Renee L. Bess

Biventricular pacing improves cardiac function and prevents further left atrial remodeling in patients with symptomatic atrial fibrillation after atrioventricular node ablation.

BACKGROUND Randomized trials have demonstrated benefits of biventricular (BiV) pacing in patients with advanced heart failure, intraventricular conduction delay, and atrial fibrillation (AF) post-atrioventricular (AV) node ablation. The AV Node Ablation with CLS and CRT Pacing Therapies for Treatment of AF trial (AVAIL CLS/CRT) was designed to demonstrate superiority of BiV pacing in patients with AF after AV node ablation, to evaluate its effects on cardiac structure and function, and to investigate additional benefits of Closed Loop Stimulation (CLS) (BIOTRONIK, Berlin, Germany). METHODS Patients with refractory AF underwent AV node ablation and were randomized (2:2:1) to BiV pacing with CLS, BiV pacing with accelerometer, or right ventricular (RV) pacing. Echocardiography was performed at baseline and 6 months, with paired data available for 108 patients. RESULTS The RV pacing contributed to significant increase in left atrial volume, left ventricular (LV) end-systolic volume, and LV mass compared to BiV pacing. Ejection fraction decreased insignificantly with RV pacing compared to significant increase with BiV pacing. Interventricular dyssynchrony significantly decreased with BiV compared with RV pacing. Closed Loop Stimulation did not result in additional echocardiographic changes; heart rate distribution was significantly wider with CLS. All groups showed significant improvement in 6-minute walk distance, quality-of-life score, and New York Heart Association class. CONCLUSION In conclusion, RV pacing results in significant increase in left atrial volume, LV mass, and worsening of LV contractility compared to patients receiving BiV pacing post-AV node ablation for refractory AF. Closed Loop Stimulation was not associated with additional structural changes but resulted in significantly wider heart rate distribution.

Technical aspects of diastology: why mitral inflow and tissue Doppler imaging are the preferred parameters?

Doppler methods for assessing left ventricular (LV) diastolic function have increased in number and complexity. However, time constraints may prevent measurement of all parameters during routine transthoracic echocardiography. Therefore, we designed a study to determine which Doppler parameters could be most successfully and quickly obtained. The recording success rate and time required to record different LV diastolic function parameters were evaluated in 80 patients. A specific recording protocol was followed by an experienced, credentialed sonographer and time intervals to record each parameter were measured. In comparison with color Doppler M‐mode of LV inflow propagation velocities (Vp) and pulmonary venous (PV) flow measurements, transmitral valve (MV) flow and tissue Doppler imaging (TDI) of the mitral annulus had the highest recording success rate and required the shortest time to record. PV flow and Vp took longer to obtain (80.1 ± 34.3 sec and 57.1 ± 29.1 sec, respectively) than did mitral valve inflow (36.3 ± 20.7sec) and mitral valve annular TDI (29.3 ± 18.4 sec for septal and 33.3 ± 14.5sec for lateral). MV flow velocities, Vp, and TDI were successfully recorded in virtually all patients (99–100%). In comparison, the PV flow velocities and durations were successfully recorded less often. The range of success rates for the six PV flow parameters was 49–84%. Since MV flow and TDI also have been shown by us to have the lowest interreader variability, measurement of these two parameters may be preferred for routine clinical evaluation of LV diastolic function in a busy echocardiography laboratory.

Relationship Between Carotid Disease on Ultrasound and Coronary Disease on CT Angiography

OBJECTIVES The purpose of this study was to assess the relationship between carotid artery disease by ultrasound and coronary artery disease by coronary computed tomography angiography (CTA) and to identify carotid ultrasound parameters predictive of coronary artery disease. BACKGROUND Carotid ultrasound and CTA are noninvasive modalities used to image atherosclerosis. Studies examining the relationship between the 2 tests, however, are lacking. METHODS We performed carotid ultrasound on predominantly nondiabetic subjects referred for CTA. Carotid intima media thickness (IMT) and plaque were assessed and compared with coronary artery calcification and the number of coronary arteries with any evidence of atherosclerosis on CTA. RESULTS A total of 150 subjects underwent both CTA and carotid ultrasound on the same day. Carotid plaque was present in 71.3% (n = 107), whereas the presence of at least 1 coronary artery with disease on CTA was present in 57.1% (n = 84). Carotid plaque was present in 47.6% (30 of 63) of subjects with a calcium score of 0 and 88.5% (77 of 87) of subjects with a calcium score >0 (p = 0.0001). Similarly carotid plaque was present in 52.4% (33 of 63) of subjects with no CTA evidence of atherosclerosis versus 85.7% (72 of 84) of subjects with any CTA evidence of atherosclerosis (p < 0.0001). Carotid plaque, IMT ≥ 1.5 mm, or averaged mean IMT >0.75 mm were associated with a calcium score >0 (odds ratio: 5.4, p < 0.0001, 2.7, p < 0.001; 2.9, p = 0.011, respectively) and disease in at least 1 vessel on CTA (odds ratio: 2.8, p = 0.03, 2.19, p = 0.073; 2.22, p = 0.058, respectively) independent of age and sex. CONCLUSIONS Carotid plaque and increased carotid IMT are associated with the presence and severity of coronary calcification and disease on CTA in ambulatory subjects.

