Association of Estimated Sodium Intake With Adverse Cardiac Structure and Function: From the HyperGEN Study

BACKGROUND

The optimal level of sodium intake remains controversial.

OBJECTIVES

This study sought to determine whether examination of left ventricular longitudinal strain (LS), circumferential strain, and e' velocity can provide insight into thresholds for the detrimental effects of estimated sodium intake (ESI) on subclinical cardiovascular disease.

METHODS

We performed speckle-tracking analysis on HyperGEN (Hypertension Genetic Epidemiology Network) study echocardiograms with available urinary sodium data (N = 2,996). We evaluated the associations among ESI and LS, circumferential strain, and e' velocity using multivariable-adjusted linear mixed-effects models (to account for relatedness among subjects) with linear splines (spline 1: ESI ≤3.7 g/day, spline 2: ESI >3.7 g/day based on visual inspection of fractional polynomial plots of the association between ESI and indices of strain and e' velocity). We performed mediation analysis to understand the indirect effects of systolic blood pressure and serum aldosterone on the relationship between ESI and strain and e' velocity.

RESULTS

Mean age of participants was 49 ± 14 years, 57% were female, 50% were African American, and 54% had hypertension. The median ESI was 3.73 (interquartile range: 3.24, 4.25) g/day. ESI >3.7 g/day was associated with larger left atrial and left ventricular dimensions (p < 0.05). After adjusting for speckle-tracking analyst, image quality, study site, age, sex, smoking status, alcohol use, daily blocks walked, diuretic use, estimated glomerular filtration rate, left ventricular mass, ejection fraction, and wall motion score index, ESI >3.7 g/day was associated with both strain parameters and e' velocity (p < 0.05 for all comparisons), but ESI ≤3.7 g/day was not (p > 0.05 for all comparisons). There were significant interactions by potassium excretion for circumferential strain. Mediation analysis suggested that systolic blood pressure explained 14% and 20% of the indirect effects between ESI and LS and e' velocity, respectively, whereas serum aldosterone explained 19% of the indirect effects between ESI and LS.

CONCLUSIONS

ESI >3.7 g/day is associated with adverse cardiac remodeling and worse systolic strain and diastolic e' velocity.

Association of Central Adiposity With Adverse Cardiac Mechanics: Findings From the Hypertension Genetic Epidemiology Network Study

BACKGROUND

Central obesity, defined by increased waist circumference or waist:hip ratio (WHR), is associated with increased cardiovascular events, including heart failure. However, the pathophysiological link between central obesity and adverse cardiovascular outcomes remains poorly understood. We hypothesized that central obesity and larger WHR are independently associated with worse cardiac mechanics (reduced left ventricular strain and systolic [s'] and early diastolic [e'] tissue velocities).

METHODS AND RESULTS

We performed speckle-tracking analysis of echocardiograms from participants in the Hypertension Genetic Epidemiology Network (HyperGEN) study, a population- and family-based epidemiological study (n=2181). Multiple indices of systolic and diastolic cardiac mechanics were measured. We evaluated the association between central obesity and cardiac mechanics using multivariable-adjusted linear mixed-effects models to account for relatedness among participants. The mean age of the cohort was 51±14 years, 58% were women, and 47% were black. Mean body mass index was 30.8±7.1 kg/m(2), waist circumference was 102±17 cm, WHR was 0.91±0.08, and 80% had central obesity based on waist circumference and WHR criteria. After adjusting for multiple potential confounders (including age, sex, race, physical activity, body mass index, heart rate, smoking status, systolic blood pressure, fasting glucose, total cholesterol, antihypertensive medication use, glomerular filtration rate, left ventricular mass index, wall motion abnormalities, and ejection fraction), central obesity and WHR remained associated with worse global longitudinal strain, early diastolic strain rate, s' velocity, and e' velocity (P<0.05 for all comparisons). There were no significant statistical interactions between WHR and obesity status.

CONCLUSIONS

In this cross-sectional study of participants with multiple comorbidities, central obesity was found to be associated with adverse cardiac mechanics.

Phenomapping for the Identification of Hypertensive Patients with the Myocardial Substrate for Heart Failure with Preserved Ejection Fraction

We sought to evaluate whether unbiased machine learning of dense phenotypic data ("phenomapping") could identify distinct hypertension subgroups that are associated with the myocardial substrate (i.e., abnormal cardiac mechanics) for heart failure with preserved ejection fraction (HFpEF). In the HyperGEN study, a population- and family-based study of hypertension, we studied 1273 hypertensive patients utilizing clinical, laboratory, and conventional echocardiographic phenotyping of the study participants. We used machine learning analysis of 47 continuous phenotypic variables to identify mutually exclusive groups constituting a novel classification of hypertension. The phenomapping analysis classified study participants into 2 distinct groups that differed markedly in clinical characteristics, cardiac structure/function, and indices of cardiac mechanics (e.g., phenogroup #2 had a decreased absolute longitudinal strain [12.8 ± 4.1 vs. 14.6 ± 3.5%] even after adjustment for traditional comorbidities [p < 0.001]). The 2 hypertension phenogroups may represent distinct subtypes that may benefit from targeted therapies for the prevention of HFpEF.

Archeological Echocardiography: Digitization and Speckle Tracking Analysis of Archival Echocardiograms in the HyperGEN Study

BACKGROUND

Several large epidemiologic studies and clinical trials have included echocardiography, but images were stored in analog format and these studies predated tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE). We hypothesized that digitization of analog echocardiograms, with subsequent quantification of cardiac mechanics using STE, is feasible, reproducible, accurate, and produces clinically valid results.

METHODS

In the NHLBI HyperGEN study (N = 2234), archived analog echocardiograms were digitized and subsequently analyzed using STE to obtain tissue velocities/strain. Echocardiograms were assigned quality scores and inter-/intra-observer agreement was calculated. Accuracy was evaluated in: (1) a separate second study (N = 50) comparing prospective digital strain versus post hoc analog-to-digital strain, and (2) in a third study (N = 95) comparing prospectively obtained TDI e' velocities with post hoc STE e' velocities. Finally, we replicated previously known associations between tissue velocities/strain, conventional echocardiographic measurements, and clinical data.

