The Spatial Ventricular Gradient is Associated with Inducibility of Ventricular Arrhythmias During Electrophysiology Study.

BACKGROUND: Myocardial electrical heterogeneity is critical for normal cardiac electromechanical function, but abnormal/excessive electrical heterogeneity is proarrhythmic. The spatial ventricular gradient (SVG), a vectorcardiographic measure of electrical heterogeneity, has been associated with arrhythmic events over long-term follow-up, but its relationship with short-term inducibility of ventricular arrhythmias (VAs) is unclear. OBJECTIVE: Determine associations between SVG and inducible VAs during electrophysiology study (EPS). METHODS: Retrospective study of adults without prior sustained VA, cardiac arrest, or implantable cardioverter-defibrillator (ICD), who underwent ventricular stimulation for evaluation of syncope, non-sustained VT, and/or risk-stratification prior to primary prevention ICD implantation. 12-lead ECGs were converted into vectorcardiograms and SVG magnitude (SVGmag) and direction (azimuth and elevation) were calculated. Odds of inducible VA were regressed using logistic models. RESULTS: Among 143 patients (median age 66, 80% male, median LVEF 47%, 52% myocardial infarction), 34 (23.8%) had inducible VAs. Inducible patients had lower median LVEF (38 vs 50%, p<0.0001), smaller SVGmag (29.5 vs 39.4mV*ms, p=0.0099), and smaller cosine SVG azimuth (cosSVGaz) (0.64 vs 0.89, p=0.0007). When LVEF, SVGmag, and cosSVGaz were dichotomized at their medians, there was a 39-fold increase in adjusted odds (p=0.002) between patients with all low LVEF, SVGmag, and cosSVGaz (65% inducible), compared to patients with all high LVEF, SVGmag, and cosSVGaz (4% [n=1] inducible). After multivariable adjustment, SVGmag, cosSVGaz, and sex, but not LVEF or other characteristics, remained associated with inducible VAs. CONCLUSION: Assessment of electrical heterogeneity via SVG, which reflects abnormal electrophysiological substrate, adds to LVEF and identifies patients at high and low risk of inducible VA at EPS.

Limits of the spatial ventricular gradient and QRST angles in patients with normal electrocardiograms and no known cardiovascular disease stratified by age, sex, and race.

INTRODUCTION: Measurement of the spatial ventricular gradient (SVG), spatial QRST angles, and other vectorcardiographic measures of myocardial electrical heterogeneity have emerged as novel risk stratification methods for sudden cardiac death and other adverse cardiovascular events. Prior studies of normal limits of these measurements included primarily young, healthy, White volunteers, but normal limits in older patients are unknown. The influence of race and body mass index (BMI) on these measurements is also unclear. METHODS: Normal 12-lead electrocardiograms (ECGs) from a single center were identified. Patients with abnormal cardiovascular, pulmonary, or renal history (assessed by International Classification of Disease [ICD-9/ICD-10] codes) or abnormal cardiovascular imaging were excluded. The SVG and QRST angles were measured and stratified by age, sex, and race. Multivariable linear regression was used to assess the influence of age, BMI, and heart rate (HR) on these measurements. RESULTS: Among 3292 patients, observed ranges of SVG and QRST angles (peak and mean) differed significantly based on sex, age, and race. Sex differences attenuated with increasing age. Men tended to have larger SVG magnitude (60.4 [46.1-77.8] vs. 52.5 [41.3-65.8] mv*ms, p < .0001) and elevation, and more anterior/negative SVG azimuth (-14.8 [-25.1 to -4.3] vs. 1.3 [-9.8 to 10.5] deg, p < .0001) compared to women. Men also had wider QRST angles. Observed ranges varied significantly with BMI and HR. SVG and QRST angle measurements were robust to different filtering bandwidths and moderate fiducial point annotation errors, but were heavily affected by changes in baseline correction. CONCLUSIONS: Age, sex, race, BMI, and HR significantly affect the range of SVG and QRST angles in patients with normal ECGs and no known cardiovascular disease, and should be accounted for in future studies. An online calculator for prediction of these "normal limits" given demographics is provided at https://bivectors.github.io/gehcalc/.

A Focus on the Right Atrium: Right Atrial Diverticulum and Atrial Flutter.

We report a case of a 70-year-old woman who presented for a cavotricuspid isthmus atrial flutter ablation that was aborted prematurely. On subsequent imaging, she was discovered to have a right atrial diverticulum, which was present on prior imaging but not reported, likely due to unfamiliarity with the entity. (Level of Difficulty: Intermediate.).

Clinical utility of remote monitoring for patients with cardiac implantable electrical devices.

