Brian D. Powell

Preoperative Aspirin Therapy Is Associated With Improved Postoperative Outcomes in Patients Undergoing Coronary Artery Bypass Grafting

Background—Aspirin is beneficial in the setting of atherosclerotic cardiovascular disease. There are limited data evaluating preoperative aspirin administration preceding coronary artery bypass grafting and associated postoperative outcomes. Methods and Results—Using prospectively collected data from 1636 consecutive patients undergoing first-time isolated coronary artery bypass surgery at our institution from January 2000 through December 2002, we evaluated the association between aspirin usage within the 5 days preceding coronary bypass surgery and risk of adverse in-hospital postoperative events. A logistic regression model, which included propensity scores, was used to adjust for remaining differences between groups. Overall, there were 36 deaths (2.2%) and 48 adverse cerebrovascular events (2.9%) in the postoperative hospitalization period. Patients receiving preoperative aspirin (n=1316) had significantly lower postoperative in-hospital mortality compared with those not receiving preoperative aspirin [1.7% versus 4.4%; adjusted odds ratio (OR), 0.34; 95% CI, 0.15 to 0.75; P=0.007]. Rates of postoperative cerebrovascular events were similar between groups (2.7% versus 3.8%; adjusted OR, 0.67; 95% CI, 0.32 to 1.50; P=0.31). Preoperative aspirin therapy was not associated with an increased risk of reoperation for bleeding (3.5% versus 3.4%; P=0.96) or requirement for postoperative blood product transfusion (adjusted OR, 1.17; 95% CI, 0.88 to 1.54; P=0.28). Conclusions—Aspirin usage within the 5 days preceding coronary artery bypass surgery is associated with a lower risk of postoperative in-hospital mortality and appears to be safe without an associated increased risk of reoperation for bleeding or need for blood product transfusion.

Comparison of Echocardiographic Dyssynchrony Assessment by Tissue Velocity and Strain Imaging in Subjects With or Without Systolic Dysfunction and With or Without Left Bundle-Branch Block

Background— Several echocardiographic dyssynchrony indexes have been proposed to identify responders to cardiac resynchronization therapy using tissue velocity and strain. The present study aimed to compare tissue velocity–derived and strain-derived dyssynchrony indexes in patients with or without systolic dysfunction and left bundle-branch block. Methods and Results— Tissue Doppler imaging was performed in 120 subjects divided into 4 groups: group 1 (n=40), normal subjects; group 2 (n=20), normal left ventricular ejection fraction and left bundle-branch block; group 3 (n=20), left ventricular ejection fraction <35% and normal conduction; and group 4 (n=40), left ventricular ejection fraction <35% and left bundle-branch block. Dyssynchrony indexes based on time to peak tissue velocity (septal-lateral delay, anteroseptal-posterior delay, and SD in time to peak systolic velocity in the 12 left ventricular segments) and strain (SD of time to peak strain in 12 segments) were measured. The SD in time to peak systolic velocity in the 12 left ventricular segments was greater in group 4 (54 ms; 25th and 75th percentiles, 46 to 64 ms) than group 1 (44 ms; 25th and 75th percentiles, 28 to 53 ms; P=0.006), but there was a considerable overlap of all tissue velocity–derived indexes among 4 groups, with 40% to 68% of group 1 having values proposed for predicting the responders of cardiac resynchronization therapy. The SD of time to peak strain in 12 segments distinguished these groups with much less overlap (P<0.01 for all pairwise comparisons). Conclusions— A substantial proportion of normal subjects have tissue velocity–derived dyssynchrony indexes higher than the cutoff value proposed for predicting beneficial effect of cardiac resynchronization therapy. Strain-derived timing index appears to be more specific for dyssynchrony in patients with systolic dysfunction and left bundle-branch block. Identifying an optimal tissue velocity– or strain-derived dyssynchrony index requires a large prospective clinical trial.

Substrate and Procedural Predictors of Outcomes After Catheter Ablation for Atrial Fibrillation in Patients with Hypertrophic Cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) is often accompanied by atrial fibrillation (AF) due to diastolic dysfunction, elevated left atrial pressure, and enlargement. Although catheter ablation for drug‐refractory AF is an effective treatment, the efficacy in HCM remains to be established.

Atrioventricular nodal ablation predicts survival benefit in patients with atrial fibrillation receiving cardiac resynchronization therapy

BACKGROUND Cardiac resynchronization therapy (CRT) benefits patients with advanced heart failure. The role of atrioventricular nodal (AVN) ablation in improving CRT outcomes, including survival benefit in CRT recipients with atrial fibrillation, is uncertain. OBJECTIVE The purpose of this study was to assess the impact of AVN ablation on clinical and survival outcomes in a large atrial fibrillation and heart failure population that met the current indication for CRT and to determine whether AVN ablation is an independent predictor of survival in CRT recipients. METHODS Of 154 patients with atrial fibrillation who received CRT-D, 45 (29%) underwent AVN ablation (+AVN-ABL group), whereas 109 (71%) received drug therapy for rate control during CRT (-AVN-ABL group). New York Heart Association (NYHA) class, electrocardiogram, and echocardiogram were assessed before and after CRT. Survival data were obtained from the national death and location database (Accurint). RESULTS CRT comparably improved left ventricular ejection fraction (8.1% +/- 10.7% vs 6.8% +/- 9.6%, P = .49) and left ventricular end-diastolic diameter (-2.1 +/- 5.9 mm vs -2.1 +/- 6.7 mm, P = .74) in both +AVN-ABL and -AVN-ABL groups. Improvement in NYHA class was significantly greater in the +AVN-ABL group than in -AVN-ABL group (-0.7 +/- 0.8 vs -0.4 +/- 0.8, P = .04). Survival estimates at 2 years were 96.0% (95% confidence interval [CI] 88.6%-100%) for +AVN-ABL group and 76.5% (95% CI 68.1%-85.8%) for-AVN-ABL group (P = .008). AVN ablation was independently associated with survival benefit from death (hazard ratio [HR] 0.13, 95% CI 0.03-0.58, P = .007) and from combined death, heart transplant, and left ventricular assist device (HR 0.19, 95% CI 0.06-0.62, P = .006) after CRT. CONCLUSION Among patients with atrial fibrillation and heart failure receiving CRT, AVN ablation for definitive biventricular pacing provides greater improvement in NYHA class and survival benefit. Larger-scale randomized trials are needed to assess the clinical and survival outcomes of this therapy.