RESULTS

Of the 2234 HyperGEN echocardiograms, 2150 (96.2%) underwent successful digitization and STE analysis. Inter/intra-observer agreement was high for all STE parameters, especially longitudinal strain (LS). In accuracy studies, LS performed best when comparing post hoc STE to prospective digital STE for strain analysis. STE-derived e' velocities correlated with, but systematically underestimated, TDI e' velocity. Several known associations between clinical variables and cardiac mechanics were replicated in HyperGEN. We also found a novel independent inverse association between fasting glucose and LS (adjusted β = -2.4 [95% CI -3.6, -1.2]% per 1-SD increase in fasting glucose; P < 0.001).

CONCLUSIONS

Archeological echocardiography, the digitization and speckle tracking analysis of archival echocardiograms, is feasible and generates indices of cardiac mechanics similar to contemporary studies.

Diastolic wall strain: a simple marker of abnormal cardiac mechanics

BACKGROUND

Diastolic wall strain (DWS), defined using posterior wall thickness (PWT) measurements from standard echocardiographic images (DWS = [PWT(systole)-PWT(diastole)]/PWT(systole)), has been proposed as a marker of left ventricular (LV) diastolic stiffness. However, the equation for DWS is closely related to systolic radial strain, and whether DWS is associated with abnormal cardiac mechanics (reduced systolic strains and diastolic tissue velocities) is unknown. We sought to determine the relationship between DWS and systolic and diastolic cardiac mechanics.

METHODS

We calculated DWS and performed speckle-tracking analysis in a large population- and family-based study (Hypertension Genetic Epidemiology Network [HyperGEN]; N=1907 after excluding patients with ejection fraction [EF] <50% or posterior wall motion abnormalities). We measured global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS, respectively) and early diastolic (e') tissue velocities, and we determined the independent association of DWS with cardiac mechanics using linear mixed effects models to account for relatedness among study participants. We also prospectively performed receiver-operating characteristic (ROC) analysis of DWS for the detection of abnormal cardiac mechanics in a separate, prospective validation study (N=35).

RESULTS

In HyperGEN (age 51 ± 14 years, 59% female, 45% African-American, 57% hypertensive), mean DWS was 0.38 ± 0.05. DWS decreased with increasing comorbidity burden (β-coefficient -0.013 [95% CI -0.015, -0.011]; P<0.0001). DWS was independently associated with GLS, GCS, GRS, and e' velocity (adjusted P<0.05) but not LV chamber compliance (EDV20, P=0.97). On prospective speckle-tracking analysis, DWS correlated well with GLS, GCS, and GRS (R=0.61, 0.57, and 0.73, respectively; P<0.001 for all comparisons). C-statistics for DWS as a diagnostic test for abnormal GLS, GCS, and GRS were: 0.78, 0.79, and 0.84, respectively.

CONCLUSIONS

DWS, a simple parameter than can be calculated from routine 2D echocardiography, is closely associated with systolic strain parameters and early diastolic (e') tissue velocities but not LV chamber compliance.

Association of comorbidity burden with abnormal cardiac mechanics: findings from the HyperGEN study

Background

Comorbidities are common in heart failure (HF), and the number of comorbidities has been associated with poor outcomes in HF patients. However, little is known about the effect of multiple comorbidities on cardiac mechanics, which could impact the pathogenesis of HF. We sought to determine the relationship between comorbidity burden and adverse cardiac mechanics.

Methods and Results

We performed speckle‐tracking analysis on echocardiograms from the HyperGEN study (n=2150). Global longitudinal, circumferential, and radial strain, and early diastolic (e') tissue velocities were measured. We evaluated the association between comorbidity number and cardiac mechanics using linear mixed effects models to account for relatedness among subjects. The mean age was 51±14 years, 58% were female, and 47% were African American. Dyslipidemia and hypertension were the most common comorbidities (61% and 58%, respectively). After adjusting for left ventricular (LV) mass index, ejection fraction, and several potential confounders, the number of comorbidities remained associated with all indices of cardiac mechanics except global circumferential strain (eg, β=−0.32 [95% CI −0.44, −0.20] per 1‐unit increase in number of comorbidities for global longitudinal strain; β=−0.16 [95% CI −0.20, −0.11] for e' velocity; P≤0.0001 for both comparisons). Results were similar after excluding participants with abnormal LV geometry (P<0.05 for all comparisons).

Conclusions

Higher comorbidity burden is associated with worse cardiac mechanics, even in the presence of normal LV geometry. The deleterious effect of multiple comorbidities on cardiac mechanics may explain both the high comorbidity burden and adverse outcomes in patients who ultimately develop HF.

Association of low-grade albuminuria with adverse cardiac mechanics: findings from the hypertension genetic epidemiology network (HyperGEN) study

BACKGROUND

Albuminuria is a marker of endothelial dysfunction and has been associated with adverse cardiovascular outcomes. The reasons for this association are unclear but may be attributable to the relationship between endothelial dysfunction and intrinsic myocardial dysfunction.

METHODS AND RESULTS

In the Hypertension Genetic Epidemiology Network (HyperGEN) Study, a population- and family-based study of hypertension, we examined the relationship between urine albumin-to-creatinine ratio (UACR) and cardiac mechanics (n=1894, all of whom had normal left ventricular ejection fraction and wall motion). We performed speckle-tracking echocardiographic analysis to quantify global longitudinal, circumferential, and radial strain, and early diastolic (e') tissue velocities. We used E/e' ratio as a marker of increased left ventricular filling pressures. We used multivariable-adjusted linear mixed effect models to determine independent associations between UACR and cardiac mechanics. The mean age was 50±14 years, 59% were female, and 46% were black. Comorbidities were increasingly prevalent among higher UACR quartiles. Albuminuria was associated with global longitudinal strain, global circumferential strain, global radial strain, e' velocity, and E/e' ratio on unadjusted analyses. After adjustment for covariates, UACR was independently associated with lower absolute global longitudinal strain (multivariable-adjusted mean global longitudinal strain [95% confidence interval] for UACR Quartile 1 = 15.3 [15.0-15.5]% versus UACR Q4 = 14.6 [14.3-14.9]%, P for trend <0.001) and increased E/e' ratio (Q1 = 25.3 [23.5-27.1] versus Q4 = 29.0 [27.0-31.0], P=0.003). The association between UACR and global longitudinal strain was present even in participants with UACR < 30 mg/g (P<0.001 after multivariable adjustment).

