P-wave duration and dispersion in patients with coronary slow flow and its relationship with Thrombolysis in Myocardial Infarction frame count

Disordered autonomic function during exposure to moderate heat or exercise in a mouse model of Dravet syndrome

OBJECTIVE

To examine autonomic regulation of core body temperature, heart rate (HR), and breathing rate (BR) in response to moderately elevated ambient temperature or moderate physical exercise in a mouse model of Dravet syndrome (DS).

METHODS

We studied video-EEG, ECG, respiration, and temperature in mice with global heterozygous Scn1a knockout (KO) (DS mice), interneuron specific Scn1a KO, and wildtype (WT) mice during exposure to increased environmental temperature and moderate treadmill exercise.

RESULTS

Core body temperatures of WT and DS mice were similar during baseline. After 15 mins of heat exposure, the peak value was lower in DS than WT mice. In the following mins of heat exposure, the temperature slowly returned close to baseline level in WT, whereas it remained elevated in DS mice. KO of Scn1a in GABAergic neurons caused similar thermoregulatory deficits in mice. During exercise, the HR increase was less prominent in DS than WT mice. After exercise, the HR was significantly more suppressed in DS. The heart rate variability (HRV) was lower in DS than WT mice during baseline and higher in DS during exercise-recovery periods.

SIGNIFICANCE

We found novel abnormalities that expand the spectrum of interictal, ictal, and postictal autonomic dysregulation in DS mice. During mild heat stress, there was a significantly blunted correction of body temperature, and a less suppression of both HR and respiration rate in DS than WT mice. These effects were seen in mice with selective KO of Scn1A in GABAergic neurons. During exercise stress, there was diminished increase in HR, followed by an exaggerated HR suppression and HRV elevation during recovery in DS mice compared to controls. These findings suggest that different environmental stressors can uncover distinct autonomic disturbances in DS mice. Interneurons play an important role in thermoregulation. Understanding the spectrum and mechanisms of autonomic disorders in DS may help develop more effective strategies to prevent seizures and SUDEP.

QT interval and P wave dispersion in slow coronary flow phenomenon

BACKGROUND

Slow coronary flow (SCF) phenomenon is an angiographic finding which is defined as slow contrast passage through coronary arteries which may predispose patients to serious cardiac complications such as fatal arrhythmias. P-wave and QT-interval dispersion are electrocardiographic findings which are related to atrial fibrillation and ventricular tachyarrhythmias. In the present study, the relation between SCF and presence of P-wave and QT-interval dispersion in electrocardiography has been evaluated.

METHODS

47 patients with normal coronary arteries and SCF and 40 patients with normal coronary artery flow without SCF were enrolled in this case control study. Standard electrocardiogram (ECG) was analyzed for P-wave and QT-interval dispersion. SCF was identified in normal coronary vessels by use of Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) method (TFC > 27). Corrected TIMI frame count (CTFC) of coronary vessels as well as mean CTFC along with QT-interval and P-wave dispersion were compared between 2 groups. The study data were analyzed by SPSS software and P value less than 0.050 was considered to be significant.

RESULTS

QT-interval [76.17 (35.23) ms versus 39.25 (19.26) ms] and P-wave [39.74 (17.48) ms versus 19.50 (8.54) ms] dispersion were significantly higher among patients with SCF phenomenon (P < 0.050). In addition, there was a positive significant linear correlation between TFC and P-wave and QT-dispersion (r = 0.857, r = 0.861, respectively, P < 0.050).

CONCLUSION

According to the results, increasing TFC among patients with SCF will result in P wave and QT interval dispersion and therefore this finding can be considered as an indicative marker for cardiac events.

Vessel heterogeneity of TIMI frame count and its relation to P-wave dispersion in patients with coronary slow flow

BACKGROUND

The vessel heterogeneity of thrombolysis in myocardial infarction (TIMI) frame count (TFC) in patients with coronary slow flow (CSF) remains to be further evaluated, and the correlation between TFC heterogeneity and P-wave dispersion (PWD) has not been elucidated. We aim to investigate the vessel heterogeneity of TFC in coronary arteries, and its relation to PWD in patients with CSF and otherwise normal coronary arteries.

METHODS

We studied 72 patients with angiographically documented CSF and 66 age- and gender-matched control subjects. The coefficient of variation (CV) and mean TFC of the three vessels were calculated. P-wave duration and PWD were measured on the standard electrocardiograms (ECGs).

RESULTS

The mean TFC and CV were both significantly higher in CSF patients than in controls (P<0.001 for both comparisons). The maximum P-wave duration (Pmax) and PWD were found to be significantly higher in CSF patients than in controls (P<0.001 for both comparisons). In patients with CSF, both Pmax and PWD were mildly correlated to mean TFC (r=0.318, P=0.009; and r=0.307, P=0.010), and were more significantly correlated to CV (r=0.506, P<0.001; and r=0.579, P<0.001).

CONCLUSIONS

These data demonstrate that variability of TFC in three coronary arteries is increased in CSF patients, and that the vessel heterogeneity in coronary flow might be intimately associated with PWD.

The influence of epidural anesthesia on the electrical activity of heart atria

Introduction

High thoracic epidural anesthesia (TEA) causes blockade of sympathetic fibers involved in innervation of the heart (segments T1-T4), which results in changes of cardiac electrophysiology. The anti-arrhythmic effects of TEA on supraventricular arrhythmias, mainly atrial fibrillation, are controversial.

