Ventricular Gradient Research Articles

Changes in global electrical heterogeneity associated with dofetilide, quinidine, ranolazine, and verapamil

Electrocardiographic (ECG) markers of antiarrhythmic drug (AAD) activity could be used to optimize efficacy and minimize toxicity. Vectorcardiographic global electrical heterogeneity (GEH) is associated with ventricular arrhythmias and sudden death, but it is unclear how GEH measurements change in response to AADs. The purpose of this study was to characterize acute effects of AADs on GEH measurements. We analyzed double-blind placebo-controlled trial data from healthy volunteers given 1 dose of placebo, dofetilide, quinidine, ranolazine, or verapamil on subsequent visits. Serial ECGs and plasma drug concentrations were collected. Vectorcardiographic GEH parameters (spatial ventricular gradient [SVG], spatial QRST angle, sum absolute QRST integral, and SVG-QRS peak angle) were measured. Placebo-corrected change from baseline was regressed on drug concentration stratified by sex using linear mixed effects models. Among 22 persons (11 (50%) male median age 27 ± 5 years), 5232 ECGs were analyzed. Dofetilide and quinidine were associated with significant changes in more GEH parameters (5) compared with verapamil (2) and ranolazine (1). The most notable change occurred in SVG azimuth, with largest changes (degrees per unit normalized drug concentration) in dofetilide (6.1; 95% confidence interval [CI] 4.2-8.0) and quinidine (9.4; 95% CI 6.7-12.0), and smaller effects in verapamil (4.4; 95% CI 2.9-5.9) and ranolazine (5.4; 95% CI 3.5-7.3). AAD-induced GEH changes significantly differed in men and women. AADs change GEH measurements. These changes, which differ by sex, are likely driven by alterations in ion channel function and dispersion of depolarization or repolarization. GEH measurement may allow early assessment of favorable or adverse AAD effects.

Anesthetic management during endocardial radiofrequency ablation of septal hypertrophy – a case report

Background: Hypertrophic cardiomyopathy (HCM) is a genetic disorder present in up to 1/500 individuals, about 20–30% of them presenting with hypertrophic obstructive cardiomyopathy (HOCM) due to left ventricle outflow tract obstruction. This is an important cause of sudden cardiac death. Endocardial radiofrequency ablation of septal hypertrophy (ERASH) might be an attractive treatment for HOCM, particularly in patients who do not respond to transcoronary alcohol septal ablation (TASA).Aim: To describe technical aspects related to the procedure and anesthetic management of an ERASH case.Case report: A 64-year-old woman with HOCM was scheduled for ERASH. She had worsening of dyspnea on exertion and generalized fatigue for the previous weeks after previous surgical myomectomy about 6 months ago. The anatomy was unfavorable for TASA and the patient was not willing to undergo another surgery. Preoperative transthoracic echocardiography (TTE) showed asymmetric mid-septal hypertrophy, systolic anterior motion with septal contact and left ventricular outflow tract maximum gradient of 68 mmHg at rest and 105 mmHg after the Valsalva maneuver. General anesthesia was performed. Pulse pressure variation, echocardiography parameters and passive leg raising test where used to guide fluid therapy. At the end of the procedure, analgesia was provided together with prophylaxis of nausea and vomiting. Extubation was uneventful and the patient was transported to the intensive care unit eupneic and hemodynamically stable. On the fourth postoperative day, TTE showed septal hypocontractility and maximum gradient reduction of 33% at rest (68 mmHg to 45 mmHg) and 31% after the Valsalva maneuver (105 mmHg to 73 mmHg). The patient was discharged from hospital at the sixth postoperative day. One month later, she reported progressive improvement of symptoms and expressed satisfaction with the results.Conclusion: Better understanding of the pathophysiology and natural history of HCM has enabled earlier diagnosis, as well as a more adequate therapeutic approach. Anesthesiologists should be aware of the pathophysiology of HOCM and must be prepared to anticipate the hemodynamic changes and cardiovascular instability that such patients may show perioperatively. ERASH is a promising therapeutic modality increasingly used for HOCM and anesthesiologists should become more familiar with it.

