Standard ECG Recordings Research Articles

Predicting Spontaneous Termination of Atrial Fibrillation Based on Analysis of Standard Electrocardiograms: ASystematic Review.

Forward prediction of atrial fibrillation (AF) termination is a challenging technical problem of increasing significance due to rising AF presentations to emergency departments worldwide. The ability to non-invasively predict which AF episodes will terminate has important implications in terms of clinical decision-making surrounding treatment and admission, with subsequent impacts on hospital capacity and the economic cost of AF hospitalizations. MEDLINE, EMCare, CINAHL, CENTRAL, and SCOPUS were searched on 29 July 2023 for articles where an attempt to predict AF termination was made using standard surface ECG recordings. The final review included 35 articles. Signal processing techniques fit into three broad categories including machine learning (n = 14), entropy analysis (n = 12), and time-frequency/frequency analysis (n = 9). Retrospectively processed ECG data was used in all studies with no prospective validation studies. Most studies (n = 33) utilized the same ECG database, which included recordings that either terminated within 1 min or continued for over 1 h. There was no significant difference in accuracy between groups (H(2) = 0.058, p-value = 0.971). Only one study assessed recordings earlier than several minutes preceding termination, achieving 92% accuracy using the central 10 s of paroxysmal episodes lasting up to 174. No studies attempted to forward predict AF termination in real-time, representing an opportunity for novel prospective validation studies. Multiple signal processing techniques have proven accurate in predicting AF termination utilizing ECG recordings sourced from a database retrospectively.

Autonomic Dysfunction and Cardiovascular Risk in Patients with Rheumatoid Arthritis: Can Heart Rate Variability Analysis Contribute to a Better Evaluation of the Cardiovascular Profile of a Patient?

(1) Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease of autoimmune etiology. Increased scientific evidence suggests that immune-mediated inflammatory dis-eases are associated with autonomic nervous system (ANS) dysfunction. Studies proved that autonomic imbalance is correlated with RA evolution and may explain augmented cardiovascular pathology and mortality not attributable to classical risk factors. (2) Methods: 75 patients (25 males, 50 females) with RA were submitted to standard ECG recording and 24 h Holter monitoring. Twenty-five healthy patients were used as controls. Both time (SDNN, SDANN, SDANN Index, RRmed, rMSSD, and pNN50) and frequency domain (TP, VLF, HF, LF and LF/HF) heart rate variability (HRV) parameters were obtained. Parameters were compared to controls, and correlations with the QTc-interval and inflammatory status expressed through the C-reactive protein (CRP) were evaluated. (3) Results: In patients with a CRP > 5 mg/L, HRV parameters were lower compared to controls and to patients with a CRP ≤ 5 mg/L. All HRV parameters generated by Holter monitoring are negatively correlated with CRP levels and QTc values. The number of premature ventricular contractions (PVC) recorded is correlated with SDNN, SDANN, and LF/HF values. (4) Conclusions: Our study supports recent data suggesting that in RA there is an autonomic system dysfunction strongly connected with the inflammatory status of the patient. The autonomic dysfunction can contribute to the increased risk of cardiovascular death observed in patients with RA.

Efficacy of Radiofrequency Catheter Ablation versus Antiarrhythmic Drugs in Treating High Burden Premature Ventricular Contractions in Children with Structurally Normal Heart

