Ana Clara Tude Rodrigues

Quantitative Assessment of Regional Myocardial Function in Mice by Tissue Doppler Imaging Comparison With Hemodynamics and Sonomicrometry

Background—Tissue Doppler imaging (TDI) is a novel echocardiographic method to quantify regional myocardial function. The objective of this study was to assess whether myocardial velocities and strain rate (SR) could be obtained by TDI in mice and whether these indices accurately quantified alterations in left ventricular (LV) systolic function. Methods and Results—TDI was performed in 10 healthy mice to measure endocardial (vendo) and epicardial systolic velocities and SR. In further experiments, TDI indices were compared with dP/dtmax and with sonomicrometer-derived regional velocities, at rest and after administration of dobutamine or esmolol. TDI indices were also studied serially in 8 mice before and 4 and 7 hours after endotoxin challenge. Myocardial velocities and SR were obtained in all mice with low measurement variability. TDI indices increased with administration of dobutamine (vendo from 2.2±0.3 to 3.8±0.2 cm/s [P<0.01]; SR from 12±2 to 20±2 s−1 [P<0.05]) and decreased with administration of esmolol (vendo 1.4±0.2 cm/s [P<0.05]; SR 6±1 s−1 [P<0.01]). Both indices correlated strongly with dP/dtmax (r2=0.79 for SR and r2= 0.69 for vendo; both P<0.0001). SR and shortening fraction were predictors of dP/dtmax even after adjustment for the confounding effect of the other variables. Vendo correlated closely with sonomicrometer-measured velocity (r2=0.71, P<0.0005). After endotoxin challenge, decreases in both vendo and SR were detected before decreases in shortening fraction became manifest. Conclusions—Myocardial velocities and SR can be measured noninvasively in mice with the use of TDI. Both indices are sensitive markers for quantifying LV global and regional function in mice.

Importance of adequately performed Valsalva maneuver to detect patent foramen ovale during transesophageal echocardiography.

BACKGROUND Transesophageal echocardiography (TEE) plays an important role in evaluating cardioembolic sources of emboli. The identification of a patent foramen ovale (PFO) is reportedly improved with TEE compared with transthoracic echocardiography (TTE), but the Valsalva maneuver during TEE may be difficult or suboptimal. The aim of this study was to assess the efficacy of the Valsalva maneuver for PFO diagnosis using TEE compared with TTE by evaluating patients with ischemic stroke referred for echocardiography. METHODS Only patients able to perform the Valsalva maneuver during TTE were included; efficacy was defined by a 20 cm/sec decrease in transmitral E velocity. A PFO was judged present when microbubbles of agitated intravenous saline were seen in the left chambers within three cycles after right atrial opacification. RESULTS Of 108 patients (mean age, 55 ± 15 years; 61 men), 48 (44%) were judged to have PFOs by TEE and/or TTE. In 36 patients (33% of the total, 75% of those with PFOs), microbubbles were observed both by TEE and TTE, in seven patients only during TTE, and in five patients only during TEE. In patients able to satisfactorily perform the Valsalva maneuver during TEE, 22 PFOs were found, and two shunts (9%) were missed, whereas in patients unable to perform this maneuver, 26 PFOs were observed, with five shunts missed (19%) (P < .05). When a PFO was missed by TTE, either the echocardiographic window was suboptimal or the shunt was small. CONCLUSIONS An adequate Valsalva maneuver is crucial for diagnosis of PFO; most patients with stroke may be screened using TTE with contrast and the Valsalva maneuver, with TEE indicated in case of suboptimal transthoracic images.

Left ventricular free wall impeding rupture in post-myocardial infarction period diagnosed by myocardial contrast echocardiography: Case report

