Shock is one of the most important and common complications in the early stage following severe burn. This article focuses on the main advances in the roles and mechanism of vascular and cardiac factors in the pathogenesis of burn shock, and the new measures for prevention and treatment of it. Further studies are still needed to elucidate the precise mechanism of increased capillary permeability and the effective measures for decreasing fluid leakage from blood vessels, and to prevent hypoxic/ischemic damage and complications of visceral tissues arising thereof.
Blood Vessels ; physiopathology ; Burns ; complications ; physiopathology ; Heart ; physiopathology ; Humans ; Shock ; etiology ; physiopathology ; therapy

Asthenia ; physiopathology ; Cyanosis ; physiopathology ; Expert Testimony ; Fatigue ; physiopathology ; Heart Defects, Congenital ; physiopathology ; Humans ; Walking

Animals ; Electroencephalography ; Heart ; physiopathology ; Immersion ; physiopathology ; Rats ; Rats, Wistar ; Seawater

OBJECTIVETo study the influence of high-voltage electric burn on the microcirculation of heart in rabbit.

METHODSOne-hundred and twenty New Zealand rabbits of clean grade were divided into control group (C) and electric burn group (EB) according to the random number table, with 60 rabbits in each group. Rabbits in EB group were subjected to high-voltage electric burn (the electrical current flow into the left foreleg at the lateral side of proximal end and out from the corresponding site of the right hind leg) with voltage regulator and experimental transformer. Rabbits in C group were sham injured with the same devices without electrification. At 15 minutes before injury, and 5 minutes, 1, 2, 4, 8 hour (s) post injury (PIM or PIH), ten rabbits in each group were chosen to examine the cardiac apex microcirculation hemoperfusion (CAMH) with laser Doppler hemoperfusion image instrument. The morphologic changes of microvessels of left ventricular wall tissues of 2 rabbits from each of the 10 rabbits collected at above-mentioned time points were observed with light microscope and transmission electron microscope. Auricular vein blood of rabbit was harvested at above-mentioned time points for the determination of aspartate amino transferase (AST), lactate dehydrogenase (LDH), hydroxybutyrate dehydrogenase (HBDH), creatine kinase (CK), and creatine kinase isozyme MB (CK-MB) by full-automatic biochemical analyzer. Data were processed with two-factor analysis of variance and LSD test.

RESULTS(1) The differences between C group and EB group in detection results were statistically significant, with F values from 425.991 to 3046.834, P values all below 0.01. Only the data within EB group were comparable. (2) At PIM 5, the CAMH value of rabbits in EB group was (1.96 ± 0.09) V, which was lower than that at 15 minutes before injury [(4.34 ± 0.35) V, P < 0.01]. The CAMH value of rabbits in EB group was increased at PIH 1 [(3.43 ± 0.30) V], and then it showed a tendency of decrease. (3) Bleeding and microthrombus formation were observed in venule and capillary vessel of rabbits in EB group at PIH 8. Breakage of basement membrane of capillary endothelial cells, mitochondrial swelling, and severe degranulation from damaged endoplasmic reticulum were observed in rabbits of EB group at PIH 8. (4) Levels of AST, LDH, HBDH, CK, and CK-MB in rabbits of EB group were significantly higher at PIH 1, 2, 4, 8 than at 15 minutes before injury (with P values all below 0.01). The AST level peaked at PIH 2 [(164 ± 39) U/L]. Levels of LDH and HBDH peaked at PIH 4, which were respectively (1016 ± 246) U/L and (487 ± 54) U/L. The CK level peaked at PIH 8 [(7799 ± 738) U/L]. The CK-MB level peaked at PIH 2 [(1848 ± 65) U/L].

CONCLUSIONSHigh-voltage electric burn can bring damage to the microvessels of heart in rabbits and change blood flow of microcirculation, which should be given adequate attention during the treatment.

Animals ; Burns, Electric ; physiopathology ; Heart ; physiopathology ; Hemodynamics ; Microcirculation ; Rabbits

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

PURPOSETo evaluate and compare the effects of heart rate on conduction velocity in the cavotricuspid isthmus (CTI) and septum in patients with and without typical atrial flutter (AF) using electro-anatomic mapping (EAM) of the right atrium (RA).

METHODSTen patients (age 53+/-10 yrs, 7M/3F) with AF and 13 patients (age 51+/-11 yrs, 5M/8F) with atrioventricular nodal reentrant tachycardia (AVNRT) underwent conventional electrophysiological study, electro-anatomic mapping and radiofrequency ablation. Using EAMs obtained during coronary sinus pacing at pacing cycle length (PCL) 600 ms, 400 ms, and 300 ms, we evaluated conduction velocities in the CTI and septum of RA in 10 patients with AF and compared EAMs to 13 patients with AVNRT to determine whether the conduction slowing required to maintain AFL was related to changes in volume alone or altered RA electrophysiology.

RESULTSConduction velocities in CTI and septum were significantly slower at all PCL when AF was compared to AVNRT (*P<0.05). Additionally, in the AF group, septal conduction velocities were slower at PCL 600 ms and 400 ms, but not at 300 ms compared to CTI (*P<0.05). In AF, during PCL 300, conduction in CTI slowed significantly compared to PCL 600 and 400 ms such that there was no difference between CTI and septum at PCL 300.

CONCLUSIONSThere is slower conduction in the septum compared to the CTI in all patients. However, in patients with AF, there is significant slowing of conduction in the CTI and septum as well as decremental rate-dependent slowing of conduction in the CTI. These findings indicate that in addition to RA enlargement, changes in atrial electrophysiology distinguish AF patients from patients with AVNRT.

Adult ; Atrial Flutter ; physiopathology ; Female ; Heart Atria ; physiopathology ; Heart Conduction System ; physiopathology ; Heart Rate ; physiology ; Humans ; Male ; Middle Aged ; Tachycardia, Atrioventricular Nodal Reentry ; physiopathology ; Tricuspid Valve ; physiopathology

Biomedical Research ; Heart Rate ; Humans ; Pneumoconiosis ; physiopathology

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

Electrocardiography ; methods ; Heart Conduction System ; physiopathology ; Heart Diseases ; diagnosis ; Humans

Due to its great clinical significance, brain injury following cardiac arrest (CA) has attracted more attention now. Meanwhile, there are currently no approved real time objective methods used to monitor brain injury following CA. In this study, we adopt the method of nonextensive Kullback-Leibler Entropy in investigating the HRV signals from brain injury and compare the result with that of corresponding EEG analysis. The comparative analysis shows that Kullback-Leibler Entropy can reveal the injury level of brain following CA. And we propose a novel quantitative approach for monitoring brain injury.
Algorithms ; Brain ; pathology ; physiopathology ; Brain Ischemia ; physiopathology ; Electroencephalography ; Heart Arrest ; complications ; Heart Rate ; physiology ; Humans