Abstract Background Scarce literature on whether antiarrhythmic drugs (AADs) or radiofrequency catheter ablation (RFCA) is more efficacious when treating idiopathic high burden premature ventricular contractions (PVCs) in children with many questions remain unanswered in this age group. Objectives To compare the efficacy of RFCA versus AADs on high burden idiopathic PVCs in children. Methods A total of 60 eligible child ≤18 years with High burden PVCs (≥10% of total beats per day) that were treated by either AADs (group A) or RFCA (group B). Both Baseline and followup clinical symptoms were collected, Physical examination, repeat standard ECG, standard or 12-lead Holter recording, and echocardiography were performed. Results Among RFCA (n = 30) and AADs (n = 30) groups, treatment success was 80.0% and 20.0% respectively, while AADs medications cessation was 73.3% and 26.7% respectively, the differences were statistically significant. Conclusion RFCA appears to be more efficacious than AADs in PVC reduction and consequently AADs medications cessation postablation. Performing RFCA in children with classical mapping and navigation was a safe and highly effective therapeutic option. Abbreviations AADs: antiarrhythmic drugs; BBB: bundle branch block; CCB: calcium channel blocker; ECG: electrocardiogram; LVEDD: left ventricular end-diastolic dimension; LVEF: left ventricular ejection fraction; LVESD: left ventricular end-systolic dimension; LVOT: left ventricular outflow tract; NSVT: non sustained ventricular tachycardia; PVC: premature ventricular contraction; RFCA: radiofrequency catheter ablation; RV: right ventricular/ventricle; RVOT: right ventricular outflow tract

PO-01-202 HEART RATE FRAGMENTATION AS A MARKER OF ALTERED ACTIVITY OF THE AUTONOMIC NERVOUS SYSTEM ACTIVITY : A NOVEL PREDICTOR OF ATRIAL FIBRILLATION OCCURRENCE IN THE GENERAL POPULATION

The dysfunction of the autonomic nervous system (ANS) plays a crucial role in atrial fibrillation (AF). But the meaning of high heart rate variability (HRV) in predicting AF is still under debate. Short-term HRV is conceptually attributed to physiologic vagal tone modulation. But recent data suggest that a component of short-term HRV, called heart rate fragmentation, is related to ANS breakdown. To assess the predictive capacity of novel short-term HRV-derived metrics regarding the occurrence of AF in the general population during long-term follow-up. A cohort study was designed to prospectively assess the predictive value of ANS activity level regarding cardiovascular events and mortality. 1011 subjects aged 65, without history of AF, and with low cardiovascular risk were enrolled in the study. A 17.8-year follow-up was managed. HRV data were acquired by 24-h Holter ECG monitoring at baseline and assessed by frequency and time-domain methods. Heart rate fragmentation using the percentage of inflection points (PIP) and alpha 1-index (using fractal evaluation of NN intervals) were also calculated. AF occurrence during follow-up was registered and defined as a standard 12-lead ECG recording or Holter recording with ≥ 30 s of AF. AF was diagnosed in 123 patients representing a cumulative incidence of 13.4%. Univariate analyses are presented in the Table. The occurrence of AF was independently predicted by the male gender (HR=1.96,95%CI:1.3-2.9,p<0.01), a higher percentage of NN intervals that differ by more than 50 ms from the previous interval (pnn50) (HR=2.01,95%CI:1.3-3.2,p<0.01), an increased percentage of inflection points (HR=2.48,95%CI:1.5-4.2,p<0.01), and a reduced alpha 1 index (HR=1.63,95%CI:1.04-2.55,p<0.01). Given these results, a predictive score was built up based on the 4 independent predictors (Panel A). A predictive score of AF occurrence during the 18-year follow-up was assigned to every patient from 0 to 4. Compared to the group of patients with a score of 0 (Panel B), AF occurrence was progressively increased in patients with a score of 2 (HR=5.93, 95%CI:0.82-43.08, p=0.08), of 3 (HR=12.75, 95%CI:1.75-92.83, p=0.01), and of 4 (HR=22.31, 95%CI:2.98-167.23, p<0.01). Markers of heart rate fragmentation independently predict the AF occurrence in the general population, such as an increased PIP and a reduced alpha 1-index. A clinical predictive score is able de segregate a population at high risk of AF occurrence among the general population.Tabled 1Univariate analysesVariablesHRCI 95%P-valueCLINICAL FEATURESMale gender1.741.22 - 2.48<0.01Hipertension1.741.22 - 2.50<0.01Overweight1.331.04 - 1.700.02Increased PAC burden2.111.31 - 3.41<0.01ANS FEATURESpnn501.841.28 - 2.64<0.01RMSSD1.901.33 - 2.71<0.01LF/HF0.600.39 - 0.940.02PIP2.201.40 - 3.47<0.01Alpha 12.191.54 - 3.12<0.01Deceleration capacity2.001.30 - 3.09<0.01 Open table in a new tab

Remote ECG Monitoring by ECG247 Smart Heart Sensor.

