Effect of cardiac resynchronization therapy in patients with moderate left ventricular systolic dysfunction and wide QRS complex: a prospective study

Background: We sought to investigate the effect of cardiac resynchronization therapy (CRT) on disease progression in patients with moderate left ventricular (LV) systolic dysfunction.
Methods and Results: This is a prospective study to explore the effect of CRT in 15 optimally treated patients (age: 66.1 ± 12.8 years; male = 13) with New York Heart Association (NYHA) class III, LV ejection fraction >35% and <45% and QRS duration >120 msec. Echocardiographic examination and standard heart failure assessment was performed before and 3 months after CRT implantation. The magnitude of echocardiographic remodeling measurements was compared with 30 age, sex, NYHA class, and heart failure etiology matched patients with conventional CRT indication. There were significant reductions in LV end-systolic (86.2 ± 24.1 to 69.7 ± 22.2 mL, P < 0.01)/end-diastolic (135.5 ± 36.8 to 120.5 ± 34.6 mL, P < 0.01) volumes, improvement in LV ejection fraction (39.1 ± 2.2 to 44.2 ± 5.5%, P = 0.01), and NYHA class (3.0 ± 0.0 to 2.07 ± 0.46, P < 0.001). There was no difference in changes in LV volumes, ejection fraction, NYHA class, and exercise capacity before and after CRT between the study and conventional groups except for greater improvement in the quality of life score in the conventional group.
Conclusion: In this prospective study, significant LV reverse remodeling by CRT in those with a wide QRS complex and moderate LV systolic dysfunction was observed. Further studies to explore the benefit of CRT in patients with less severe heart failure are recommended.     

Prevalence of asymptomatic left ventricular systolic dysfunction in hypertensive Nigerians: echocardiographic study of 832 subjects

Background

We sought to determine the prevalence of echocardiographically determined left ventricular systolic dysfunction in asymptomatic hypertensive subjects seen in Abeokuta, Nigeria.

Methods

Echocardiography was performed in 832 consecutive hypertensive subjects referred for cardiac evaluation over a three-year period.

Results

Data were obtained in 832 subjects (50.1% women) aged 56.0 ± 12.7 years (men 56.9 ± 13.3 years, women 55.0 ± 12.0 years, range 15–88). The prevalence of left ventricular systolic dysfunction (LVSD) was 18.1% in the study population (mild LVSD = 9.6%, moderate LVSD = 3.7% and severe LVSD = 4.8%). In a multivariate analysis, male gender, body mass index and LV mass were the predictors of LVSD.

Conclusion

Significant numbers of hypertensive subjects in this study had varying degrees of left ventricular systolic dysfunction. Early introduction of disease-modifying drugs in these patients, such as angiotensin converting enzyme inhibitors or angiotensin receptor blockers may retard or prevent the progression to overt heart failure.     

Ambulatory ECG-based T-wave alternans predicts sudden cardiac death in high-risk post-MI patients with left ventricular dysfunction in the EPHESUS study

Background: Exercise microvolt T‐wave alternans (TWA) identifies sudden cardiac death (SCD) risk. TWA can be measured from ambulatory ECGs (AECGs) using modified moving average (MMA) method. Whether MMA TWA from AECGs predicts SCD in post‐MI patients with left ventricular dysfunction (LVD) is unknown. Methods: EPHESUS enrolled hospitalized post‐MI patients with heart failure and/or diabetes with LVD. Before randomization to drug treatment, AECGs were obtained in 493 patients. Of them, 46 died of cardiovascular causes, including 18 of SCD. Patients alive at end of follow‐up (N = 92) were matched with 46 nonsurvivors based on age, gender, and diabetes. MMA TWA was analyzed using MARSPC system (GE Healthcare, Milwaukee, WI, USA). The three highest TWA values from artifact‐free periods were averaged for AECG channels corresponding to leads V₁ and V₃. SCD prediction was tested with a prespecified 47 μV cutpoint and at a cutpoint maximizing the separation between SCD patients versus survivors or non‐SCD. Results: TWA in either lead was higher for patients with SCD (P ≤ 0.05) versus survivors or non‐SCD. TWA ≥ 47 μV was associated with RR = 5.2 (95%CI = 1.8–13.6, P = 0.002) in V₁ and RR = 5.5 (95% CI = 2.2–13.8, P < 0.001) in V₃ for SCD. The optimal cutpoint for TWA in V₁ was ≥43 μV (RR = 5.9 [95%CI = 2.2–15.8, P < 0.001]). The optimal cutpoint in V₃ was ≥47 μV. TWA greater than the optimal cutpoint in either lead was associated with RR = 7.1 (95%CI = 2.7–18.3, P < 0.001) for SCD, with 11 out of 18 patients dying of SCD. Conclusions: AECG‐based TWA measured with MMA is a powerful predictor of SCD in high‐risk post‐MI patients with LV dysfunction.     

