Cardiorespiratory fitness and hippocampal volume predict faster episodic associative learning in older adults.

Declining episodic memory is common among otherwise healthy older adults, in part due to negative effects of aging on hippocampal circuits. However, there is significant variability between individuals in severity of aging effects on the hippocampus and subsequent memory decline. Importantly, variability may be influenced by modifiable protective physiological factors such as cardiorespiratory fitness (CRF). More research is needed to better understand which aspects of cognition that decline with aging benefit most from CRF. The current study evaluated the relation of CRF with learning rate on the episodic associative learning (EAL) task, a task designed specifically to target hippocampal-dependent relational binding and to evaluate learning with repeated occurrences. Results show higher CRF was associated with faster learning rate. Larger hippocampal volume was also associated with faster learning rate, though hippocampal volume did not mediate the relationship between CRF and learning rate. Furthermore, to support the distinction between learning item relations and learning higher-order sequences, which declines with aging but is largely reliant on extra-hippocampal learning systems, we found learning rate on the EAL task was not related to motor sequence learning on the alternating serial reaction time task. Motor sequence learning was also not correlated with hippocampal volume. Thus, for the first time, we show that both higher CRF and larger hippocampal volume in healthy older adults are related to enhanced rate of relational memory acquisition.

Prognostic Value of Coronary Artery Calcium Score in Acute Chest Pain Patients Without Known Coronary Artery Disease: Systematic Review and Meta-analysis.

STUDY OBJECTIVE: Coronary artery calcium score (CACS) is a well-established test for risk stratifying asymptomatic patients. Recent studies also indicate that CACS may accurately risk stratify stable patients presenting to the emergency department (ED) with acute chest pain; however, many were underpowered. The purpose of this systematic review and meta-analysis is to evaluate the prognostic value and accuracy of a zero (normal) CACS for identifying patients at acceptable low risk for future cardiovascular events who might be safely discharged home from the ED. METHODS: We searched multiple databases for longitudinal studies of CACS in symptomatic patients without known coronary artery disease that reported major adverse cardiovascular events (MACEs), including death and myocardial infarction. Pooled risk ratios, sensitivity, specificity, and likelihood ratios were analyzed. RESULTS: Eight studies evaluated 3,556 patients, with a median follow-up of 10.5 months. Pooled prevalence of zero CACS was 60%. Patients with CACS=0 had a significantly lower risk of cardiovascular events compared with those with CACS greater than 0 (MACEs: relative risk 0.06, 95% confidence interval 0.04 to 0.11, I2=0%; death/myocardial infarction: relative risk 0.19; 95% confidence interval 0.08 to 0.47, I2=0%). The pooled event rates for CACS=0 (MACEs 0.8%/year; death/myocardial infarction 0.5%/year) were significantly lower than for CACS greater than 0 (MACEs 14.6%/year; death/myocardial infarction 3.5%/year). Analysis of summary testing parameters showed a sensitivity of 96%, specificity of 60%, positive likelihood ratio of 2.36, and negative likelihood ratio of 0.07. CONCLUSION: Acute chest pain patients without history of coronary artery disease, ischemic ECG changes, or increased cardiac enzyme levels commonly have a CACS of zero, with a very low subsequent risk of MACEs or death or myocardial infarction. This meta-analysis proffers the potential role of initial CACS testing for avoiding unnecessary hospitalization and further cardiac testing in acute chest pain patients with a CACS of zero.

Cardiac surgery in patients with Fabry's disease: review of literature.

Fabry's disease is a rare but important cause of structural cardiac disease that may influence cardiac surgical decision making. Herein we present a case of mitral valve repair in a patient with Fabry's disease and review the cardiac-related literature on this lysosomal storage disease.

Telephone titration of heart failure medications.