Background Heart rhythm disorders are common and may be associated with serious complications. The quality of the ECG signal is crucial to detect and classify arrhythmias. Most available devices for assessment arrhythmias do not allow for remote monitoring. The Norwegian ECG247 Smart Heart Sensor is a new remote patch monitor developed to simplify the assessment of arrhythmias. This study was aimed at evaluating the quality of the ECG signal from the ECG247 Smart Heart Sensor compared to standard 12-lead ECG. Methods ECG recordings with ECG247 Smart Heart Sensor and a standard 12-lead ECG recorder were performed in 97 volunteers at Sorlandet Hospital, Arendal, Norway, in 2019. All ECGs were analysed by two independent cardiologists. Results A total of 97 participants (53% men, age 48 (±14) years) were included in the study. The ability for both systems to use recorded ECG data for arrhythmia detection was good (100%). The quality of the P-wave (mean score 1.1 vs. 1.5) and the QRS complex (mean score 1.0 vs. 1.0) from the ECG247 Smart Heart Sensor and that from the 12-lead ECG were comparable (scale: 1: extremely good, 9: not accepted). Noise artefacts were a minor issue in all recordings. Conclusions The ECG quality from the ECG247 Smart Heart Sensor was comparable to the ECG quality from the standard 12-lead ECG. The ECG247 Smart Heart Sensor may enable easy and remote diagnostics of heart rhythm disorders. This trial is registered with NCT04700865.

QT Interval Prolongation in Patients with Systemic Sclerosis-Are the Holter ECG Recordings a Better Option for QT Interval Evaluation?

Background and Objectives: Cardiac involvement in systemic sclerosis has important consequences on patient survival. Myocardial fibrosis and microcirculation involvement can generate arrhythmic complications, which can be associated with a higher death risk. QT interval prolongation is considered as a risk factor for ectopic ventricular events and can be evaluated using standard short ECG recordings or 24-h Holter ECG recordings. Materials and Methods: 39 patients with systemic sclerosis were submitted to a standard ECG recording at admission and 24-h Holter ECG monitoring. Results: QT interval values resulted from Holter ECG monitoring are higher than the values generated by the short-term ECG recordings. Holter ECG monitoring permits the detection of ventricular ectopy in patients with no events on standard ECG. Conclusions: In patients with systemic sclerosis, 24-h Holter ECG recordings can realize a more precise evaluation of the extent of QTc interval prolongation and ventricular ectopic events associated with myocardial involvement.

The Role of Telecardiology in Dealing with Patients with Cardiac Rhythm Disorders in Family Medicine - Systematic Review.

PurposeHeart rhythm disorders (HRD) are often present in patients visiting their family physician (FP). Dealing with their problems is not always simple, efficient and cost effective. The aim of this paper is to review the existing literature about the use and experience of telecardiology in patients experiencing HRD.MethodsWe conducted a review of literature in PubMed biographical databases (MeSH thesaurus), Web of Science and Cochrane, between 1995 and 2019. We included original articles in English that describe the use of telecardiology at primary and secondary healthcare levels. Exclusion criteria are those publications that discuss heart failure or observation of the activity of pacemakers or defibrillators and the age of patients under 18 years. A total of 19 papers met the inclusion criteria, thirteen of them were original scientific articles and we included them in the analysis.ResultsUse of telemedicine can shorten the time from diagnosis to the necessary treatment (2/13), telemedicine can reduce mortality in patients with acute myocardial infarction (4/13), it can shorten the time to diagnose atrial fibrillations (4/13), it can help determine the diagnosis for patients complaining about heart rhythm disorders which were not detected on the standard ECG recording (2/13) and can also help identify cardiac causes for syncope or collapse (2/13). All studies have confirmed that the use of telecardiology significantly reduces the number of unnecessary referrals to a cardiologist or hospitalization, and shortens the time needed to treat patients with life-threatening conditions.ConclusionThe use of telecardiological techniques increases the quality and safety of work in managing patients with cardiovascular disease in FP practice. Usage of telecardiologic devices can also save money and bridge the gap between the primary and secondary healthcare levels.