What parameters affect left ventricular diastolic flow propagation velocity? In vitro studies using color M-mode Doppler echocardiography.

BackgroundInsufficient data describe the relationship of hemodynamic parameters to left ventricular (LV) diastolic flow propagation velocity (Vp) measured using color M-mode Doppler echocardiography.MethodsAn in vitro LV model used to simulate LV diastolic inflow with Vp measured under conditions of varying: 1) Stroke volume, 2) heart rate (HR), 3) LV volume, 4) LV compliance, and 5) transmitral flow (TMF) waveforms (Type 1: constant low diastasis flow and Type 2: no diastasis flow).ResultsUnivariate analysis revealed excellent correlations of Vp with stroke volume (r = 0.98), LV compliance (r = 0.94), and HR with Type 1 TMF (r = 0.97). However, with Type 2 TMF, HR was not associated with Vp. LV volume was not related to Vp under low compliance, but inversely related to Vp under high compliance conditions (r = -0.56).ConclusionThese in vitro findings may help elucidate the relationship of hemodynamic parameters to early diastolic LV filling.

Endothelial function and urine albumin levels among asymptomatic Mexican-Americans and non-Hispanic whites

Background-Mexican-Americans (MA) exhibit increases in various cardiovascular disease (CVD) risk factors compared to non-Hispanic Whites (NHW), yet are reported to have lower CVD mortality rates. Our aim was to help explain this apparent paradox by evaluating endothelial function and urine albumin levels in MA and NHW.Methods-One hundred-five MA and 100 NHW adults were studied by brachial artery flow-mediated dilatation (FMD), blood and urine tests. Participants were studied by ultrasound-determined brachial artery flow-mediated dilatation (FMD), blood and urine tests, at a single visit.Results-Despite higher BMI and triglycerides in MA, MA demonstrated higher FMD than did NHW (9.1 ± 7.3% vs. 7.1 ± 6.3%, p < 0.04). Among MA, urinary albumin was consistently lower in participants with FMD ≥ 7% FMD versus < 7% FMD (p < 0.006). In multivariate analyses in MA men, urinary albumin was inversely related to FMD (r = -0.26, p < 0.05), as were BMI and systolic blood pressure. In MA women, urinary albumin:creatinine ratio was an independent inverse predictor of FMD (p < 0.05 ).Conclusion-To our knowledge, this is the first study to analyze, in asymptomatic adults, the relation of MA and NHW ethnicity to FMD and urine albumin levels. The findings confirm ethnic differences in these important subclinical CVD measures.

Do Differences in Subclinical Cardiovascular Disease in Mexican Americans Versus European Americans Help Explain the Hispanic Paradox

Mexican Americans have exhibited increases in various coronary heart disease risk factors compared to European Americans but have also had reportedly lower coronary heart disease mortality from vital statistics studies. We hypothesized this apparent paradox might relate to lower levels of subclinical disease in Mexican Americans. A total of 105 adult Mexican Americans (42 men and 63 women, age 46 +/- 14 years) and 100 European Americans (59 men and 41 women, age 50 +/- 11 years) were studied using blood tests, transthoracic echocardiography, and computed tomography coronary artery calcium (CAC) scans. Despite a greater body mass index and triglycerides in Mexican Americans (p <0.001), the Mexican Americans demonstrated less subclinical disease than did the European Americans (14.4% vs 25.7% with CAC scores >0, p <0.05 and mean left ventricular mass [LV] of 146 vs 160 g, p <0.05). Also, the LV mass was significantly greater in Mexican Americans with than in those without CAC (mean 172 vs 140 g, p <0.05). On logistic regression analysis, age and diastolic blood pressure were associated with an increased likelihood of CAC (p <0.001 and p <0.01, respectively), and Mexican-American ethnicity was associated with a decreased likelihood of CAC (odds ratio 0.33, 95% confidence interval 0.12 to 0.87, p <0.05). On multiple regression analysis, male gender, body surface area, and systolic blood pressure were independently associated with an increased LV mass (all p <0.001). The body mass index was less strongly related to the LV mass than was the body surface area and was not related to CAC. In conclusion, Mexican-American ethnicity is associated with both a lower LV mass and a lower prevalence of CAC, although the differences in LV mass did not remain after adjustment for other factors. Although systolic blood pressure, body surface area, and male gender were most strongly associated with the LV mass, age and diastolic blood pressure, in addition to Mexican-American ethnicity, were the most important indicators of CAC.

