Machine Learning Assessment of Left Ventricular Diastolic Function Based on Electrocardiographic Features.

BACKGROUND: Left ventricular (LV) diastolic dysfunction is recognized as playing a major role in the pathophysiology of heart failure; however, clinical tools for identifying diastolic dysfunction before echocardiography remain imprecise. OBJECTIVES: This study sought to develop machine-learning models that quantitatively estimate myocardial relaxation using clinical and electrocardiography (ECG) variables as a first step in the detection of LV diastolic dysfunction. METHODS: A multicenter prospective study was conducted at 4 institutions in North America enrolling a total of 1,202 subjects. Patients from 3 institutions (n = 814) formed an internal cohort and were randomly divided into training and internal test sets (80:20). Machine-learning models were developed using signal-processed ECG, traditional ECG, and clinical features and were tested using the test set. Data from the fourth institution was reserved as an external test set (n = 388) to evaluate the model generalizability. RESULTS: Despite diversity in subjects, the machine-learning model predicted the quantitative values of the LV relaxation velocities (e') measured by echocardiography in both internal and external test sets (mean absolute error: 1.46 and 1.93 cm/s; adjusted R2 = 0.57 and 0.46, respectively). Analysis of the area under the receiver operating characteristic curve (AUC) revealed that the estimated e' discriminated the guideline-recommended thresholds for abnormal myocardial relaxation and diastolic and systolic dysfunction (LV ejection fraction) the internal (area under the curve [AUC]: 0.83, 0.76, and 0.75) and external test sets (0.84, 0.80, and 0.81), respectively. Moreover, the estimated e' allowed prediction of LV diastolic dysfunction based on multiple age- and sex-adjusted reference limits (AUC: 0.88 and 0.94 in the internal and external sets, respectively). CONCLUSIONS: A quantitative prediction of myocardial relaxation can be performed using easily obtained clinical and ECG features. This cost-effective strategy may be a valuable first clinical step for assessing the presence of LV dysfunction and may potentially aid in the early diagnosis and management of heart failure patients.

Metabolomics assessment reveals oxidative stress and altered energy production in the heart after ischemic acute kidney injury in mice.

Acute kidney injury (AKI) is a systemic disease associated with widespread effects on distant organs, including the heart. Normal cardiac function is dependent on constant ATP generation, and the preferred method of energy production is via oxidative phosphorylation. Following direct ischemic cardiac injury, the cardiac metabolome is characterized by inadequate oxidative phosphorylation, increased oxidative stress, and increased alternate energy utilization. We assessed the impact of ischemic AKI on the metabolomics profile in the heart. Ischemic AKI was induced by 22 minutes of renal pedicle clamping, and 124 metabolites were measured in the heart at 4 hours, 24 hours, and 7 days post-procedure. Forty-one percent of measured metabolites were affected, with the most prominent changes observed 24 hours post-AKI. The post-AKI cardiac metabolome was characterized by amino acid depletion, increased oxidative stress, and evidence of alternative energy production, including a shift to anaerobic forms of energy production. These metabolomic effects were associated with significant cardiac ATP depletion and with echocardiographic evidence of diastolic dysfunction. In the kidney, metabolomics analysis revealed shifts suggestive of energy depletion and oxidative stress, which were reflected systemically in the plasma. This is the first study to examine the cardiac metabolome after AKI, and demonstrates that effects of ischemic AKI on the heart are akin to the effects of direct ischemic cardiac injury.

Constrictive Pericarditis: A Practical Clinical Approach.

