ECG Response Research Articles

Unconsciously interactive Films in a cinema environment—a demonstrative case study

ABSTRACT‘Many worlds’ is a short narrative live-action film written and directed so as to provide multiple linear routes through the plot to one of four endings, and designed for showing in a cinema environment. At two points during the film, decisions are made based on audience bio-signals as to which plot route to take. The use of bio-signals is to allow the audience to remain immersed in the film, rather than explicitly selecting plot direction. Four audience members have a bio-signal measured sensor for each person: ECG (heart rate), EMG (muscle tension), EEG (‘brain waves’) and Galvanic Skin Response (perspiration). The four are interpreted as a single average of emotional arousal. ‘Many worlds’ was the first live-action linear plotted film to be screened in a cinema to the general public utilizing multiple biosensor types. The film has been shown publically a number of times, and lessons learned from the technical and cinematic production are detailed in this paper.

ECG response to submaximal exercise from the perspective of Golden Ratio harmonic rhythm

Abstract Background The Golden Ratio (GR), derived from the Fibonacci sequences, has multiple representations in nature, as expressions of the repetition of specific geometric shapes called fractals. Methods The aim of the study focused on investigation of the cardiovascular homeostasis, at rest and during effort testing, with determination of the validity of the GR at the level of variables extracted from serial ECG. We used a group of 230 young subjects (average age 19.21 ± 1.87), each subject performing a 6 min submaximal exercise ergometer test (Astrand & Rhyming Protocol). We were interested in estimate the ratio between the electrical diastole and electrical systole (TQ/QT) and between the cardiac cycle and electrical diastole (RR/TQ), which has been much discussed as being related to GR value. Results We proposed using a new synthetic fractal indicator (SFI), with dynamic nonlinear evolution and we determined the intervals of acceptability for SFI. The mean values of the SFI of our subjects were significantly close to GR value, aspect that suggests the presence of harmonic rhythm, under different conditions of existence and adaptation of the human organism (rest and submaximal effort). The SFI and the heart rate values had very strong correlations, at rest (R = 0.88, p Conclusions Our results show a fractal dimension of the ECG interval dynamics for the study group. The proposed SFI imposes itself as a relatively simple parameter for assessing heart’s electrical functionality during cardiac cycle that can be applied both at rest and exercise.

Identification of biotypes in Attention-Deficit/Hyperactivity Disorder, a report from a randomized, controlled trial

Attention-Deficit/Hyperactivity Disorder (ADHD) is a heterogeneous disorder. Current subtypes lack longitudinal stability or prognostic utility. We aimed to identify data-driven biotypes using multiple cognitive measures, then to validate these biotypes using EEG, ECG, and clinical response to atomoxetine as external validators. Study design was a double-blind, randomized, placebo-controlled crossover trial of atomoxetine including 116 subjects ages 6 through 17 with diagnosis of ADHD and 56 typically developing controls. Initial features for unsupervised machine learning included a cognitive battery with 20 measures affected in ADHD. External validators included baseline mechanistic validators (using electroencephalogram/EEG and electrocardiogram/ECG) and clinical response (ADHD Rating Scale and correlation with cognitive change). One biotype, labeled impulsive cognition, was characterized by increased errors of commission and shorter reaction time, had greater EEG slow wave (theta/delta) power and greater resting heart rate. The second biotype, labeled inattentive cognition, was characterized by longer/more variable reaction time and errors of omission, had lower EEG fast wave (beta) power, resting heart rate that did not differ from controls, and a strong correlation (r=−0.447, p<0.001) between clinical response to atomoxetine and improvement in verbal memory immediate recall. ADHD comprises at least two biotypes that cut across current subtype criteria and that may reflect distinct arousal mechanisms. The findings provide evidence that further investigation of cognitive subtypes may be at least as fruitful as symptom checklist-based subtypes for development of biologically-based diagnostics and interventions for ADHD.

