Cardiac resynchronization therapy (CRT) has emerged as an attractive intervention to improve left ventricular mechanical function by changing the sequence of electrical activation. Unfortunately, ...many patients receiving CRT do not benefit but are subjected to device complications and costs. Thus, there is a need for better selection criteria. Current criteria for CRT eligibility include a QRS duration ≥120 ms. However, QRS morphology is not considered, although it can indicate the cause of delayed conduction. Recent studies have suggested that only patients with left bundle branch block (LBBB) benefit from CRT, and not patients with right bundle branch block or nonspecific intraventricular conduction delay. The authors review the pathophysiologic and clinical evidence supporting why only patients with complete LBBB benefit from CRT. Furthermore, they review how the threshold of 120 ms to define LBBB was derived subjectively at a time when criteria for LBBB and right bundle branch block were mistakenly reversed. Three key studies over the past 65 years have suggested that 1/3 of patients diagnosed with LBBB by conventional electrocardiographic criteria may not have true complete LBBB, but likely have a combination of left ventricular hypertrophy and left anterior fascicular block. On the basis of additional insights from computer simulations, the investigators propose stricter criteria for complete LBBB that include a QRS duration ≥140 ms for men and ≥130 ms for women, along with mid-QRS notching or slurring in ≥2 contiguous leads. Further studies are needed to reinvestigate the electrocardiographic criteria for complete LBBB and the implications of these criteria for selecting patients for CRT.
Background Up to one-third of patients diagnosed with left bundle branch block (LBBB) by conventional electrocardiographic (ECG) criteria are misdiagnosed. Strict LBBB shows decreased left ...ventricular pumping efficiency compared with nonstrict LBBB. However, no previous study has evaluated the frequency of strict LBBB after transcatheter aortic valve replacement (TAVR). The aim of this study was to determine the incidence of developing strict versus nonstrict LBBB after TAVR and test the hypothesis that preprocedure QRS duration does not predict strict LBBB but predicts development of nonstrict LBBB. Methods All patients receiving TAVR between 4/2011 and 2/2013 (n = 71) with no preexisting bundle branch block or permanent pacemaker were included. Twelve-lead ECGs were acquired preprocedure and both 1-day and 1-month postprocedure. All ECGs were classified as strict LBBB, nonstrict LBBB, or no LBBB. Results Sixty-eight patients had ECGs eligible for final analysis. On postprocedure day 1, 25 (37%) of 68 patients developed strict LBBB, and 2 patients (3%) developed nonstrict LBBB. At 1-month follow-up, the 2 patients diagnosed with nonstrict LBBB had resolved to normal, and 5 (20%) of 25 patients with strict LBBB had resolved to normal. Preprocedure QRS duration did not predict strict LBBB ( P = .51). Because of the low incidence of nonstrict LBBB, QRS duration as a predictor of nonstrict LBBB could not be tested. Conclusions Almost all patients who developed evidence of LBBB after TAVR met the new strict criteria, indicating probable procedural injury to the left bundle branch. Preprocedural QRS duration did not predict the development of strict LBBB.
OBJECTIVES: To describe patterns of cognitive deficits and activities of daily living (ADLs) in older people with diabetes mellitus.
DESIGN: Cross‐sectional, population‐based study.
SETTING: Three ...homecare agency areas in Boston, Massachusetts.
PARTICIPANTS: Two hundred ninety‐one homebound people aged 60 and older; 40% with diabetes mellitus.
MEASUREMENTS: Demographic data; evidence of diabetes mellitus and other diseases; Mini‐Mental State Examination and tests of memory and executive function; ADLs.
RESULTS: Executive and visuospatial functions were more impaired in individuals with diabetes mellitus than in those without, as assessed using Block Design (mean score±standard deviation 17.1±8.6 vs 20.5±9.6, P=.003) and Trails B (median seconds to accomplish the task: 255 vs 201, P=.03). For memory, word retention score was lower in those with diabetes mellitus than without (39.1±28.9 vs 48.0±29.7, P=.01), but the other memory tests did not show a difference between these two subgroups. More individuals with diabetes mellitus suffered from depressive symptoms than those without (55% vs 42%, P=.03). The ADL scores of those with diabetes mellitus were higher than those without.
CONCLUSION: The pattern of cognitive deficits in people with diabetes mellitus suggests frontal‐subcortical dysfunction, as seen in microvascular disease of the brain. The impairment in ADLs may be associated with this executive dysfunction, which cerebral microvascular disease in diabetes mellitus may cause.
Sympathetic nerve activity is important to cardiac arrhythmogenesis.