Diagnostic accuracy of a novel predictive model for ischemic events based on small dense LDL-cholesterol concentration (SDLDL-C) and lipid characterization by NMR

Proper adaptation of ventricular repolarization (VR) to rapid heart rate (HR) increase is crucial for cardiac electro-mechanical function. The pattern and temporal aspects of this adaptation and its components (duration and dispersion) during normal conduction are, however, incompletely known in humans and were the topic of this study.The VR duration (QT & QTpeak) and dispersion (Tamplitude, Tarea & ventricular gradient; VG) responses were studied by continuous vectorcardiogram after a bolus injection of atropine 0.04 mg/kg b.w. in 31 healthy young adults (16 men). The primary measure (T90 End) was the time to reach 90% change from baseline to end value 300 s later.Mean (SD) of T90 End was 23 (9) s for a 41% RR decrease, 130 (35) s for a 16% QTend decrease and 110 (36) s for a 19% QTpeak decrease; the response was single-exponential for these measures. For 35–43% decreases of Tamplitude, Tarea & VG, mean (SD) of T90 End were 21 (10), 38 (20) and 40 (23) s and the response pattern was double-exponential with varying overshoot.VR duration and dispersion responses to a very rapid HR increase during normal conduction differed substantially. In contrast to the well-known single-exponential delay in VR duration adaptation the responses of VR dispersion measures were double-exponential and much more rapid. We describe a new and completely non-invasive phenotypic characterization of different components of VR adaptation.

Short- and long-term outcomes of alcohol septal ablation for hypertrophic obstructive cardiomyopathy in patients with mild left ventricular hypertrophy: a propensity score matching analysis.

Based on European guidelines, alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) is indicated only in patients with interventricular septum (IVS) thickness >16 mm. The aim of this study was to evaluate the short- and long-term outcomes in ASA patients with mild hypertrophy (IVS ≤ 16 mm). We retrospectively evaluated 1505 consecutive ASA patients and used propensity score to match 172 pairs (344 patients) in groups IVS ≤ 16 mm or IVS > 16 mm. There was no occurrence of post-ASA ventriculoseptal defect in the whole cohort (n = 1505). Matched patients had 30-day mortality rate 0% in IVS ≤ 16 mm group and 0.6% in IVS > 16 mm group (P = 1). Patients in IVS ≤ 16 mm group had more ASA-attributable early complications (16% vs. 9%; P = 0.049), which was driven by higher need for pacemaker implantation (13% vs. 8%; P = 0.22). The mean follow-up was 5.4 ± 4.3 years and the annual all-cause mortality rate was 1.8 and 3.2 deaths per 100-patient-years in IVS ≤ 16 group and IVS > 16 group, respectively (log-rank test P = 0.04). There were no differences in symptom relief and left ventricular (LV) gradient reduction. Patients with IVS ≤ 16 mm had less repeated septal reduction procedures (log-rank test P = 0.03). Selected patients with HOCM and mild hypertrophy (IVS ≤ 16 mm) had more early post-ASA complications driven by need for pacemaker implantation, but their long-term survival is better than in patients with IVS >16 mm. While relief of symptoms and LV obstruction reduction is similar in both groups, a need for repeat septal reduction is higher in patients with IVS > 16 mm.

An echocardiographic study of left ventricular torsion in patients with latent obstructive hypertrophic cardiomyopathy

Objective To explore the changes of left ventricular torsion function in patients with latent obstructive hypertrophic cardiomyopathy(HCM), and provide quantitative informations for clinical evaluation of cardiac function. Methods A total of 49 consecutive patients with HCM without left ventricular outflow tract obstruction at rest were enrolled.All subjects underwent exercise stress echocardiography. After exercise left ventricular outflow tract pressure gradient(LVOT-PG)≥30 mmHg was positive for exercise stress test (latent obstruction), while LVOT-PG<30 mmHg was negative for exercise stress test (non-obstruction). An ultrasound system obtained two-dimensional ultrasound images of resting and moving peaks. The global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS) of the left ventricle 16 segments and left ventricular rotation, twist were analysis using off-line EchoPAC software. The differences of the above parameters were compared between the two groups. Results There were no significant differences in GLS, GRS, GCS and Rotation-B between the two groups in resting and peak period of exercise (all P>0.05), GRS in both groups were significantly increased compared with that before exercise (all P 0.05). Conclusions Left ventricular torsion function is significantly changed in rest and after exercise in latent obstructive HCM patients, providing valuable quantitative information for clinical comprehensive evaluation of cardiac function. Key words: Echocardiography, stress; Latent left ventricular outflow tract obstruction; Cardiomyopathy, hypertrophic; Two-dimensional strain; Left ventricular twist

