Quantification of left ventricular asynchrony throughout the whole cardiac cycle with a computed algorithm: application for optimizing resynchronization therapy

INTRODUCTION

Measurement of left ventricular (LV) asynchrony is usually determined on single time points from spectral tissue Doppler imaging (TDI) scans that are frequently difficult to identify or not representative of the whole cardiac cycle. Our aim was to validate a new asynchrony index that evaluates the motion of the LV walls throughout the whole cardiac cycle.

METHODS AND RESULTS

Ten healthy volunteers and 50 patients undergoing cardiac resynchronization therapy (CRT) were studied with TDI. Wall displacement tracings from the septal and lateral LV walls were analyzed. Cross-correlation was calculated and 2 indices were obtained to assess LV asynchrony: the time delay and the superposition index (SI) between wall displacements. These results were compared between healthy volunteers and CRT patients, and between responders and nonresponders to CRT. Also, the optimal interventricular (VV) interval was based upon the best matching level. Volunteers showed lower asynchrony indices (83 +/- 2% SI, 17 +/- 8 ms time delay) as compared with CRT patients (63 +/- 15% SI, 73 +/- 60 ms time delay, P < 0.05). Responders also had more LV dyssynchrony than nonresponders (58 +/- 15% SI and 92 +/- 66 ms vs 68 +/- 12% and 48 +/- 34 ms, P < 0.05). The optimum VV interval selected by the computed algorithm showed an excellent concordance (Kappa = 0.90, P < 0.05) with that determined by other validated methods for optimizing the programming of CRT devices.

CONCLUSIONS

This approach allows measurement of LV intraventricular asynchrony throughout the cardiac cycle, being useful to determine the optimum VV interval and to select candidates for CRT.

[Intermediate care units. Health care consequences in a reference hospital]

INTRODUCTION

Intermediate Care Units are forms to provide health care services to potentially critical patients that allow for improved cost-benefit ratio of the care offered by Intensive Medicine Departments.

OBJECTIVE

Analyze heart care repercussion that the permanent opening of this type of unit had in a reference teaching center.

DESIGN

Prospective.

PERIOD

From the beginning of 2003 to the end of 2005.

SCOPE

Intensive Medicine Department (IMD), with teaching accreditation, which has 15 conventional ICU beds and 4 intermediate care beds.

PATIENTS AND METHODS

Analysis of demographic data (gender and age, type of patient, and origin or admission), of severity (SAPS 2), prognosis (MPM II 0 and SAPS2) and health care burden (NEMS) in 3,392 consecutive admissions to IMD. Specific analysis of the stay and mortality (intra- and post ICU).

RESULTS

Permanent opening of an intermediate care unit is associated with an increase of patients seen by the IMD and makes it possible to clearly identify two different types of patients according to the site linked to the cause of the admission. The patients seen in the Intermediate Care Unit have a shorter stay, less seriousness, greater survival prognosis and less care burden. However, the initiation of this service does not decrease the interval of total mortality (intra+post- ICU).

CONCLUSION

Initiating an intermediate care unit depending on an IMD increases its health care capacity and that of the center it gives service to without affecting global mortality.

Physical activity, height, and left atrial size are independent risk factors for lone atrial fibrillation in middle-aged healthy individuals

AIMS

The aetiology of atrial fibrillation (AF) remains unknown in some patients. The aim of the study was to identify new risk factors for developing lone AF (LAF).

METHODS AND RESULTS

A series of 107 consecutive patients younger than 65, seen in the emergency room for an episode of LAF of <48 h duration were included in the study. A group of 107 healthy volunteers matched for age and sex were recruited as controls. All subjects answered a validated questionnaire concerning leisure and occupational activities performed throughout their lifetimes to estimate accumulated hours of physical effort, classified in four levels of intensity. Demographic and echocardiographic measurements were also recorded. There were 69% of males and mean age was 48 +/- 11 years. AF was paroxysmal in 57% and persistent in the remaining 43%. Patients with AF performed more hours of both moderate and heavy intensity physical activity. They also were taller, and had a larger left atria, ventricle, and body surface area. At the multivariable analysis, only moderate and heavy physical activity, height, and anteroposterior atrial diameter were independently associated with LAF.

