In this study, we applied generalized autoregressive conditional heteroskedasticity (GARCH) model to conditional fluctuation characteristics of heart rate variation (HRV) series (congestive heart failure, Normal), with all the data from PhysioNet ECG database. Research results proved the existence of condition fluctuation characteristic in the series of changing rate of HRV. In the GARCH model family, threshold GARCH (1,1)(TGARCH (1,1)) model performs best in fitting changing rate of HRV. Although the structure of ARCH (1) model is simple, its error is the closest to that of TGARCH (1, 1) model. The results also showed that the difference was obvious between disease group and normal group. All these results provide a new method to the research and clinical application of HRV.
Cardiology ; trends ; Heart Failure ; physiopathology ; Heart Rate ; Humans ; Models, Cardiovascular

OBJECTIVETo observe the action potential duration restitution (APDR) change and potential association with ventricular arrhythmia (VA) in Langendorff-perfused chronic heart failure rabbit hearts.

METHODSMale rabbits were randomly divided into two groups: control (CTL, n=15) group and chronic heart failure (CHF, n=15) group. CHF was induced by injecting isoproterenol (300 µg×kg(-1) ×d(-1)) for 14 days. Four weeks later, cardiac function and structure change of both groups were assessed by echocardiography. In the whole Langendorff-perfused hearts, the monophasic action potential (MAP) and the effective refractory period (ERP) were recorded from left anterior basal ventricle, left anterior free wall, left anterior apex and left posterior basal ventricle, left posterior free wall and left posterior apex, the APD curves were also constructed in both groups; at the six sites of every isolated heart, the programmed electrical stimulation and burst pacing were used to induce action potential duration (APD) alternans and VA, respectively.

RESULTSLeft ventricular ejection was reduced and end-dimension was enlarged in rabbits of CHF group. Compared with the same sites of CTL group, the 90% of MAP duration (MAPD90), the ERP, the max slope (Smax) of APDR curves, the pacing cycle length of inducing the APD alternans and the VAs were significantly increased (all P<0.05) in CHF group; the spatial dispersions of MAPD90, ERP and Smax of APDR curves in CHF group were also greater than in CTL group (all P<0.05).

CONCLUSIONThe ventricular APD alternans might be linked with occurrence of the VA in CHF rabbits. Increase of the Smax from APDR curves and the spatial dispersions of Smax in this CHF model might facilitate the development of ventricular arrhythmia.

Action Potentials ; Animals ; Arrhythmias, Cardiac ; physiopathology ; Electrocardiography ; Heart Failure ; physiopathology ; Heart Ventricles ; physiopathology ; Male ; Rabbits ; Ventricular Fibrillation ; physiopathology

Animals ; Disease Models, Animal ; Heart Failure ; pathology ; physiopathology

Renalase, a novel amine oxidase, is secreted by kidney. It regulates heart function and blood pressure by degrading catecholamines. Hormones secreted by the kidney are associated with cardiovascular disease. Renalase, as a new biomarker of heart and kidney functional correlation, can lower blood pressure, protect ischemic heart muscle, improve heart function and degrade catecholamine.
Animals ; Cardiovascular Diseases ; physiopathology ; Heart Failure ; physiopathology ; Humans ; Hypertension ; physiopathology ; Monoamine Oxidase ; genetics ; physiology ; Myocardial Ischemia ; physiopathology