BACKGROUND: In clinical practice, heart failure (HF) medications are underused and prescribed at lower than recommended doses. Telephone care is an option that could help to titrate HF medication in a timely manner. We describe our experience of a nurse-run, cardiologist- or nurse practitioner-supervised clinic to up-titrate HF medications via telephone. METHODS: Patients with the diagnosis of HF, New York Heart Association classes I to III, were referred to a registered nurse-run, cardiologist-/nurse practitioner-supervised HF medication titration clinic. Clinical and medication data collected at enrollment to the clinic and at 3 to 6 months after optimization of HF medications in patients who did or did not reach the target doses were compared. Effect on left ventricular (LV) function was also evaluated. RESULTS: There were 79 patients in the evaluation: 64 with HF and LV systolic dysfunction (LVSD) and the remaining 15 with HF and preserved ejection fraction (EF). Seventy-two percent of patients with LVSD were on an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB), and 61% were on a ß-blocker at baseline, and this increased to 98% and 97%, respectively, after optimization. Target doses was achieved in 50% of patients for ACEI or ARB, and in 41% for ß-blockers. The median time to optimization was 54 days (interquartile range, 20-97 days). The average number of phone calls at the time of optimization were 5.4 (SD, 3.7), and the average number of clinic visits was 1.9 (SD, 1.3). Reasons for not reaching the target doses included hypotension, hyperkalemia, and renal dysfunction for ACEI and bradycardia for ß-blockers. Overall, the EF increased by 10% (SD, 10%) after 6 months, and 35% or greater in 42% of patients whose baseline EF was less than 35%. There were no adverse events related to the dose up-titration. CONCLUSION: Telephonic titration of HF medications was feasible and safe and was achieved in 97% patients on ACEI/ARB and ß-blockers. Medication titration was associated with significant improvement in LV function, avoiding the need for device therapy in many patients.

Proximity of right coronary artery to cavotricuspid isthmus as determined by computed tomography.

BACKGROUND: Radiofrequency ablation of atrial flutter is a commonly performed procedure. Ablation success depends upon complete transmural atrial tissue injury to achieve bidirectional cavotricuspid isthmus (CTI) block. Transmural ablation increases risk of injury to the adjacent right coronary artery (RCA). Distance between the RCA and the endocardium within the CTI area is not well described. We aimed to perform in vivo measurements of the distance between the CTI area and adjacent RCA. METHODS: Thirty-three consecutive patients underwent electrocardiogram-gated contrast-enhanced computed tomography. CTI area was divided into nine segments based on three common catheter locations (paraseptal, central, and lateral or 5, 6, and 7 o'clock) and ventricular to atrial ablation line. RESULTS: Mean age was 64 ± 11 years and 97% of the participants were male. Paraseptal, central, and lateral measurements at the tricuspid annulus ridge showed endocardial to RCA distance 9 ± 3, 6 ± 2, and 5 ± 3 mm, respectively (range 2-17 mm). Corresponding measurements for the ventricular side were 5 ± 3, 4 ± 2, and 4 ± 2 mm and atrial side measurements were 3 ± 2, 3 ± 2, and 3 ± 3 mm. Distance was ≤2 mm in 14% of segments on the ventricular side and 39% of segments on the atrial side. Paired t-test showed significant difference (P < 0.001) between tricuspid annulus ridge measurements and adjacent atrial or ventricular measurements. CONCLUSIONS: Distance between endocardium and RCA lumen is reduced in areas adjacent to the tricuspid annulus ridge.

A guide for pre-procedural imaging for transcatheter aortic valve replacement patients.

Safe and accurate pre-procedural assessment of cardiovascular anatomy, physiology, and pathophysiology prior to TAVR procedures can mean the difference between success and catastrophic failure. It is imperative that clinical care team members share a basic understanding of the preprocedural imaging technologies available for optimizing the care of TAVR patients. Herein, we review current imaging technology for assessing the anatomy, physiology, and pathophysiology of the aortic valvular complex, ventricular function, and peripheral vasculature, including echocardiography, cardiac catheterization, cardiac computed tomography, and cardiac magnetic resonance prior to a TAVR procedure. The authorship includes cardiac-trained anesthesiologists, anesthesiologists with expertise in pre-procedural cardiac assessment and optimization, and interventional cardiologists with expertise in cardiovascular imaging prior to TAVRs. Improving the understanding of all team members will undoubtedly translate into safer, more coordinated patient care.