ECG Response: May 3, 2016

HomeCirculationVol. 133, No. 18ECG Response: May 3, 2016 Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBECG Response: May 3, 2016 Originally published3 May 2016https://doi.org/10.1161/CIRCULATIONAHA.116.022763Circulation. 2016;133:1827IntroductionECG Challenge: A 34-year-old man with a history of atrioventricular nodal reentrant tachycardia being treated with a β-blocker and verapamil presents to the emergency department with complaints of fatigue and a slow heartrate. A 12-lead ECG is obtained.Download figureDownload PowerPointThe rhythm is irregular as a result of 2 premature QRS complexes (↓). Therefore, the rhythm is regularly irregular. The other QRS complexes are occurring at a regular interval and a rate of 42 bpm. These regular QRS complexes are normal in width (0.08 second) and have a normal morphology and axis between 0° and +90° (positive QRS complex in leads I and aVF). There is a tall R wave in lead V2 (v) that is consistent with early transition or counterclockwise rotation of the electric axis in the horizontal plane. This is determined by imagining the heart as if viewed from under the diaphragm. With counterclockwise rotation, left ventricular forces develop early, and there is a tall R wave in lead V2. The QT/QTc intervals are normal (440/370 milliseconds). No P waves are seen before any of these QRS complexes, but there are P waves after each QRS complex (+) with an inconsistent relationship with the QRS complex; that is, there is a variable RP interval with a gradually prolonging RP interval consistent with retrograde or VA Wenckebach. Although the P wave might be considered to be retrograde resulting from the junctional complex, the P wave is positive in leads I, II, aVF, and V5. Hence, this is a sinus P wave, and there is a stable PP interval (└┘) at a rate of 32 bpm. Therefore, there is atrioventricular dissociation. There are 2 causes of atrioventricular dissociation: complete heart block (with an atrial rate faster than the rate of the QRS complexes) and an accelerated lower pacemaker (atrial rate slower than the rates of the QRS complexes). Thus, this is an accelerated junctional rhythm. The 2 premature QRS complexes are preceded by an on-time P wave (*), and the PR interval is the same (^). Hence, these 2 complexes are captured or conducted. These captured complexes have a right bundle-branch block with an RSR’ morphology in lead V1 (←) and a broad S wave in leads I and V5 (→). The right bundle-branch block is rate related, resulting from the shorter RR interval.FootnotesCorrespondence to Philip J. Podrid, MD, West Roxbury VA Hospital, Section of Cardiology, 1400 VFW Pkwy, West Roxbury, MA 02132. E-mail [email protected] Previous Back to top Next FiguresReferencesRelatedDetails May 3, 2016Vol 133, Issue 18 Advertisement Article InformationMetrics © 2016 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.116.022763PMID: 27143551 Originally publishedMay 3, 2016 PDF download Advertisement

