Mechanical alternans in patients with chronic heart failure.

BACKGROUND: Clinical implications of mechanical alternans in patients with chronic heart failure have remained uncertain. In this study, prevalence, characteristics, and prognostic implications of mechanical alternans were investigated. METHODS AND RESULTS: Consecutive 51 patients with dilated cardiomyopathy underwent diagnostic cardiac catheterization using a micromanometer-tipped catheter. Under basal conditions, 7 of 35 patients with sinus rhythm showed mechanical alternans. Physiologic tachycardia (110 bpm) induced mechanical alternans in another 15 patients with sinus rhythm and in another 10 of 16 patients with atrial fibrillation. Low doses of dobutamine also induced mechanical alternans in another 8 patients, but a high dose of dobutamine eliminated mechanical alternans. Consequently, 40 patients (78%) showed mechanical alternans. Mechanical alternans was always accompanied by alternating changes of positive dP/dt, a parameter of contractility during isovolumetric contraction time, but negative dP/dt was occasionally constant. Concordant mechanical alternans between both ventricles was more prevalent than discordant alternans. The left ventricular end-diastolic volume indices and end-systolic volume indices of patients with mechanical alternans were larger than those of patients without. The left ventricular ejection fraction of patients with alternans was significantly lower than that of patients without. CONCLUSIONS: Mechanical alternans was highly prevalent in patients with chronic heart failure. The origin of mechanical alternans seems to exist before or at the isovolumetric contraction time.     

Endogenous plasma endothelin concentrations and coronary circulation in patients with mild dilated cardiomyopathy

OBJECTIVE: To determine whether increased plasma concentrations of endothelin-1 (ET-1) and big endothelin (BET) play a role in the regulation of coronary circulation in patients with idiopathic dilated cardiomyopathy (IDCM). SETTING: Tertiary referral centre for cardiac diseases. PATIENTS: Fourteen patients (eight male/six female; mean (SD) age 59 (9) years) with IDCM (ejection fraction 36 (9)%) and five normotensive subjects (two male/three female; age 52 (7) years) serving as controls were studied. METHODS: Functional status was classified according to New York Heart Association (NYHA) class. Endogenous ET-1 and BET plasma concentrations from the aorta and the coronary sinus were determined by radioimmunoassay. Coronary blood flow, using the inert chromatographic argon method, myocardial oxygen consumption, and coronary sinus oxygen content under basal conditions were determined. RESULTS: In the aorta, mean (SD) concentrations of ET-1 (IDCM 0.76 (0.25) v controls 0.31 (0.06) fmol/ml; p = 0.002) and BET (IDCM 3.58 (1.06) v controls 2.11 (0.58) fmol/ml; p = 0.014) were increased in patients with IDCM. Aortic ET-1 concentrations correlated positively with NYHA class (r = 0. 731; p < 0.001), myocardial oxygen consumption (r = 0.749; p < 0. 001), and coronary blood flow (r = 0.645; p = 0.003), but inversely with coronary sinus oxygen content (r = -0.633; p = 0.004), which was significantly decreased in IDCM patients (IDCM 4.68 (1.05) v controls 6.70 (1.06) vol%; p = 0.003). CONCLUSIONS: The coronary circulation in patients with IDCM is exposed to an increased endothelin load. ET-1 concentrations correlate with functional deterioration. A decrease of the coronary sinus content of oxygen suggests a mismatch between coronary blood flow and metabolic demand. Thus, ET-1 might be a marker of a disequilibrium between myocardial oxygen demand and coronary blood flow in IDCM.     