Dyssynchrony Indices To Predict Response to Cardiac Resynchronization Therapy A Comprehensive Prospective Single-Center Study

Background—Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results—Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions—These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.

Dyssynchrony Indices To Predict Response to Cardiac Resynchronization Therapy

Background—Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results—Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions—These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.

Strain Dyssynchrony Index Correlates With Improvement in Left Ventricular Volume After Cardiac Resynchronization Therapy Better Than Tissue Velocity Dyssynchrony Indexes

Background—Various dyssynchrony indexes derived from tissue velocity and strain imaging have been proposed to predict the effectiveness of cardiac resynchronization therapy (CRT). We sought to compare the effect of CRT on dyssynchrony indexes derived by tissue velocity and strain and to determine which baseline intraventricular dyssynchrony parameters correlate with improvement in left ventricular volume after CRT. Methods and Results—Echocardiography with tissue Doppler imaging was performed in 45 patients with systolic heart failure at baseline, 1 day after CRT, and a median of 6 months after CRT. We calculated septal–lateral delay and anteroseptal–posterior delay and standard deviation of time to peak systolic velocity in the 12 basal and mid-left ventricular segments (Tv-SD). The standard deviation for time to peak strain in the 12 basal and mid-left ventricular segments (Tϵ-SD) was calculated as a strain-derived dyssynchrony index. None of the tissue velocity–derived dyssynchrony indexes improved after CRT (septal–lateral delay, P=0.39; anteroseptal–posterior delay, P=0.46; Tv-SD, P=0.30), whereas Tϵ-SD decreased significantly after CRT (P<0.001). Improvement in Tϵ-SD 1 day after CRT correlated with the reduction in end-systolic volume at follow-up (r=0.66; P<0.001). Baseline Tϵ-SD demonstrated significant correlation with the reduction of end-systolic volume at follow-up (r=0.57; P<0.001); however, baseline tissue velocity–derived dyssynchrony indexes failed to predict the effect of CRT. Conclusions—The strain-derived dyssynchrony index is a better measurement than the tissue velocity dyssynchrony index for monitoring changes in mechanical dyssynchrony after CRT and for predicting reduction in left ventricular volume after CRT.

Left ventricular discoordination index measured by speckle tracking strain rate imaging predicts reverse remodelling and survival after cardiac resynchronization therapy.

This study aimed to evaluate the predictive value of a baseline speckle tracking strain rate imaging‐derived discoordination index for response to cardiac resynchronization therapy (CRT).

Successful cryoablation in the noncoronary aortic cusp for a left anteroseptal accessory pathway

Catheter ablation of anteroseptal accessory pathways may be difficult because of the neighboring conduction tissue that may be damaged with ablation. We report a case of an accessory pathway localized to the anteroseptal region. A pathway potential found in the noncoronary cusp of the aortic valve was successfully targeted for ablation with cryo energy. Observations during tachycardia and pacing maneuvers suggest that the supravalvar aortic musculature may be an integral component of left anteroseptal pathways that can be safely targeted for cryoablation without injury of the atrioventricular conduction system.

Impact of Myocardial Scarring on Outcomes of Cardiac Resynchronization Therapy: Extent or Location?

Refining the criteria for patient selection for cardiac resynchronization therapy (CRT) may improve its outcomes. The study objective was to determine the effect of scar location, scar burden, and left ventricular (LV) lead position on CRT outcomes. Methods: The study included 213 consecutive CRT recipients with radionuclide myocardial perfusion imaging before CRT between January 2002 and December 2008. Scar localization and myocardial viability were analyzed using a 17-segment model and a 5-point semiquantitative scale. New York Heart Association (NYHA) class and echocardiography were assessed before and after CRT. The anatomic LV lead location in the 17-segment model was assessed by review of fluoroscopic cinegrams in right and left anterior oblique views. As in published studies, clinical response was defined as an absolute improvement in LV ejection fraction of ≥5 percentage points after CRT. Results: A total of 651 scar segments was identified in 213 patients. Eighty-three percent of scar segments were located in the LV anterior, posterior, septal, and apical regions, whereas 84% of LV leads were in the lateral wall. Only 11% of LV leads were positioned in scar segments. The extent of scarring was significantly higher in nonresponders than in responders (18.0% vs. 6%, P = 0.001). Compared with patients with scarring >22%, patients ≤70 y with scarring ≤22% of the left ventricle had a greater increase in LV ejection fraction (10.1% ± 10.5% vs. 0.8% ± 6.1%; P < 0.001) and improvement in NYHA class (–0.9 ± 0.7 vs. –0.5 ± 0.8; P = 0.02). Conclusion: LV leads were often located in viable myocardial regions. Less scar burden was associated with a greater improvement in heart failure but only in relatively younger CRT recipients.