Pacing-induced increase in QT dispersion predicts sudden cardiac death following cardiac resynchronization therapy.

OBJECTIVES: This study was designed to determine whether cardiac resynchronization therapy (CRT) by means of biventricular pacing (BiVP) alters the QT interval (QT(c)) and QT dispersion (QTD), and whether such changes relate to the risk of developing major arrhythmic events (MAE). BACKGROUND: Prolonged QT(c) is associated with MAE. Left ventricular pacing and BiVP alter QT(c). METHODS: A total of 75 patients with drug-resistant heart failure (New York Heart Association functional class III/IV) and QRS duration > or =120 ms underwent CRT. The QT(c) and QTD were measured before and 48 days after BiVP. RESULTS: Over 807 days (range 93 to 1,543 days), 11 patients had a MAE. Compared to baseline, at 48 days after CRT, QTD increased in 47% of patients and QT(c) decreased in 53%. The QT(c) at follow-up was higher in MAE patients compared with no-MAE patients (35.9 +/- 14.2 ms vs. 0.52 +/- 6.0 ms; p = 0.0323). Similar differential responses for QTD were observed (46.4 +/- 13.5 ms in MAE vs. -5.1 +/- 4.1 ms in no MAE, p < 0.0001). The MAE occurred in 29% of patients exhibiting an increase in QTD and in 3% of those exhibiting a decrease (p = 0.0017). In multiple regression analyses, change in QTD from baseline (DeltaQTD) strongly predicted MAE, independent of DeltaQT(c), QRS duration, and left ventricular ejection fraction and end-diastolic volume (p < 0.001). Differences in survival curves were observed when patients were dichotomized according to whether QTD increased or decreased in relation to baseline values (p < 0.0001). CONCLUSIONS: The MAE in patients with BiVP are related to pacing-induced increases in QTD. Measures of ventricular repolarization at the time of pacemaker implantation may guide selection of patients for combined CRT and defibrillator therapy.     

Treatment of ventricular dysrhythmias and sudden cardiac death: a guideline-based approach for patients with chronic left ventricular dysfunction

With the rise in the use of device therapy implants, we are better identifying appropriate chronic heart failure patients for primary implantable defibrillator therapy who are at risk of ventricular arrhythmia. As our knowledge expands, however, controversial issues emerge. Guidelines have been endorsed by the major international societies, such as the American College of Cardiology (ACC), the American Heart Association (AHA), and the European Society of Cardiology. In view of certain variances in recommendations and new data, a recent joint guideline statement has been issued from these 3 societies regarding management of ventricular arrhythmia and preventing sudden cardiac death in patients with left ventricular dysfunction and heart failure. In this review, the recent joint statement is compared with those from the Heart Failure Society of America (Heart Failure Practice Guidelines 2006) and ACC/AHA (Heart Failure Guidelines 2005), with a special emphasis on new expanded criteria for primary prevention in both ischemic and nonischemic heart disease. In addition, the authors review current guidelines for electrophysiology testing in chronic left ventricular dysfunction and the emerging role of microvolt T-wave alternans as a means of risk stratification.     