Prognostic value of mechanical efficiency in ambulatory patients with idiopathic dilated cardiomyopathy in sinus rhythm

OBJECTIVES: The purpose of this study was to determine, by analyzing the pressure-volume relationship, the prognostic value of parameters related to myocardial energetics for predicting mortality in patients with dilated cardiomyopathy (DCM) in sinus rhythm. BACKGROUND: The relationship between the myocardial energetics and the prognosis of patients with DCM in sinus rhythm remains unclear. METHODS: We followed 114 ambulatory patients with nonischemic DCM in sinus rhythm for a mean period of 5.8 +/- 3.9 years. Over 70% of our patients were in New York Heart Association functional class I and class II. Pressure-volume data were obtained by the conductance method, and myocardial oxygen consumption per beat (VO(2)) measurements were obtained. RESULTS: The 3-, 5-, and 10-year cumulative survival rates were 88.6%, 80.0%, and 73.9%, respectively. Of the 114 patients, 47 were selected randomly to assess their myocardial energetics. By univariate analysis, the mechanical efficiency (ME, external work/VO(2)), left ventricular (LV) ejection fraction and the LV end-diastolic pressure were statistically associated with cardiac death. The ME was the strongest predictor of survival in a Cox proportional-hazards analysis (p = 0.011). The best cutoff point of ME identified by the receiver-operating curve was 11%. This value had a sensitivity of 100%, a specificity of 87% and an overall predictive accuracy of 88% to distinguish survivors from nonsurvivors. CONCLUSIONS: This study clearly demonstrates that ME is a powerful clinical predictor for cardiac death in patients with mild to moderate heart failure and with sinus rhythm. Whether these conclusions apply to patients with more severe heart failure requires further investigations.     

特发性扩张型心肌病合并左心室室壁瘤形成的临床分析

目的 观察特发性扩张型心肌病(idiopathic dilated cardiomyopathy,IDCM)合并左心室室壁瘤(left ventricular aneurysm,LVA)形成的发生率及其血液动力学和心脏电生理的特点.方法 回顾我院2003年至今诊断为IDCM的患者的病历资料,经冠状动脉造影排除缺血性心肌病同时经左心室造影证实合并LVA形成者入选为研究组.随机入选12例性别、年龄及左心室内径大小匹配的IDCM患者作为对照组.两组的临床资料和检查结果进行对比分析.结果 998例IDCM患者中有6例患者证实同时合并LVA形成,发生率为0.60%.研究组的左心室收缩期最大压力显著高于对照组[(130±10)mm Hg(1 mm Hg=0.133 kPa)比(117±9)mm Hg,P<0.05].研究组左心室舒张末期容积显著高于对照组[(272±57)ml比(207±60)ml,P<0.05].研究组左心室射血分数略低于对照组[(27±9)%比(35±6)%,P=0.09].室性心律失常在研究组的发生率更高.结论 IDCM合并LVA在临床上较为少见.合并LVA的IDCM患者左心室舒张末期容积增大,左心室收缩期压力升高,而左心室收缩功能下降,更容易发生室性心律失常.     

Carnitine deficiency in patients with coeliac disease and idiopathic dilated cardiomyopathy

BACKGROUND AND AIMS: Idiopathic dilated cardiomyopathy (IDCM) and coeliac disease (CD) are two pathological conditions which may lead, by different mechanisms, to malabsorption of various micronutrients, including carnitine, active in cardiac metabolism. The aim of the present investigation was primarily to evaluate differences in serum concentrations of total carnitine between IDCM patients and patients with IDCM associated with CD and then also to evaluate, in the latter, the effect of a gluten-free diet on serum concentrations of total carnitine. METHOD AND RESULTS: Serum carnitine was determined by enzymatic spectrophotometric assay in three groups of individuals: group A, 10 patients (5 males, 5 females), mean age 46.5+/-10.8 years, presenting isolated IDCM; group B, 3 patients (2 males, 1 female), mean age 34+/-8 years, with IDCM+CD; and group C, 10 healthy subjects (5 males, 5 females), mean age 38.6+/-11.1 years. All patients with IDCM belonged to class NYHA I-II. Mean concentrations of total serum carnitine in the group of patients with isolated IDCM (group A) were found to be lower than in the controls (group C). The concentrations in patients with IDCM associated with CD (group B) were lower than in the control group and also lower than in the isolated IDCM (group A). After 2 years on a gluten-free diet, patients presenting IDCM associated with CD showed a progressive increase in mean serum carnitine levels compared to values observed prior to the diet. CONCLUSIONS: Patients presenting IDCM associated with CD show a greater decrease in serum total carnitine levels than patients presenting the isolated form of IDCM. A gluten-free diet, in these patients, leads to a progressive increase in serum levels of this substance.     