Dependence of QT (QTc) interval duration on the blood pressure level in patients with arterial hypertension

Introduction. Arterial hypertension is associated with electric instability of the myocardium and the development of fatal ventricular arrhythmias. One of the main causes for the electric instability of the myocardium is the in homogeneity of the ventricular repolarization processes, which can be estimated by studying QT interval duration and dispersion. Objectives.To study the dependence of QT interval (QTc) duration on the level of blood pressure in patients with arterial hypertension using a standard ECG recording and an ambulatory ECG monitoring. Materials and methods. Were examined147 patients, 124 of which with arterial hypertension and 23 without arterial hypertension. Patients were divided into 5 groups according to their blood pressure level: group 1 – normal or elevated blood pressure on a background of antihypertensive therapy: 56 patients (38.1 %), group 2 –grade 1 hypertension; 39 patients (26, 5 %), group 3 –grade 2 hypertension: 22 patients (15 %), group 4 –grade 3 hypertension: 7 patients (4.8 %), the fifth group – normal or elevated pressure: 23 patients, which is 15.6 % (comparison group, without arterial hypertension). The study of the dependence of QT interval (QTc) duration on the level of BP was carried out according to the analysis of the data of standard ECG, ECG Holter monitoring and 24-hour blood pressure monitoring. Results. A statistically significant regression dependence of the duration of minimal nocturnal QT intervals and corrected QTc on the stage of arterial hypertension in groups 1 and 4 with p &lt; 0.05 was establishedon the basis of Student’s t-test for independent samples. Conclusions. There was a statistically significant regression dependence of the minimum QT interval at night and the minimum corrected interval QTc at night on the daily level of variability 1 of systolic blood pressure, which indicates a direct dependence of the QT interval and QTc on blood pressure.

Long-term prognosis of patients with J-wave syndrome

ObjectiveLimited data are currently available regarding the long-term prognosis of patients with J-wave syndrome (JWS). The aim of this study was to investigate the long-term prognosis of patients with JWS...

Differences in Brugada Syndrome Patients Through Ventricular Repolarization Analysis During Sleep.

Brugada syndrome (BS) is a genetic pathology that might cause sudden cardiac death (SCD) in patients with a structurally normal heart. Repolarization disorders have been postulated as a potential substrate for triggering cardiac arrhythmia in BS, that usually occur at rest or during sleep. In this paper, we have characterized ventricular repolarization markers during sleep on patients suffering from BS. To this end, standard 12-lead ECG recordings were analyzed in a population of 110 BS patients (25 symptomatic). The QT and the T-wave peak to T-wave end intervals (respectively QT and Tpe) were assessed from lead V5. The linear relationship between these markers and the instantaneous heart rate period (RR interval) are determined during each hour and for the whole sleep period. From the models obtained, corrected QT and Tpe measures were then estimated for each patient at 60 beats/min (QT60 and Tpe60) and at the mean heart rate observed during the involved time interval (QTHR and TpeHR). Results show larger values for symptomatic patients in all markers, with significant differences with respect to the asymptomatic group in the case of Tpe (Tpe60: p = 0.0012; TpeHR: p = 0.0014). Moreover, the temporal profiles of these markers reveal major differences among BS subgroups during the last 3 hours of sleep, where symptomatic patients presented increased QT60/HR (p = 0.01) and Tpe60/HR (p <; 0.001), as compared to the initial sleep hours. We conclude that BS patients present different repolarization properties according to their symptomatology, especially during the final stage of sleep.