Rats are Protected from the Stress of Chronic Pressure Overload Compared with Mice

Little is known about differences in responses to cardiac stress in different rodent species, i.e., rats vs mice. The goal of this investigation was to compare the effects of chronic, 1‐month, thoracic aortic constriction (TAC) in Sprague Dawley rats and C57BL/6 mice. Sham and TAC procedures were conducted in both rodent groups. TAC, in the thoracic aorta, just distal to the aortic valve, induced similar left ventricular (LV) aortic pressure gradients across the aortic constriction, but there was no pressure gradient in sham operated animals. LV ejection fraction was no different in sham rats and mice (73 ± 1%), and did not fall with TAC in the rats, but fell significantly, p&lt;0.05, in mice with TAC to 59 ± 2%. LV end diastolic pressure was also not different in sham rats and mice (5 ± 1 mmHg) and did not increase with TAC in rats, but increased, p&lt;0.05, in TAC mice to 15 ± 2 mmHg. The next goal was to examine potential mechanisms mediating these major differences in LV function. First, we examined LV systolic wall stress, which was also similar in sham rats and mice (73 ± 1 kdyn/cm2) and did not rise significantly in TAC rats, but rose, p&lt;0.05, to 117 ± 7kdyn/cm2 in TAC mice. Since TAC induces LV hypertrophy, which in turn, impairs subendocardial coronary perfusion and coronary reserve, and consequently LV function, angiogenesis and arteriogenesis were examined next, as these mechanisms could alleviate the coronary subendocardial hypoperfusion. Immunofluorescent Ki67 staining of capillaries and arterioles revealed increased angiogenesis, i.e., greater increases, p&lt;0.05, in capillaries in TAC rats (6.7 ± 0.3 Ki67+Isolectin positive cells/field) than in TAC mice (4.2 ± 1.1 Ki67+Isolectin positive cells/field). Arteriogenesis was also increased more in TAC rats than TAC mice, reflected by greater increases, p&lt;0.05, in Ki67 stained arterioles in TAC rats (19.8 ± 0.3 Ki67+SMCα positive cells/field) vs TAC mice (7.9 ± 1.2 Ki67+SMCα positive cells/field). Thus, rats are more resistant to development of cardiac failure with chronic TAC compared with mice. The mechanism of this protection involved reduced LV systolic wall stress and increased angiogenesis and arteriogenesis in the rats with chronic pressure overload.Support or Funding InformationFunding support: NIH R01 HL124282This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Thick Hearts Can't Keep Up: Exercise Limitations in Patients With Hypertrophic Cardiomyopathy