Acute Exercise Effects Predict Training Change in Cognition and Connectivity.

PURPOSE: Previous studies report memory and functional connectivity of memory systems improve acutely after a single aerobic exercise session or with training, suggesting that the acute effects of aerobic exercise may reflect initial changes that adapt over time. In this trial, for the first time, we test the proof-of-concept of whether the acute and training effects of aerobic exercise on working memory and brain network connectivity are related in the same participants. METHODS: Cognitively normal older participants (N = 34) were enrolled in a randomized clinical trial (NCT02453178). Participants completed fMRI resting state and a face working memory N-back task acutely after light- and moderate-intensity exercises and after a 12-wk aerobic training intervention. RESULTS: Functional connectivity did not change more after moderate-intensity training compared with light-intensity training. However, both training groups showed similar changes in cardiorespiratory fitness (CRF) (maximal exercise oxygen uptake, V˙O2peak), limiting group-level comparisons. Acute effects of moderate-intensity aerobic exercise on connections primarily in the default network predicted training enhancements in the same connections. Working memory also improved acutely, especially after moderate-intensity, and greater acute improvements predicted greater working memory improvement with training. Exercise effects on functional connectivity of right lateralized frontoparietal connections were related to both acute and training gains in working memory. CONCLUSIONS: Our data support the concept of acute aerobic exercise effects on functional brain systems and performance as an activity-evoked biomarker for exercise training benefits in the same outcomes. These findings may lead to new insights and methods for improving memory outcomes with aerobic exercise training.

Low complement C4B gene copy number predicts short-term mortality after acute myocardial infarction.

BACKGROUND AND OBJECTIVES: Some recent data indicate that risk of death after acute coronary syndrome is under genetic control. Previously, we found that the C4B*Q0 genotype (low copy number of the C4B gene that encodes the fourth component of complement) is strongly associated with morbidity and mortality of cardiovascular diseases (CVD). The +252 G allele of the lymphotoxin-alpha (LTA) gene encoded close to the C4B gene was also reported to be related to CVD-related mortality in an Oriental population. METHODS: The relationship between the copy number of the genes encoding the fourth component of complement (C4A and C4B) and LTA 252 single-nucleotide polymorphism (SNP) on the one hand and mortality after acute myocardial infarction (AMI) was studied in 142 Icelandic patients. The number of the C4A and C4B genes was determined in genomic DNA samples by a newly developed real-time PCR-based method; lymphotoxin-alpha (LTA) +252 A>G polymorphism was determined by PCR-restriction fragment length polymorphism analysis. RESULTS: The C4B*Q0 genotype was found to be strongly associated with 1-year mortality, with a hazard ratio of 3.50 (1.38-8.87) (P = 0.008) (adjusted Cox regression analysis). This association was, however, restricted to ever-smoking patients. By contrast, neither C4A gene copy numbers nor LTA 252 SNP did confer increased risk of mortality after AMI. CONCLUSIONS: This observation indicates that low C4B copy number is a strong risk factor for short-term mortality after AMI in smoking Icelandic patients, whereas LTA 252 G allele is not a risk factor in Caucasian population.

CT for assessing ventricular remodeling: is it ready for prime time?

Reliable assessment of left ventricular size and systolic function has important prognostic and therapeutic implications for patients with heart disease. CT technology is advancing rapidly and can be used for noninvasive assessment of the coronary anatomy. Without additional radiation or contrast, the already acquired image data set can be used for analysis of left ventricular size, mass, and systolic function. In comparison with other noninvasive modalities, multidetector CT has superior spatial resolution but temporal resolution has suffered. Recent advances, including multisegment reconstruction and dual-source scanning, have improved the temporal resolution substantially. MRI is the current gold standard for assessing the left ventricle. Many small comparative studies suggest that CT has good agreement with MRI and that it could potentially replace MRI in some patients, especially those with internal cardiac devices. The use of CT to assess ventricular remodeling is limited by the use of contrast and radiation, but its widespread availability, ease of use, and improved temporal resolution suggest that multidetector CT will have expansive use in the future.