Evaluation of the diagnostic accuracy of smartphone electrocardiogram recorder compared to standard 12 lead electrocardiography in hospital settings

Objectives: To evaluate Smartphone-based Electrocardiogram Recorders (S-ECG-R) diagnostic accuracy compared to standard 12 lead ECG. Methods: A cross-sectional comparative study was conducted in a tertiary cardiac center in Riyadh, Kingdom of Saudi Arabia from December 2017 to February 2018. A total of 403 patients underwent both standard 12 leads ECG and S-ECG-R recordings in the same time. All recordings were checked initially by an electrophysiologist to confirm the accurate diagnosis. Then, the 806 recordings were randomly distributed among 6 certified cardiologists to interpret the rhythms and to evaluate rhythms quality. Results: In this study 211 (52%) males and 192 (48%) females were included, with a mean age of 52±18 years. Of the included rhythms,149 (37%) were abnormal. The majority of which were atrial fibrillation 46 (11%), sinus tachycardia 35 (9%) and premature ventricular contractions 33 (8%). Analysis revealed an overall similar diagnostic sensitivity and specificity of S-ECG-R to the standard 12 lead ECG recording, sensitivity (97.3% versus (vs) 98%) and specificity (99.6% vs. 99.6%). However, cardiologists were more confident during interpreting standard ECG recordings in 91% of the recordings while in 71% of S-ECG-R recordings. Conclusion: The ECG rhythms produced by smartphone accessory have a good diagnostic accuracy in diagnosing arrhythmias. The utility of using S-ECG-R for out-patient is to be determined. Saudi Med J 2019; Vol. 40 (6): 575-581 doi: 10.15537/smj.2019.6.24206 How to cite this article: Towhari J, Masud N, Alanazi H. Evaluation of the diagnostic accuracy of smartphone electrocardiogram recorder compared to standard 12 lead electrocardiography in hospital settings . Saudi Med J 2019; 40 (6): 575-581. doi: 10.15537/smj.2019.6.24206.

Advanced techniques in ECG

Over the course of nearly a century, the 12-lead ECG has proven to be a valuable investigation in the diagnosis and assessment of a wide range of conditions. Like all tests, it has limitations. However, in certain circumstances, and in relation to particular conditions, modification of the standard ECG recording procedure can greatly increase the diagnostic value of the test. The authors look at how modified chest electrode positions and an ajmaline provocation test can unmask Brugada syndrome that is not evident from the standard ECG; how high-resolution signal-averaged ECGs may reveal late ventricular potentials that suggest an increased risk of malignant arrhythmias or the presence of arrhythmogenic right ventricular cardiomyopathy; and how multi-site body surface mapping may prove to be of value, particularly when combined with cardiac imaging, in elucidating the origin, and guiding the curative treatment, of certain arrhythmias.

Heart rate turbulence after ventricular premature beats in healthy Doberman pinschers and those with dilated cardiomyopathy

ObjectivesTo describe the measurement of heart rate turbulence (HRT) after ventricular premature beats and compare HRT in healthy Doberman pinschers and those with dilated cardiomyopathy (DCM), with and without congestive heart failure (CHF). AnimalsSixty-five client-owned Dobermans: 20 healthy (NORMAL), 31 with preclinical DCM and 14 with DCM and CHF (DCM + CHF). MethodsA retrospective study of data retrieved from clinical records and ambulatory ECG (Holter) archives, including data collected previously for a large-scale prospective study of Dobermans with preclinical DCM. Holter data were reanalysed quantitatively, including conventional time-domain heart rate variability and the HRT parameters turbulence onset and turbulence slope. ResultsHeart rate turbulence could be measured in 58/65 dogs. Six Holter recordings had inadequate ventricular premature contractions (VPCs) and one exhibited VPCs too similar to sinus morphology. Heart rate turbulence parameter, turbulence onset, was significantly reduced in DCM dogs, whereas conventional heart rate variability measures were not. Heart rate variability and HRT markers were reduced in DCM + CHF dogs as expected. ConclusionsHeart rate turbulence can be measured from the majority of good quality standard canine 24-hour Holter recordings with >5 VPCs. Turbulence onset is significantly reduced in Dobermans with preclinical DCM which indicates vagal withdrawal early in the course of disease. Heart rate turbulence is a powerful prognostic indicator in human cardiac disease which can be measured from standard 24-hour ambulatory ECG (Holter) recordings using appropriate computer software. Further studies are warranted to assess whether HRT may be of prognostic value in dogs with preclinical DCM and in other canine cardiac disease.