CONCLUSIONS

Accumulated lifetime physical activity, height, and left atrial size are risk factors for LAF in healthy middle-aged individuals.

Pre-procedural predictors of atrial fibrillation recurrence after circumferential pulmonary vein ablation

AIMS

The success rate of circumferential pulmonary vein ablation (CPVA) to treat atrial fibrillation (AF) ranges from 60 to 90%, depending on the series. The objective of the study was to identify predictors of AF recurrence after a standardized CPVA procedure.

METHODS AND RESULTS

A series of 148 consecutive patients undergoing CPVA for symptomatic paroxysmal (60.8%), persistent (23.6%), or permanent (15.5%) AF refractory to antiarrhythmic drugs were included in the study. CPVA with the creation of supplementary block lines along the posterior wall and mitral isthmus was performed and a minimum of 6 months follow-up completed in all patients. Structural heart disease was present in 19.6% and hypertension in 33.8% of patients. After 13.1 +/- 8.4 months follow-up, 73.6% of patients were free of AF recurrences after a mean of 1.18 +/- 0.45 procedures/patient (one procedure in 85.2%, two procedures in 14.8%, and three procedures in 2.7%). Univariable analysis showed that the risk of AF recurrence increases with age (HR 1.03; 95% CI 1.00-1.06, P = 0.031), with the presence of previous hypertension (HR 2.7; 95% CI 1.43-5.07, P = 0.002), and if AF is permanent (HR 2.23; 95% CI 1.08-4.59, P = 0.042). In addition, larger anteroposterior left atrial diameter (LAD) (HR 1.11; 95% CI 1.05-1.18, P = 0.001) and larger left ventricular end-systolic diameter (HR 1.07; 95% CI 1.00-1.15, P = 0.029) prior to the procedure were associated with AF recurrence after CPVA. Cox regression analysis showed that hypertension (OR = 2.8; 95% CI 1.5-5.4; P = 0.002) and LAD (OR = 1.1; 95% CI 1.05-1.19, P < 0.001) were independent predictors of AF recurrence. The mean predicted proportion of patients with AF recurrence after CPVA of the multivariable model showed a linear relationship with the increase in LAD prior to the procedure. The presence of hypertension further increased the mean predicted proportion of patients with AF recurrence at each LAD.

CONCLUSION

Hypertension and LAD are independent pre-procedural predictors of AF recurrence after CPVA to treat AF. These data may help in patient selection for AF ablation.

Cardiac resynchronization therapy: predictive factors of unsuccessful left ventricular lead implant

AIMS

Cardiac resynchronization therapy is an established therapy for advanced heart failure. However, coronary sinus access and pacing is not achieved in about 5-10% of patients. The aim of this study was to identify predictive factors for failure of left ventricular (LV) lead transvenous implant.

METHODS AND RESULTS

We evaluated 212 consecutive patients who received a cardiac resynchronization system. In 26 patients (12.3%), the attempt to pace the LV was unsuccessful. At univariate analysis, in patients with an unsuccessful implant a higher proportion of permanent atrial fibrillation (AF), valvular heart disease, and previous heart surgery were observed. Anteroposterior, longitudinal, and transversal left atrium diameters (LAD) were also larger among patients with an unsuccessful implant. The anteroposterior LAD (APLAD) with an optimal value to predict implant failure was 48.5 mm. At logistic regression analysis, the presence of permanent AF and APLAD were independent predictors of failed implant (OR 7.7, 95% CI 2.5-23.9, P=0.002 and OR 11.7, 95% CI 3.1-37.6, P<0.001, respectively).

CONCLUSION

The presence of permanent AF and APLAD are factors that predict unsuccessful pacing from the LV.