Patients with hypertrophic cardiomyopathy (HCM) may experience intolerance to submaximal and maximal exercise. While ejection fraction is generally preserved, reduced left ventricular end diastolic volume may limit stroke volume reserve and potentially attenuate maximal oxygen uptake (V̇O2max). Whether the relationship between supply (cardiac output, Q̇c) and demand (oxygen uptake, V̇O2) remains intact in these patients is unclear.PURPOSETo quantify the cardiac output response to a given metabolic demand during submaximal and maximal exercise in patients with HCM.METHODSEight patients with HCM (45.8±8.8 years, 75% female, left ventricular outflow tract pressure gradient 13±12mmHg) completed two bouts of submaximal steady‐state treadmill exercise (SS1 ~45% and SS2 ~60% V̇O2max), followed by an incremental treadmill test to exhaustion. V̇O2 (Douglas bag technique), Q̇c, (acetylene rebreathing), stroke volume (Q̇c/heart rate) and arterio‐venous difference (av‐O2 diff, Fick principle) were measured during rest, SS1, SS2 and maximal exercise. Stroke volume reserve was calculated as the percent increase in stroke volume from rest to maximal exercise. The relationship between Q̇c and V̇O2 (Q̇c/V̇O2 slope) was quantified using data collected at rest, submaximal and maximal exercise. Healthy sedentary adults (n=8) and subjects with left ventricular hypertrophy from hypertension (LVH, n=8) were included for age and sex‐matched comparison.RESULTSPatients with HCM had lower relative V̇O2max than healthy subjects and patients with LVH (HCM: 21.1±4.8mL/kg/min, healthy: 27.5±3.4 mL/kg/min, LVH 24.4±7.5 mL/kg/ min). The Q̇c response to a given metabolic demand was impaired in patients with HCM when compared to healthy controls and patients with LVH (HCM: 4.6, control: 5.4, LVH: 5.5; Figure 1). The blunted Q̇c/V̇O2 slope was primarily due to a smaller stroke volume reserve (HCM 28.8±27.0%, healthy 52.2±19.6%, LVH 48.6±25.0%), but also a significantly lower maximal heart rate compared to healthy controls (154±24 vs. 178±10 beats per minute, respectively; P&lt;0.05), though 75% of HCM patients were on beta‐blockade and/or calcium channel‐blockade therapy. Remarkably, five HCM patients were able to compensate for a blunted Q̇c/V̇O2 slope (4.2±0.4) and still achieve &gt;80% of predicted V̇O2max by significantly augmenting av‐O2 diff from rest to maximal exercise (Δav‐O2 diff 10.6±1.6 vs. 6.2±1.5 in HCM patients who did not achieve 80% of predicted V̇O2 max, P&lt;0.05).CONCLUSIONAlthough ejection fraction is preserved, patients with HCM may be unable to sufficiently match Q̇c to metabolic demands. However, some patients appear to compensate by significantly augmenting peripheral oxygen extraction and achieve at least 80% of predicted V̇O2max.Support or Funding InformationSupported by The Center for Regenerative Science and Medicine, UTSW Medical Center, Biotronik Inc., and the Research Endowment from The American College of Sports Medicine Foundation.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Alcohol septal ablation in hypertrophic obstructive cardiomyopathy: a case with a very high left ventricular outflow tract gradient

For more than years alcohol septal ablation ASA has shown to be a safe and effective procedure in the treatment of hypertrophic obstructive cardiomyopathy HOCM with results similar to those of surgical myectomy To our knowledge we present the first documented case of a HOCM with a very high left ventricular outflow tract LVOT gradient gt mm Hg managed with ASA with a decrease of gt of gradient after the procedure

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

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

Electrical remodeling after percutaneous atrial septal defect closure in pediatric and adult patients

BackgroundSeveral studies have reported changes in electrocardiographic variables after atrial septal defect (ASD) closure. However no temporal electro-and vectorcardiographic changes have been described from acute to long-term follow-up at different ages. We aimed to study electrical remodeling after percutaneous ASD closure in pediatric and adult patients. MethodsECGs of 69 children and 75 adults (median age 6 [IQR 4–11] years and 45 [IQR 33–54] years, respectively) were retrospectively selected before percutaneous ASD closure and at acute (1–7 days), intermediate (4–14 weeks) and late (6–18 months) follow-up. Apart from electrocardiographic variables, spatial QRS-T angle and ventricular gradient (VG) were derived from mathematically-synthesized vectorcardiograms. ResultsIn both pediatric and adult patients, the heart rate decreased immediately post-closure, which persisted to late follow-up. The P-wave amplitude also decreased acutely post-closure, but remained unchanged at later follow-up. The PQ duration shortened immediately in children and at intermediate follow-up in adults. The QRS duration and QTc interval decreased at intermediate-term follow-up in both children and adults. In both groups the spatial QRS-T angle decreased at late follow-up. The VG magnitude increased at intermediate follow-up in children and at late follow-up in adults, after an initial decrease in children. ConclusionIn both pediatric and adult ASD patients, electrocardiographic changes mainly occurred directly after ASD closure except for shortening of QRS duration and QTc interval, which occurred at later follow-up. Adults also showed late changes in PQ duration. At 6-to-18 month post-closure, the spatial QRS-T angle decreased, reflecting increased electrocardiographic concordance. The initial acute decrease in VG in children, which was followed by a significant increase, may be the effect of action potential duration dynamics directly after percutaneous ASD closure.