Impact of mild to moderate renal dysfunction on left ventricular relaxation function and prognosis in ambulatory patients with nonischemic dilated cardiomyopathy

The relationship between mild-to-moderate renal dysfunction and cardiac diastolic dysfunction and cardiac events in patients with nonischemic dilated cardiomyopathy (NDCM) has not been fully elucidated. The aim of this study was to investigate the relationship between renal and cardiac function, as well as clinical outcome in patients with NDCM.We measured plasma BNP and eGFR, and performed cardiac catheterization in 135 patients with NDCM. LV dP/dt(max)and T(1/2) were determined as indexes of LV contractility and isovolumic relaxation, respectively. During a mean follow-up of 4.8 years, we monitored all patients for the occurrence of cardiac events, which were defined as cardiac death (from worsening HF or sudden death) and unscheduled admission for decompensated HF. Patients were classified into 3 groups on the basis of eGFR (mL min(-1) 1.73 m(-2)): eGFR ≥ 90 (n = 23, group A), 60 ≤ eGFR < 90 (n = 70, group B), and 30 ≤ eGFR < 60 (n = 42, group C). Whereas LV dP/dt(max) did not significantly differ among the 3 groups, T(1/2) was significantly longer in groups B and C than in group A (P < 0.01). Event-free survival in group C was significantly lower than that in groups A and B (P = 0.014, log-rank test). These results suggest that even mild renal dysfunction is associated with LV isovolumic relaxation impairment. In addition, moderate impairment of renal function is independently associated with cardiac events in patients with NDCM.     

Echocardiographic parameters in reversible idiopathic dilated cardiomyopathy

BACKGROUND: Reversible idiopathic dilated cardiomyopathy (IDCM) is a rare entity. It has been hypothesized that the degree of left ventricular end diastolic dilation is an important independent predictor of prognosis. We undertook a study to identify cases of reversible IDCM and to evaluate the echocardiographic findings in these patients. METHODS: We identified 5 patients with IDCM who showed normalization of left ventricular function over a follow up period of 5 months. The findings were compared with those of 10 patients with IDCM who did not show improvement of left ventricular function. The mean (+/-SE) left atrial and left ventricular (LV) dimensions and ejection fraction at baseline and follow-up were compared in both groups. RESULTS: There were no statistical differences between the mean (+/-SE) left atrium sizes in the cases and control group at baseline [4.52 (+/-0.24) cm v4.6 (+/-0.13) cm; P = 0.758]. Also, no differences were observed between mean (+/-SE) LV dimensions in diastole and systole in both groups at baseline [LV diastole, 6.72 (+/-0.35) cm versus 6.56 (+/-0.22) cm; P = 0.711; LV systole, 5.6 (+/-0.27) cm versus 5.59 (+/-0.29) cm; P = 0.712] as well as in mean (+/-SE) ejection fraction [24% (+/-3.96) versus 21.7% (+/-3.30); P = 0.623]. CONCLUSION: Based on initial echocardiographic parameters, chamber dimensions and baseline LV ejection fraction are not predictors of reversibility.     