BACKGROUND: Remote monitoring of cardiac implantable electronic devices (CIEDs) offers practical and clinical benefits juxtaposed against burdens associated with high transmission volume. METHODS: We identified patients receiving de novo pacemakers (PPMs) and implantable cardiac defibrillators (ICDs) at a single academic medical center (January 2016-December 2019) with at least 1 year of follow-up device care. We collected patient- and device-specific data at time of implant and assessed all remote and in-person interrogation reports for clinically actionable findings based on pre-specified criteria. RESULTS: Among 963 patients (mean age of 71 (± 14) years, 37% female), 655 (68%) underwent PPM, and 308 (32%) underwent ICD implant. Median follow-up was 874 (627-1221) days, during which time patients underwent a mean of 13 (10-16) total interrogations; remote interrogations comprised 53% of all device evaluations; and of these, 96% were scheduled transmissions. Overall, 22% of all CIED interrogations yielded significant findings with a slightly higher rate in the PPM than in the ICD group (23% vs. 20%, p < 0.01). Only 8% of remote interrogations produced clinically meaningful results, compared with 38% of in-person ones. In adjusted models, routine, remote transmissions were least likely to be useful for both PPM and ICD patients (p < 0.001), whereas time from initial device implant was inversely associated with probability of obtaining a useful interrogation (p < 0.001). CONCLUSIONS: Routine remote interrogations constitute the majority of device evaluations performed, but uncommonly identify clinically actionable findings.

Global electrical heterogeneity associated with drug-induced torsades de pointes.

BACKGROUND: Drugs belonging to diverse therapeutic classes can prolong myocardial refractoriness or slow conduction. These drugs may be effective and well-tolerated, but the risk of sudden cardiac death from torsades de pointes (TdP) remains a major concern. The corrected QT interval has significant limitations when used for risk stratification. Measurement of global electrical heterogeneity (GEH) could help identify the substrate vulnerable to drug-induced ventricular arrhythmias. OBJECTIVE: The purpose of this study was to improve risk stratification for drug-induced TdP by measuring GEH on the electrocardiogram (ECG). METHODS: We analyzed ECG data from a case-control study of patients with a history of drug-induced TdP as well as age- and sex-matched controls. Vectorcardiograms were constructed from ECGs. GEH was measured via the spatial ventricular gradient (SVG) vector (magnitude, azimuth, and elevation). Log odds coefficients for TdP were estimated using multivariable logistic regression. RESULTS: Among 17 cases (47% male; age 58.9 ± 12.5 years) and 17 controls (29% male; age 61.0 ± 12.2 years), 34 ECGs were analyzed. SVG azimuth was significantly different between cases and controls (3.4 vs 22.0 degrees, respectively; P = 0.02). After adjusting for sex and QTc interval, odds of TdP increased by a factor of 3.2 for each 1 SD change in SVG azimuth from the control group mean (95% confidence interval 1.07-9.14; P = .04). QTc was not significant in the multivariable analysis (P = .20). CONCLUSION: SVG azimuth is correlated with a history of drug-induced TdP independent of QTc. GEH measurement may help identify patients at high risk for drug-induced arrhythmias.

Factors Associated With Functional Recovery Among Older Survivors of Major Surgery.

OBJECTIVE: The objectives of the current study were 2-fold: first, to evaluate the incidence and time to recovery of premorbid function within 6 months of major surgery and second, to identify factors associated with functional recovery among older persons who survive a major surgery with increased disability. BACKGROUND: Most older persons would not choose a surgical treatment resulting in persistently increased postsurgical disability, even if survival was assured. Potential predictors of functional recovery after major surgery have, however, not been well-studied among geriatric patients. METHODS: It is a prospective longitudinal study of 754 community-living persons 70 years or older. The analytic sample included 266 person-admissions in which participants survived major surgery with increased disability and were monitored on a monthly basis for 6 months. RESULTS: Of the 266 person-admissions assessed, 174 (65.4%) recovered to their presurgical level of function, with median time to recovery of 2 months (interquartile range, 1-3), whereas 16 (6.0%) died. Two factors were significantly associated with an increased likelihood of functional recovery: being nonfrail (hazard ratio 1.60; 95% confidence interval 1.03-2.51; P = 0.038) and having elective surgery (hazard ratio 1.72; 95% confidence interval 1.14-2.59; P = 0.009). Three factors were associated with a reduced likelihood of functional recovery: hearing impairment, greater increase in postsurgical disability in the month after hospital discharge, and years of education. CONCLUSIONS: Among older persons, nonfrailty and elective surgery were positively associated with functional recovery, whereas hearing impairment, greater increases in postsurgical disability, and years of education were associated with higher risk of protracted disability.

Functional Trajectories Before and After Major Surgery in Older Adults.