Serial electrocardiography to detect newly emerging or aggravating cardiac pathology: a deep-learning approach

BackgroundSerial electrocardiography aims to contribute to electrocardiogram (ECG) diagnosis by comparing the ECG under consideration with a previously made ECG in the same individual. Here, we present a novel algorithm to construct dedicated deep-learning neural networks (NNs) that are specialized in detecting newly emerging or aggravating existing cardiac pathology in serial ECGs.MethodsWe developed a novel deep-learning method for serial ECG analysis and tested its performance in detection of heart failure in post-infarction patients, and in the detection of ischemia in patients who underwent elective percutaneous coronary intervention. Core of the method is the repeated structuring and learning procedure that, when fed with 13 serial ECG difference features (intra-individual differences in: QRS duration; QT interval; QRS maximum; T-wave maximum; QRS integral; T-wave integral; QRS complexity; T-wave complexity; ventricular gradient; QRS-T spatial angle; heart rate; J-point amplitude; and T-wave symmetry), dynamically creates a NN of at most three hidden layers. An optimization process reduces the possibility of obtaining an inefficient NN due to adverse initialization.ResultsApplication of our method to the two clinical ECG databases yielded 3-layer NN architectures, both showing high testing performances (areas under the receiver operating curves were 84% and 83%, respectively).ConclusionsOur method was successful in two different clinical serial ECG applications. Further studies will investigate if other problem-specific NNs can successfully be constructed, and even if it will be possible to construct a universal NN to detect any pathologic ECG change.

An Echocardiographic Comparison of Sutureless and Conventional Aortic Valve Replacement: a Matched Case-Control Study

Background Patients at a high operative risk for conventional aortic valve replacement (AVR) may be offered sutureless valve implantation. Sutureless valves resemble conventional valves but incorporate an anchoring mechanism without using annular sutures. Methods Pre-operative and six month post-operative echocardiography data from our first year, single centre experience of sutureless valves was compared to conventional aortic valve replacements in patients matched for operative risk. Left ventricular ejection fraction, mean and peak AV gradients and inter-ventricular septal thickness, effective orifice area (EOA) and indexed effective orifice area (iEOA) were measured. Results The drops in mean and peak pre- to post-operative gradients were greater in the sutureless group, p=0.039 and p=0.001 respectively. Post-operative EOA was 1.69 cm2 and 1.26 cm2 (p=0.001) in the sutureless and conventional groups. Similarly iEOA was 0.93 cm2 and 0.74 cm2 (p=0.001) in the sutureless and conventional groups. There was also a reduction in patient prosthesis mismatch (PPM) in the sutureless group as compared to the conventional group (Chi square test p=0.026). Post-operative inter-ventricular septal thickness was 1.13 cm2 in the sutureless group and 1.35 cm2 in the conventional group (p=0.011). Conclusions Use of sutureless valves with a stent framework resulted in larger EOA and iEOA and a diminution in PPM; and lead to a statistically significant faster regression in inter-ventricular septal thickness that is a measure of left ventricular mass. The rate and extent of regression in left ventricular hypertrophy after AVR is important since it determines long-term survival including mortality, heart failure and decreased admission rates.

Spatial QRS-T angle and electrocardiographic ventricular gradient in different forms of pre-capillary pulmonary hypertension

Spatial QRS-T angle and electrocardiographic ventricular gradient in different forms of pre-capillary pulmonary hypertension

The Reproducibility of Global Electrical Heterogeneity ECG Measurements.

Global electrical heterogeneity (GEH) is a useful predictor of adverse clinical outcomes. However, reproducibility of GEH measurements on 10-second routine clinical ECG is unknown. Data of the prospective cohort study of incident hemodialysis patients (n=253; mean age 54.6±13.5y; 56% male; 79% African American) were analysed. Two random 10-second segments of 5-minute ECG recording in sinus rhythm were compared. GEH was measured as spatial QRS-T angle, spatial ventricular gradient (SVG) magnitude and direction (azimuth and elevation), and a scalar value of SVG measured by (1) sum absolute QRST integral (SAI QRST), and (2) QT integral on vector magnitude signal (iVMQT). Bland-Altman analysis was used to calculate agreement. For all studied vectorcardiographic metrics, agreement was substantial (Lin's concordance coefficient >0.98), and precision was perfect (>99.99%). 95% limits of agreement were ±14° for spatial QRS-T angle, ±13° for SVG azimuth, ±4° for SVG elevation, ±14 mV*ms for SVG magnitude, and ±17 mV*ms for SAI QRST. SAI QRST and iVMQT were in substantial agreement with each other. Reproducibility of a 10-second automated GEH ECG measurements was substantial, and precision was perfect.