The prognostic value of early left ventricular longitudinal systolic dysfunction in asymptomatic subjects with cardiovascular risk factors

Background:

Early diagnosis of left ventricular (LV) dysfunction represents a major challenge in asymptomatic subjects with cardiovascular (CV) risk factors. Tissue Doppler imaging (TDI) has emerged as an important tool with clinical relevance in several cardiac diseases.

Hypothesis:

To evaluate the prognostic ability of TDI in detecting early longitudinal ventricular dysfunction in a large group of asymptomatic subjects with CV risk factors (RsF), normal LV systolic function, and normal diastolic function.

Methods:

A total of 554 subjects (mean age 55 ± 13 years, 39% men) formed our study population: controls, 144 healthy subjects; group 1, 163 subjects with 1 CV RsF; group 2, 147 subjects with 2 CV RsF; group 3, 100 subjects with ≥3 CV RsF. All subjects underwent a comprehensive standard echo‐Doppler evaluation, including posterior wall TDI study. Follow‐up data were available in all the studied samples (mean 28 ± 16 mo).

Results:

Upon follow‐up, 18 individuals (3.2%) developed a first overt CV event. The presence of a peak systolic velocity <7.5 cm/second showed a significant additional predictive value compared with the presence of CV RsF (P<0.001).

Conclusions:

Tissue Doppler imaging is able to identify early longitudinal LV systolic abnormalities in the presence of apparently normal systolic and diastolic function. It demonstrated a significant additional prognostic value compared with the simple presence of coexisting CV RsF. These findings could be clinically relevant in identifying asymptomatic subjects with CV RsF who need early, tailored preventive treatment. © 2011 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.     

Population-based analysis of sudden cardiac death with and without left ventricular systolic dysfunction: two-year findings from the Oregon Sudden Unexpected Death Study.

OBJECTIVES: We sought to evaluate the contribution of left ventricular (LV) dysfunction toward occurrence of sudden cardiac death (SCD) in the general population, and to identify distinguishing characteristics of SCD in the absence of LV dysfunction. BACKGROUND: Patients who manifest warning symptoms and signs are more likely to undergo evaluation before SCD. Although prevalence of LV dysfunction in this subgroup may overestimate the prevalence in overall SCD, this is the only means of assessment in the general population. METHODS: All cases of SCD in Multnomah County, Oregon (population 660,486; 2002 to 2004) were prospectively ascertained in the ongoing Oregon Sudden Unexpected Death Study. We retrospectively assessed LV ejection fraction (LVEF) among subjects who underwent evaluation of LV function before SCD (normal: > or =55%; mildly to moderately reduced: 36% to 54%; and severely reduced: < or =35%). Of a total of 714 SCD cases (annual incidence 54 per 100,000), LV function was assessed in 121 (17%). RESULTS: The LVEF was severely reduced in 36 patients (30%), mildly to moderately reduced in 27 (22%), and normal in 58 (48%). Patients with normal LVEF were distinguishable by younger age (66 +/- 15 years vs. 74 +/- 10 years; p = 0.001), higher proportion of females (47% vs. 27%; p = 0.025), higher prevalence of seizure disorder (14% vs. 0%; p = 0.002), and lower prevalence of established coronary artery disease (50% vs. 81%; p < 0.001). CONCLUSIONS: In this community-wide study, only one-third of the evaluated SCD cases had severe LV dysfunction meeting current criteria for prophylactic cardioverter-defibrillator implantation. The SCD cases with normal LV function had several distinguishing clinical characteristics. These findings support the aggressive development of alternative screening methods to enhance identification of patients at risk.     