CONCLUSIONS

Albuminuria, even at low levels, is associated with adverse cardiac mechanics and higher E/e' ratio.

Association of the frontal QRS-T angle with adverse cardiac remodeling, impaired left and right ventricular function, and worse outcomes in heart failure with preserved ejection fraction

BACKGROUND

No prior studies have investigated the association of QRS-T angle with cardiac structure and function and outcomes in heart failure with preserved ejection fraction (HFpEF). The aim of this study was to test the hypothesis that increased frontal QRS-T angle is associated with worse cardiac function and remodeling and adverse outcomes in HFpEF.

METHODS

A total of 376 patients with HFpEF (i.e., symptomatic heart failure with left ventricular ejection fraction > 50%) were prospectively studied. The frontal QRS-T angle was calculated from the 12-lead electrocardiogram. Patients were divided into tertiles by frontal QRS-T angle (0°-26°, 27°-75°, and 76°-179°), and clinical, laboratory, and echocardiographic data were compared among groups. Cox proportional-hazards analyses were performed to determine the association between QRS-T angle and outcomes.

RESULTS

The mean age of the cohort was 64 ± 13 years, 65% were women, and the mean QRS-T angle was 61 ± 51°. Patients with increased QRS-T angles were older; had lower body mass indices; more frequently had coronary artery disease, diabetes, chronic kidney disease, and atrial fibrillation; and had higher B-type natriuretic peptide levels (P < .05 for all comparisons). After multivariate adjustment, patients with increased QRS-T angles had higher B-type natriuretic peptide levels in addition to higher left ventricular mass indices, worse diastolic function parameters, more right ventricular remodeling, and worse right ventricular systolic function (P < .05 for all associations). QRS-T angle was independently associated with the composite outcome of cardiovascular hospitalization or death on multivariate analysis, even after adjusting for B-type natriuretic peptide (heart rate for the highest QRS-T tertile, 2.0; 95% confidence interval, 1.2-3.4; P = .008).

CONCLUSIONS

In HFpEF, increased QRS-T angle is independently associated with worse left and right ventricular function and remodeling and adverse outcomes.

Percutaneous balloon mitral valvuloplasty in comparison with open mitral valve commissurotomy for mitral stenosis during pregnancy

OBJECTIVES

We sought to compare the maternal and fetal outcomes of patients with severe mitral stenosis submitted to percutaneous balloon dilation versus open mitral valve commissurotomy (MVC) during pregnancy.

BACKGROUND

Heart failure in patients with mitral stenosis complicating pregnancy is a common problem in developing countries. Since 1984, percutaneous dilation of the mitral valve using a balloon catheter has become a therapeutic alternative to open heart surgery. Although the efficacy of percutaneous mitral valve balloon dilation is well established, its results have never before been compared with the results of commissurotomy during pregnancy.

METHODS

We compared the clinical and obstetric complications in 45 women who were treated with percutaneous mitral valve balloon dilation (group I, n = 21; from 1990 to 1995) or open MVC (group II, n = 24; from 1985 to 1990) for severe heart failure due to mitral stenosis during pregnancy.

RESULTS

In our study, percutaneous balloon dilation of the mitral valve had a success rate of 95% (Gorlin formula) and 90.5% (echocardiographic "pressure half-time" method), as demonstrated by the final mitral valve area achieved. This improvement was followed by a marked decrease in the mitral valve gradient, left atrial pressure and mean pulmonary artery pressure. Patients in both groups had similar improvements in symptoms. Patients who underwent percutaneous balloon dilation had significantly fewer fetal complications, with a reduction in fetal and neonatal mortality (1 death in group I vs. 8 in group II, p = 0.025).

CONCLUSIONS

Percutaneous balloon mitral valvuloplasty is safe and effective and appears to be preferable for the fetus, compared with open MVC during pregnancy.

Noninvasive diagnosis of allograft vascular disease after heart transplantation

OBJECTIVE

To determine the predictive values of noninvasive tests for the detection of allograft vascular disease.

METHODS

We studied 39 patients with mean ages of 48+/-13 years and a follow-up period of 86+/-13 months. The diagnosis of allograft vascular disease was made by cine-coronary arteriography, and it was considered as positive if lesions existed that caused > or =50% obstruction of the lumen. Patients underwent 24h Holter monitoring, thallium scintigraphy, a treadmill stress test, and dobutamine stress echocardiography. Sensitivity, specificity, and positive and negative predictive values were determined in percentages for each method, as compared with the cine-coronary arteriography results.

RESULTS

Allograft vascular disease was found in 15 (38%) patients. The Holter test showed 15.4% sensitivity, 95.5% specificity. For the treadmill stress test, sensitivity was 10%, specificity was 100%. When thallium scintigraphy was used, sensitivity was 40%, specificity 95.8%. On echocardiography with dobutamine, we found a 63.6% sensitivity, 91.3% specificity. When the dobutamine echocardiogram was associated with scintigraphy, sensitivity was 71.4%, specificity was 87%.

CONCLUSION

In this group of patients, the combination of two noninvasive methods (dobutamine echocardiography and thallium scintigraphy) may be a good alternative for the detection of allograft vascular disease in asymptomatic patients with normal ventricular function.