Diagnostic Accuracy of Coronary Computed Tomography Before Aortic Valve Replacement: Systematic Review and Meta-Analysis.

PURPOSE: In aortic stenosis patients referred for surgical and transcatheter aortic valve replacement (AVR), the evidence of diagnostic accuracy of coronary computed tomography angiography (CCTA) has been limited. The objective of this study was to investigate the diagnostic accuracy of CCTA for significant coronary artery disease (CAD) in patients referred for AVR using invasive coronary angiography (ICA) as the gold standard. MATERIALS AND METHODS: We searched databases for all diagnostic studies of CCTA in patients referred for AVR, which reported diagnostic testing characteristics on patient-based analysis required to pool summary sensitivity, specificity, positive-likelihood ratio, and negative-likelihood ratio. Significant CAD in both CCTA and ICA was defined by >50% stenosis in any coronary artery, coronary stent, or bypass graft. RESULTS: Thirteen studies evaluated 1498 patients (mean age, 74 y; 47% men; 76% transcatheter AVR). The pooled prevalence of significant stenosis determined by ICA was 43%. Hierarchical summary receiver-operating characteristic analysis demonstrated a summary area under curve of 0.96. The pooled sensitivity, specificity, and positive-likelihood and negative-likelihood ratios of CCTA in identifying significant stenosis determined by ICA were 95%, 79%, 4.48, and 0.06, respectively. In subgroup analysis, the diagnostic profiles of CCTA were comparable between surgical and transcatheter AVR. CONCLUSIONS: Despite the higher prevalence of significant CAD in patients with aortic stenosis than with other valvular heart diseases, our meta-analysis has shown that CCTA has a suitable diagnostic accuracy profile as a gatekeeper test for ICA. Our study illustrates a need for further study of the potential role of CCTA in preoperative planning for AVR.

Temporal Trends of High-Intensity Statin Therapy Among Veterans Treated With Percutaneous Coronary Intervention.

BACKGROUND: The 2013 American College of Cardiology/American Heart Association blood cholesterol guideline recommends high-intensity statin therapy among certain groups of patients, but full implementation of the guideline has not yet been satisfactory. We aimed to investigate the temporal trends and predictors of high-intensity statin therapy among veterans who had been treated with percutaneous coronary intervention (PCI) and followed up by cardiologists within the Veterans Health Administrative system. METHODS AND RESULTS: A retrospective cohort study was conducted at the Veterans Health Administrative system including all patients >18 years old who had their PCI procedure between October 2010 and September 2016. National Veterans Health Administrative databases were used to retrieve study participant's demographics, comorbid conditions, statin type and dose within 90 days before and after the PCI procedure. There were 48 862 patients who underwent a PCI procedure during the study period. High-intensity statin use at 90 days post-PCI rose from 23% in 2010 to 37% before release of the 2013 American College of Cardiology/American Heart Association cholesterol guideline, then rose sharply to 80% by 2016. The projected 10-year risk of arteriosclerotic cardiovascular disease events among our study population was projected to be ≈1841 fewer if the cohort had received high-intensity statin therapy versus moderate-intensity statin. CONCLUSIONS: By 2016, the 2013 American College of Cardiology/American Heart Association blood cholesterol guideline was well implemented among veterans who had a PCI procedure in the Veterans Health Administrative system, suggesting systems of care can be improved to increase rates of high-intensity statin initiation.

Detection of pulmonary vein stenosis by transesophageal echocardiography: comparison with multidetector computed tomography.