Hereditary hemochromatosis gene (HFE) mutations C282Y, H63D and S65C in patients with idiopathic dilated cardiomyopathy

BACKGROUND: Hereditary hemochromatosis (HH), a common autosomal recessive disease, leads to excessive iron accumulation in some organs, including the heart. It is therefore not surprising that cardiomyopathy is one of the most severe complications of HH. The HFE gene defects have been thought to contribute to idiopathic dilated cardiomyopathy (IDCM) in some patients, even though the results of genotype analyses have so far been contradictory. Hence we set out here to evaluate the prevalence and potential role of HFE mutations in patients with IDCM. METHODS: A total of 91 IDCM patients and 102 controls were subjected to HFE mutation analyses, in which C282Y, H63D and S65C mutations were determined for each patient. We also analyzed the impact of the C282Y and H63D mutations on the left ventricular end-diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) functional classes. RESULTS: The prevalences of heterozygosity for the C282Y, H63D and S65C mutations in the IDCM patients were 13.2%, 22.0% and 2.2%, respectively. LVEDD was significantly higher (P=0.037) in those with the C282Y mutation at the end of the follow-up period than in those with no mutation. CONCLUSIONS: Our data showed no significant deviations in C282Y, H63D and S65C mutation frequencies between the IDCM patients and controls, suggesting that these mutations do not increase the risk of IDCM. Heterozygosity for the C282Y mutation may nevertheless be a modifying factor contributing to LV dilatation and remodeling.     

Endocardial and epicardial repolarization alternans in human cardiomyopathy: evidence for spatiotemporal heterogeneity and correlation with body surface T-wave alternans.

OBJECTIVES: The aim of this study was to define the spatiotemporal distribution of intracardiac alternans and its relationship to body surface alternans in humans. BACKGROUND: Spatial heterogeneity of alternans exists in the animal heart owing to nonuniform calcium cycling and restitution kinetics. Patients with cardiomyopathy manifest similar myocardial substrate, which might influence the distribution of intracardiac alternans and its projection onto the body surface. METHODS: Repolarization alternans was simultaneously measured from unipolar electrograms in the right ventricular endocardium, left ventricular (LV) epicardium, and the surface electrocardiogram in patients with cardiomyopathy (n = 14, LV ejection fraction 29 +/- 2%) during atrial pacing at cycle length (CL) 800, 600, and 500 ms. Alternans was determined from the entire JT interval as well as the early, mid, and late JT interval with spectral analysis. RESULTS: Alternans was not uniformly distributed within the heart, with alternating and nonalternating myocardial segments lying adjacent to one another. A greater number of epicardial sites exhibited alternans than endocardial sites at CL 600 ms. Temporal heterogeneity in alternans was present along the JT interval, and apical segments had proportionately less alternans in the late JT interval than mid or basal segments, resulting in apicobasal alternans heterogeneity in late JT interval. Discordant alternans was seen in 5 patients confined to the epicardium. Patients with surface alternans had a greater proportion of intracardiac sites with alternans when compared with those patients without surface alternans. CONCLUSIONS: Spatiotemporal heterogeneity and discordant alternans are evident in patients with cardiomyopathy. Greater spatial distribution of intracardiac alternans is associated with measurable body surface alternans.     

Myocardial asynchronism is a determinant of changes in functional mitral regurgitation severity during dynamic exercise in patients with chronic heart failure due to severe left ventricular systolic dysfunction.