ECG Response: December 22/29, 2015

HomeCirculationVol. 132, No. 25ECG Response: December 22/29, 2015 Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBECG Response: December 22/29, 2015 Originally published22 Dec 2015https://doi.org/10.1161/CIRCULATIONAHA.115.020213Circulation. 2015;132:2423ECG Challenge: A 65-year-old man with a history of hypertension being treated with a β-blocker presents to his physician for a routine physical examination. His pulse is noted to be slower than usual; hence, an ECG is obtained.Download figureDownload PowerPointThere is a regular rhythm at a rate of 48 bpm. The QRS complex duration is normal (0.08 second), and there is a normal morphology, as well as an axis between 0° and 90° (positive QRS complex in leads I and aVF). The QT/QTc intervals are normal (440/390 milliseconds). P waves are seen (+), but there is no relationship to the QRS complexes; that is, there are variable PR intervals. This represents atrioventricular dissociation. The P waves are positive in leads I, II, aVF, and V4 through V6. Hence, there is an underlying sinus rhythm. Most of the PP intervals are constant (└┘) with a rate of 75 bpm. There are 2 causes of atrioventricular dissociation: complete (third-degree) heart block in which the atrial rate is faster than the rate of the QRS complexes or an accelerated lower pacemaker (ie, junctional or ventricular) in which the atrial rate is slower than the rate of the QRS complexes. This is therefore complete heart block, and the escape rhythm is junctional. The etiology of the escape rhythm is not based on the rate of the escape rhythm but it established by the QRS morphology, which in this case is normal. There are 2 longer PP intervals (↔). Each of these longer PP intervals is associated with a QRS complex (third, fourth, and sixth; [v]) that has a slightly different morphology as a result of a negative deflection that is seen after these QRS complexes (^). This represents a retrograde P wave, a result of ventriculoatrial conduction associated with the junctional complex. As a result of retrograde atrial activation, the sinus node is reset, accounting for the long PP interval. Although there is complete atrioventricular block, ventriculoatrial conduction may be seen in up to 40% of cases. This is attributable to different antegrade and retrograde atrioventricular nodal conduction parameters; dual atrioventricular nodal pathways, 1 of which is capable of ventriculoatrial conduction; or the presence of a concealed bypass tract that conducts only in a retrograde fashion.In addition, 2 premature P wave (*) have a morphology that is different from the morphology of the sinus P waves. These are premature atrial complexes that are not conducted, that is, blocked premature atrial complexes. These non conducted P waves can also reset the sinus node automaticity.Please go to the journal’s blog, OpenHeart, for more ECG Challenges: http://goo.gl/tQPNFp. Challenges are posted on Tuesdays and Responses on Wednesdays.FootnotesCorrespondence to Philip J. Podrid, MD, West Roxbury VA Hospital, Section of Cardiology, 1400 VFW Pkwy, West Roxbury, MA 02132. E-mail [email protected] Previous Back to top Next FiguresReferencesRelatedDetailsCited By Kim H, Lee C, Lee H and Yang H EUU FTA (EU's FTA Strategies in Its New Trade Policy Initiatives and Policy Implications), SSRN Electronic Journal, 10.2139/ssrn.2946654 December 1, 2015Vol 132, Issue 25 Advertisement Article InformationMetrics © 2015 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.115.020213PMID: 26700009 Originally publishedDecember 22, 2015 PDF download Advertisement

Prediction of revascularization after myocardial perfusion SPECT by machine learning in a large population

ObjectiveWe aimed to investigate if early revascularization in patients with suspected coronary artery disease can be effectively predicted by integrating clinical data and quantitative image features derived from perfusion SPECT (MPS) by machine learning (ML) approach. Methods713 rest 201Thallium/stress 99mTechnetium MPS studies with correlating invasive angiography with 372 revascularization events (275 PCI/97 CABG) within 90 days after MPS (91% within 30 days) were considered. Transient ischemic dilation, stress combined supine/prone total perfusion deficit (TPD), supine rest and stress TPD, exercise ejection fraction, and end-systolic volume, along with clinical parameters including patient gender, history of hypertension and diabetes mellitus, ST-depression on baseline ECG, ECG and clinical response during stress, and post-ECG probability by boosted ensemble ML algorithm (LogitBoost) to predict revascularization events. These features were selected using an automated feature selection algorithm from all available clinical and quantitative data (33 parameters). Tenfold cross-validation was utilized to train and test the prediction model. The prediction of revascularization by ML algorithm was compared to standalone measures of perfusion and visual analysis by two experienced readers utilizing all imaging, quantitative, and clinical data. ResultsThe sensitivity of machine learning (ML) (73.6% ± 4.3%) for prediction of revascularization was similar to one reader (73.9% ± 4.6%) and standalone measures of perfusion (75.5% ± 4.5%). The specificity of ML (74.7% ± 4.2%) was also better than both expert readers (67.2% ± 4.9% and 66.0% ± 5.0%, P < .05), but was similar to ischemic TPD (68.3% ± 4.9%, P < .05). The receiver operator characteristics areas under curve for ML (0.81 ± 0.02) was similar to reader 1 (0.81 ± 0.02) but superior to reader 2 (0.72 ± 0.02, P < .01) and standalone measure of perfusion (0.77 ± 0.02, P < .01). ConclusionML approach is comparable or better than experienced readers in prediction of the early revascularization after MPS, and is significantly better than standalone measures of perfusion derived from MPS.