Extrinsic compression of the left main coronary artery by a dilated pulmonary artery: clinical, angiographic, and hemodynamic determinants

Extrinsic compression of the left main coronary artery (LMC) by the pulmonary artery (PA) is a very unusual and poorly understood entity, usually associated with the presence of adult congenital heart disease. We identified 12 patients (age range, 6 months to 55 years) with LMC stenosis (> or = 50%) presumably secondary to compression by a dilated main PA and related to various forms of heart disease (11 congenital, 1 pulmonary hypertension). In all cases, the main PA was dilated with the main PA/aortic root diameter increased (mean, 2.0; normal value, < or = 1.0), and in all but two, PA pressures were increased (> 30 mm Hg systolic). Left coronary trunk stenosis was usually visualized in only one angiographic view (best seen in 45 degrees left anterior oblique, 30 degrees cranial projection). The LMC also appeared to be inferiorly displaced and in close contact with the left aortic sinus (mean angle between sinus and LMC was 23 degrees +/- 13 degrees, a control group was 70 degrees +/- 15 degrees ). In one patient, surgical correction of the dilated PA was associated with a reduction in LMC stenosis from 85% to < 50% and less inferior left main displacement (from 25 degrees to 50 degrees ). Patients with a dilated main PA may exhibit extrinsic LMC compression leading to significant eccentric narrowing and downward displacement of the LMC. In the presence of significant dilatation of the main PA from any etiology, functional and/or anatomic studies should be performed to exclude significant LM obstruction.

High versus low-pressure balloon inflation during multilinktrade mark stent implantation: acute and long-term angiographic results

We compared the impact of low and high-pressure balloon inflation on acute and late angiographic results of Multilink stent. Low-pressure balloon inflation (9.5 +/- 1.9 atm) was used in 43 stents and high pressure (17.1 +/- 1.5 atm) in 44. A larger immediate luminal gain was achieved in stents with high-pressure balloon inflation (1.80 +/- 0.26 vs. 1.47 +/- 0.62; P = 0.002), resulting in a larger mean diameter in this group (2.71 +/- 0.37 vs. 2.48 +/- 0.47; P = 0.017). At follow-up, a larger luminal diameter was achieved in the high pressure group (1.93 +/- 0.72 vs. 1.45 +/- 0.66; P = 0.002) and a trend to a lower rate of angiographic restenosis (15% vs. 38%, P = 0.08).

Angiographic and electrophysiological substrates for ventricular tachycardia mapping through the coronary veins

OBJECTIVE

To study the value of epicardial mapping through the coronary venous system in patients with sustained ventricular tachycardia.

DESIGN

20 consecutive patients with sustained ventricular tachycardia who were candidates for radiofrequency ablation.

SETTING

Electrophysiological laboratory.

INTERVENTIONS

Coronary venous angiography was performed with a catheter, which provided coronary sinus occlusion during injection of contrast media. Multipolar microelectrode catheters were then manoeuvred into the tributaries of coronary sinus, using an over-wire system or an on-wire system. An endocardial ablation catheter was positioned in the left ventricle. Conventional programmed ventricular stimulation was performed for sustained ventricular tachycardia induction. Endocardial radiofrequency ablation was performed using impedance or temperature monitoring.

RESULTS

Coronary veins were catheterised in all patients; 20 had induction of sustained ventricular tachycardia, 14 were stable. Presystolic epicardial electrograms were recorded in six patients and concealed entrainment in two, helping as a landmark for endocardial ablation. After simultaneous epicardial and endocardial mapping, successful endocardial radiofrequency ablation was achieved in nine of 14 patients with stable ventricular tachycardia (64%).

CONCLUSIONS

Epicardial mapping through the coronary veins in patients with ventricular tachycardia is feasible, safe, and can be a useful landmark for endocardial catheter mapping and ablation.

Chagas' disease reactivation after heart transplantation: efficacy of allopurinol treatment

BACKGROUND

Chagas' disease is a parasitic infection that provokes a severe form of dilated cardiomyopathy. In the initial experience with heart transplantation with Chagas' disease, a high rate of acute reactivation has been reported. Although benzinidazole and nifurtimox are effective in the treatment of reactivation or of the acute phase of the disease they are associated with important adverse effects. Allopurinol has substantial activity against Trypanosoma cruzi in vitro, in the experimental laboratory and in chronic human Chagas' disease; however, there is no information regarding its action in Chagas' reactivation after heart transplantation.

METHODS AND RESULTS

We describe two patients with Chagas' disease who underwent heart transplantation. The first one had asthenia, anorexia, and several painful subcutaneous nodules in the legs after transplantation; biopsy showed an inflammatory infiltrate with intracytoplasmatic nests of Trypanosoma cruzi, confirmed by immunohistochemical stains with monoclonal antibodies specific to parasitic antigens. Allopurinol (600 mg/day) produced complete regression of the symptoms and the nodules with a negative control biopsy within 2 weeks. Treatment was maintained for 2 months. Mild leukopenia developed which improved after azathioprine reduction, and no further side-effects were noted. The second patient had sudden heart failure months after transplantation; endomyocardial biopsy showed myocardial fibers infested with Trypanosoma, and a concomitantly performed right heart catheterization showed a low cardiac index and highfilling pressures. The patient received allopurinol at a daily dose of 900 mg and conventional treatment for heart failure. Echocardiogram showed improved wall motion and decreased left ventricular dimensions, and control biopsy showed no inflammatory activity; cardiac index and filling pressures normalized. Treatment was maintained for 2 months without side effects. The two patients have not had recurrences and were in New York Heart Association functional class I 12 and 3 months, respectively, after discontinuation of allopurinol.

CONCLUSIONS

Allopurinol seems to be safe and effective in treating Chagas' disease reactivation after heart transplantation. A larger number of case studies seems to be necessary to properly evaluate its role in the treatment of Chagas' disease reactivation.