Use of AliveCor Heart Monitor for Heart Rate and Rhythm Evaluation in Dairy Water Buffalo Calves (Bubalis Bubalis)

Smartphone-based ECG recording devices are a promising new diagnostic in veterinary medicine. However, these devices have not yet been demonstrated to work in water buffalo. A commercial, non-invasive, smartphone-based ECG (AliveCor Vet TM) monitoring device was field tested on water buffalo calves. Six neonatal water buffalo calves had an ECG simultaneously recorded with a standard medical ECG recorder and the AliveCor Vet device. A correlation of 0.75053 was observed between average heart rates obtained between AliveCor recordings when compared to those from the 6 lead ECG. 100% Rhythm agreement was met for all 12 recordings. The recordings of 4/6 calves most closely resembled lead aVR, recordings of 2/6 calves more closely resembled lead II. No significant difference was observed between standard and AliveCor quality scores (P=0.3632). We conclude that the AliveCor device allows for accurate rate diagnosis, and accurate diagnosis of a normal sinus rhythm in neonatal diary water buffalo calves in a field setting

Electrocardiogram reconstruction from high resolution voltage optical mapping.

Electrocardiogram recordings during opucal mapping experiments in heart tissue are commonly used tu monitor the health of the preparation and to obtain dominant frequencies during arrhythmic and defibrillatory studies. However the use of ECG reconstructed from optical mapping is seldom used and to date it has not been strictly validated. In this manuscript we present the first detailed validation and comparison of Optical Mapping ECG, or OM-ECG, with standard ECG recordings by calculating the electrostatic potential in space as a function of the voltage measured optically and describe the different approximations that can be used to obtain unipolar or bipolar ECG recordings. We found that in small/medium hearts, such as rabbits, leads that are aligned apex to base only require activation recording from one surface (anterior or posterior) for the OM-ECG to match the ECG while leads aligned left to right may require both an anterior and posterior optical mapping recording. The discrepancy between leads is due to symmetries in the ventricular activations. In the case of ischemic hearts where activations even-out more, the match between the OM-ECG and standard ECG may require only one surface recording for both left-right and base-apex leads. We believe that this methodology has two main and direct applications in the study of cardiac dynamics. The first is during studies of defibrillation where information after the shock may be crucial in the development of new strategies, OM-ECGs do not suffer the current artifacts of standard ECGs during shocks and can be calculated during the entire activation. We present examples in rabbit ventricles where even low amplitude pacing artifacts are captured by the ECG but do not appear in the OM-ECG. The second use of this technique is for reconstructions of intramural dynamics in larger hearts where differences between the ECG and OM-ECG obtained from anterior and posterior recordings can be used to derive the intramural activation.

