Person:

Baggish, Aaron

Background: Non-diagnostic dobutamine stress echocardiography (ndDSE, failure to achieve 85% of maximal predicted heart rate (HR) without evidence of inducible ischemia) is an important limitation affecting quality of DSE testing. The objectives of this study were to identify the clinical variables associated with a non-diagnostic Dobutamine Stress Echocardiogram (ndDSE) and further evaluate the patterns of subsequent testing for myocardial ischemia. Methods: Consecutive DSE’s over a 17 month period (January 2008 to June 2009) were studied. Baseline demographics, medical history, and vital signs were collected. Subsequent testing was determined for up to 6 months after the initial DSE. Univariate and multivariate logistic regression analysis was performed to identify clinical factors associated with ndDSE. Results: Of 467 total DSE, 314 (67%) were negative for ischemia, 69 (15%) were positive, and 84 (18%) were ndDSE. Of those recommended for further nuclear MPI testing 12 (14%) had an ndDSE compared to 16 (4%) patients with a diagnostic DSE (P = 0.001). Fifty percent of the ndDSE nuclear MPI tests were positive for ischemia. In the univariate analysis, Diabetes Mellitus (DM; P = 0.003), calcium channel antagonist (CCA) use (P = 0.047), Hypertension (HTN; P = 0.06), low baseline HR (P < 0.001), and younger age group (P = 0.02) were predictive of ndDSE. Of these, all except CCA use remained independent predictors of ndDSE in multivariate analysis. A 4 variable model for predicting ndDSE was developed from the multivariate logistic regression displayed in Table 1 (age and baseline HR were categorized and scored 0-2; DM and HTN were scored as 0 (absent) or 1 (present)). Figure 2 demonstrates how risk of ndDSE correlated with a higher score, with each increment having an odds ratio of 2.1 (P < 0.001). Conclusions: DM, HTN, younger age, and lower baseline HR affect the quality of DSE testing, resulting in non-diagnostic tests. A model combining these factors can identify patients most likely to have this outcome. Identification of this cohort may improve referral patterns and improve the quality of stress testing.

Background: Although illicit anabolic-androgenic steroid (AAS) use is widespread, the cardiac effects of long-term AAS use remain inadequately characterized. We compared cardiac parameters in weightlifters reporting long-term AAS use to those in otherwise similar weightlifters without prior AAS exposure. Methods & Results: We performed 2-dimensional, tissue-Doppler, and speckle-tracking echocardiography to assess left ventricular (LV) ejection fraction, LV systolic strain, and conventional indices of diastolic function in long-term AAS users (n=12) and otherwise similar AAS non-users (n=7). AAS users (median [Q1,Q3] cumulative lifetime AAS exposure 468 [169–520] weeks) closely resembled non-users in age, prior duration of weightlifting, and current intensity of weight training. LV structural parameters were similar between the two groups. However, AAS users had significantly lower LV ejection fraction (50.6% [48.4, 53.6] versus 59.1% [58.0, 61.7]; p = 0.003 by Wilcoxon rank sum test, two-tailed); longitudinal strain (16.9% [14.0, 19.0] versus 21.0% [20.2, 22.9]; p = 0.004), and radial strain (38.3 [28.5, 43.7] versus 50.1 [44.3, 61.8]; p = 0.02). Ten of the 12 AAS users showed LV ejection fractions below the accepted limit of normal (≥55%). AAS users also demonstrated decreased diastolic function compared to non-users, as evidenced by a markedly lower E′ velocity (7.4 [6.8, 7.9] versus 9.9 [8.3, 10.5]; p = 0.005) and E/A ratio (0.93 [0.88, 1.39] versus 1.80 [1.48, 2.00]; p = 0.003). Conclusions: Cardiac dysfunction in long-term AAS users appears more severe than previously reported, and may be sufficient to increase the risk of heart failure.