Physiologic multivalvular regurgitation during pregnancy: a longitudinal Doppler echocardiographic study

Valvular function, assessed by Doppler technique, has not been extensively investigated during normal pregnancy. To prospectively study this feature, 18 normal pregnant women were followed during their pregnancies and puerperium, with serial clinical and pulsed-continuous Doppler echocardiographic examinations. In four gestational periods and the puerperium, we analysed: (a) ventricular and atrial dimensions, as well as valve annular diameters; (b) prevalence and characteristics of trivial valvular regurgitations. During pregnancy, slight but significant increases of the four cardiac chamber dimensions and valve annular diameters were observed, except for the aortic ring. The prevalence of physiologic valvular regurgitation in early pregnancy (mitral, 0%; tricuspid, 38.9%; pulmonary, 22.2%; aortic, 0%), was similar to a control group of 18 healthy non-pregnant women. As pregnancy evolved, there was a progressive and significant increase of multivalvular regurgitation, maximal at full-term (mitral, 27.8%; tricuspid, 94.4%; pulmonary, 94.4%, P < 0.05 vs. early pregnancy). Aortic regurgitation was not detected in any stage of pregnancy. In the puerperium, mitral regurgitation resolved, but tricuspid and pulmonary regurgitation were still significantly prevalent (83.3% and 66.7%, respectively, P < 0.05 vs. early pregnancy). It is concluded that physiologic multivalvular regurgitation is frequent in pregnancy, mainly involving right-sided valves in late gestational periods, occasionally persisting in the early puerperium. Chamber enlargement, valve annular dilatation, and increased prevalence of trivial valve regurgitation are time-related events during normal pregnancy, resulting from a reversible cardiac remodeling process induced by physiologic volume overload. These aspects should be considered for a correct interpretation of Doppler echocardiographic findings in pregnant women with suspected heart disease.

Cardiopulmonary exercise testing early after catheter-balloon mitral valvuloplasty in patients with mitral stenosis

Seven female patients (age 27 to 53 yr) with significant mitral stenosis performed continuous, incremental, maximal treadmill exercise tests the day before and within 3-5 days after catheter-balloon valvuloplasty. Mitral valve area determined by the echo-Doppler method increased from 0.9 +/- 0.3 cm2 to 1.9 +/- 0.7 cm2 (p < 0.02). Mean left atrial pressure was reduced from 24 +/- 8 to 13 +/- 7 mmHg (p < 0.01) and mean pulmonary artery pressure from 36 +/- 13 to 28 +/- 10 mmHg (p < 0.02) with a non-significant increase in cardiac output from 3.6 +/- 1.2 to 4.0 +/- 1.7 l/min. After catheter-balloon valvuloplasty all patients reached a higher maximal workload during exercise, and mean value of oxygen consumption and pulmonary ventilation were significantly lower in submaximal workloads. The calculated ventilatory equivalent for oxygen was significantly reduced in submaximal and in maximal workloads after catheter-balloon valvuloplasty. Peak oxygen consumption and the ventilatory anaerobic threshold were not changed after catheter-balloon valvuloplasty (pre 15.59 +/- 2.72 vs post 16.90 +/- 3.44 and pre 12.10 +/- 2.55 vs post 12.62 +/- 2.71 ml/kg/min, respectively). We concluded that after catheter-balloon valvuloplasty the cost of breathing was reduced and the oxygen consumed was more effectively utilized during exercise. Increases in peak oxygen consumption and in ventilatory anaerobic threshold would require circulatory and metabolic adaptations in response to increased physical activity and were not observed when cardiopulmonary tests were performed early after catheter-balloon valvuloplasty.

Pregnancy in patients with prosthetic heart valves: the effects of anticoagulation on mother, fetus, and neonate

Maternal and fetal complications in a consecutive series of 60 pregnancies in 49 patients with prosthetic heart valves were prospectively evaluated. Group 1 consisted of 40 pregnancies in 31 patients who were taking oral anticoagulants. No oral anticoagulation was used in 20 pregnancies in 19 patients (group 2). In group 1 there were three instances of acute valvular thrombosis during the 35 pregnancies in patients with mechanical prostheses, with two maternal deaths. There were two episodes of cerebral embolism, one in group 1 and one in group 2. Patients with isolated aortic valve replacement had fewer maternal complications (2 of 13) than patients with isolated mitral valve replacement (15 of 42) without statistical significance. Severe bioprosthesis dysfunction occurred in 4 of 25 pregnancies (one rupture and three stenosis) with two maternal deaths, one in the puerperium and the other in the postoperative period of cardiac surgery during pregnancy. When analyzing obstetric events we observed seven spontaneous abortions and one hydatidiform mole. All spontaneous abortions occurred in group 1. The incidences of prematurity and low birth weight were significantly higher in group 1 than in group 2 (46.6% vs 10.5%, p less than 0.05, and 50% vs 10.5%, p less than 0.05, respectively). Moreover, there was a significant association between prematurity and the mother's New York Heart Association functional class (61.5% in classes III and IV vs 22.2% in classes I and II, p less than 0.05). There were five neonatal deaths, all in group 1 (p = NS vs group 2). Three infants had warfarin-related congenital defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Chagas cardiomyopathy and captopril

Chagas disease is a leading cause of heart failure in Latin America. Sudden death occurs in approximately 40% of patients with heart failure due to Chagas disease. We report a single blind, cross-over trial of prolonged treatment with captopril and placebo in 18 Chagas disease patients with class IV NYHA heart failure. Ventricular dimensions, neurohormones, electrolytes and ventricular arrhythmias were analysed in 11 men and seven women receiving stable doses of digoxin and frusemide who were randomly divided into two intervention groups. Group I patients were given increasing doses of captopril up to 150 mg.day-1 maintained for 6 weeks, group II received the placebo. A 24 h Holter, 2-D echocardiogram, urinary catecholamines, plasma renin and electrolyte determinations were performed at the end of each phase. After a 2-week washout period, the two groups crossed over and another period of 6 weeks was observed. Ventricular arrhythmias were analysed by either Mann-Whitney or the Wilcoxon test. Remaining data were assessed by the Student t-test. A significant reduction in heart rate and urinary catecholamine levels, and enhanced plasma levels of renin, together with a reduction in ventricular couplets was found in the captopril-treated group. We conclude that captopril has a beneficial effect on neurohormones with a subsequently reduced heart rate and diminished incidence of ventricular arrhythmias in patients with Chagas disease. This effect might result in a reduction of mortality caused by the disease, suggesting the need for further investigations.