The purpose of this study was to develop a method for simultaneous noninvasive recording of skin sympathetic nerve activity (SKNA) ...and electrocardiogram (ECG) using conventional ECG electrodes. This method (neuECG) can be used to adequately estimate sympathetic tone.
We recorded neuECG signals from the skin of 56 human subjects. The signals were low-pass filtered to show the ECG and high-pass filtered to show nerve activity. Protocol 1 included 12 healthy volunteers who underwent cold water pressor test and Valsalva maneuver. Protocol 2 included 19 inpatients with epilepsy but without known heart diseases monitored for 24 hours. Protocol 3 included 22 patients admitted with electrical storm and monitored for 39.0 ± 28.2 hours. Protocol 4 included 3 patients who underwent bilateral stellate ganglion blockade with lidocaine injection.
In patients without heart diseases, spontaneous nerve discharges were frequently observed at baseline and were associated with heart rate acceleration. SKNA recorded from chest leads (V
-V
) during cold water pressor test and Valsalva maneuver (protocol 1) was invariably higher than during baseline and recovery periods (P < .001). In protocol 2, the average SKNA correlated with heart rate acceleration (r = 0.73 ± 0.14, P < .05) and shortening of QT interval (P < .001). Among 146 spontaneous ventricular tachycardia episodes recorded in 9 patients of protocol 3, 106 episodes (73%) were preceded by SKNA within 30 seconds of onset. Protocol 4 showed that bilateral stellate ganglia blockade by lidocaine inhibited SKNA.
SKNA is detectable using conventional ECG electrodes in humans and may be useful in estimating sympathetic tone.
An Elastic, Biodegradable Cardiac Patch Induces Contractile Smooth Muscle and Improves Cardiac Remodeling and Function in Subacute Myocardial Infarction Kazuro L. Fujimoto, Kimimasa Tobita, W. David ...Merryman, Jianjun Guan, Nobuo Momoi, Donna B. Stolz, Michael S. Sacks, Bradley B. Keller, William R. Wagner To prevent chronic adverse cardiac remodeling and subsequent dysfunction after myocardial infarction, we implanted an elastic, biodegradable material, polyester urethane urea (PEUU), as a cardiac patch onto subacute infarcts in a rat model. Eight weeks after implantation, echocardiography revealed that cardiac dilatation was prevented and contractile function improved in the PEUU patch group. Histology revealed contractile smooth muscle bundles in the PEUU implanted site and increased wall thickness, compared to the infarction control. The myocardial compliance of the PEUU group was distributed between normal myocardium and the infarction control. These findings suggest a new therapeutic option against post-infarct cardiac failure.
Guidelines recommend that patients with suggestive symptoms of myocardial ischemia and ST-segment elevation (STE) in ≥2 adjacent electrocardiographic leads should receive immediate reperfusion ...therapy. Novel strategies aimed to reduce door-to-balloon time, such as prehospital wireless electrocardiographic transmission, may be dependent on the interpretation accuracy of the electrocardiogram (ECG) readers. We assessed the ability of experienced electrocardiographers to differentiate among STE, acute STE myocardial infarction (STEMI), and nonischemic STE (NISTE). A total of 116 consecutive ECGs showing STE were studied. Fifteen experienced cardiologists were asked to decide, based on the ECG and assuming that the patient had compatible symptoms, whether they would send each patient for primary percutaneous coronary intervention (PPCI). If NISTE was chosen, the reader selected 1 or more 12 possible options to explain the choice. Of 116 patients, only 8 had STEMI. The percentage of ECGs for which PPCI was recommended for the patient by the individual readers varied widely (7.8% to 33%). There was no significant difference between the North American and Other Countries readers (p = 0.13). The sensitivity and specificity of the individual readers ranged from 50% to 100% (average 75%) and 73% to 97% (average 85%), respectively. There were broad inconsistencies among the readers in the chosen reasons used to classify NISTE. In conclusion, we found wide variations among experienced electrocardiographers in reading ECGs with STE and differentiating STEMI with need for PPCI from NISTE. There is a need to revise our current electrocardiographic criteria for differentiating STEMI from NISTE.