Tunable and reconfigurable photonic microwave filter based on stimulated Brillouin scattering

A high Q-factor photonic microwave filter showing tuning and reshaping capabilities and based on stimulated Brillouin scattering is demonstrated. The filter bandpass can be continuously tuned, changing the microwave oscillator used to generate the pump power, and the filter shape can be modified by modulating the microwave tone. A single bandpass over the microwave spectrum can be obtained by using single-sideband suppressed carrier modulation. Experimental results demonstrate the wide tuning range of the filter, its reshaping capability, and Q factor of 670.

[Prognostic estimation in critical patients. Validation of a new and very simple system of prognostic estimation of survival in an intensive care unit]

OBJECTIVE

To make the validation of a new system of prognostic estimation of survival in critical patients (EPEC) seen in a multidisciplinar Intensive care unit (ICU).

DESIGN AND SCOPE

Prospective analysis of a patient cohort seen in the ICU of a multidisciplinar Intensive Medicine Service of a reference teaching hospital with 19 beds.

PATIENTS AND METHOD

Four hundred eighty four patients admitted consecutively over 6 months in 2003. Data collection of a basic minimum data set that includes patient identification data (gender, age), reason for admission and their origin, prognostic estimation of survival by EPEC, MPM II 0 and SAPS II (the latter two considered as gold standard). Mortality was evaluated on hospital discharge. EPEC validation was done with analysis of its discriminating capacity (ROC curve), calibration of its prognostic capacity (Hosmer Lemeshow C test), resolution of the 2 x 2 Contingency tables around different probability values (20, 50, 70 and mean value of prognostic estimation). The standardized mortality rate (SMR) for each one of the methods was calculated. Linear regression of the EPEC regarding the MPM II 0 and SAPS II was established and concordance analyses were done (Bland-Altman test) of the prediction of mortality by the three systems.

RESULTS

In spite of an apparently good linear correlation, similar accuracy of prediction and discrimination capacity, EPEC is not well-calibrated (no likelihood of death greater than 50%) and the concordance analyses show that more than 10% of the pairs were outside the 95% confidence interval.

CONCLUSION

In spite of its ease of application and calculation and of incorporating delay of admission in ICU as a variable, EPEC does not offer any predictive advantage on MPM II 0 or SAPS II, and its predictions adapt to reality worse.

[Radial artery spasm in transradial cardiac catheterization. Assessment of factors related to its occurrence, and of its consequences during follow-up]

INTRODUCTION AND OBJECTIVES

Radial artery spasm is the most frequent complication of transradial cardiac catheterization. It causes patient discomfort and reduces the procedure's success rate. The aims of this study were to identify variables associated with this complication, such as clinical parameters, angiographic characteristics of the radial artery and factors related to the procedure, and to analyze the clinical consequences of spasm, both generally and for radial artery patency, during follow-up.

PATIENTS AND METHOD

The study included 637 patients who were undergoing transradial cardiac catheterization. Radial artery spasm was recorded using a scale that reflected the presence of pain and the technical difficulty of the procedure.

RESULTS

Radial artery spasm was reported in 127 patients (20.2%). Multivariate analysis showed that the variables associated with radial artery spasm were radial artery anatomical anomalies (odds ratio [OR]=5.1; 95% confidence interval [95% CI]: 2.1-11.4), use of >size-3 catheters (OR=3.0; 95% CI: 1.9-4.7), moderate-to-severe pain during radial artery cannulation (OR=2.6; 95% CI: 1.4-4.9), the use of phentolamine as a spasmolytic (OR=1.8; 95% CI: 1.1-2.9), and postvasodilation radial artery diameter (OR=0.98; 95% CI: 0.98-0.99). At follow-up [20 (18) days], severe pain in the forearm was more frequent in patients who presented with radial artery spasm (12.4% vs 5.3%), but there was no significant difference in the radial artery occlusion rate (4.5% vs 2.2%).

CONCLUSION

Radial artery spasm during transradial catheterization mainly depends on radial artery characteristics and procedural variables. At follow-up, radial artery spasm was associated with more frequent severe pain in the forearm, but the radial artery occlusion rate was not increased.

