Hung-Hao Lee

Anemia as an Independent Predictor of Adverse Cardiac Outcomes in Patients with Atrial Fibrillation.

Background: Anemia and echocardiographic systolic and diastolic parameters are useful predictors of cardiovascular outcomes in patients with atrial fibrillation (AF). However, no studies have evaluated the use of anemia for predicting cardiovascular outcome in AF patients when the important echocardiographic parameters are known. Therefore, this study was designed to evaluate whether low hemoglobin is a useful parameter for predicting poor cardiac outcome after adjustment for important echocardiographic parameters in AF patients. Methods: Index beat method was used to measure echocardiographic parameters in 166 patients with persistent AF. Cardiac events were defined as death and hospitalization for heart failure. The association of hemoglobin with adverse cardiac events was assessed by Cox proportional hazards model. Results: The 49 cardiac events identified in this population included 21 deaths and 28 hospitalizations for heart failure during an average follow-up of 20 months (25th-75th percentile: 14-32 months). Multivariable analysis showed that increased left ventricular mass index (LVMI) and decreased body mass index, estimated glomerular filtration rate, and hemoglobin (hazard ratio 0.827; P = 0.015) were independently associated with increased cardiac events. Additionally, tests of a Cox model that included important clinic variables, LVMI, left ventricular ejection fraction, and the ratio of transmitral E-wave velocity to early diastolic mitral annulus velocity showed that including hemoglobin significantly increased value in predicting adverse cardiac events (P = 0.010). Conclusions: Hemoglobin is a useful parameter for predicting adverse cardiac events, and including hemoglobin may improve the prognostic prediction of conventional clinical and echocardiographic parameters in patients with AF.

Association of Increased Epicardial Adipose Tissue Thickness With Adverse Cardiovascular Outcomes in Patients With Atrial Fibrillation

AbstractThe thickness of epicardial adipose tissue (EAT) was reported to be highly associated with the incidence and severity of atrial fibrillation (AF). This study was conducted to analyze the ability of EAT thickness in predicting adverse cardiovascular (CV) events in AF.In 190 persistent AF patients, we performed a comprehensive transthoracic echocardiographic examination with assessment of EAT thickness. The definition of CV events included CV mortality, hospitalization for heart failure, myocardial infarction, and stroke.There were 69 CV events including 19 CV deaths, 32 hospitalizations for heart failure, 3 myocardial infarctions, and 15 strokes during a mean follow-up of 29 (25th–75th percentile: 17–36) months. The multivariable analysis demonstrates that chronic heart failure, increased left ventricular (LV) mass index and the ratio of transmitral E-wave velocity to early diastolic mitral annulus velocity, decreased body mass index, and increased EAT thickness (per 1-mm increase, odds ratio 1.224, 95% confidence interval [CI] 1.096–1.368, P < 0.001) were associated with adverse CV events. Additionally, the addition of EAT thickness to a model containing CHA2DS2-VASc score, left atrial volume index, and LV systolic and diastolic function significantly improved the values in predicting CV events (global &khgr;2 increase 14.65, P < 0.001 and integrated discrimination improvement 0.10, 95% CI 0.04–0.16, P < 0.001).In AF, EAT thickness was useful in predicting adverse CV events. Additionally, EAT thickness could provide incremental value for CV outcome prediction over traditional clinical and echocardiographic parameters in AF.

Heart Rate Significantly Influences the Relationship between Atrial Fibrillation and Arterial Stiffness

Background. Atrial fibrillation (AF) and vascular disease share several risk factors and the two diseases often coexist. Heart rate (HR) is reported to be a major determinant of arterial stiffness. AF patients often have a transiently or persistently rapid HR. Hence, this study was to assess whether AF was significantly associated with arterial stiffness and HR could significantly influence the relationship between AF and arterial stiffness. Besides, we also determine the main correlates of arterial stiffness in AF patients and see whether HR was correlated with arterial stiffness in these patients. Methods. We included 166 AF and 1336 non-AF patients from subjects arranged for echocardiographic examinations. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV). Results. Compared to non-AF patients, AF patients had a higher baPWV (p <0.001). In a multivariate model, including covariates of age, sex, blood pressures and so on, the presence of AF was significantly associated with baPWV (β = 0.079, P = 0.001). However, further adjustment for HR made this association disappear (β = 0.005, P = 0.832). In addition to age and systolic blood pressure, increased HR (β = 0.309, p <0.001) was a major determinant of increased baPWV in our AF patients. Conclusions. This study demonstrated the presence of AF was associated with increased baPWV, but this association became insignificant after further adjustment for HR, which suggested HR could significantly influence the relationship between AF and baPWV. Besides, HR was positively correlated with arterial stiffness in our AF patients.

