. The pacemaker-mediated tachycardia, tachycardia fibrillo-flutter in patients with pacemakers, and runaway pacemakers, have a similar surface electrocardiogram, but respond to different therapeutic measures. The tachycardia response to the application of a magnet over the pacemaker could help in the differential diagnosis, and in some cases will be therapeutic, as in the case of a tachycardia-mediated pacemaker. Although these conditions are diagnosed and treated in hospitals with catheterization laboratories using the application programmer over the pacemaker, patients presenting in primary care clinic and emergency forced us to make a diagnosis and treat the haemodynamically unstable patient prior to referral.

Two pacing spikes on the QRS complex in a single-chamber pacemaker

AutoCapture algorithm helps the pacemakers to automatically adjust output close to the pacing threshold. This algorithm monitors the evoked response signal of myocardial depolarization, and delivers a high output back-up pulse if there is a loss of capture. This case, with two pacemaker spikes on the QRS complexes in a patient with VVI pacemaker, simulating a sensing failure, demands clear understanding of AutoCapture function before labeling the pacemaker malfunction.

Common pitfalls in interpreting pacemaker electrocardiograms in the emergency department

The number of patients receiving pacemakers and defibrillators has grown substantially over the last 20 years. In addition, the complexity and sophistication of these devices have increased, making diagnosis of pacemaker problems using the electrocardiogram (ECG) more difficult for clinicians in the emergency department. This article will focus on a few of the pitfalls to be avoided when interpreting paced ECGs. Pacemaker algorithms designed to minimize right ventricular pacing may be confused with pathologic failure to output. Automatic capture threshold detection schemes may be misinterpreted as failure to capture as well as undersensing due to the extra “backup” pacemaker spikes noted on rhythm strips. Device testing done in the emergency department may produce waveforms on monitor resembling ventricular tachycardia if pacemaker-mediated tachycardia is produced accidentally. Ventricular safety pacing algorithms may also be misinterpreted as failure to sense appropriately, triggering questions about pacemaker malfunction. Certain types of true undersensing may resemble morphologies consistent with pacemaker lead dislodgment. In addition, sophisticated programming features designed to mimic normal physiology could be misconstrued as pacemaker malfunction. These include pacemaker hysteresis and sleep mode. The presence of frequent premature ventricular complexes would cause a pacemaker to inhibit ventricular pacing appropriately. However, this could produce a palpated heart rate that is substantially lower than the programmed lower rate of the device due to reduced perfusion by the premature ventricular complexes, again raising questions about the appropriate functioning of the pacemaker. All of these situations will be discussed in detail along with approaches to systematically examining the paced ECGs to minimize the risk of misinterpretation. Pacemaker timing cycles as they relate to troubleshooting of the paced ECG will also be introduced.

Usefulness of Management of Cardiac Pacemaker Implanted Patients by a Portable Electrocardiogram Monitoring System

Purpose: Opportunity has increased difficulty to periodical postoperative management of cardiac pacemaker implanted patients by aging and remote place. Therefore, we verified whether portable ECG monitor system would be effective and useful to these care. Object and Method: Objects are 50 cardiac pacemaker patients. 30 men and 20 women and average age was 76 years old. The implanted pacemaker mode was the various types of VVIR, AAIR, or DODR. Underlying diseases are advanced AV block, sinus bradycardia, bradycardic Af, and SSS. These patients was managed using a portable ECG monitor system to evaluate pacemaker condition et al. Result: The ECG was recorded all cases although noises in some elderly patients followed by acceptable ECG record. Pacemaker spike orrhythm have been certainly recognized by portable ECG as same as cases with 12 leads ECG. Moreover, there was no problem of data transmission with internet by the patient itself. During this study, the case which shows pacing insufficiency and remarkable battery consumption was not seen. Conclusion: Management of the pacemaker implanted patient by a portable ECG monitoring system was very effective and satisfied in accuracy. Frequency of a pacemaker check could probably be reduced from the field of patient satisfaction and convenience of life.

Part 6: Electrical Therapies

The recommendations for electrical therapies described in this section are designed to improve survival from SCA and life-threatening arrhythmias. Whenever defibrillation is attempted, rescuers must coordinate high-quality CPR with defibrillation to minimize interruptions in chest compressions and to ensure immediate resumption of chest compressions after shock delivery. The high first-shock efficacy of newer biphasic defibrillators led to the recommendation of single shocks plus immediate CPR instead of 3-shock sequences that were recommended prior to 2005 to treat VF. Further data are needed to refine recommendations for energy levels for defibrillation and cardioversion using biphasic waveforms.

Part 6: Defibrillation

Part 6: Defibrillation