AIMS: Functional mitral regurgitation (MR) and myocardial asynchronism occur commonly in patients with dilated cardiomyopathy and affect adversely their prognosis and symptoms. The aim of this study was to evaluate the mechanisms of changes in MR severity during dynamic exercise in patients with chronic heart failure (CHF). METHODS AND RESULTS: Seventy patients with CHF due to left ventricular (LV) systolic dysfunction [LV ejection fraction (EF) <40%] and functional MR were studied. All were in sinus rhythm. Medications were left unchanged for the study. Each patient performed a maximal symptom-limited exercise test with continuous 2D-Doppler echocardiography. Mitral regurgitant volume (RV) and effective regurgitant orifice (ERO) were determined at rest and during exercise. LV asynchrony using Doppler tissue imaging and interventricular asynchrony using conventional pulsed-Doppler were evaluated at rest. Resting LV EF averaged 25+/-8%. Mean resting LV and interventricular mechanical delays were 56+/-50 and 43+/-37 ms, respectively. The overall median values for mitral ERO and RV did not significantly change during dynamic exercise (11 [7-16] vs. 11 [6-21] mm2 and 14 [10-22] vs. 12 [9-23] mL, respectively). However, changes in mitral ERO and RV were individually variable and significantly correlated with the degree of LV asynchronism (r=0.66, P<0.0001 and r=0.66, P<0.0001, respectively). CONCLUSION: Changes in MR are variable during dynamic exercise. LV asynchronism at rest substantially contributes to worsening of functional MR during dynamic exercise in patients with CHF due to LV systolic dysfunction.     

Left ventricular thrombosis is associated with increased mean platelet volume in patients with dilated cardiomyopathy and sinus rhythm

OBJECTIVE: Dilated cardiomyopathy has been associated with left ventricular thrombosis, which leads to substantial morbidity and mortality as a site for peripheral emboli. There are some studies on patients with dilated cardiomyopathy showing altered haemostasis and platelet behaviour despite sinus rhythm. Mean platelet volume, which is the most accurate and simple estimate of platelet reactivity, may be associated with the development of left ventricular thrombosis. METHODS AND RESULTS: We prospectively enrolled 48 consecutive patients with dilated cardiomyopathy and sinus rhythm with left ventricular thrombosis and compared them with an age-sex-matched control group having dilated cardiomyopathy without left ventricular thrombosis. We found that in patients with left ventricular thrombosis mean platelet volume is significantly higher than those without (9.5 +/- 0.8 vs. 8.7 +/- 0.6, p < 0.001). CONCLUSIONS: Mean platelet volume is increased in patients with dilated cardiomyopathy and sinus rhythm having left ventricular thrombosis. This might be reflecting a causal relationship, which in turn requires further study to establish the role of antiplatelet agents both in prevention and in treatment.     

Variable patterns of septal activation in patients with left bundle branch block and heart failure

INTRODUCTION: Little is known about the septal activation pattern in patients with heart failure and left bundle branch block (LBBB-HF). METHODS AND RESULTS: The right ventricular (RV) and left ventricular (LV) activation patterns of 12 patients (mean age 67 +/- 11 years) with LBBB-HF and 5 patients (mean age 45 +/- 14) with normal hearts were studied during sinus rhythm using a three-dimensional mapping system. The etiology of HF was myocardial infarction (n = 4) or idiopathic dilated cardiomyopathy (n = 8). In patients with LBBB-HF, endocardial activation usually started before the onset of the surface QRS complex on the RV free wall. Latest RV activation occurred in the basal region, and total RV activation time was longer than in patients with normal hearts. In patients with LBBB-HF, the left septum was activated via slowly conducting LBB or via right-to-left transseptal conduction. In both patients with LBBB-HF and those with normal hearts, latest LV activation occurred either in the posterior or posterolateral-basal region. Conduction velocity was slower in the peri-scar region, in patients with previous myocardial infarct and globally slow, in patients with idiopathic dilated cardiomyopathy. CONCLUSION: The two types of left septal activation observed in patients with LBBB-HF may have consequences for biventricular hemodynamic performance. Conduction slowing along the LV, regionally or globally, suggests a contribution outside the specific conduction system in the ECG pattern of LBBB.     