OBJECTIVES: We hypothesized that distinct sets of functional trajectories can be identified in the year before and after major surgery, with unique transition probabilities from pre to postsurgical functional trajectories, and that outcomes would be better among participants undergoing elective versus nonelective surgery. BACKGROUND: Major surgery is common and can be highly morbid in older persons. The relationship between the course of disability (ie, functional trajectory) before and after surgery in older adults has not been well-studied for most operations. METHODS: Prospective cohort study of 754 community-living persons 70 years or older. The analytic sample included 250 participants who underwent their first major surgery during the study period. RESULTS: Before surgery, 4 functional trajectories were identified: no disability (n = 60, 24.0%), and mild (n = 84, 33.6%), moderate (n = 73, 29.2%), and severe (n = 33, 13.2%) disability. After surgery, 4 functional trajectories were identified: rapid (n = 39, 15.6%), gradual (n = 76, 30.4%), partial (n = 70, 28.0%), and little (n = 57, 22.8%) improvement. Rapid improvement was seen for n = 31 (51.7%) participants with no disability before surgery, but was uncommon among those with mild disability (n = 8, 9.5%) and was not observed in the moderate and severe trajectory groups. For participants with mild to moderate disability before surgery, gradual improvement (n = 46, 54.8%) and partial improvement (n = 36, 49.3%) were most common. Most participants with severe disability (n = 27, 81.8%) before surgery exhibited little improvement. Outcomes were better for participants undergoing elective versus nonelective surgery. CONCLUSIONS: Functional prognosis in the year after major surgery is highly dependent on premorbid function.

Restricting Symptoms Before and After Admission to Hospice.

BACKGROUND: Prior work has shown that symptoms leading to restrictions in daily activities are common at the end of life. Hospice is a Medicare benefit designed to alleviate distressing symptoms in the last 6 months of life. The effect of hospice on the burden of such symptoms is uncertain. METHODS: From an ongoing cohort study of 754 community-dwelling older persons, aged ≥70 years, we evaluated 241 participants who were admitted to hospice from March 1998 to December 2013. A set of 15 physical and psychological symptoms leading to restricted activity (ie, cut down on usual activities or spend at least half the day in bed) were ascertained during monthly telephone interviews in the year before and 3 months after hospice admission. RESULTS: The prevalence and mean number of restricting symptoms increased progressively until about 2 months before hospice admission, before increasing precipitously to a peak around the time of hospice admission. After the start of hospice, both the prevalence and the mean number of restricting symptoms dropped markedly. For several symptoms deemed most amenable to hospice treatment, including depression and anxiety, the prevalence dropped to levels comparable to or lower than those observed 12 months before the start of hospice. The trends observed in symptom prevalence and mean number of symptoms before and after hospice did not differ appreciably according to hospice admission diagnosis or sex. The median duration of hospice (before death) was only 15 days. CONCLUSION: The burden of restricting symptoms increases progressively several months before the start of hospice, peaks around the time of hospice admission, and decreases substantially after the start of hospice. These results, coupled with the short duration of hospice, suggest that earlier referral to hospice may help to alleviate the burden of distressing symptoms at the end of life.

Functional trajectories in the year before hospice.

PURPOSE: We undertook a study to identify distinct functional trajectories in the year before hospice, to determine how patients with these trajectories differ according to demographic characteristics and hospice diagnosis, and to evaluate the association between these trajectories and subsequent outcomes. METHODS: From an ongoing cohort study of 754 community-living persons aged 70 years or older, we evaluated data on 213 persons who were subsequently enrolled in hospice from March 1998 to December 2011. Disability in 13 basic, instrumental, and mobility activities was assessed during monthly telephone interviews through June 2012. RESULTS: In the year before hospice, we identified 5 clinically distinct functional trajectories, representing worsening cumulative burden of disability: late decline (10.8%), accelerated (10.8%), moderate (21.1%), progressively severe (24.9%), and persistently severe (32.4%). Participants with a cancer diagnosis (34.7%) had the most favorable functional trajectories (ie, lowest burden of disability), whereas those with neurodegenerative disease (21.1%) had the worst. Median survival in hospice was only 14 days and did not differ significantly by functional trajectory. Compared with participants in the persistently severe trajectory, those in the moderate trajectory had the highest likelihood of surviving and being independent in at least 1 activity in the month after hospice admission (adjusted odds ratio = 5.5; 95% CI, 1.9-35.9). CONCLUSIONS: The course of disability in the year before hospice differs greatly among older persons but is particularly poor among those with neurodegenerative disease. Late admission to hospice (as shown by the short survival), coupled with high levels of severe disability before hospice, highlight potential unmet palliative care needs for many older persons at the end of life.