Speckle tracking echocardiography (STE) has been applied to the evaluation of cardiac contraction dysfunction. However, there were few studies on alteration of global and regional STE parameters in the process of myocardial hypertrophy and heart failure. In this study, STE was applied to evaluate the global and regional cardiac function under heart failure and hypertrophy in the mice model of pressure overload. Adult mice were subjected to mild or severe aortic banding with a 25 Gauge (G) or 27 G needle. After surgery, STE and conventional echocardiography were used in the sham group (n=10), mild trans-aortic banding (TAB) group (n=14) and severe TAB group (n=10) for 8 weeks. The results showed that the mice subjected to severe TAB showed a significant change in fractional shortening (FS), left ventricular (LV) mass, and left ventricular end diastolic diameter (LVEDD) (P<0.05 for each). Meanwhile, there were no significant differences in FS and LVEDD between the sham group and mild TAB group during the experimental procedures (P>0.05 for both). STE analysis revealed that longitudinal strain (LS) was significantly decreased in the severe TAB group as compared with the sham and mild TAB groups (P<0.05 for both) from the postoperative week 1. LS in the mild TAB group was reduced as compared to the sham group (P<0.05). Radial strain (RS) and circumferential strain (CS) were significantly decreased in the severe TAB group as compared to the sham group and the mild TAB group (P<0.05 for both) from the postoperative week 1 (P<0.05 for both). Compared to the sham group, CS in the mild TAB group maintained unchanged during the test period, and RS was reduced only on the postoperative week 6 (P<0.05). Finally, regional contraction dysfunction was analyzed in both hypertrophic and failing myocardium in longitudinal and radial directions. It was found that LS was largest in the apex region and RS was smallest in the apex region in the healthy and hypertrophic myocardium. It was also found that compared to the sham group, only base longitudinal strain in the mild TAB group was decreased. Each of regional strain in the severe TAB group was uniformly depressed in radial and longitudinal directions. It is concluded that STE has provided a non-invasive and highly feasible way to explore the global and regional contraction dysfunction in hypertrophic and heart failure myocardium in the murine model of pressure overload.
Animals ; Cardiomegaly ; physiopathology ; Disease Models, Animal ; Echocardiography ; methods ; Heart Failure ; physiopathology ; Male ; Mice ; Mice, Inbred C57BL

OBJECTIVEThis study aimed to investigate the feature of D(L)CO (Diffusion Lung Capacity for Carbon Monoxide) in CHF (left ventricular heart failure) patients, underlying pathophysiological mechanism and clinical significance.

METHODSWe retrospectively studied the D(L)CO, pulmonary ventilation function, cardiopulmonary exercise testing and related clinical information in severer HF patients.

RESULTSPeak VO2 severely decreased to 34 ± 7 percentage of predicted(%pred) and anaerobic threshold to 48 ± 11%pred in all patients. D(L)CO moderately decreased to 63 ± 12%pred and there were 25 patients lower than 80%pred. FVC, FEV1, FEV1/FVC and TLC were 75 ± 14%pred, 71 ± 17%pred, 97 ± 11%pred, and 79 ± 13%pred, which indicated borderline or mild restrictive ventilatory dysfunction. The decrease of D(L)CO was more severe than those of TLC, FEV1 and FVC.

CONCLUSIONFor patients with severe CHF, cardiopulmonary exercise function is extremely limited, D(L)CO generally moderately declines and ventilation function is merely mildly limited. D(L)CO is the parameter for cardiopulmonary coupling, reflecting limitation of the cardiovascular dysfunction while without ventilatory limit.

Blood Gas Analysis ; Heart Failure ; physiopathology ; Humans ; Respiratory Function Tests ; Retrospective Studies ; Ventricular Dysfunction, Left ; physiopathology

Apoptosis ; Child ; Heart Failure ; metabolism ; physiopathology ; Humans ; Signal Transduction ; Sympathetic Nervous System ; metabolism ; physiopathology ; Ventricular Remodeling

Ebstein malformation is a congenital heart disease characterized pathologically by displacement of the septal leaflet of the tricuspid valve towards the apex of the right ventricle of the heart. Hypoplasia, dysfunction of the right ventricle and tricuspid regurgitation cause an increased volume load of the right heart and result in the clinical manifestations of chest tightness, shortness of breath and fatigue after activities, palpitation, cyanosis and heart failure. We report a case of Ebstein's anomaly with refractory right heart failure and leg ulcers.
Ebstein Anomaly ; Heart Failure ; Heart Ventricles ; physiopathology ; Humans ; Leg Ulcer ; Tricuspid Valve Insufficiency