Global Electrical Heterogeneity: Mechanisms and Clinical Significance.

This review summarizes recent findings and discusses a clinical significance of a vectorcardiographic (VCG) Global electrical heterogeneity (GEH). GEH concept is based on the concept of the spatial ventricular gradient (SVG), which is a global measure of the dispersion of total recovery time. We quantify GEH by measuring five features of the SVG vector (SVG magnitude, direction (azimuth and elevation), a scalar value, and spatial QRS-T angle) on orthogonal XYZ ECG. In analysis of more than 20,000 adults we showed that GEH is independently associated with sudden cardiac death (SCD) after adjustment for demographics, cardiovascular disease (time-updated incident non-fatal cardiovascular events [coronary heart disease, heart failure, stroke, atrial fibrillation, use of beta-blockers], and known risk factors [cholesterol, triglycerides, physical activity index, smoking, diabetes, obesity, hypertension, anti-hypertensive medications, creatinine, alcohol intake, left ventricular ejection fraction, and time-updated ECG metrics (heart rate, QTc, QRS duration, ECG-left ventricular hypertrophy, bundle branch block or interventricular conduction delay)]. This finding suggests that GEH represents an independent electrophysiological substrate of SCD.

Hypertrophic cardiomyopathy with dynamic obstruction and high left ventricular outflow gradients associated with paradoxical apical ballooning.

Acute left ventricular (LV) apical ballooning with normal coronary angiography occurs rarely in obstructive hypertrophic cardiomyopathy (OHCM); it may be associated with severe hemodynamic instability. We searched for acute LV ballooning with apical hypokinesia/akinesia in databases of two HCM treatment programs. Diagnosis of OHCM was made by conventional criteria of LV hypertrophy in the absence of a clinical cause for hypertrophy and mitral-septal contact. Among 1519 patients, we observed acute LV ballooning in 13 (0.9%), associated with dynamic left ventricular outflow tract (LVOT) obstruction and high gradients, 92±37mmHg, 10 female (77%), age 64±7years, LVEF 31.6±10%. Septal hypertrophy was mild compared to that of the rest of our HCM cohort, 15 vs 20mm (P<0.00001). An elongated anterior mitral leaflet or anteriorly displaced papillary muscles occurred in 77%. Course was complicated by cardiogenic shock and heart failure in 5, and refractory heart failure in 1. High-dose beta-blockade was the mainstay of therapy. Three patients required urgent surgical relief of LVOT obstruction, 2 for refractory cardiogenic shock, and one for refractory heart failure. In the three patients, surgery immediately normalized refractory severe LV dysfunction, and immediately reversed cardiogenic shock and heart failure. All have normal LV systolic function at 45-month follow-up, and all have survived. Acute LV apical ballooning, associated with high dynamic LVOT gradients, may punctuate the course of obstructive HCM. The syndrome is important to recognize on echocardiography because it may be associated with profound reversible LV decompensation.

Importance of the heart vector origin point definition for an ECG analysis: The Atherosclerosis Risk in Communities (ARIC) study

AimOur goal was to investigate the effect of a global XYZ median beat construction and the heart vector origin point definition on predictive accuracy of ECG biomarkers of sudden cardiac death (SCD). MethodsAtherosclerosis Risk In Community study participants with analyzable digital ECGs were included (n = 15,768; 55% female, 73% white, mean age 54.2 ± 5.8 y). We developed an algorithm to automatically detect the heart vector origin point on a median beat. Three different approaches to construct a global XYZ beat and two methods to locate origin point were compared. Global electrical heterogeneity was measured by sum absolute QRST integral (SAI QRST), spatial QRS-T angle, and spatial ventricular gradient (SVG) magnitude, azimuth, and elevation. Adjudicated SCD served as the primary outcome. ResultsThere was high intra-observer (kappa 0.972) and inter-observer (kappa 0.984) agreement in a heart vector origin definition between an automated algorithm and a human. QRS was wider in a median beat that was constructed using R-peak alignment than in time-coherent beat (88.1 ± 16.7 vs. 83.7 ± 15.9 ms; P < 0.0001), and on a median beat constructed using QRS-onset as a zeroed baseline, vs. isoelectric origin point (86.7 ± 15.9 vs. 83.7 ± 15.9 ms; P < 0.0001). ROC AUC was significantly larger for QRS, QT, peak QRS-T angle, SVG elevation, and SAI QRST if measured on a time-coherent median beat, and for SAI QRST and SVG magnitude if measured on a median beat using isoelectric origin point. ConclusionTime-coherent global XYZ median beat with physiologically meaningful definition of the heart vector's origin point improved predictive accuracy of SCD biomarkers.