Constrictive pericarditis (CP) represents a form of severe diastolic heart failure (HF), secondary to a noncompliant pericardium. The true prevalence of CP is unknown but it is observed in 0.2-0.4% of patients who have undergone cardiac surgery or have had pericardial trauma or inflammation due to a variety of etiologies. Despite its poor prognosis if untreated, CP is a potentially curable disease and surgical pericardiectomy can now be performed at low perioperative mortality in tertiary centers with surgical expertise in pericardial diseases. Cardiologists should have a high index of suspicion for CP in patients presenting with predominant right-sided (HF), particularly when a history of cardiac surgery, pericarditis or pericardial effusion is present. Transthoracic two-dimensional and Doppler echocardiography is usually the first diagnostic tool in the evaluation of HF and can reliably identify CP in most patients by characteristic real-time motion of the heart and hemodynamic features. Computerized tomography and magnetic resonance imaging provide incremental data for the diagnosis and management of CP and are especially helpful when clinical or echocardiographic findings are inconclusive. Cardiac catheterization has been the gold-standard for the diagnosis of CP, but may not be necessary if non-invasive test(s) demonstrate diagnostic features of CP; it should then be reserved for selected cases or for assessment of concomitant coronary disease. Although most patients with CP require pericardiectomy, anti-inflammatory therapy may be curative in patients presenting with subacute symptoms, especially when evidence of marked ongoing inflammation is seen.

Assessment of left ventricular diastolic function with cardiovascular MRI: what radiologists should know.

Diastolic dysfunction is a common entity and the predominant cause of heart failure in 40%-50% of patients. Diagnosis of diastolic dysfunction is clinically relevant and associated with a poor prognosis. The aim of this essay was to review the pathophysiology and different grades of diastolic dysfunction and to provide an overview on the role of cardiovascular magnetic resonance imaging in the assessment of diastolic function.

Assessment of cardiac diastolic dysfunction in HIV-infected people without cardiovascular symptoms in China.

This study assessed cardiac diastolic dysfunction (DD) in HIV-infected subjects without cardiovascular symptoms in China. Eighty-four HIV-infected patients without cardiovascular symptoms were recruited and compared with 30 HIV-negative control subjects. Cardiac DD was evaluated using echocardiography including tissue Doppler imaging. DD was detected in 47.6% of AIDS patients and 42.8% of HIV-positive patients, which was significantly higher than in HIV-negative controls. After logistic regression analysis, HIV infection was independently correlated with cardiac DD (P < 0.05). Among HIV-positive subjects, logistic regression analysis showed that zidovudine exposure was associated with higher prevalence of DD (P < 0.05). Asymptomatic cardiac DD was observed frequently in HIV-infected subjects. HIV infection itself and zidovudine exposure were correlated with a higher prevalence of cardiac DD.

Direct comparison of B-type natriuretic peptide and N-terminal pro-BNP for assessment of cardiac function in a large population of symptomatic patients.

BACKGROUNDS: B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NTproBNP) levels showed frequent discrepancies in individual patients. OBJECTIVES: The aims were 1) to compare the abilities of BNP and NTproBNP for the detection of left ventricular systolic dysfunction (LVSD) or diastolic dysfunction (LVDD) in the symptomatic patients, and 2) to assess the direct correlation and its independent determinants between them. METHODS: 1032 patients with dyspnea underwent BNP and NTproBNP measurements simultaneously. 967/1032 (93.7%) patients underwent echocardiography. Using the receiver operation characteristic curve analyses for the detection of LVSD (EF<45%) or advanced LVDD, the area under the curves (AUC) of both biomarkers was compared according to age, gender, body mass index (BMI), hemoglobin (Hb), and glomerular filtration rate (eGFR). Using multiple regression analysis, the direct correlation and its independent determinants were identified between them. RESULTS: In the entire population, the AUCs of BNP and NTproBNP had no significant differences (LVSD: 0.909 vs. 0.893, p=0.20; advanced LVDD: 0.897 vs. 0.879, p=0.13). In patients with BMI<25, the AUCs of BNP were significantly higher than those of NTproBNP (LVSD: 0.897 vs. 0.869, p=0.03; advanced LVDD: 0.916 vs. 0.885, p=0.02). They had strong correlation (r=0.895, p<0.001) and LVEF, eGFR<60 ml/min, Hb<12 g/dl and use of diuretics were the independent determinants between them. CONCLUSION: BNP and NTproBNP displayed strong correlation and near-identical performances for the screening of cardiac dysfunction. However, LVEF, renal function, Hb and use of diuretics should be considered for clinical interpretation.

Application of magnetic resonance imaging in vivo for the assessment of the progression of systolic and diastolic dysfunction in a mouse model of dilated cardiomyopathy.