ECG Response: September 22, 2015

ECG Response: September 22, 2015

Diagnostic and prognostic significance of ischemic electrocardiographic changes with regadenoson-stress myocardial perfusion imaging

BackgroundThe diagnostic and prognostic value of regadenoson-induced ST-segment depression (ST↓) is not defined. Due to the low incidence of ST↓ ≥1.0 mm with vasodilator stress, a lower threshold to define ischemic ECG response may provide improved clinical utility. MethodsWe conducted a retrospective cohort study of patients who underwent regadenoson-stress SPECT myocardial perfusion imaging (MPI) followed by coronary angiography within 6 months. Ischemic ST↓ was defined as ≥0.5 mm. The prevalence of angiographically severe coronary artery disease (CAD) and the rates of major adverse cardiac events (MACE) including cardiac death, myocardial infarction, and coronary revascularization were determined. ResultsIn a diagnostic cohort of 629 subjects, 117 (18.6%) had ST↓ ≥0.5 mm. Severe CAD was more prevalent in the ST↓ ≥0.5 vs ST <0.5 group (13.7% vs 5.3%, P = .001). Among patients with normal MPI (n = 229), the prevalence of severe CAD was higher in the ST↓ ≥0.5 group (8.2% vs 2.2%, P = .04). Adjusting for clinical and imaging covariates, ST↓ ≥0.5 mm was independently predictive of severe CAD [odds ratio = 3.37, 95% confidence interval (CI) = 1.67-6.83, P = .001], and provided incremental diagnostic value (Chi square increment = 10.3, P = .001). In an outcome cohort of 748 subjects, after adjusting for clinical and imaging covariates, ST↓ ≥0.5 mm was associated with increased MACE rate in the entire cohort [hazard ratio = 1.41, CI 1.01-1.96, P = .04] and in the subgroup of patients with normal MPI [hazard ratio = 2.2, CI 1.11-4.39, P = .02], and provided incremental prognostic value (Chi square increment = 3.9, P = .049). A diagnostic ST↓ threshold of 0.5 mm provided greater discriminatory capacity than a 1.0 mm cutoff (P = .03). ConclusionsAmong patients selected to undergo coronary angiography, regadenoson-induced ST↓ ≥0.5 mm was associated with higher rates of severe CAD and MACE, irrespective of MPI finding.

ECG Response: July 21, 2015

ECG Response: July 21, 2015

ECG Response: January 27, 2015

HomeCirculationVol. 131, No. 4ECG Response: January 27, 2015 Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBECG Response: January 27, 2015 Originally published27 Jan 2015https://doi.org/10.1161/CIRCULATIONAHA.114.014806Circulation. 2015;131:427–428ECG Challenge: A 75-year-old man has a history of hypertension associated with left ventricular hypertrophy and also coronary artery disease. He has not undergone any previous intervention but has chronic stable angina. He presents to his cardiologist for a routine follow-up. He has no complaints. His physical examination is normal. As part of his visit an ECG is obtained.Download figureDownload PowerPointThere is a regular rhythm at a rate of 60 beats per minute. The QRS complexes have 2 different morphologies. The first 3 QRS complexes are wide (0.12 sec) and have a right bundle-branch block morphology with an RSR’ complex in lead V1 (←) and a terminal S wave in leads I and V5 (↑). The axis of these QRS complexes is extremely leftward between −30° and −90° (positive QRS complex in lead I and negative QRS complex in leads II and aVF). This left axis may be attributable to either an old inferior wall myocardial infarction in which the negative complex is the result of a deep Q wave in leads II and aVF, or a left anterior fascicular block in which there is an rS morphology in leads II and aVF. Hence this is a left anterior fascicular block. Along with the right bundle-branch block this indicates bifascicular block or disease. The next 6 complexes are also wide (0.12 sec) but they have a left bundle-branch block morphology with a QS complex in lead V1 (→) and a broad R wave in lead V5-V6 (↓). Because there is an underlying sinus rhythm with a stable rhythm and rate, this reflects the presence of conduction abnormalities effecting both bundle branches and it has been termed bibundle-branch block, a manifestation of trifascicular disease. The QT/QTc intervals are normal (400/400 ms). There is a P wave before each QRS complex and it is positive in leads I, II, aVF, and V4–V6. Hence there is a normal sinus rhythm. However, the PR intervals are not constant. The QRS complex with a right bundle-branch block has a longer PR interval (0.24 sec; └┘) compared with the PR interval of 0.20 sec (↔) associated with the QRS complex that has a left bundle-branch block. The likely explanation is that conduction through only the left bundle (which occurs when there is a right bundle-branch block) is slower than conduction through only the right bundle (which occurs when there is a left bundle-branch block).Please go to the journal’s blog, OpenHeart, for more ECG Challenges: http://goo.gl/tQPNFp. Challenges are posted on Tuesdays and Responses on Wednesdays.FootnotesCorrespondence to Philip J. Podrid, MD, West Roxbury VA Hospital, Section of Cardiology, 1400 VFW Parkway, West Roxbury, MA 02132. E-mail [email protected] Previous Back to top Next FiguresReferencesRelatedDetails January 27, 2015Vol 131, Issue 4 Advertisement Article InformationMetrics © 2015 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.114.014806PMID: 25623125 Originally publishedJanuary 27, 2015 PDF download Advertisement SubjectsElectrocardiology (ECG)