Changes in the occurrence of mechanical alternans after long-term beta-blocker therapy in patients with chronic heart failure

Mechanical alternans has been observed in patients with severe congestive heart failure, and the phenomenon is considered to be a terminal sign. Therapeutic strategies for chronic heart failure have significantly developed, but it is uncertain whether patients with mechanical alternans can be effectively treated or not. Seventeen consecutive patients with dilated cardiomyopathy were enrolled: 11 were treated with beta-blockers on conventional therapeutic regimens and 6 patients were not indicated for or were unable to continue beta-blockade. Mechanical alternans was detected during cardiac catheterization in the patients under physiologic tachycardia (110 beats/min) and stepwise dobutamine loading. In the initial study, mechanical alternans occurred in 70.6% of the patients: 8 of the 11 being treated with beta-blockers and 4 of the 6 without beta-blockade therapy. In the second study, none of the patients taking beta-blockers showed mechanical alternans under the same protocol; the occurrence of mechanical alternans did not change in the patients who were not being treated with beta-blockers. The left ventricular ejection fraction increased in patients whose mechanical alternans could not be induced during the follow up, but decreased in the patients in whom mechanical alternans was repeatedly inducible. It is concluded that mechanical alternans is associated with the failing myocardium and may be potentially correctable.     

Decline of plasma brain natriuretic peptide level after carvedilol therapy to treat dilated cardiomyopathy presenting with mechanical alternans

Mechanical alternans is observed in patients with severe left ventricular dysfunction. We report a case of dilated cardiomyopathy with mechanical alternans. He presented with a remarkable decrease in plasma brain natriuretic peptide (BNP) levels after beta-blocker therapy despite persistency of the mechanical alternans. Mechanical alternans may persist after improvement of hemodynamics, diastolic function, and plasma BNP levels. Mechanical alternans may reflect persistent organic or functional myocardial damage such as abnormal intracellular Ca(2+) cycling in cardiomyocytes.     

Does left ventricular shape influence clinical outcome in heart failure?

BACKGROUND: Left ventricular (LV) shape tends to become spherical in patients with dilated cardiomyopathy of diverse etiology. Clinical and echocardiographic factors which affect the degree of LV spherical distortion and the impact of altered LV shape on prognosis have not been studied adequately. HYPOTHESIS: This study was undertaken to investigate the prognostic implications of altered LV shape on clinical outcome in dilated cardiomyopathy. METHODS: In 112 patients with depressed LV ejection fraction (19 +/- 9%) and symptomatic heart failure, and in 10 age- and gender-matched normal controls, we performed 2-dimensional echocardiography to assess LV shape using the eccentricity index. Eccentricity index was defined as the ratio of the LV long axis to the LV transverse diameter, measured at end systole and end diastole in the apical four-chamber view. We sought univariate and multivariate clinical and echocardiographic correlates of LV shape. Further, we sought correlations between eccentricity index and clinical outcomes (death and composite outcome of death or emergent heart transplant). RESULTS: Compared with controls, patients with cardiomyopathy had significantly lower systolic (2.04 vs. 1.56; p = 0.001) and diastolic (1.75 vs. 1.53; p = 0.003) eccentricity index, implying a more spherical LV shape. Of all clinical and echocardiographic variables tested, mitral regurgitation, right ventricular dysfunction, and increased LV mass were independently associated with spherical LV shape. At a follow-up period of 17 +/- 12 months, no correlation was found between eccentricity index and the occurrence of death or the combined endpoint of death or emergent heart transplant, in univariate or multivariate analysis. CONCLUSIONS: In patients with dilated cardiomyopathy, the degree of spherical distortion of the LV does not correlate with prognosis.     

Arterial Mechanics in Ischemic versus Nonischemic Cardiomyopathy: Clinical and Diagnostic Impact