Towards the clinical use of concentric electrodes in ECG recordings: influence of ring dimensions and electrode position

To overcome the limited spatial resolution of standard 12-lead ECG recordings, concentric ring electrodes (CRE) have been proposed to provide valuable data for the diagnosis of a wide range of cardiac abnormalities, including infarction and arrhythmia. Although theoretical studies indicate that the dimensions of the CRE regulate the depth of the electric dipoles sensed by these electrodes, this has not been experimentally confirmed. The aim of this work was to analyze the influence of CRE dimensions and position of a wireless multi-CRE sensor node on the cardiac signal recorded. For this, four wireless multichannel ECG recording nodes based on flexible multi-ring electrodes were placed at positions CMV1 (position comparable to V1), CMV2, CMV4R and CMV5; each node providing three bipolar concentric ECG signals (BC-ECG). Standard 12-lead ECG and 12 BC-ECG signals were recorded in 29 volunteers. The results revealed that a ring with an outer diameter of 33.5 mm achieves a balance between the ease-of-use and spatial resolution of smaller electrodes and improved detectability and higher amplitudes of signals from larger ring electrodes. Although a standard 12-lead ECG outperforms BC-ECC recordings in detectability of cardiac waves, if the relative amplitude of the wave is also considered, BC-ECG at CMV1 proved superior at picking up atrial activity. In fact, in most of the BC-ECG signals picked up at CMV1, P1 and P2 atrial activity waves were more clearly identified than in simultaneous 12-Lead ECG signals. Likewise, BC-ECG signals revealed higher spatial resolution in detecting anomalous electrical activity in local regions, such as impaired intraventricular driving, or atrioventricular blocks. Finally, the wireless multi-CRE sensor node provides enhanced comfort and handling to both patient and clinician over wired systems.

Dynamic changes of repolarization abnormalities in takotsubo cardiomyopathy

Objective This study analyses dynamic changes in dispersion of ventricular repolarization over the time course of takotsubo cardiomyopathy (TC), and their relationships with clinical features and life-threatening arrhythmias.Methods and results All consecutive patients admitted to our division between January 2008 and December 2011 with a diagnosis of TC were analysed. Patients with prior myocardial infarction, symptoms-onset-to-admission time greater than 12 hours, an implanted pacemaker, or under treatment with drugs aff ecting QT interval, were excluded. Standard 12-lead ECG recordings during the acute, subacute and chronic phases were collected for each patient. Twentyfour patients (23 women, 63 ± 14 years) were included in our analysis. Only one patient experienced ventricular arrhythmias (4.2%). Signifi cant increases were observed in QT and QTc intervals (from 420 ± 423 to 505 ± 66 ms, P < 0.00001, and from 479 ± 33 to 551 ± 51 ms, P < 0.00001, respectively), QT dispersion (from 59 ± 18 to 100 ± 44 ms, P = 0.0006), Tpeak-to-Tend (from 82 ± 20 to 123 ± 39 ms, P = 0.00006) and Tpeak-to-Tend/QT (from 0.20 ± 0.33 to 0.26 ± 0.57, P = 0.0003) during the subacute phase. All these parameters returned to baseline values in the chronic phase and did not show any signifi cant diff erences between the acute and chronic phases.Conclusions A marked increase in QTc, QT dispersion, Tpeak-to-Tend and Tpeak-to-Tend/QT was observed during the subacute phase; this increase was transient and reverted in all patients before hospital discharge. Of note, these fi ndings were not associated with an increased risk of life-threatening arrhythmias.

Abstract 17230: Respiratory Sinus Arrhythmia Quantified from Standard ECG for Risk Stratification of Post-Infarction Patients