Absence of an aortic valve cusp, a cause of severe aortic regurgitation in infancy

Congenital aortic regurgitation is an extremely rare cardiac lesion. This is a case report of an infant with a severe degree of valve regurgitation due to absence of the noncoronary aortic cusp. We show the echocardiographic, angiographic, and surgical aspects of the case, emphasizing the importance of a precise anatomical diagnosis and the problems of early valve replacement.

Lung and myocardial thallium-201 kinetics in resting patients with congestive heart failure: correlation with pulmonary capillary wedge pressure

Increased lung thallium-201 activity occurs with exercise in patients with severe coronary artery disease as a result of increased pulmonary capillary wedge pressure. No study has shown resting lung kinetics in chronic congestive heart failure. To better understand the relationship between lung and myocardial thallium uptake and pulmonary capillary wedge pressure, this study was performed. Resting lung and myocardial thallium uptake, expressed as a ratio, were compared with simultaneous pulmonary capillary wedge pressure in 16 patients with congestive heart failure and cardiomyopathy, all New York Heart Association class IV. There were no variations in pulmonary capillary wedge pressure throughout the study protocol. There was a significant reduction in the lung/myocardium thallium ratio from 10 to 60 minutes (0.83 +/- 0.30 to 0.59 +/- 0.17; p less than 0.001). At 60 minutes after thallium injection there was a linear correlation between the lung/myocardium ratio and capillary wedge pressure with an r value of 0.62 (p less than 0.01). Thus thallium-201 washout is rapid despite persistence of pulmonary capillary wedge pressure elevation, indicating that clearance does not imply resolution of congestive heart failure. In addition, a significant but imprecise correlation was found between capillary pressure and the lung/myocardium ratio. Rapid changes in lung activity during the early postinjection period may limit the clinical use of the lung/myocardium ratio.

Segmental atrial fibrillation resulting in chronic atrial dissociation. A case report

Atrial arrhythmias are diagnosed on the basis of the analysis of P wave morphology, timing and rate, the surface electrocardiogram, and intracardiac recordings. Recent intracardiac studies have demonstrated dissimilar atrial rhythms with direct intra-atrial recordings, the former otherwise not evident on the surface ECG (Zipes et al. 1972, Wu et al. 1975, Friedman et al. 1974, Gomes et al. 1981). This paper reports the electrocardiographic diagnosis of atrial dissociation made on the surface electrocardiogram. The findings suggest the following: (1) That sinus rhythm exists, with the dominant sinus rhythm depolarizing the major portion of the right as well as the left atrium; (2) Atrial fibrillation localized specifically to lead III, and at times to leads III and AVL, on the surface electrocardiogram; and (3) Intraesophageal recordings and echocardiography revealed an area of the posterior right and left atria that had wall motion abnormalities and electrical activity compatible with those of atrial fibrillation.

Left ventricular hypertrophy as a risk factor for arrhythmias in hemodialysis patients

The contribution of left ventricular hypertrophy in determining ventricular arrhythmias (VAS) was studied in 81 chronic renal failure patients in chronic hemodialysis using two-dimensional echocardiographic and electrocardiogram Holter monitoring. The prevalence of LVH was 93% (96% in hypertensive and 87% in normotensive patients). The prevalence of VA was 48%. These arrhythmias were associated with increased cardiac mass, lack of potassium supplementation to the hemodialysis bath, and low K+ and PaO2 during dialysis. Severe forms of VA occurred in 19 of 78 patients, and the risk factors for this occurrence were (a) largely increased cardiac mass indices (exceeding in more than 40% the upper limit of normal for each sex) and (b) prolonged periods of time in hemodialysis treatment (34 +/- 5.5 vs. 17 +/- 2.7 months, p less than 0.05). Changes in potassium or oxygen content of the blood were not significantly associated with the occurrence of severe forms of VA.

Dipyridamole-thallium tests are predictive of severe cardiac arrhythmias in patients with left ventricular hypertrophy

In a population of patients with chronic renal failure (CRF) and a high prevalence of left ventricular hypertrophy (LVH) undergoing chronic hemodialysis, we investigated the association between the results of dipyridamole-thallium tests (DTTs) and the occurrence of ventricular arrhythmias. We observed a positive significant association between positive DTTs and the occurrence of severe forms of ventricular arrhythmias. A significant association was also observed between the presence of severe LVH and the occurrence of severe ventricular arrhythmias. However, no association was found between the presence of LVH and the positivity of the DTT. As most of our patients with positive DTTs had unimpaired coronary circulations, we conclude that positive DTTs, although falsely indicative of impaired myocardial blood supply, does have an important clinical relevance, indicating increased risk of morbidity (and, possibly, mortality) due to ventricular arrhythmias in a population of CRF patients submitted to chronic renal function replacement program.

Modified liquid chromatographic method for determination of gentian violet in animal feed

A modified liquid chromatographic method is described for the determination of Gentian Violet (GV) in animal feed. The reliable detection limit is 0.5 ng (reference standards), and 1 ppm GV was reliably determined in feed. The calibration curve was linear between 1 and 40 micrograms/mL. The method, developed in a study by the National Center for Toxicological Research, was modified to use methanol-water (9 + 1) instead of benzene-methanol as the eluting solution in the column cleanup. GV is extracted from feed with methanol-1N HCl (99 + 1), cleaned up on a Sephadex LH-20 column to remove any remaining interferences, separated on a Nova-Pak C18 column fitted with a precolumn filter, and determined at 588 nm. The identity of GV is confirmed by thin-layer chromatography (Rf = 0.47) by comparison with a reference standard. Average recoveries from 3 sets of 5 feed samples containing 2.5, 5.0, and 10.0 ppm GV were 115, 95, and 102%, respectively.