OBJECTIVE: The objective of this study is to compare the use of transesophageal echocardiography (TEE) vs multidetector computed tomography (MDCT) for detecting pulmonary vein stenosis. BACKGROUND: Pulmonary vein isolation is increasingly used to treat atrial fibrillation. Pulmonary vein stenosis remains a potential complication of pulmonary vein isolation and ideal methods for detection of stenosis are still to be determined. METHODS: Thirty-six subjects who underwent pulmonary vein isolation returned for follow-up MDCT and TEE. Percent diameter loss was reported for each pulmonary vein stenosis by MDCT. A 50% narrowing was considered as an indication of a stenosis. Pulsed-wave Doppler using TEE was used to measure peak velocities of all pulmonary veins. RESULTS: Multidetector computed tomography and TEE were performed in all subjects (58 +/- 10 years) at 4 +/- 2 months after pulmonary vein isolation. Atrial fibrillation was present in 14% at time of follow-up. Multidetector computed tomography was able to evaluate all 4 (100%) pulmonary veins in 36 subjects, whereas full interrogation by TEE was possible in 138 (96%) of 144 veins. Pulmonary vein stenosis >50% by MDCT was present in 7 pulmonary veins. Analysis of the receiver operating curve for TEE showed that it had optimum detection of pulmonary vein stenosis at peak velocities approximately 100 cm/s with 86% sensitivity and 95% specificity. Area under the curve for TEE was 0.93. Clinically significant stenosis was observed in 2 subjects and was detected by both TEE and MDCT. CONCLUSIONS: Transesophageal echocardiography was able to detect most pulmonary veins with good sensitivity and specificity in comparison to MDCT. Pulmonary veins may be visualized more frequently by MDCT; however, TEE provides additional data about the functional significance of a pulmonary vein stenosis.

Simultaneous transfemoral aortic and transseptal mitral valve replacement utilising SAPIEN 3 valves in native aortic and mitral valves.

AIMS: Concomitant severe calcific aortic and mitral stenosis is a relatively uncommon but very challenging valvular heart disease to manage. We sought to evaluate the feasibility of a fully percutaneous approach to replace both stenotic native mitral and aortic valves using SAPIEN 3 valves. METHODS AND RESULTS: An 87-year-old woman with chronic kidney disease stage 3, pul-monary hypertension, chronic obstructive pulmonary disease, a permanent pacemaker, and atrial fibrillation was referred with Class III heart failure symptoms. Her echocardiogram showed a decreased ejection fraction at 45%, severe mitral stenosis (mean gradient 13 mmHg, area 0.8 cm2) with severe MAC, and severe AS (mean gradient 35 mmHg, area 0.6 cm2). Surgical risk was felt to be very high after evaluation by our cardiothoracic sur-gery group (Society of Thoracic Surgeons risk score of 19%). She underwent simultaneous and fully percutaneous trans-femoral TAVR and transseptal TMVR using SAPIEN 3 valves. Post-implant TEE showed trace paravalvular mitral regurgitation and a mean gradient of 4 mmHg and mean aortic gradient of 8 mmHg with trace paravalvular leak. There was no LVOT obstruction. The patient was discharged seven days after the intervention. CONCLUSIONS: After careful evaluation by experienced Heart Teams, combined native stenotic mitral and aortic valves can be percutaneously replaced using transcatheter SAPIEN 3 valves via transfemoral access in carefully selected high surgical risk patients.

Coronary artery calcium score as a predictor for incident stroke: Systematic review and meta-analysis.

BACKGROUND: Coronary artery calcium score (CACS) is a well-established test for risk stratifying asymptomatic patients for overall cardiovascular or coronary events. However; the prognostic value for incident stroke remains controversial. The objective of this study was to investigate the predictive value of CACS obtained by non-contrast electrocardiogram-gated computed tomography for incident stroke. METHODS: We searched PubMed, EMBASE, Cochrane databases for prospective longitudinal studies of CACS which reported the incidence of stroke. Incidence of stroke was compared in patients with and without coronary calcification. RESULTS: Three studies evaluated 13,262 asymptomatic patients (mean age=60years, 50% men) without apparent cardiovascular diseases. During a follow-up of 7.2years (median 5years, range 4.4-9.5years, 95,434patient-years), the overall pooled incidence of stroke was 0.26%/year. The pooled risk ratio of CACS>0 for incident stroke was 2.95 (95% CI: 2.18-4.01, p<0.001) compared to CACS=0. The heterogeneity among studies was low (I2=0%). The pooled incidence rate of stroke categorized by CACS was 0.12%/year for CACS 0, 0.26%/year for CACS 1-99, 0.41%/year for CACS 100-399 and 0.70%/year for CACS ≥400. CONCLUSIONS: In asymptomatic patients without apparent cardiovascular diseases, the incidence of stroke was overall low. The presence and severity of coronary artery calcification were associated with incident stroke over mid-long term follow-up.