Early left ventricular longitudinal systolic dysfunction and cardiovascular risk factors in 1,371 asymptomatic subjects with normal ejection fraction: a tissue Doppler study

Background: Nowadays early diagnosis of left ventricular (LV) dysfunction represents a major challenge in asymptomatic subjects with cardiovascular (CV) risk factors. Tissue Doppler imaging (TDI) recently emerged as an important tool with clinical relevance in several cardiac diseases. Aim: To evaluate the ability of TDI in detecting early longitudinal ventricular dysfunction in asymptomatic subjects, with LV ejection fraction >55%, normal diastolic function, and its relationship with CV risk factors. Methods: A total of 1,371 subjects (median age 60 years, 595 males) formed our study population: Controls, 265 healthy subjects; Group I, 434 subjects with one CV risk factor; Group II, 401 subjects with two CV risk factors; Group III, 271 subjects with ≥ 3 CV risk factors. All subjects underwent a comprehensive standard echo Doppler evaluation, including PW‐TDI study. Results: Diastolic parameters such as (E\A, A‐wave, Em\Am; E\Em) were able to discriminate the number of CV risk factors. The only systolic parameter that progressively reduced by increasing the number of CV risk factors was LV global longitudinal systolic function (Sm), (P < 0.0001). At multivariate analysis, the only functional parameter able to predict the increasing number of CV risk factors was Sm (P < 0.001). Conclusions: TDI is able to identify early longitudinal LV systolic abnormalities in presence of apparently normal systolic and diastolic function and progressively impairs with increasing CV risk factors. These findings could be clinically relevant in identifying asymptomatic subjects who need a early tailored preventive treatment. (Echocardiography 2011;28:268‐275)     

Elevated interleukin-6 levels in patients with asymptomatic left ventricular systolic dysfunction

BACKGROUND: Elevated interleukin-6 (IL-6) levels are present in patients with New York Heart Association (NYHA) class III and IV congestive heart failure (CHF) and are associated with a poor prognosis. We sought to determine whether elevated IL-6 levels are also present in patients with left ventricular (LV) dysfunction but without clinical symptoms. METHODS: Blood samples were obtained from the femoral artery of 58 patients who underwent cardiac catheterization for recognized clinical indications. In a subgroup of 44 patients, samples were also obtained from the femoral vein, the left main coronary artery, and the coronary sinus. Patients with prior coronary artery bypass surgery, recent acute coronary syndrome, or steroid therapy were excluded. All samples were obtained before heparin or contrast administration. IL-6 was measured by enzyme-linked immunosorbent assay and values are expressed in picograms per milliliter. RESULTS: Three groups of patients were identified: controls, no CHF, LV ejection fraction >/=0.55 (n = 32); asymptomatic LV systolic dysfunction, no CHF, LV ejection fraction <0.55 (n = 14); and CHF, pulmonary edema (n = 12). IL-6 levels were higher at all sampling sites in both the asymptomatic LV systolic dysfunction and CHF groups compared with controls with the IL-6 levels inversely related to LV ejection fraction. CONCLUSIONS: Elevated IL-6 levels are present in patients with LV dysfunction even in the absence of the clinical syndrome of CHF. These data suggest that IL-6 may be involved in the progression of subclinical LV dysfunction to clinical CHF. IL-6 may be a marker of patients at risk for progression to clinical CHF or a novel target for therapeutic intervention.     

Early left ventricular systolic dysfunction in asymptomatic patients with type 1 diabetes: a single-center,pilot study

AimsPrevalence and risk factors of pre-symptomatic left ventricular systolic dysfunction (LVSD) in individuals with type 1 diabetes (T1D) have not been adequately studied. The present cross-sectional study assessed the prevalence of early LVSD in asymptomatic patients with type 1 diabetes and investigated potential risk factors.MethodsConsecutive patients with T1D, free of cardiovascular disease and significant evident microvascular complications were examined. LVSD was assessed by speckle-tracking echocardiography and calculation of global longitudinal strain (GLS). Abnormal GLS was defined as a value>-18.7%. We looked for possible associations between the presence of LVSD and patient demographic, clinical and laboratory characteristics, as well as with autonomic nervous system (ANS) function and arterial stiffness.ResultsWe enrolled 155 T1D patients (29.7% men, age 36.7 ± 13.1 years, diabetes duration 19.1 ± 10.0 years, HbA1c 7.5 ± 1.4% [58 ± 15 mmol/mol]). Early LVSD was prevalent in 53 (34.2%) patients. Multivariable analysis identified male gender (OR:4.14; 95% CI:1.39–12.31, p = 0.011), HbA1c (OR:1.59 per 1% increase; 95% CI:1.11–2.28, p = 0.011), glomerular filtration rate (GFR, OR:0.97; 95% CI:0.95–0.99, p = 0.010) and BMI (OR:1.19; 95% CI:1.06–1.34, p = 0.003) as independent predictors of LVSD presence.ConclusionsEarly subclinical LVSD is a common finding in asymptomatic patients with T1D, free of macrovascular and significant microvascular complications. Apart from chronic hyperglycemia, increased adiposity may be implicated in its etiology. Further investigation is warranted to identify patients at high risk for whom early screening is required and to determine possible associations between risk markers identified in the present analysis and long-term outcomes.     