Objectives: Respiratory sinus arrhythmia (RSA) reflects modulation of the sinoatrial node discharge frequency by the autonomic nervous system. Impaired autonomic function is associated with adverse outcome in cardiac patients. We developed a method for calculating RSA from standard ECG recordings and investigated its association with mortality in survivors of acute myocardial infarction. Methods: Consecutive patients (n=941, mean age 61 years, 19% female) presenting with acute myocardial infarction and sinus rhythm were enrolled between May 2000 and March 2005 and followed up until August 2010. The main study outcome was 5-year all-cause mortality. Patients underwent 30-minute ECG recordings. Auxiliary respiratory muscle activity derived from high pass-filtered ECG signal was used to define respiratory phase. The influence of expiration on RR intervals (RRI) was assessed by bivariate phase-rectified signal averaging (PRSA), and RSA PRSA was quantified by Haar wavelet analysis. RSA PRSA ≤0 was defined as abnormal. Results: During the follow-up, 72 patients died. Five-year mortality rates in patients with normal and abnormal RSA PRSA were 4% and 14%, respectively. Under univariable analysis, RSA PRSA was a significant predictor of death (p&lt;0.001), as were GRACE score (p&lt;0.001), LVEF (p&lt;0.001), and the presence of diabetes mellitus (p&lt;0.001). Under multivariable analysis, RSA PRSA , GRACE score, LVEF, and diabetes mellitus were independently and significantly associated with outcome. Conclusions: Respiratory sinus arrhythmia, quantified by bivariate PRSA from standard ECG recordings, is an independent predictor of mortality risk in post-infarction patients.

96 hours ECG monitoring for patients with ischemic cryptogenic stroke or transient ischaemic attack

Atrial fibrillation (AF) is intermittent in 30% of patients with cardioembolic stroke and, therefore, might not be seen in a single standard ECG recording. The aim of this study was to evaluate if prolonged ECG monitoring (96h) finds episodes of intermittent AF beyond the 24h ECG monitoring in patients with cryptogenic stroke or transient ischemic attack (TIA). We prospectively evaluated consecutive patients affected by cryptogenic stroke or TIA who had sinus rhythm on a 12-lead ECG on admission, and during ECG monitoring performed in the acute phase (for at least 24h). Patients had continuous 96h Holter ECG monitoring within 30days from stroke onset. 114 patients were included in the study (mean age 63.1±15.1, 59 males). AF was found in 29 patients (24.3%). In 20 patients, AF was found in the first 24h of recording, and in nine patients after 24h. In addition, several other dysrhythmias such as supraventricular ectopic activity (33), ventricular tachycardia (10), sinus pause (4) and sinus-atrial block (1) were found. In patients with cryptogenic stroke or TIA, 96h ECG monitoring detected a high rate of AF. One-third of AF was seen beyond 24h of ECG monitoring.

The acute effects of palonosetron on ECG parameters in patients with cancer.

e19693 Background: Serotonin receptor (5HT3) antagonists like dolasetron, ondansetron, granisetron and tropisetron have shown to cause QT prolongation. However, there is few data about palonosetron-related cardiac side effects. In this study, we aimed to determine the acute effects of palonosetron on QT interval, heart rate and arterial blood pressure. Methods: 101 cancer patients (51 female, 50 male) were enrolled to the study. Pts with acute ischemic heart disease and arrhythmia were excluded. Pts received 0.25 mg of palonosetron for prevention of chemotherapy-induced emesis. Standard 12-lead ECG recordings, heart rate (HR) and blood pressure (BP) measurements were performed at baseline, 30 minutes and 60 minutes after the palonosetron administration. By using Bazzet Formula, corrected QT interval (QTc) and QT dispersion (QTd) were calculated. Results: The mean age of pts was 54 ±13 years. In whole patient group, there were no differences in QTc, QTd measurements at 30 and 60 minutes after palonosetron injection when compared to baseline measurements. However, HR significantly decreased at 30 and 60 minutes after palonosetron injection. Compared with the baseline, systolic BP decreased nonsignificantly at 30 minute and then returned to baseline levels at 60 minute after palonosetron administration. When body surface area was taken into consideration, patients who received palonosetron over a dose of 0.13 mg/m2 had a decrease of QTc, HR and systolic BP at 30 minute and increase of these parameters at 60 minute. Conclusions: Palonosetron does not cause QT prolongation in standard doses, but causes a decrease in heart rate. Although there is no significant risk of QT prolongation with palonosetron, caution should be taken when QT prolonging drugs are used concomitantly and in patients with long QT syndrome. The routine administration of the drug at a fixed dose without any adjustment for body weight and body surface area can increase the risk of cardiac side effects in lean patients.