Workload from Nuclear Power Plant Task Types Across Repeated Sessions

Nuclear Power Plant (NPP) operators complete multiple types of tasks within Emergency Operating Procedures (EOPs). Due to the potential serious consequences of committing an error, it is important to determine if the workload (WL) demands operators encounter are at acceptable levels. This study investigates whether there are workload differences are distinct between task types and if there is a difference between each task type over multiple sessions in a simulated environment. Previous research supports that EEG, ECG, and the NASA-TLX are sensitive to changes in WL. The present preliminary experiment sought to investigate WL changes for experienced participants over a number of sessions and task types. During each session, participants completed tasks derived from a combination of EOPs and subject matter expert input that consisted of checking, detection, and response implementation task types. WL changes were measured through EEG, ECG, and NASA-TLX responses. The results indicate that WL differences were found among the different task types, but not sessions. The implications for these findings are discussed in detail.

ECG Response: July 1, 2014

ECG Response: July 1, 2014

Association of Changes in Fitness and Body Composition with Cancer Mortality in Men

Both baseline cardiorespiratory fitness and adiposity predict the risk of cancer mortality. However, the effects of changes in these two factors over time have not been evaluated thoroughly. The aim of this study was to examine the independent and joint associations of changes in cardiorespiratory fitness and body composition on cancer mortality. The cohort consisted of 13,930 men (initially cancer-free) with two or more medical examinations from 1974 to 2002. Cardiorespiratory fitness was assessed by a maximal treadmill exercise test, and body composition was expressed by body mass index (BMI) and percent body fat. Changes in cardiorespiratory fitness and body composition between the baseline and the last examination were classified into loss, stable, and gain groups. There were 386 deaths from cancer during an average of 12.5 yr of follow-up. After adjusting for possible confounders and BMI, change hazard ratios (95% confidence intervals) of cancer mortality were 0.74 (0.57-0.96) for stable fitness and 0.74 (0.56-0.98) for fitness gain. Inverse dose-response relationships were observed between changes in maximal METs and cancer mortality (P for linear trend = 0.05). Neither BMI change nor percent body fat change was associated with cancer mortality after adjusting for possible confounders and maximal METs change. In the joint analyses, men who became less fit had a higher risk of cancer mortality (P for linear trend = 0.03) compared with those who became more fit, regardless of BMI change levels. Being unfit or losing cardiorespiratory fitness over time was found to predict cancer mortality in men. Improving or maintaining adequate levels of cardiorespiratory fitness appears to be important for decreasing cancer mortality in men.

Development and validation of a novel algorithm based on the ECG magnet response for rapid identification of any unknown pacemaker.