Carotid ß-stiffness index is associated with slower processing speed but not working memory or white matter integrity in healthy middle-aged/older adults.

Aging is associated with increased carotid artery stiffness, a predictor of incident stroke, and reduced cognitive performance and brain white matter integrity (WMI) in humans. Therefore, we hypothesized that higher carotid stiffness/lower compliance would be independently associated with slower processing speed, higher working memory cost, and lower WMI in healthy middle-aged/older (MA/O) adults. Carotid ß-stiffness (P < 0.001) was greater and compliance (P < 0.001) was lower in MA/O (n = 32; 64.4 ± 4.3 yr) vs. young (n = 19; 23.8 ± 2.9 yr) adults. MA/O adults demonstrated slower processing speed (27.4 ± 4.6 vs. 35.4 ± 5.0 U/60 s, P < 0.001) and higher working memory cost (-15.4 ± 0.14 vs. -2.2 ± 0.05%, P < 0.001) vs. young adults. Global WMI was lower in MA/O adults (P < 0.001) and regionally in the frontal lobe (P = 0.020) and genu (P = 0.009). In the entire cohort, multiple regression analysis that included education, sex, and body mass index, carotid ß-stiffness index (B = -0.53 ± 0.15 U, P = 0.001) and age group (B = -4.61 ± 1.7, P = 0.012, adjusted R2 = 0.4) predicted processing speed but not working memory cost or WMI. Among MA/O adults, higher ß-stiffness (B = -0.60 ± 0.18, P = 0.002) and lower compliance (B = 0.93 ± 0.26, P = 0.002) were associated with slower processing speed but not working memory cost or WMI. These data suggest that greater carotid artery stiffness is independently and selectively associated with slower processing speed but not working memory among MA/O adults. Carotid artery stiffening may modulate reductions in processing speed earlier than working memory with healthy aging in humans.NEW & NOTEWORTHY Previously, studies investigating the relation between large elastic artery stiffness, cognition, and brain structure have focused mainly on aortic stiffness in aged individuals with cardiovascular disease risk factors and other comorbidities. This study adds to the field by demonstrating that the age-related increases in carotid artery stiffness, but not aortic stiffness, is independently and selectively associated with slower processing speed but not working memory among middle-aged/older adults with low cardiovascular disease risk factor burden.

Gender Differences in the Trends of Hospitalizations for Acute Stroke Among Patients With Atrial Fibrillation in the United States: 2005 to 2014.

Female gender was included in stroke prediction algorithms in an attempt to improve anticoagulation rates in women with atrial fibrillation (AF). It is unclear if these efforts reduced stroke burden in women with AF. To bridge this literature gap, using the Nationwide Inpatient Sample, we assessed gender differences in the trends of hospitalizations for stroke among patients with AF in the United States in 2005 to 2014. International classification of diseases, 9th revision, clinical modification codes were used to abstract AF and stroke diagnoses. From 2005 to 2014, 18,413,291 hospitalizations of women with AF and 18,035,866 hospitalizations of men with AF were reported. Of these, 740,635 hospitalizations in women and 595,730 hospitalizations in men had stroke as the primary diagnosis. Age-adjusted stroke hospitalizations increased in women (443 per million in 2005 to 495 per million in 2014) as well as in men (351 per million in 2005 to 453 per million in 2014) (p trend < 0.001). Further, anticoagulation rates increased in women (11.5% in 2005 to 24.0% in 2014) as well as in men (11.7% in 2005 to 24.9% in 2014). Stroke hospitalizations involving anticoagulated patients with AF decreased in women (411 per million in 2005 to 347 per million in 2014) as well as in men (402 per million in 2005 to 311 per million in 2014) (p trend < 0.001). In conclusion, although we noted an increasing trend of stroke hospitalizations in both genders, it is reassuring to note that stroke hospitalizations involving anticoagulated patients with AF is decreasing in both genders and in particular among women.