Dopaminergic Inhibition of Reproduction in Teleost Fishes: Ecophysiological and Evolutionary Implications

In many teleosts, dopamine (DA) exerts direct inhibitory control on gonadotropes, counteracting the stimulatory effect of gonadotropin-releasing hormone (GnRH) on gonadotropin release. This dual control by GnRH and DA has been demonstrated in various adult teleosts and has major implications for aquaculture. Because of its unique life cycle, the European eel has provided a powerful model for demonstrating the key role of DA in the control of puberty. Data from tetrapods suggest that the inhibitory role of DA on reproduction is not restricted to the teleosts. Thus, DA inhibitory control could represent an ancient evolutionary component in the neuroendocrine regulation of reproduction that may have been differentially maintained throughout vertebrate evolution. The intensity of DA inhibition, its main site of action, and its involvement in the control of puberty, seasonal reproduction, ovulation, spermiation, or even sex change may differ among classes of vertebrates, as well as within smaller phylogenetic units such as teleosts or mammals. An inhibitory role for DA has been reported also in some invertebrates, indicating that neuronal DA pathways may have been recruited in various groups of metazoa to participate in the control of reproduction. In addition to the incontestable GnRH neurons, the recruitment of DA neurons for the neuroendocrine control of reproduction provides an additional brain pathway for the integration of various species-specific, internal, and environmental cues. In teleosts, the plasticity of the DA neuroendocrine role may have contributed to their large diversity of biological cycles and to their successful adaptation to various environments.

Brain Expression of Tyrosine Hydroxylase and Its Regulation by Steroid Hormones in the European Eel Quantified by Real-Time PCR

In the eel, dopamine inhibits pubertal development. To investigate the regulatory mechanisms involved, we developed a quantitative real-time RT-PCR assay for measurement of brain expression of tyrosine hydroxylase (TH), the rate-limiting enzyme in the biosynthesis of dopamine. TH expression was highest in the olfactory bulb, followed by the di-/mesencephalic areas and the telencephalon/preoptic area. TH expression in the optic lobes and hindbrain was low or below the detection limit. In vivo treatment with testosterone, but not estradiol, resulted in increased TH expression in the forebrain, except the optic tectum, but not in the hindbrain. The results were confirmed by in situ hybridization.

[Radial artery spasm in transradial cardiac catheterization. Assessment of factors related to its occurrence, and of its consequences during follow-up]

INTRODUCTION AND OBJECTIVES

Radial artery spasm is the most frequent complication of transradial cardiac catheterization. It causes patient discomfort and reduces the procedure's success rate. The aims of this study were to identify variables associated with this complication, such as clinical parameters, angiographic characteristics of the radial artery and factors related to the procedure, and to analyze the clinical consequences of spasm, both generally and for radial artery patency, during follow-up.

PATIENTS AND METHOD

The study included 637 patients who were undergoing transradial cardiac catheterization. Radial artery spasm was recorded using a scale that reflected the presence of pain and the technical difficulty of the procedure.

RESULTS

Radial artery spasm was reported in 127 patients (20.2%). Multivariate analysis showed that the variables associated with radial artery spasm were radial artery anatomical anomalies (odds ratio [OR]=5.1; 95% confidence interval [95% CI]: 2.1-11.4), use of >size-3 catheters (OR=3.0; 95% CI: 1.9-4.7), moderate-to-severe pain during radial artery cannulation (OR=2.6; 95% CI: 1.4-4.9), the use of phentolamine as a spasmolytic (OR=1.8; 95% CI: 1.1-2.9), and postvasodilation radial artery diameter (OR=0.98; 95% CI: 0.98-0.99). At follow-up [20 (18) days], severe pain in the forearm was more frequent in patients who presented with radial artery spasm (12.4% vs 5.3%), but there was no significant difference in the radial artery occlusion rate (4.5% vs 2.2%).

CONCLUSION

Radial artery spasm during transradial catheterization mainly depends on radial artery characteristics and procedural variables. At follow-up, radial artery spasm was associated with more frequent severe pain in the forearm, but the radial artery occlusion rate was not increased.