Pacemaker (PM) interrogation requires correct manufacturer identification. However, an unidentified PM is a frequent occurrence, requiring time-consuming steps to identify the device. The purpose of this study was to develop and validate a novel algorithm for PM manufacturer identification, using the ECG response to magnet application. Data on the magnet responses of all recent PM models (≤15 years) from the 5 major manufacturers were collected. An algorithm based on the ECG response to magnet application to identify the PM manufacturer was subsequently developed. Patients undergoing ECG during magnet application in various clinical situations were prospectively recruited in 7 centers. The algorithm was applied in the analysis of every ECG by a cardiologist blinded to PM information. A second blinded cardiologist analyzed a sample of randomly selected ECGs in order to assess the reproducibility of the results. A total of 250 ECGs were analyzed during magnet application. The algorithm led to the correct single manufacturer choice in 242 ECGs (96.8%), whereas 7 (2.8%) could only be narrowed to either 1 of 2 manufacturer possibilities. Only 2 (0.4%) incorrect manufacturer identifications occurred. The algorithm identified Medtronic and Sorin Group PMs with 100% sensitivity and specificity, Biotronik PMs with 100% sensitivity and 99.5% specificity, and St. Jude and Boston Scientific PMs with 92% sensitivity and 100% specificity. The results were reproducible between the 2 blinded cardiologists with 92% concordant findings. Unknown PM manufacturers can be accurately identified by analyzing the ECG magnet response using this newly developed algorithm.

ECG Response: April 8, 2014

HomeCirculationVol. 129, No. 14ECG Response: April 8, 2014 Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBECG Response: April 8, 2014 Originally published8 Apr 2014https://doi.org/10.1161/CIRCULATIONAHA.114.009858Circulation. 2014;129:1538–1539IntroductionECG Challenge: A 65-year-old woman with a history of hypertension for which she is taking a β-blocker and angiotensin-converting enzyme inhibitor is admitted to the hospital because of a cerebrovascular accident. While on telemetry, she is noted to have a significant bradycardia and an ECG is obtained.Download figureDownload PowerPointThe rhythm is irregular, but there some RR intervals that are similar to each other (↔, ┌┐). Therefore the rhythm is regularly irregular. The average rate is 36 bpm. P waves are seen (+) at a regular rate of 56 bpm. The P waves are positive in leads I, II, aVF, and V4 to V6 with a constant PP interval. Therefore, this is a sinus bradycardia. The P wave is broad and prominently notched in leads II, aVF, and V3 to V4 (P mitrale), consistent with left atrial hypertrophy or abnormality. There is a P wave before each QRS complex, but the PR interval is not constant. The PR intervals associated with complexes 2, 5, and 6 are the same (0.20 s), but the PR intervals of the third and fourth QRS complexes show progressive lengthening (from the baseline PR interval of 0.20 s to 0.28 and 0.40 s, respectively) (↑). The P wave after the fourth QRS complex is nonconducted (o). Hence, this is a second-degree atrioventricular block with a pattern of 4:3 Wenckebach or Mobitz type I. The first QRS complex is preceded by a P wave and a PR interval of 0.44 s. After this complex, there is a nonconducted P wave (↓); hence, this QRS complex represents the end of a Wenckebach cycle. Following the fifth QRS complex, it can be seen that there is another nonconducted P wave (▲) (ie, a pattern of 2:1 atrioventricular block [or atrioventricular conduction] that is 2:1 Wenckebach).The QRS complexes have 2 different morphologies. Complexes 1, 3, and 4 (▼) are wide (0.12 s) with a right bundle-branch pattern with a broad terminal S wave in lead I and an R′ in aVR. Complexes 2, 5, and 6 have a normal duration (0.08 s) and morphology. The voltage is increased in lead V5 (R wave= 40 mm; }), and, along with the S wave in lead V2 (20 mm; {), the criteria for left ventricular hypertrophy are met (ie, S wave V2 + R wave V5 = 60 mm). There is J-point and ST-segment elevation (^) in leads V3 to V5, consistent with early repolarization, which is often seen with left ventricular hypertrophy or tall QRS complex amplitude. The T waves are also tall and appear to be peaked. However, they are asymmetrical in morphology (upstroke slower than downstroke), and, hence, the T waves are normal. Prominent and tall peak P waves may be seen with left ventricular hypertrophy or tall QRS voltage. The QT/QTc intervals are normal (480/370 ms). It can be seen that the QRS complexes with a right bundle-branch block are associated with a shorter RR interval. Therefore, the right bundle-branch block is rate related.Please go to the journal’s Facebook page for more ECG Challenges: http://goo.gl/cm4K7. Challenges are posted on Tuesdays and Responses on Wednesdays.FootnotesCorrespondence to Philip J. Podrid, MD, West Roxbury VA Hospital, Section of Cardiology, 1400 VFW Pkwy, West Roxbury, MA 02132. E-mail [email protected] Previous Back to top Next FiguresReferencesRelatedDetails April 8, 2014Vol 129, Issue 14 Advertisement Article InformationMetrics © 2014 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.114.009858PMID: 24709868 Originally publishedApril 8, 2014 PDF download Advertisement SubjectsElectrocardiology (ECG)