Liquid chromatographic determination of tetracycline residues in animal feeds

A liquid chromatographic method for the multiresidue determination of tetracyclines (TCs) in feeds is described. The levels of quantitation were 10 ppm each for tetracycline-HCl (TC), oxytetracycline (OTC), and chlortetracycline-HCl (CTC); the detection limit was 40 ppb for each. The calibration curves were linear between 2.5 and 100 ppm. The procedure involved double extraction with pH 2.0 and pH 4.5 McIlvain buffers, cleanup on a Sephadex LH-20 column, separation on a Nova-Pak C18 column, and detection at 370 nm. Recoveries of 10 micrograms/g of each TC in multiresidue feed samples ranged from 55.8 to 75.5% for OTC, 71.6 to 100% for TC, and 22.4 to 60.6% for CTC. The identities of the TCs were confirmed by thin layer chromatography.

The effects of glucose on myocardial substrate utilization in acute myocardial infarction or angina pectoris

Infusion of glucose-insulin-potassium during acute myocardial infarction has favorable clinical and hemodynamic effects, presumably as a result of decreased myocardial utilization of free fatty acids. In 14 patients with coronary artery disease, hypertonic glucose (a bolus of 10 g followed by infusion of a 30% glucose solution at a constant rate of 10 mg/kg/min) was infused and arterial and coronary sinus levels of glucose, lactate and free fatty acids were measured before and after 15 and 30 minutes of infusion. Arterial glucose and lactate levels increased significantly after glucose infusion, whereas free fatty acid levels decreased significantly. Modest but significant correlations also existed between glucose arterial levels and the arterial-coronary sinus glucose difference (r = 0.53, p less than 0.001); arterial lactate and the arterial-coronary sinus lactate difference (r = 0.35, p less than 0.01); arterial free fatty acids; and the arterial-coronary sinus free fatty acid difference (r = 0.62, p less than 0.001). These results with a hypertonic glucose infusion are similar to those reported after infusion of glucose-insulin-potassium without the potential for harmful adverse effects from infusions of insulin or potassium. Therefore, infusion of hypertonic glucose may be beneficial in patients with coronary artery disease. Further work is necessary to study its effects in different subgroups of patients with coronary artery disease.

Liquid chromatographic determination of multiresidue fluorescent derivatives of ionophore compounds, monensin, salinomycin, narasin, and lasalocid, in beef liver tissue

A liquid chromatographic (LC) method with fluorometric detection was developed to quantitatively determine residue levels of monensin, salinomycin, narasin, and lasalocid in beef liver tissue. The ionophores are extracted from the tissue, purified by both alumina and Sephadex LH-20 column chromatography, and then derivatized. Lasalocid was directly esterified with 9-anthryldiazomethane (ADAM), but monensin, salinomycin, and narasin were first acetylated with acetic anhydride and then esterified with ADAM. The ADAM derivatives were purified on a silica gel column and separated by LC using an RP C-8 5 micron column. A fluorescence detector set at 365 nm (excitation) and 418 nm (emission) was used to monitor the column effluent. The detection limits were 0.15 ppm, and the calibration curves were linear between 0.5 and 5.0 ppm for all 4 ionophores. Mean recoveries were 57, 70, 75, and 90% for lasalocid (5 ppm), monensin (2.5 ppm), salinomycin (2.5 ppm), and narasin (2.5 ppm), respectively. The ionophores were also separated and semiquantitated by using bioautography and thin layer chromatography with a vanillin spray.

Echocardiographic routine analysis of the coronary sinus by an apical view: normal and abnormal features

The echocardiographic aspects of the coronary sinus have not received much attention in the literature. In the few published articles about anomalous venous connection to the coronary sinus, the parasternal long axis view has been suggested as ideal for its visualization. More recently, it has been suggested that the coronary sinus in normal hearts is best visualized from the apical transducer position. The purpose of this study was to assess the appearance of the coronary sinus from an apical view in a group of 400 consecutive patients with ages varying from 5 days to 80 years. In ten patients with persistent left superior vena cava, the coronary sinus was markedly dilated throughout its extension. All cases were confirmed either by angiography or surgery. In another three patients with Ebstein's anomaly studied postoperatively, it was observed that the coronary sinus was abnormally draining into the right ventricle below the prosthesis plane. These findings were confirmed by the surgical reports. The routine evaluation of the coronary sinus was better performed by an apical view, which provided detailed information not only of normal, but also abnormal anatomy of this segment of the heart. We speculate that it could be especially useful in diagnosing coronary sinus atresia and thrombosis, and coronary ostium atresia, as well as total anomalous intracardiac pulmonary venous drainage.

Echocardiographic and hemodynamic features of severe aortic regurgitation with diastolic opening of the aortic valve

Severe aortic regurgitation may be associated with premature aortic valve opening. Several possible etiologies for this diastolic opening have been suggested. We present a patient with hemodynamic data, M-mode and 2-D echocardiography in the setting of severe aortic regurgitation and diastolic aortic valve opening. Our data lead us to conclude that aortic valve opening in this situation is neither from passive flotation nor dependent on atrial systole. We believe that active ventricular recoil mechanisms can facilitate increases in diastolic ventricular pressure which then can transiently exceed aortic pressure in the setting of severe aortic regurgitation. This hemodynamic observation suggests that the valve opening is an active process.

Determination of monensin sodium residues in beef liver tissue by liquid chromatography of a fluorescent derivative

Monensin sodium does not have an ultraviolet (UV) absorbance above 220 nm, and therefore cannot be detected by liquid chromatography (LC) with a UV detector. A method was developed in which monensin residues are extracted from beef liver tissue, acetylated, partitioned, and reacted with 9-anthryldiazomethane to form a fluorescent derivative for quantitation by LC. The reliable level of sensitivity is 50 ppb, but 15 ppb can be detected. Recoveries ranged between 71 and 96% with an average of 83.5%.