Background: Differential diagnosis between ischemic (IDCM) and the nonischemic type (NIDCM) of cardiomyopathy constitutes a challenge in the daily medical practice. Carotid and aortic elastic properties deteriorate in patients with coronary artery disease. However, their predictive role in differentiating IDCM from NIDCM has not been addressed so far. Aim of the work: To examine carotid and aortic mechanical functions using conventional and Doppler tissue echocardiography in the distinction between IDCM and NIDCM in patients with clinically undetermined etiology. Methods: 70 patients with dilatation and diffuse impairment of the left ventricular (LV) contraction were studied. All patients underwent carotid duplex for measuring intima‐media (IMT) thickness, peak systolic velocity (PSV), and luminal diameters (LD). Aortic distensibility, strain, and aortic wall velocities (systolic (Sa), early diastolic (Ea), late diastolic (Aa) velocities, Sa_t, and Ea_t) were measured. According to coronary angiographic results, patients were categorized into IDCM (n = 36) (age 57.9 ± 9.2 years) and NIDCM groups (n = 34) (age 56.0 ± 8.3 years); they were compared to 30 age‐ and sex‐matched healthy individuals as a control group. Results: The aortic pulsatile change, aortic strain, and distensibility were significantly reduced in both patient groups in comparison to control (P < 0.001). These parameters were much impaired in patients with IDCM compared with NIDCM (P < 0.001). IDCM have more deterioration of Sa, Ea, and Aa compared with NIDCM group (7.6 ± 2.4 vs. 8.9 ± 1.58, 7.5 ± 2.8 vs. 10.6 ± 1.5, 9.0 ± 1.4 vs. 6.9 ± 2.4 cm/sec; P < 0.001), respectively. In IDCM, the variables of aortic elastic properties were correlated only to age, while in NIDCM they were correlated to hemodynamics, LV volumes, wall thickness, and mass. Both carotid diameter and IMT were significantly increased in IDCM in comparison to NIDCM and control (P < 0.001). Carotid distensibility was significantly reduced in IDCM compared with NIDCM and control (P < 0.001). However, the carotid properties strongly correlated to risk factors in IDCM and to hemodynamics and LV function in NIDCM. Using ROC curve, a cutoff value ≤4.7 (cm²/dyne/10³) for aortic distensibility, value <8 cm/sec for Sa and IMT >0.8 mm predicted IDCM with 94.4%, 72.7%, and 97.2% sensitivity and 88.2%, 85.3%, and 97.1% specificity, respectively. Conclusion: Both carotid and aortic mechanical functions are more deteriorated in ischemic compared with nonischemic dilated cardiomyopathy. Different functional and structural mechanisms might be responsible for the deterioration of arterial elastic properties in each category.     

Effect of optimizing the VV interval on left ventricular contractility in cardiac resynchronization therapy

Simultaneous biventricular pacing improves left ventricular (LV) function in patients with heart failure and LV asynchrony. Proper timing of the interventricular pacing interval (VV interval) may further optimize LV function. We investigated the acute hemodynamic response of changing the VV interval using maximum LV dP/dt (LV dP/dt_max) as a parameter for LV function. A biventricular pacemaker was implanted in 53 patients with severely impaired LV function, New York Heart Association class III and IV heart failure, left bundle branch block, LV asynchrony, and a QRS interval >150 ms. Optimization of the atrioventricular and VV intervals was based on measurement of LV dP/dt_max by a 0.014-in sensor-tipped pressure guidewire. Measurement of LV dP/dt_max was obtained without complications in all patients. In patients in sinus rhythm with ischemic cardiomyopathy or idiopathic dilated cardiomyopathy, mean improvements by simultaneous biventricular pacing were 17% and 18%, respectively. Patients in atrial fibrillation showed an improvement of 21%. Optimizing the VV interval resulted in further absolute increases of 8%, 7%, and 3%, respectively, in dP/dt_max in the 3 groups. Maximum dP/dt was achieved with LV pacing first in 44 patients, simultaneous right and left ventricular pacing in 6 patients, and right ventricular pacing first in 3 patients. The mean optimal VV intervals were 37 ± 32 ms in the atrial fibrillation group, 28 ± 30 ms in the idiopathic dilated cardiomyopathy group, and 52 ± 31 ms in the ischemic cardiomyopathy group. Optimization of the VV interval significantly increased LV dP/dt_max compared with simultaneous biventricular pacing, and such optimization could be easily, accurately, and reliably evaluated by a 0.014-in sensor-tipped pressure guidewire.     