The aim of the study

The aim of the study was to assess the influence of epidural anesthesia on the electrical function of heart atria, including proven markers of increased risk of perioperative atrial fibrillation, such as P wave dispersion and P wave maximum duration.

Material and methods

The study involved 50 male patients, without a history of previous heart diseases, scheduled for elective surgical procedures. Patients received thoracic epidural anesthesia (group T, n = 25) or lumbar epidural anesthesia (group L, n = 25). The measurements were obtained from a continuous recording of ECG before epidural anesthesia and after the detection of blockade (T1 or T8 segment sensory block in groups T and L, respectively).

Results

The statistical analysis of electrocardiographic parameters, including the maximum, minimum and mean P wave duration; P wave dispersion; the maximum, minimum and mean PR interval duration; and PR interval dispersion, did not show any inter- or intragroup differences at selected time points.

Conclusions

Regardless of its location, epidural anesthesia and sympathetic blockade associated with this procedure do not significantly affect the electrical functions of the cardiac atria reflected in superficial ECG, including the electrocardiographic parameters that are considered to be markers of increased risk of perioperative atrial fibrillation, such as P wave dispersion and its maximum duration.

Thrombin activatable fibrinolysis inhibitor : its role in slow coronary flow

BACKGROUND

The slow coronary flow (SCF) phenomenon is characterized by slow progression of angiographic contrast medium in the coronary arteries in the absence of stenosis in the epicardial vessels. The pathophysiological mechanisms of SCF phenomenon remain uncertain. Several hypotheses, however, have been suggested for SCF phenomenon, including an early form of atherosclerosis, small vessel dysfunction, dilatation of coronary vessels, imbalance between vasoconstrictor and vasodilatory factors, platelet function disorder, and inflammation. Atherosclerosis and inflammation are the most accepted mechanisms for the pathogenesis of SCF. Thrombin activatable fibrinolysis inhibitor (TAFI) was described as a new inhibitor of fibrinolysis recently and plays an important role in coagulation and fibrinolysis. In previous studies, the role of TAFI was associated with inflammation and evolution of atherosclerosis in coronary artery disease. There are no data available about TAFI levels in patients with SCF phenomenon investigated by angiography. Our goal was to evaluate TAFI antigen (Ag) levels in patients with SCF and to determine the association of the TAFI Ag level with traditional cardiovascular risk factors in our study.

METHODS

The study group constituted 41 patients with angiographically confirmed SCF and 46 patients with normal coronary flow as the control group. The TAFI Ag levels of each patient were determined.

RESULTS

Between the control and study group, a statistical difference in the levels of TAFI Ag (p < 0.05) was observed. The TAFI Ag level was significantly higher in the SCF group than the control group (132.21 ± 21.14 versus 122.15 ± 21.59).

CONCLUSION

We have demonstrated that TAFI might be a risk factor for the development of SCF independently of conventional cardiovascular risk factors. In addition, TAFI Ag levels were positively correlated with C-reactive protein (CRP) known as an acute phase reactant. Our findings support the reports of previous studies that increased TAFI levels may be associated with inflammation. Further large studies are required to evaluate the importance of TAFI antigen levels in relation to the development of SCF.

Interatrial block: the pandemic remains poorly perceived

Interatrial block (IAB; P duration >or=110 ms) is a common electrocardiogram abnormality, which in addition to reduced left atrial function predicts atrial fibrillation and other arrhythmias. P terminal force (Ptf) +/- biphasic P in lead V(1)>or= the area of one small square on the grid also indicates left atrial abnormality, particularly left atrial enlargement, which is a strong correlate of IAB. Among 482 consecutively recorded electrocardiograms, IAB and Ptf were strongly and significantly correlated (chi(2)= 68.041; P <or= 0.001).In conclusion, interatrial block exists in pandemic proportions in unselected hospital patients. Because of its pathologic implications it requires widespread attention which, heretofore, has been lacking.

Use of the TIMI frame count in the assessment of coronary artery blood flow and microvascular function over the past 15 years

Since its introduction, the TIMI frame count method has contributed to the understanding of the pathophysiology of coronary artery disease. In this article, the evolution of the TFC method and its applicability in the assessment of various therapeutic modalities are described.

The increase in P-wave dispersion is associated with the duration of disease in patients with Behçet's disease

AIM

P-wave dispersion (PD) has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. Behçet's disease (BD) is a chronic multi-system disease presenting with recurrent oral and genital ulceration, and relapsing uveitis. Left ventricular diastolic dysfunction, ventricular arrhythmia and sudden cardiac death have been documented in Behçet's disease. The aim of this study was to evaluate myocardial involvement noninvasively in patients with BD by measuring PD.

METHODS

Study population included 29 patients with BD (group I), (16 males, mean age: 60.4+/-10.1 years), and 45 normal (group II), (23 males, mean age: 61.2+/-12.0 years). The maximum and minimum P-wave duration (Pmax and Pmin) and PD were measured from the 12-lead surface electrocardiogram. Echocardiographic examination was also performed.

RESULTS

There was no statistically significant difference between two groups in respect to age, gender, hypertension, diabetes mellitus, hyperlipidemia and cigarette smoking (p>0.05). Pmax and PD of patients with BD were found to be significantly higher than those of control subjects (116.2+/-14.0 ms vs. 102.0+/-16.5 and 49.3+/-12.7 ms vs. 29.3+/-8.5 ms, respectively p<0.0001). Moreover, we found a significant positive correlation between PD with BD duration (r=0.78, p<0.0001).

CONCLUSION

Pmax and PD are found to be greater in patients with BD than in controls and are related with the duration of the disease.