Background:Left ventricular free wall rupture occurs in up to 10% of the in-hospital deaths following myocardial infarction. It is mainly associated with posterolateral myocardial infarction and its antemortem diagnosis is rarely made. Contrast echocardiography has been increasingly used for the evaluation of myocardial perfusion in patients with acute myocardial infarction, with important prognostic implications. In this case, we reported its use for the detection of a mechanical complication following myocardial infarction.Case presentation:A 50-year-old man with acute myocardial infarction in the lateral wall underwent myocardial contrast echocardiography for the evaluation of myocardial perfusion in the third day post-infarction. A perfusion defect was detected in lateral and inferior walls as well as the presence of contrast extrusion from the left ventricular cavity into the myocardium, forming a serpiginous duct extending from the endocardium to the epicardial region of the lateral wall, without communication with the pericardial space. Magnetic resonance imaging confirmed the diagnosis of impending rupture of the left ventricular free wall. While waiting for cardiac surgery, patient presented with cardiogenic shock and died. Anatomopathological findings were consistent with acute myocardial infarction in the lateral wall and a left ventricular free wall rupture at the infarct site.Conclusion:This case illustrates the early diagnosis of left ventricular free wall rupture by contrast echocardiography. Due to its ability to be performed at bedside this modality of imaging has the potential to identify this catastrophic condition in patients with acute myocardial infarction and help to treat these patients with emergent surgery.

Analysis of left ventricular regional dyssynchrony: comparison between real time 3D echocardiography and tissue Doppler imaging.

Background: There is a paucity of information concerning left ventricular (LV) dyssynchrony assessment by real time three‐dimensional (3D) echocardiography (RT3DE) versus tissue Doppler imaging (TDI). Aims: To compare RT3DE and TDI LV dyssynchrony assessment. Methods: A prospective study of 92 individuals (56 men, age 47 ± 10 years), 32 with dilated cardiomyopathy (CMP), and 60 healthy individuals. By RT3DE, we measured the LV% dyssynchrony index (DI) of 6, 12, and 16 segments (SDI). By pulsed‐wave TDI, we measured the QS electromechanical interval in the basal segments of the mitral valve annulus of the septum, the lateral, anterior and inferior walls, and the TDI% DI. Results: In the normal group, the 3D DI was 1.1 ± 0.8%, 1.4 ± 1.3%, 1.8 ± 1.7%, for 6 segments, 12 segments, and SDI, respectively. The correlation coefficient (Pearsons r) for the TDI DI and SDI was r = 0.2381 (P = 0.0470). In CMP group, the 3D DI was 4.6 ± 5.4%, 7.9 ± 7.1%, 11.1 ± 7.1%, for 6 segments, 12 segments, and SDI, respectively. The correlation coefficient for TDI DI and SDI was r = 0.7838 (P < 0.0001). Conclusions: We observed a good correlation between RT3DE and tissue Doppler LV dyssynchrony assessment in patients with advanced heart failure. (ECHOCARDIOGRAPHY, Volume 26, July 2009)

Infarct Size Assessment in Mice

Genetically modified mice are used extensively in models of ischemia reperfusion (I/R) and nonreperfused myocardial infarction (MI) to gain insights into pathways involved in these pathologies. Echocardiography is an ideal noninvasive tool to serially monitor the cardiac murine phenotype. The present review details the surgical aspects of I/R and MI models and the measurement of MI size by pathology techniques and the input of echocardiographic techniques including the extent of wall motion abnormality and of perfusion defects using myocardial contrast echocardiography in the assessment of murine area at risk and MI size.

Day–night pattern of autonomic nervous system modulation in patients with heart failure with and without sleep apnea

INTRODUCTION Among patients with congestive heart failure (CHF) both obstructive and central sleep apnea (SA) are associated with increased sympathetic activity. However, the day-night pattern of cardiac autonomic nervous system modulation in CHF patients with and without sleep apnea is unknown. MATERIAL AND METHODS Twenty-five CHF patients underwent polysomnography with simultaneous beat-to-beat blood pressure (Portapres), respiration and electrocardiogram monitoring. Patients were divided according to the presence (SA, n=17) and absence of SA (NoSA, n=8). Power spectral analyses of heart rate variability (HRV) and spontaneous baroreflex sensitivity (BRS) were determined in periods with stable breathing while awake at 6 am, 10 am, 10 pm, as well as during stage 2 sleep. In addition, muscle sympathetic nerve activity (MSNA) was evaluated at 10 am. RESULTS RR variance, low-frequency (LF), high-frequency (HF) powers of HRV, and BRS were significantly lower in patients with SA compared with NoSA in all periods. HF power, a marker of vagal activity, increased during sleep in patients with NoSA but in contrast did not change across the 24-hour period in patients with SA. MSNA was significantly higher in patients with SA compared with NoSA. RR variance, LF and HF powers correlated inversely with simultaneous MSNA (r=-0.64, -0.61, and -0.61 respectively; P<0.01). CONCLUSIONS Patients with CHF and SA present a reduced and blunted cardiac autonomic modulation across the 24-hour period. These findings may help to explain the increased cardiovascular risk in patients with CHF and SA.