Human immunodeficiency virus infection and systolic myocardial performance

Cardiac dysfunction in HIV-infected patients is being increasingly recognized. The present echocardiographic and Doppler study was undertaken to evaluate left ventricular (LV) systolic performance during the different stages of the disease. Twenty-nine anti-HIV (positive (+) ambulatory patients (19 with AIDS and 10 with asymptomatic HIV infection) without cardiac symptoms were evaluated by two-dimensional and M-mode echocardiography. Four groups were identified: group A, 10 patients (9 without AIDS) with a normal echocardiogram; group B, 6 patients with LV dilatation but normal LV function; group C, 9 patients with abnormal regional contractility but normal global function; group D, 4 patients with dilated cardiomyopathy (DC). Doppler study of the aortic systolic flow was performed in the four groups and in a normal control group. Doppler parameters—peak aortic velocity, ejection time, and flow velocity integral—were similar in controls and in groups A and B. Groups C and D (with abnormal contractility by echocardiography) had lower values for all Doppler parameters and were significantly different from controls and from groups A and B. Patients with dilated cardiomyopathy (group D) had the lowest values for all Doppler data, consistent with their low systolic performance. This group also had the lowest CD4+ lymphocyte counts and the longest mean probable time of HIV infection (6.5 years), being significantly different from group A patients, who presented a mean probable time of infection of 2.7 years and higher CD4+ counts. The results confirm that myocardial dysfunction affecting HIV-infected patients is more common in the late stages of the disease. It is also shown that Doppler study of the aortic systolic flow relates more closely to global LV performance than conventional echocardiography alone, and better differentiates patients with normal from those with abnormal LV function.Presented at the 35th World Congress, International College of Angiology, Copenhagen, Denmark, July 1993     

Marked elevation of myocardial trace elements in idiopathic dilated cardiomyopathy compared with secondary cardiac dysfunction.

OBJECTIVES: We sought to investigate the possible pathogenetic role of myocardial trace elements (TE) in patients with various forms of cardiac failure. BACKGROUND: Both myocardial TE accumulation and deficiency have been associated with the development of heart failure indistinguishable from an idiopathic dilated cardiomyopathy. METHODS: Myocardial and muscular content of 32 TE has been assessed in biopsy samples of 13 patients (pts) with clinical, hemodynamic and histologic diagnosis of idiopathic dilated cardiomyopathy (IDCM), all without past or current exposure to TE. One muscular and one left ventricular (LV) endomyocardial specimen from each patient, drawn with metal contamination-free technique, were analyzed by neutron activation analysis and compared with 1) similar surgical samples from patients with valvular (12 pts) and ischemic (13 pts) heart disease comparable for age and degree of LV dysfunction; 2) papillary and skeletal muscle surgical biopsies from 10 pts with mitral stenosis and normal LV function, and 3) LV endomyocardial biopsies from four normal subjects. RESULTS: A large increase (>10,000 times for mercury and antimony) of TE concentration has been observed in myocardial but not in muscular samples in all pts with IDCM. Patients with secondary cardiac dysfunction had mild increase (< or = 5 times) of myocardial TE and normal muscular TE. In particular, in pts with IDCM mean mercury concentration was 22,000 times (178,400 ng/g vs. 8 ng/g), antimony 12,000 times (19,260 ng/g vs. 1.5 ng/g), gold 11 times (26 ng/g vs. 2.3 ng/g), chromium 13 times (2,300 ng/g vs. 177 ng/g) and cobalt 4 times (86,5 ng/g vs. 20 ng/g) higher than in control subjects. CONCLUSIONS: A large, significant increase of myocardial TE is present in IDCM but not in secondary cardiac dysfunction. The increased concentration of TE in pts with IDCM may adversely affect mitochondrial activity and myocardial metabolism and worsen cellular function.