Gender-specific differences of cardiac remodeling in subjects with left ventricular dysfunction: a population-based study

BACKGROUND: Recent studies suggest that female gender is associated with a lower prevalence and a more benign prognosis of heart failure. In the current population-based study, it was our objective to evaluate the implications of gender on the association between impaired left ventricular (LV) function and mass as well as neurohumoral activation. METHODS AND RESULTS: A total of 1883 subjects (992 female, 891 male) of two MONICA surveys in Augsburg, Germany, were analyzed. Participants of one of these surveys were additionally characterized with respect to neurohormonal activation. As compared to men, women were characterized by a slightly higher LV ejection fraction (EF, Teichholz-Method, 65.4 +/- 0.3% vs. 63.4 +/- 0.3, P<0.01) and a markedly lower LV mass index (LVMI 81 +/- 1 g/m(2) vs. 96 +/- 1, P<0.01). As compared to men with normal LV function, those with LV dysfunction (EF below mean minus two standard deviations, S.D.) were characterized by significantly increased LV mass (LVMI +48%, P<0.01), plasma BNP (+373%, P<0.01) and ANP (+57%, P<0.01), while no significant changes were observed in women (LVMI +3%, BNP +48%, ANP +27%, all P=n.s). Only a small subgroup of women with severe LVD (EF below mean - 3 S.D.) was characterized by significantly increased LV mass (LVMI +23%, P<0.05 vs. control and LVD), however, this increase was less pronounced as compared to men with severe LVD (LVMI +46%, P<0.01 vs. control). Gender-specific differences between LV function and structure were also confirmed by multivariate analysis. While LVMI was independently and significantly correlated with EF in male subjects in addition to systolic blood pressure, age, and body mass index (all P<0.01), these parameters displaced EF as a predictor of LVMI in female subjects. CONCLUSIONS: Men with moderate or severe LV dysfunction are characterized by an increase in both LV mass and cardiac natriuretic peptide plasma concentrations. In contrast, LV mass and natriuretic peptide concentrations increase to a lesser extent and only with severe LV dysfunction in women. These observational data suggest gender-specific control of myocardial adaptations to hemodynamic overload and a more rapid induction of LV hypertrophy during myocardial dysfunction in male subjects.     

螺内酯对无症状左室收缩功能障碍患者心室重构的影响

目的:探讨螺内酯对无症状左室收缩功能障碍患者心室重构的影响.方法:入选我院2007-12-2009-06门诊及住院无症状左室收缩功能障碍[左室射血分数(LVEF)＜40%,左室舒张末期容积指数(LVEDVI)＞75 ml/m2,纽约心脏病协会心功能分级Ⅰ级]患者63例,在常规治疗的基础上随机分为螺内酯干预组32例(螺内酯40 mg/d),对照组31例,所有患者在入选前及药物应用6个月后行超声心动图检查评估LVEDVI、左室收缩末期容积指数(LVESVI)、左室质量指数(LVMI)和LVEF的变化.结果:治疗6个月后,2组LVEDVI、LVESVI、 LVMI和 LVEF均较治疗前有明显改善,且差异有统计学意义(均P<0.05),螺内酯组改善更为显著(均P<0.05).结论:在常规治疗的基础上加用螺内酯治疗可进一步改善无症状左室收缩功能障碍患者的心室重构.