BACKGROUND: The impairment of cardiac diastolic function is essential for the development and progression of heart failure, regardless of the systolic performance of the heart. Novel methods of diagnosis of diastolic dysfunction in experimental animals are needed in order to validate the effectiveness of novel heart failure treatment. AIM: The in vivo characterisation of diastolic and systolic function of the heart during heart failure progression in Tgalphaq*44 mice using magnetic resonance imaging (MRI) and original image analysis. METHODS: Cardiac function in vivo in both Tgalphaq*44 and FVB mice was analysed using MRI at 4.7 T. Magnetic resonance imaging was performed using an ECG triggered fast gradient echo (cine-like flow compensated FLASH) sequence. For the assessment of left ventricle (LV) dynamics at least 20 images per cardiac cycle were acquired in the midventricular short-axis projection at the level of papillary muscles. End-systolic (ESA) and end-diastolic (EDA) areas were estimated from the minimum and maximum values found in the area-time plot. Fractional area change (FAC) defined as (EDA-ESA)/EDA, ejection (ER) and filling (FR) rates defined as slope of the beginning part of the systolic and diastolic limbs were calculated. In addition, heart failure progression in Tgalphaq*44 mice was assessed by morphometric parameters (ventricular weight to body weight index and wet to dry lung weight index), level of BNP mRNA expression as well as survival. RESULTS: Systolic function assessed by FAC% and ER was stable but slightly impaired up to 10 months of age in Tgalphaq*44 mice as compared to the FVB mice. After 12 months of age of the Tgalphaq*44 mice there was a progressive deterioration of systolic function (ER at 10, 12, 14 months of age were 0.0188 +/- 0.00434, 0.0140 +/- 0.00474, 0.0115 +/- 0.00469 1/ms, respectively). Diastolic function of the Tgalphaq*44 hearts was preserved or even slightly augmented between 4 and 10 months of age, then at the age of 12 months and later profoundly impaired (FR at 10, 12, 14 months of age were 0.0280 +/- 0.01031, 0.0196 +/- 0.01050, 0.0158 +/- 0.00833 1/ms, respectively). CONCLUSIONS: The MRI allows reliable in vivo assessment of the systolic and diastolic function in Tgalphaq*44 mice. In Tgalphaq*44 mice after few months of stable and compensated phase of the heart failure decompensation develops that involves impairment of both systolic and diastolic and leads to the fully symptomatic dilated cardiomyopathy. The precise molecular mechanisms of the systolic and diastolic dysfunction and their relative contribution to the heart failure progression in Tgalphaq*44 mice remain to be established.

Diastolic dysfunction--a case of trouble relaxing.

In this issue of the Journal of Insurance Medicine, Dr. Clifford S. Hale reviews a frequent and important condition that we frequently come across during medical underwriting. The term "diastolic dysfunction" is often noted in echocardiography reports and this term gives rise to a lot of uncertainty in terms of how much emphasis we should put on it and how much rating that it should carry.

Diastolic heart failure: state of the science on best treatment practices.

PURPOSE: The purpose of this article is to increase awareness among nurse practitioners (NPs) of the current state of the science on diastolic heart failure (DHF), the American College of Cardiology (ACC) and the American Heart Association (AHA) guidelines for DHF, and pathophysiology, diagnosis, and nonpharmacological and pharmacological management of DHF. DATA SOURCES: The articles included in the review of the state of the science were retrieved by a search of PUBMED literature using the following key search terms: heart failure, diastolic heart failure, preserved systolic function, heart failure management, treatment of diastolic heart failure, treatment of diastolic dysfunction, and treatment of preserved systolic function. Current published guidelines from the ACC and AHA were reviewed to establish clinical recommendations for patients with DHF. CONCLUSIONS: The state of the science and clinical recommendations for DHF are in the early stages compared to those for systolic heart failure (SHF). The need for more randomized clinical trials on nonpharmacological and pharmacological management and the development of standardized guidelines for DHF patients are clearly apparent. IMPLICATIONS FOR PRACTICE: Both nonpharmacologic and pharmacologic management are effective and necessary to control the clinical signs and symptoms of DHF and improve overall quality of life. Successful tailoring of a treatment plan to suit each individual patient's needs and including the family are important for the NP to consider.