Relation of metabolic syndrome components to left ventricular mass in Mexican Americans versus non-Hispanic whites

Metabolic syndrome (MetS) is associated with increased risk for cardiovascular disease (CVD). Mexican Americans (MA) exhibit increases in CVD risk factors compared with non-Hispanic whites (NHW), but few data exist comparing the relation of MetS to subclinical CVD, for example, left ventricular (LV) mass. Asymptomatic subjects (104 MA and 101 NHW, 52.2% female, aged 48 ± 12 years) were studied by echocardiography (echo) and by blood and urine tests. Metabolic syndrome was defined based on the American Heart Association/National Heart, Lung, and Blood Institute definition. Echo LV mass was compared with the presence or absence of MetS and with the number of MetS components. Multiple linear regression also examined the association of MetS with LV mass adjusted for non-MetS risk factors. Left ventricular mass was lower in MA (145.5 ± 43.9 g) compared with NHW (160.2 ± 49.9 g) (P < .05), although this difference was attenuated after adjusting for MetS and other risk factors. Left ventricular mass was higher in those with vs without MetS in both MA and NHW men and women (P < .05 to P < .01). There was a significant (P < .001) graded increase in echo LV mass with increasing number of MetS components both in MA (108.3 to 153.8 g) and NHW (144.3 to 215.1 g). In multiple regression analysis, male sex and MetS remained independently associated (P < .0001) with LV mass; however, body mass index explained much of this association, indicating the strong association of obesity with LV mass. Mean LV mass in both MA and NHW adults was higher in those with vs without MetS and with increasing number of MetS components, with body mass index the principal component of MetS associated with LV mass. The prognostic significance of LV mass in persons with MetS requires further study.

The Relationship Between Anthropometric and Body Composition Measures and Carotid Intima Media Thickness

Objective:� Toexaminetherelationshipofcarotid� intimamediathickness� (cIMT)� andanthropometric� measures,�bodymassindex�(BMI),�andpercentage� bodyfat� (%BF)� aftercontrollingforcardiovascular� disease�(CVD)�riskfactors. •� Methods:� WemeasuredthecIMTfromthebulb,� internal,�andcommoncarotidarteriesin�150�patients� (age�46.5�±�10.6�years;�57%�female,�68%�black)�who� presentedwithchestpainandnoknownpriorhistory� ofCVDtoourclinicaldecisionunit.�BMI,�anthropomet- ricmeasures,�andbioelectricalimpedancewerealso� measured.�ThegreatestvalueofmaximalcIMTfromall� segmentswascategorizedas�<�1.0�or�≥1.0�mm�(asa� markerforincreasedcIMT).�Datawereanalyzedusing� Studentsttest,�theMann-WhitneyUtest,�χ 2 �analyses,� andmultivariatestepwiselogisticregression. •� Results:� 90%� (n� =� 135)� ofpatientshadmaximal� cIMT� ≥�1.0�mm.�Hypertensionwaspresentin�41%,� hyperlipidemiain� 25%,� smokingin� 30%,� diabetes� in� 15%,� andCVDfamilyhistoryin� 43%.� Findings� fromunivariateanalysisshowthatincreasedcIMT� wassignificantlyassociatedwithage� (P� <� 0.001),� hypertension� (P� =� 0.005),� BMI� (P� =� 0.001),� waist� circumference� (P� =� 0.002),� neckcircumference� (P�=�0.08),�andwaist-to-heightratio�(P�=�0.006).�How- ever,�%BFdidnotshowanystatisticalsignificance� (P� =� 0.25).� Forwardstepwiselogisticregressions� wereperformedforeachbodycompositionmeasure� thatwassignificantonunivariateanalysis,�withthe� inclusionofageandhypertensionascovariates.�After� controllingforage,�BMI,�waistcircumferenceandtotal� bodyfatwerestatisticallysignificantpredictorsof�

Acute Left Ventricular Remodeling After Myocardial Infarction on Transthoracic Echocardiography: A Case Series

The authors describe left ventricular myocardial changes on transthoracic echocardiography in patients imaged within 72 hours of acute infarction. Endocardial separation from the mid myocardium, echocardiographic contrast penetration into the myocardium, and regional contrast swirling were observed. This case series also illustrates how contrast imaging may enhance recognition of early postinfarction remodeling.