ECG Response: March 25, 2014

ECG Challenge: A 72-year-old man with a history of chronic obstructive pulmonary disease presents with an increase in shortness of breath that began 2 weeks ago after experiencing an upper respiratory infection presenting with a cough productive of yellowish sputum, pleuritic chest pain, and a low grade fever with temperatures of up to 100°. He did not seek medical attention, but because of worsening shortness of breath he presented to the emergency room. On physical examination he has bilateral rhonchous sounds and wheezing. A chest x-ray showed evidence of chronic obstructive pulmonary disease with hyperaeration and fibrous streaking. His O2 saturation was 88% on room air. He was placed on supplemental O2 via a nasal cannula at 4 L/min. He received albuterol therapy via a nebulizer. Shortly after his first treatment he was noted to have a transient increase in heart rate and an ECG was obtained. The first 4 QRS complexes have a …

ECG Response: March 11, 2014

ECG Challenge: A 48-year-old man with a history of hyperlipidemia, hypertension, diabetes mellitus, and cigarette smoking presents to his primary care physician for a routine physical examination. The results of his examination are normal, but his pulse is noted to be irregular, resulting in an ECG. The rhythm is regular at a rate of 90 bpm. However, there are 2 long RR intervals (rate, 58 bpm; ↔) that are equal to each other. Therefore, the rhythm is regularly irregular. The QRS complex duration is normal (0.08 s), and there is a normal morphology. The axis is normal between 0° and +90° (positive QRS …