Identification and semiquantitation of monensin sodium in liver tissue

A bioautographic technique for the determination of monensin sodium in animal feed has been applied to chicken and beef liver tissues. The reliable limit of sensitivity is 100 ppb, but 10 ppb can be detected. This technique can be used to semiquantitate monensin in tissues by comparing the zones of inhibition of unknown test samples against monensin standards.

Exercise testing in the latent phase of Chagas' disease

Exercise stress testing was performed in 50 completely asymptomatic patients in the latent phase of Chagas' disease. In 32 (64%) abnormalities were found consisting of either abnormal ST depression, exercise-induced arrhythmias, or chronotropic incompetence. The latter was determined by comparing the heart rate response to 50 age- and sex-matched control patients without serologic evidence of Chagas' disease. In the absence of an adequate control population we can only speculate as to the significance of the ST depression and arrhythmias during exercise. However, chronotropic incompetence may be a specific marker for Trypanosomal infestation in an endemic area. It probably is an early manifestation of autonomic dysfunction secondary to Chagas' disease.

Identification and semiquantitation of monensin sodium in animal feeds by thin layer bioautography

A bioautographic technique for the determination of monensin sodium contamination in animal feeds is described. The feeds are extracted in aqueous methanol and the initial monensin extracts are isolated by filtration through an alumina column. These eluates are partitioned between 5% NaCl and methylene chloride, and are further purified through a Sephadex LH-20 column. A 10 mL eluate containing the monensin is collected from the Sephadex column and evaporated, and the residue is dissolved in methylene chloride. Aliquots are spotted on a thin layer plate and monensin is detected by a thin layer bioautographic technique, using Bacillus subtilis as the test organism. The reliable limit of sensitivity is 100 ppb, but 10 ppb can be detected. This technique can be used to semiquantitate monensin by comparing the zones of inhibition of unknown test samples against monensin standards.

Comparative Efficiency of Brilliant Green, Bismuth Sulfite, Salmonella-Shigella, Hektoen Enteric, and Xylose Lysine Desoxycholate Agars for the Recovery of Salmonella from Foods: Collaborative Study

The relative efficiency of brilliant green (BG), bismuth sulfite (BS), Salmonella-Shigella (SS), xylose lysine desoxycholate (XLD), and Hektoen enteric (HE) agars for the recovery of Salmonella from 5 foods was collaboratively studied in 11 laboratories. The analytical efficiency of various paired combinations of the 5 agars was statistically compared according to 3 parameters: (1) productivity or recovery of Salmonella, (2) rate of enumeration of cultures that were false positive for Salmonella, and (3) rate of enumeration of false-negative reactions. In descending order of productivity, the sequential rankingwasBS, XLD, HE, BG, and SS agars. In ascending order, the rates of false-positive reactions based on a statistical analysis of paired agar combinations was HE, BS, BG and XLD (tie), and SS agars. Analogously, in ascending order, the sequence of false-negative reaction rates was BS, XLD, HE, BG, and SS agars. The combination of BS, XLD, and HE agars is more efficient for recovery of Salmonella from foods than is the present official combination of BG, BS, and SS agars. The revision of official final action method 46.054 to replace the combination of BG, BS, and SS agars with a combination of BS, XLD, and HE agars has been adopted official first action.

Hemodynamic correlates of late diastolic posterior motion of the aortic root

Motion of the posterior aortic root on echocardiography is related to left atrial volume changes. Early diastolic posterior motion of the aortic root reflects both LA emptying and filling and has been measured as the atrial emptying index. To study late diastolic motion of the aortic root, we measured the slope of posterior motion of the aortic root after left atrial systole (following the P wave of the ECG) in 25 subjects without heart disease (Group 1), in 15 patients with left ventricular hypertrophy due to pressure overload (Group 3) with mitral stenosis. The aortic root slope measured (mean +/- SEM) 58.0 +/- 1.9 mm./sec. in Group 1, 50.6 +/- 4.5 mm./sec. in Group 2 (NS vs 1) and 28.8 +/- 4.5 mm./sec. in Group 3, (p < 0.01 vs 1 or 2). In 16 patients (four in Group 1 and 12 in Group 2) studied at catheterization, an inverse correlation ( r = -0.74, p < 0.01) was found between the aortic root slope (over a range of 30 to 73 mm./sec.) and left ventricular late diastolic chamber stiffness measured with simultaneous left ventricular echo and high-fidelity pressure recordings. No correlation was found between this slope and either left atrial size, total aortic root excursion, left ventricular pressure pre "A" wave, height of the A wave, end-diastolic pressure, or the atrial contribution to left ventricular filling. Therefore, the aortic root slope in late diastole is decreased in mitral stenosis and in the absence of mitral stenosis, it appears to be related to late diastolic properties of the left ventricle.

The influence of left ventricular late diastolic filling on the A wave of the left ventricular pressure trace

To study the influence of left ventricular (LV) late diastolic filling on the A wave of the LV pressure, simultaneously recorded echocardiographic LV dimensions and high-fidelity LV pressure measurements were taken in 24 patients. Group 1 comprised eight patients without LV hypertrophy (LVH) and LV end-diastolic pressure (LVEDP) less than or equal to 13 mm Hg. Group 2 comprised 16 patients with LVH secondary to aortic stenosis, idiopathic hypertrophic subaortic stenosis, or hypertension and increased LVEDP. Patients in group 2 had significantly thicker left ventricles, decreased mitral E-to-F slopes, and larger A waves in the LV pressure curve. On the basis of end-diastolic chamber stiffness, we divided group 2 into two populations: 12 patients (group 2A) with end-diastolic chamber stiffness similar to that in group 1, and four patients (group 2B) with markedly elevated end-diastolic chamber stiffness. Patients in group 2A had a larger atrial contribution to LV filling than those with markedly abnormal stiffness (group 2B). Therefore, in LVH an increased A wave in the LV pressure may be related to either elevated end-diastolic chamber stiffness or augmented left atrial volume transport.