Use of tissue Doppler imaging to guide tube current modulation in cardiac multidetector computed tomographic angiography.

In multidetector computed tomographic coronary angiography, strategies to minimize effective radiation dose (ERD) are urgently needed. Prospective tube current modulation (TCM) allows a decrease in ERD, although it may limit reconstruction options. We sought to determine if tissue Doppler imaging (TDI) by echocardiography could predict an optimal phase for multidetector computed tomography and be used to guide TCM. Echocardiographic studies were performed in 94 patients immediately before multidetector computed tomography (83% men; mean 60 +/- 11 years of age, mean body mass index 27.7+/-4.1 kg/m2) and identified the most quiescent phase of the cardiac cycle within the atrioventricular groove. In 40 patients, prospective TCM was programmed according to TDI (TCM(TDI) group); 54 patients underwent multidetector computed tomography without TCM (no-TCM). In 25 patients assigned to the TCM(TDI) group, multidetector computed tomograms were correlated with invasive quantitative coronary angiograms to ensure maintenance of diagnostic accuracy. Optimal phase determined by TDI was 71 +/- 11%, with a distinct bi-modal distribution. Compared with no-TCM, effective radiation dose was decreased by 42% in the TCM(TDI) group (6.6 +/- 1.2 vs 11.4 +/- 2.2 mSv, p < 0.0001). Only 8 segments (3%) were unevaluable due to motion artifact. In 296 segments, sensitivity, specificity, and positive and negative predictive values to detect lesions > 50% by multidetector computed tomography were 92%, 94%, 65%, and 99%, respectively. There was good correlation between quantitative coronary angiography and multidetector computed tomography for absolute degree of stenosis (r = 0.70, p < 0.0001). In conclusion, TDI is a useful tool to guide prospective TCM in multidetector computed tomography. ERD in multidetector computed tomography may be significantly decreased using this technique while maintaining excellent image quality.

Tissue synchronization imaging and optimal left ventricular pacing site in cardiac resynchronization therapy.

The optimal pacing site in cardiac resynchronization therapy (CRT) remains controversial. Tissue synchronization imaging is a novel echocardiographic technique that color-codes for areas of maximal delay in myocardial velocities. This study aimed to identify whether the left ventricular (LV) pacing lead position in CRT should be guided by a patient's area of maximal mechanical delay. Fifty-four patients with advanced heart failure were assessed echocardiographically before and 6 months after CRT. Response was analyzed according to the relation between the LV lead position and the area of maximal delay to peak velocity by tissue synchronization imaging in the first half of the ejection phase: group 1 (n = 22) had lead placement corresponding to the segment of maximal delay; group 2 (n = 13) had lead placement 1 segment adjacent; and group 3 (n = 19) had lead placement remote from this site. Evidence of LV reverse remodeling and improved systolic function was documented in group 1 (mean percentage decrease in end-systolic volume 23%) more than in group 2 (mean decrease 15%), and more than in group 3 (mean increase 8.9%, p <0.0001 compared with groups 1 and 2). In group 1, 16 of 22 patients had reverse remodeling (>15% decrease in end-systolic volume); reverse remodeling was seen in 7 of 13 patients in group 2 and 1 of 19 in group 3. The placing of the lead position proximal to the site of maximal delay by tissue synchronization imaging was correlated with reverse remodeling (r = 0.449, p = 001). Of 7 patients with delay confined to the septum and anterior wall only, none had evidence of reverse remodeling after CRT. In conclusion, pacing at the site of maximal mechanical delay was associated with reverse remodeling. Individually tailored LV lead positioning should be considered before CRT.