This study investigated the influence of age, National Institutes of Health Stroke Scale (NIHSS) score, time from stroke onset, infarct location and volume in predicting placement of a percutaneous ...endoscopic gastrostomy (PEG) tube in patients with severe dysphagia from an acute-subacute hemispheric infarction. We performed a retrospective analysis of a hospital-based patient cohort to analyze the effect of the aforementioned variables on the decision of whether or not to place a PEG tube. Consecutive patients were identified using International Classification of Diseases, Ninth Revision (ICD-9) codes for acute ischemic stroke, Current Procedural Terminology (CPT)-4 codes for a formal swallowing evaluation by a speech pathologist, and procedure codes for PEG placement over a 5-year period from existing medical records at our institution. Only patients with severe dysphagia were enrolled. A total of 77 patients met inclusion criteria; 20 of them underwent PEG placement. The relationship between age (dichotomized; < and ≥75 years), time from stroke onset (days), NIHSS score, acute infarct lesion volume (dichotomized; < and ≥100 cc), and infarct location (ie, insula, anterior insula, periventricular white matter, inferior frontal gyrus, motor cortex, or bilateral hemispheres) with PEG tube placement were analyzed using logistic regression analysis. In univariate analysis, NIHSS score ( P = .005), lesion volume ( P = .022), and presence of bihemispheric infarction ( P = .005) were found to be the main predictors of interest. After multivariate adjustment, only NIHSS score (odds ratio OR, 1.15; 90% confidence interval CI, 1.02-1.29; P = .04) and presence of bihemispheric infarcts (OR, 4.67; 90% CI, 1.58-13.75; P = .018) remained significant. Our data indicates that baseline NIHSS score and the presence of bihemispheric infarcts predict PEG placement during hospitalization from an acute-subacute hemispheric infarction in patients with severe dysphagia. These results require further validation in future studies.
Abstract Background There is a need for improved selection criteria for cardiac resynchronization therapy (CRT). High myocardial scar burden has been associated with worse outcome in CRT patients. ...However, it is unclear whether high scar burden prevents CRT clinical benefit or is merely predictive of prognosis in heart failure (HF) patients regardless of CRT implantation. We aimed to study the predictive value of scar burden estimated by electrocardiographic Selvester QRS scoring in determining CRT benefit in the multicenter automatic defibrillator implantation trial-cardiac resynchronization therapy (MADIT-CRT) population. Methods Selvester QRS scoring was performed on all 1820 ECGs of the MADIT-CRT population by a single observer. In both arms and in their respective LBBB subgroups, QRS score was analyzed in comparison to echocardiographic volumes and in relation to time to HF event or death using Cox proportional hazard ratios. To determine effect on CRT clinical benefit, we tested for interaction between the effects of CRT assignment and QRS score on time to HF event or death. Results In the CRT-D arm, a significant correlation was found between higher continuous QRS score and less increase of left ventricular ejection fraction (LVEF) as well as less decrease of left ventricular end-systolic volume (LVESV) (multivariate -p-values: < 0.001). QRS score was significantly correlated with HF event/death in the left bundle branch block (LBBB) subgroup ( n = 1037, multivariate HR 1.07 per point, p = 0.046). Scar extent estimated by QRS scoring was neither predictive of CRT clinical benefit in the total study population (interaction -p-value = 0.25) nor in the LBBB subgroup (interaction p-value = 0.86). Conclusion High scar burden estimated by Selvester QRS score is predictive of adverse overall prognosis in LBBB patients regardless of CRT implantation. However, QRS score does not identify patients who benefit clinically from CRT-D compared to implantation of ICD only.
Abstract Background Estimation of the infarct size from body-surface ECGs in post-myocardial infarction patients has become possible using the Selvester scoring method. Automation of this scoring has ...been proposed in order to speed-up the measurement of the score and improving the inter-observer variability in computing a score that requires strong expertise in electrocardiography. In this work, we evaluated the quality of the QuAReSS software for delivering correct Selvester scoring in a set of standard 12-lead ECGs. Method Standard 12-lead ECGs were recorded in 105 post-MI patients prescribed implantation of an implantable cardiodefibrillator (ICD). Amongst the 105 patients with standard clinical left bundle branch block (LBBB) patterns, 67 had a LBBB pattern meeting the strict criteria. The QuAReSS software was applied to these 67 tracings by two independent groups of cardiologists (from a clinical group and an ECG core laboratory) to measure the Selvester score semi-automatically. Using various level of agreement metrics, we compared the scores between groups and when automatically measured by the software. Results The average of the absolute difference in Selvester scores measured by the two independent groups was 1.4 ± 1.5 score points, whereas the difference between automatic method and the two manual adjudications were 1.2 ± 1.2 and 1.3 ± 1.2 points. Eighty-two percent score agreement was observed between the two independent measurements when the difference of score was within two point ranges, while 90% and 84% score agreements were reached using the automatic method compared to the two manual adjudications. Conclusion The study confirms that the QuAReSS software provides valid measurements of the Selvester score in patients with strict LBBB with minimal correction from cardiologists.
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