Myocardial performance index derived from pre-ejection period as a novel and useful predictor of cardiovascular events in atrial fibrillation

PURPOSE The pre-ejection period-derived myocardial performance index measured from tissue Doppler echocardiography (PEPa-derived MPI) was reported to be associated with left ventricular systolic and diastolic function in atrial fibrillation (AF). However, its relationship with cardiovascular outcomes in AF has never been evaluated. This study sought to examine the ability of PEPa-derived MPI in predicting adverse cardiovascular events in AF patients. METHODS In 196 persistent AF patients, we performed comprehensive echocardiography with measurement of PEPa-derived MPI using index beat method. The index beat was defined as the beat following the nearly equal preceding (RR1) and pre-preceding (RR2) intervals. The cycle length of index beat and RR1 and RR2 must be >500ms and the difference between RR1 and RR2 must be <60ms. Cardiovascular events were defined as cardiovascular death, nonfatal stroke, and hospitalization for heart failure. RESULTS In the multivariate analysis, chronic heart failure and increased ratio of transmitral E-wave velocity to early diastolic mitral annulus velocity (E/Ea) and PEPa-derived MPI (per 0.1 increase, hazard ratio, 1.104; 95% confidence interval, 1.032-1.182, p=0.004) were associated with increased cardiovascular events. The addition of PEPa-derived MPI to a Cox model containing chronic heart failure, systolic blood pressure, age, diabetes, prior stroke, left ventricular ejection fraction, and E/Ea provided an additional benefit in prediction of adverse cardiovascular events (p=0.015). CONCLUSIONS In AF patients, the PEPa-derived MPI was a useful predictor of adverse cardiovascular events and could offer an additional prognostic benefit over conventional clinical and echocardiographic parameters.

Prognostic role of left atrial strain and its combination index with transmitral E-wave velocity in patients with atrial fibrillation.

Left atrial (LA) strain can reflect LA remodeling and is reduced in atrial fibrillation (AF) patients with prior stroke. This study sought to examine the ability of LA strain in predicting subsequent stroke event in AF and also evaluated whether E/LA strain could predict cardiovascular (CV) events in these patients. In 190 persistent AF patients, we performed comprehensive echocardiography with assessment of LA strain. There were 69 CV events including 19 CV death, 32 hospitalizations for heart failure, 3 myocardial infarctions, and 15 strokes during an average follow-up of 29 months. Multivariate analysis showed old age, chronic heart failure, increased left ventricular (LV) mass index, and increased E/LA strain were associated with CV events and decreased LA strain was associated with subsequent stroke event. The addition of E/LA strain and LA strain to a model containing CHA2DS2-VASc score and LV function significantly improved the values in predicting CV events and subsequent stroke event, respectively. In conclusion, E/LA strain and LA strain were respectively useful in predicting CV events and subsequent stroke event in AF. E/LA strain and LA strain could provide incremental values for CV outcome and subsequent stroke outcome prediction over conventional clinical and echocardiographic parameters in AF, respectively.

Systolic time intervals derived from electrocardiographic gated intra-renal artery Doppler waveform associated with left ventricular systolic function.

The aims of this study were to investigate the correlation between renal and cardiac STIs, including pre-ejection period (PEP), ejection time (ET), and PEP/ET, and to assess the diagnostic values of renal STIs in predicting left ventricular ejection fraction (LVEF) <50%. The cross sectional observation study enrolled 230 participants. The renal STIs, including renal PEP (rPEP), renal ET (rET), and rPEP/rET, were measured from electrocardiographic gated renal Doppler ultrasound and cardiac PEP, ET, and PEP/ET were measured from echocardiography. Renal STIs were correlated with cardiac STIs (all P < 0.001). Multivariate analyses showed that rPEP/rET was independently associated with LVEF (unstandardized coefficient β = −0.116, P = 0.046) and LVEF <50% (odds ratio = 2.145, per 0.11 increase; P = 0.017). The areas under the curve for rPEP, 1/rET, and rPEP/rET in predicting LVEF <50% were 0.773, 0.764, and 0.821, respectively. The sensitivity and specificity of rPEP/rET > 0.46 in prediction of LVEF <50% were 76.7% and 78.1%, respectively. Our study demonstrated that the novel parameters of renal STIs were significantly associated with cardiac STIs. However, the clinical application of renal STIs needs to be investigated in future studies.