ECG Response: February 25, 2014

HomeCirculationVol. 129, No. 8ECG Response: February 25, 2014 Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBECG Response: February 25, 2014 Originally published25 Feb 2014https://doi.org/10.1161/CIRCULATIONAHA.114.008852Circulation. 2014;129:922IntroductionA 20-year-old female college student presents to the college health service with complaints of an irregular heart rate. She does not have any known cardiac disease but has noted palpitation in the past. However, the palpitations have lasted for only 1 to 2 hours and have been infrequent. She has never seen a physician for these palpitations. However, she has never noted her heartbeat to be irregular.The rhythm in ECG A is irregular, and there is no pattern to the irregularity. Therefore, the rhythm is irregularly irregular. There are only 3 supraventricular rhythms that are irregularly irregular: sinus arrhythmia (1 P-wave morphology and stable PR interval); wandering atrial pacemaker (or multifocal atrial rhythm), which has a rate <100 bpm, or multifocal atrial tachycardia, which has a rate >100 bpm (≥3 different P-wave morphologies without any 1 dominant P wave); or atrial fibrillation (no organized atrial activity). There are no organized P waves noted before any of the QRS complex; hence, this is atrial fibrillation. Two different QRS complex morphologies are noted. The narrow complexes (complexes 6, 12, and 14; +) have a normal duration and morphology. The wide QRS complexes (duration, 0.16 second; *) have a tall R wave in lead V1, but the morphology is not typical for a right bundle-branch block nor do they resemble a left bundle branch block. Therefore, they do not have a morphology typical for aberration due to a bundle branch block. In addition, there is positive concordance across the precordium (ie, tall R wave in V1-V6). These features are seen with direct myocardial activation (ie, QRS complex that is ventricular, paced or due to Wolff-Parkinson-White). The QRS complexes are very irregular and are therefore not likely ventricular in origin. There are no pacing stimuli seen. More important, there is no relationship between QRS complex width (duration) and rate (or RR interval). It can be seen that there are narrow complexes associated with fast rates (short RR intervals) (└┘) and wide QRS complexes at slow rates (long RR intervals; ↔). This is not seen with typical rate-related aberration but is associated with an accessory pathway or pre-excitation, specifically Wolff-Parkinson-White syndrome.Download figureDownload PowerPointECG B is her baseline ECG, which was obtained after sinus rhythm was restored. The rhythm is regular at a rate of 60 bpm. There is a P wave before each QRS complex (+), and there is a stable but short PR interval (0.12 second). The P wave is positive in leads I, II, aVF, and V4 through V6. Hence, this is a normal sinus rhythm with a short PR interval. The QRS complex morphology is identical to what was seen in ECG A. The widened QRS complex is due to a “slurred” upstroke (↑), known as a delta wave. The delta wave is due to initial activation that is directly through the ventricular myocardium and thus slow; there is then fusion with later activation through the normal conduction system. The short PR interval and the delta wave are characteristic of a Wolff-Parkinson-White pattern. The presence of a Q wave in leads I and aVL (▴), and the positive delta wave in lead V1 are seen with a left lateral bypass tract. The QT/QTc intervals are slightly prolonged (480/480 milliseconds) but are normal when the prolonged QRS complex duration is considered (420/420 milliseconds). Because the QT interval includes the QRS complex, ST segment, and T wave, prolongation of the QRS complex duration needs to be considered when establishing the QTc interval. The amount of widening of the QRS complex that is above the normal width needs to be subtracted from the QT interval measurement before the QT is corrected for heart rate.Download figureDownload PowerPointPlease go to the journal’s Facebook page for more ECG Challenges: http://goo.gl/cm4K7. Challenges are posted on Tuesdays and Responses on Wednesdays.FootnotesCorrespondence to Philip J. Podrid, MD, West Roxbury VA Hospital, Section of Cardiology, 1400 VFW Pkwy, West Roxbury, MA 02132. E-mail [email protected] Previous Back to top Next FiguresReferencesRelatedDetails February 25, 2014Vol 129, Issue 8 Advertisement Article InformationMetrics © 2014 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.114.008852PMID: 24566067 Originally publishedFebruary 25, 2014 PDF download Advertisement

ECG Response: February 11, 2014

ECG Challenge: A 59-year-old woman has a history of lupus with renal involvement for which she is taking glucocorticoids. She has no known heart disease. She presents to her rheumatologist with concerns of intermittent palpitations that first began ≈1 month ago. She was referred to a cardiologist and an ECG was obtained. The ECG shows a regular rhythm with 2 different rates. The initial portion of the ECG shows a regular rhythm with a rate of 72 bpm. The second part of the ECG shows a regular rhythm at a rate of 160 bpm. All the QRS complexes (except for the 8th QRS complex; ↓) have the same morphology. The QRS complex duration is normal (0.08 s), and there is a normal morphology and a normal axis between 0° and +90° (positive QRS complex in leads I and aVF). The …

Perception of verticality and cardiovascular responses during short-radius centrifugation

Artificial gravity using short-radius centrifugation has been proposed as an integrative countermeasure during spaceflight. To determine the rotation parameters of a short-radius centrifuge so that subjects rotating in the dark would feel as if they were standing upright. Twelve subjects were lying supine in a nacelle on a 2.8 m-radius centrifuge with their head closer to the axis of rotation and their feet pointing radially outwards. Subjects verbally reported body orientation for 26 combinations of centrifuge rotation rate and nacelle pitch tilt. ECG and respiratory responses were also recorded. Five subjects felt like they were vertical when centrifugation elicited 1 g at their center of mass along their body longitudinal axis, whereas seven subjects felt they were vertical when they experienced about 1 g at ear level, regardless of the nacelle tilt angle. Heart rate variability varied with the subjects' perception of verticality. These results suggest that one group of subject was relying principally on the otolith organs for the perception of verticality, whereas the other group was also relying on extravestibular somatosensory receptors. The crewmember's perception of verticality might be a factor to take into account for the prescription for artificial gravity during spaceflight.