Background: Inferior lead early repolarization pattern (ERP) has recently been associated with sudden cardiac death. Although ERP is common among athletes, prevalence, ECG lead distribution, clinical characteristics, and effects of physical training remain uncertain. We sought to examine the non-anterior early repolarization pattern (ERP) in competitive athletes. Methods and Results: ERP was assessed in a cross-sectional cohort of collegiate athletes (n=879). The relationship between ERP and cardiac structure were then examined in a longitudinal subgroup (n=146) before and after a 90-day period of exercise training. ERP was defined as J-point elevation ≥ 0.1 mV in at least two leads within a non-anterior territory (inferior [II, III, aVF] or lateral [I, aVL, V4-V6]). Non-anterior ERP was present in 25.1% (221/879) of athletes including the inferior subtype in 3.8% (33/879). Exercise training led to significant increases in the prevalence of ERP and the inferior subtype but there were no associations between ERP and echocardiographic measures of left ventricular remodeling. In a multivariable model, ERP was associated with black race (OR 5.84, CI 3.54-9.61, p<0.001), increased QRS voltage (OR 2.08, CI 1.71-2.52, p<0.001), and slower HR (OR 1.54, CI 1.26-1.87, p<0.001). Conclusions: Non-anterior ERP including the inferior subtype are common and have strong clinical associations among competitive athletes. The finding of increased ERP prevalence following intense physical training establishes a strong association between exercise and the ERP.

Background: Left ventricular (LV) rotation results from contraction of obliquely oriented myocardial fibers. The net difference between systolic apical counterclockwise rotation and basal clockwise rotation is left ventricular torsion (LVT). Although LVT is altered in various cardiac diseases, determinants of LVT are incompletely understood. Methods and Results: LV end-diastolic volume (LVEDV), LV apical and basal rotation, peak systolic LVT, and peak early diastolic untwisting rate (UTR) were measured by speckle tracking echocardiography in healthy subjects (n=8) before and after infusion of a weight-based normal saline bolus (2.1±0.3 L). Saline infusion lead to a significant increase in end-diastolic LV internal diameter (45.9±3.7 versus 47.6±4.2 mm; p=0.002) and LVEDV (90.0±21.6 versus 98.3±19.6 mL; p=0.01). Stroke volume (51.3±10.9 versus 63.0±15.5 mL; p = 0.003) and cardiac output (3.4±0.8 versus 4.4±1.5 L/min; p = 0.007) increased while there was no change in heart rate and blood pressure. There was a significant increase in the magnitude of peak systolic apical rotation (7.5±2.4 versus 10.5±2.8 degrees; p < 0.001) but no change in basal rotation (-4.1±2.3 versus -4.8±3.1 degrees; p = 0.44). Accordingly, peak systolic LVT increased by 33% following saline infusion (11.2±1.3 versus 14.9±1.7 degrees; p < 0.001). This saline-induced increase in LVT was associated with a marked increase in peak early diastolic UTR (72.3±21.4 versus 136.8±30.0 degrees/s; p < 0.001). Conclusions: Peak systolic LVT and peak early diastolic UTR are preload dependent. Changes in LV preload should be considered when interpreting results of future LVT studies.

Background-—In epidemiologic studies, obesity has been associated with reduced natriuretic peptide (NP) concentrations. Reduced NP production could impair the ability of obese individuals to respond to salt loads, increasing the risk of hypertension and other disorders. We hypothesized that weight loss enhances NP production before and after salt loading. Methods and Results-—We enrolled 15 obese individuals (mean BMI 45 5.4 kg/m2) undergoing gastric bypass surgery. Before and 6 months after surgery, subjects were admitted to the clinical research center and administered a large-volume intravenous saline challenge. Echocardiography and serial blood sampling were performed. From the pre-operative visit to 6 months after surgery, subjects had a mean BMI decrease of 27%. At the 6-month visit, N-terminal pro-atrial NP (Nt-proANP) levels were 40% higher before, during, and after the saline infusion, compared with levels measured at the same time points during the pre-operative visit (P<0.001). The rise in Nt-pro-ANP induced by the saline infusion (50%) was similar both before and after surgery (saline, P<0.001; interaction, P=0.2). Similar results were obtained for BNP and Nt-proBNP; resting concentrations increased by 50% and 31%, respectively, after gastric bypass surgery. The increase in NP concentrations after surgery was accompanied by significant decreases in mean arterial pressure (P=0.004) and heart rate (P<0.001), and an increase in mitral annular diastolic velocity (P=0.02). Conclusion-—In obese individuals, weight loss is associated with a substantial increase in the “setpoint” of circulating NP concentrations. Higher NP concentrations could contribute to an enhanced ability to handle salt loads after weight loss.