Atrial fibrillation per se was a major determinant of global left ventricular longitudinal systolic strain

AbstractAtrial fibrillation (AF) may cause systolic abnormality via inadequate diastolic filling and tachycardia-induced cardiomyopathy. Global longitudinal strain (GLS) is a very sensitive method for detecting subtle left ventricular systolic dysfunction. Hence, this study aimed to evaluate whether AF patients had a more impaired GLS, AF was a major determinant of GLS, and determine the major correlates of GLS in AF patients.The study included 137 patients with persistent AF and left ventricular ejection fraction (LVEF) above 50% and 137 non-AF patients matched according to age, gender, and LVEF. Comprehensive echocardiography with GLS assessment was performed for all cases.Compared with non-AF patients, AF patients had a more impaired GLS, a larger left atrial volume index, higher transmitral E wave velocity (E), and early diastolic mitral velocity (Ea) (all P < 0.001) but comparable E/Ea. After adjustment for baseline and echocardiographic characteristics, the presence of AF remained significantly associated with impaired GLS (&bgr; = 0.533, P < 0.001). In addition, multivariate analysis of AF patients indicated that faster heart rates and decreased E, Ea, and LVEF were associated with more impaired GLS.This study demonstrated that AF patients had a more impaired GLS than non-AF patients, although LVEF was comparable between the 2 groups. AF was a major determinant of GLS even after adjustment for relevant clinical and echocardiographic parameters.

Nicorandil-Induced Hyperkalemia in a Uremic Patient

Nicorandil is an antianginal agent with nitrate-like and ATP-sensitive potassium channel activator properties. After activation of potassium channels, potassium ions are expelled out of the cells, which lead to membrane hyperpolarization, closure of voltage-gated calcium channels, and finally vasodilation. We present a uremic case suffering from repeated junctional bradycardia, especially before hemodialysis. After detailed evaluation, nicorandil was suspected to be the cause of hyperkalemia which induced bradycardia. This case reminds us that physicians should be aware of this potential complication in patients receiving ATP-sensitive potassium channel activator.

Acute effect of ionic high osmolar contrast medium on renal antioxidant enzyme activity in streptozotocin-induced diabetic rats.

Acute contrast medium-induced nephrotoxicity was estimated in 3%–12% of patients receiving cardiac angiography, especially in advanced age, renal insufficiency and diabetic patients. As intrinsic renal antioxidant enzyme activities may play a crucial role in defence against renal oxidant injury, this study was designed to investigate the acute effect of ionic high osmolar diatrizoate meglumine/diatrizoate sodium on renal antioxidant activities in normal or streptozotocin (STZ)-induced diabetic rats at two time points (1 h and 24 h). A total of 40 Wistar rats were separated to normal and STZ-induced diabetic groups. Ten of each group were injected with diatrizoate (10 ml/kg) via tail vein and 10 with 10 ml/kg of 0.9% NaCl as control. This study shows that diabetic rats had higher renal glutathione peroxidase (GPx) activities than those of normal rats. GPx activities decreased significantly after diatrizoate injection at the first hour (717.4±104.0 to 578.6±92.1 mU/mg in the diabetic group, 466.4±30.6 to 371.4±75.5 mU/mg in the normal group, all P=0.032) but the difference faded 24 h later. The increase of superoxide dismutase (SOD) activities was enhanced (673.5±100.2 to 750.4±129.8 U/mg, P=0.04) in the normal group, but not in the diabetic group (624.1±156.6 to 671.1±136.7 U/mg, P=0.15) after diatrizoate injection at the first hour. At 24 h, renal SOD activities were still significantly higher in the diatrizoate injection group. In summary, intrinsic renal antioxidant activities are adapted in STZ-induced diabetes and ionic high osmolar diatrizoate could modify their activities. Furthermore, diabetics have abnormal response of renal antioxidant activities by contrast media and are at risk for contrast-mediated nephrotoxicity.

Estimated Glomerular Filtration Rate and Systolic Time Intervals in Risk Stratification for Increased Left Ventricular Mass Index and Left Ventricular Hypertrophy.

AbstractEither decreased renal function or increased systolic time interval is associated with cardiac hypertrophy and poor cardiac outcome. The aim of this study was to evaluate combination of renal function and brachial systolic time intervals were associated with increased left ventricular mass index (LVMI) and left ventricular hypertrophy (LVH).In total of 990 patients were consecutively included in this study from January 2011 to December 2012. All study participants were further classified into 4 groups by the values of estimated glomerular filtration rate (eGFR) and ratio of brachial preejection period (bPEP) to brachial ejection time (bET). The classification of 4 groups were eGFR ≥ 45 mL/min/1.73 m2 and bPEP/bET < 0.38 (group 1), eGFR ≥ 45 ml/min/1.73 m2 and bPEP/bET ≥ 0.38 (group 2), eGFR < 45 mL/min/1.73 m2 and bPEP/bET < 0.38 (group 3), and eGFR < 45 mL/min/1.73 m2 and bPEP/bET ≥ 0.38 (group 4), respectively. Patients in groups 1 and 4 had the lowest and highest LVMI among 4 groups, respectively (P < 0.001). In multivariable analyses, increased LVMI and LVH were significantly associated with patients in groups 2, 3 and 4 (vs group 1) (P ⩽ 0.019).Our study demonstrated that joined parameter of renal function and systolic time intervals, in terms of eGFR and bPEP/bET, might be an alternative method in risk stratification for increased LVMI and LVH.