In order to verify the hypothesis that left ventricular epicardial (LV-Epi) pacing and biventricular (BiV) pacing unavoidably influence the myocardial electrophysiological characters and may result in high risk of malignant ventricular arrhythmia, we calculated, in both normal mongrel dogs and dog models with rapid-right-ventricular-pacing induced dilated cardiomyopathy congestive heart failure (DCM-CHF), the monophasic action potential duration (MAPD) and the transmural dispersion of repolarization (TDR) in intracardiac electrogram together with the QT interval and T(peak)-T(end) (T(p(-T(e)) interval in surface electrocardiogram (ECG) during LV-Epi and BiV pacing, compared with those during right ventricular endocardial (RV-Endo) pacing. To prepare the DCM-CHF dog model, rapid right ventricular pacing (250 bpm) was performed for 23.6+/-2.57 days to the dog. All the normal and DCM-CHF dogs were given radio frequency catheter ablation (RFCA) to His bundle with the guide of X-ray fluoroscopy. After the RFCA procedures, the animals were under the situation of complete atrioventricular block so that the canine heart rates could be voluntarily controlled in the following experiments. After a thoracotomy, ECG and monophasic action potentials (MAP) of subendocardial, subepicardial and mid-layer myocardium were recorded synchronously in 8 normal and 5 DCM-CHF dogs during pacing from endocardium of RV apex (RV-Endo), epicardium of LV anterior wall (LV-Epi) and simultaneously both of the above (biventricular, BiV), the later was similar to the ventricular resynchronization therapy to congestive heart failure patients in clinic. The Tp-Te) meant the interval from the peak to the end of T wave, which was a representative index of TDR in surface ECG. The TDR was defined as the difference between the longest and the shortest MAPD of subendocardial, subepicardial and mid-layer myocardium. Our results showed that in normal dogs, pacing participating of LV (LV-Epi, BiV) prolonged MAPD of all the three layers of the myocardium (P<0.05) with the character that mid-layer MAPD was the longest and subepicardial MAPD was the shortest following subendocardial MAPD. At the same time, TDR prolonged from 26.75 ms at RV-Endo pacing to 37.54 ms at BiV pacing and to 47.16 ms at LV-Epi pacing (P<0.001). Meanwhile in surface ECG, BiV and LV-Epi pacing resulted in a longer Tp-Te) interval compared with RV-Endo pacing (P<0.01), without parallel QT interval prolongation. Furthermore, all the DCM-CHF model dogs showed manifestations of congestive heart failure and enlargement of left ventricles. Based on the lengthening of mid-layer MAPD from 257.35 ms to 276.30 ms (P<0.0001) and increase of TDR from 27.58 ms to 33.80 ms (P equals;0.002) in DCM-CHF model due to the structural disorders of myocardium compared with the normal dog, LV-Epi and BiV pacing also led to the effect of prolonging MAPD of three layers of the myocardium and enlarging TDR. From these results we make the conclusions that prolongation of MAPD of subendocardial, subepicardial and mid-layer myocardium and increase in TDR during pacing participating of LV (LV-Epi, BiV) may contribute to the formation of unidirectional block and reentry, which play roles or at least are the high risk factors in the development of malignant ventricular arrhythmia, especially in case of structural disorders of myocardium. These findings must be considered seriously when ventricular resynchronization therapy is performed to congestive heart failure patients.
Action Potentials ; Animals ; Bundle-Branch Block ; complications ; physiopathology ; Cardiomyopathy, Dilated ; complications ; physiopathology ; Dogs ; Female ; Heart Conduction System ; physiopathology ; Heart Failure ; etiology ; physiopathology ; Heart Ventricles ; physiopathology ; Male ; Torsades de Pointes ; physiopathology ; Ventricular Dysfunction, Left ; physiopathology ; Ventricular Function, Left

There are many differences between cardiac resynchronization therapy (CRT) and conventional pacing therapy in terms of indications and implant techniques. Generally speaking, CRT requires implanting 3 pacing leads in heart failure patients with ventricular dysynchrony. A left ventricular lead is implanted via intravenous coronary sinus. The pacing site of left ventricle has important influence on therapy response. Sometimes open chest implant or other pacing modes are adopted to compensate the anatomical limitation of coronary sinus and its branches. In addition, the pacing sites and modes of right atrium and right ventricle are also under research to further improve CRT response.
Cardiac Pacing, Artificial ; methods ; Electrodes, Implanted ; Heart Atria ; Heart Failure ; physiopathology ; therapy ; Heart Ventricles ; Humans ; Ventricular Dysfunction, Left ; physiopathology ; Ventricular Dysfunction, Right ; physiopathology