Physiological left ventricular segmental myocardial mechanics: Multiparametric polar mapping to determine intraventricular gradients of myocardial dynamics.

We investigated physiological systolic left ventricular (LV) myocardial mechanics and gradients to provide a database for later studies of diseased hearts. The analyses were performed in 131 heart-healthy individuals and included seven parameters of myocardial mechanics using speckle tracking echocardiography (STE). Basal to apical and circumferentially significant physiological intraventricular parameter gradients of myocardial activity were determined. Global mean values and segmental ranges were peak systolic longitudinal strain -21.2±3.3%, 95% confidence interval [CI] -21.8% to -20.6%), gradient (basal to apical) -16.0% to -26.7%; peak systolic longitudinal strain rate -1.24±0.31%/s, 95% CI -1.29% to -1.19%/s, gradient (basal to apical) -0.91% to -1.61%/s; post-systolic index 2.6±3.2%, 95% CI 3.15%-2.05%, gradient (basal/medial/apical) 7.0/1.2/2.4%; pre-systolic stretch index 1.3±2.7%, 95% CI 1.77%-0.83%, gradient (basal/medial/apical) 6.5/0.2/1.3%; peak longitudinal displacement 12.2±2.6mm, 95% CI 12.6-11.8mm, gradient (basal to apical) 21.0-3.4mm; time-to-peak longitudinal strain 370±43ms, 95% CI 377-363ms, gradient (basal to apical) 396-361ms; and time-to-peak longitudinal strain rate 180±47ms, 95% CI 188-172ms, gradient (basal to apical) 150-200ms. This study generated a database of seven STE-derived parameters of physiological segmental and global myocardial LV mechanics. The resulting sets of three-dimensional intraventricular mappings of the entire LV provide physiological parameter gradients in baso-apical and circumferential direction by applying the 17-segment polar model. This will facilitate comparison of systolic myocardial activity of the healthy LV with diseased or otherwise altered (eg, sports) hearts.

Right Mini-Thoracotomy Subaortic Membrane Resection.

Subaortic membrane is an anatomical intracardiac anomaly that may cause discrete subaortic stenosis and aortic insufficiency. Patients requiring subaortic membrane resection may benefit from a minimally invasive approach; however, subaortic membranes are typically resected through a median sternotomy. We present our initial clinical experience of adult patients who have undergone a mini-thoracotomy subaortic membrane resection. Eight patients who underwent an elective subaortic membrane resection performed through a mini-thoracotomy were retrospectively reviewed. A 5-cm mini-thoracotomy incision was made in the 2nd intercostal space; a videoscope was inserted through a separate incision within the same interspace. Cardiopulmonary bypass (CPB) was instituted via central arterial and peripheral venous cannulation and an aortotomy was made. The subaortic membrane was resected with shafted instruments. The left ventricular outflow tract was inspected and CPB was weaned. Thirty-day mortality, intensive care and hospital length of stay, ventilation time, operative times, postoperative morbidity, and need for additional procedures were evaluated. The median CPB and cross-clamp times were 60 and 42 minutes, respectively. The median time to extubation was 3.6 hours. The median intensive care unit and hospital stay were 22 hours and 3 days, respectively. The postoperative left ventricular outflow tract mean gradients decreased significantly (26.5 vs. 9.4 mm Hg, P = 0.001). There were no conversions to sternotomy, perioperative strokes, or 30-day mortality. Subaortic membranes can be resected through a mini-thoracotomy approach with excellent clinical results.

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

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