Primary and secondary development of Cyperus giganteus Vahl rhizome (Cyperaceae)

In Cyperus giganteus, like in other Monocotyledoneae, the protoderm, procambium, fundamental meristem and primary thickening meristem (PTM) are differentiated from the rhizome promeristem. The PTM produces the inner cortical parenchyma, endodermis, pericycle and amphivasal vascular bundles, which are formed by the procambium too. After the primary body differentiates, cellular divisions continue only in the pericycle, and originate an irregular vascular system with vessel elements shorter and more branched than those found in the primary growth. This change of activity in the pericycle defines a secondary growth, where the secondary thickening meristem (STM) is the pericycle itself.

Right Ventricular Abnormalities in Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy, described as transient regional contractile abnormalities limited to the apical and mid‐segments of the left ventricle (LV), has also been reported to involve basal and/or mid LV segments (inverted Takotsubo); fewer reports, however, have addressed right ventricular (RV) dysfunction.

Nitric oxide synthase 2 and pressure-overload-induced left ventricular remodelling in mice.

Nitric oxide synthase 2 (NOS2) has been reported to increase in hypertrophied cardiomyocytes; however, whether NOS2 plays a role in the development of hypertrophy is unknown. To investigate the relationship of NOS2 with left ventricular (LV) remodelling and hypertrophy following prolonged pressure overload, we studied 18 male wild‐type (WT) and 20 male NOS2‐deficient (NOS2–/–) mice before and 7, 14 and 28 days after transverse aortic constriction (TAC) using echocardiography. A subgroup of eight WT and eight NOS2–/– mice were studied 42 days after TAC. Haemodynamic measurements were obtained before killing. Left ventricular size and function were similar for both genotypes at baseline. After TAC for 28 days, both groups developed LV hypertrophy, with echo‐derived LV mass increasing from 78 ± 2 to 147 ± 10 mg in WT and from 86 ± 3 to 142 ± 10 mg in NOS2–/– mice. Twenty‐eight days after TAC, LV weight and cardiomyocyte width were also similar in both genotypes. Fractional shortening (FS) decreased on day 7 from 57 ± 1 to 48 ± 2% in WT and from 59 ± 1 to 49 ± 2% in NOS2–/– mice. Although this decrease in FS was transient in WT mice, it persisted in NOS2–/– mice. Invasively measured parameters of systolic and diastolic function, however, were similar in the two genotypes both 28 and 42 days after TAC. A load‐independent index of contractility, Emax, was similar in both strains 42 days after TAC. In conclusion, NOS2 does not appear to have a critical role in the development of LV hypertrophy after chronic pressure overload.

Noninvasive diagnosis of allograft vascular disease after heart transplantation

OBJECTIVE To determine the predictive values of noninvasive tests for the detection of allograft vascular disease. METHODS We studied 39 patients with mean ages of 48+/-13 years and a follow-up period of 86+/-13 months. The diagnosis of allograft vascular disease was made by cine-coronary arteriography, and it was considered as positive if lesions existed that caused > or =50% obstruction of the lumen. Patients underwent 24h Holter monitoring, thallium scintigraphy, a treadmill stress test, and dobutamine stress echocardiography. Sensitivity, specificity, and positive and negative predictive values were determined in percentages for each method, as compared with the cine-coronary arteriography results. RESULTS Allograft vascular disease was found in 15 (38%) patients. The Holter test showed 15.4% sensitivity, 95.5% specificity. For the treadmill stress test, sensitivity was 10%, specificity was 100%. When thallium scintigraphy was used, sensitivity was 40%, specificity 95.8%. On echocardiography with dobutamine, we found a 63.6% sensitivity, 91.3% specificity. When the dobutamine echocardiogram was associated with scintigraphy, sensitivity was 71.4%, specificity was 87%. CONCLUSION In this group of patients, the combination of two noninvasive methods (dobutamine echocardiography and thallium scintigraphy) may be a good alternative for the detection of allograft vascular disease in asymptomatic patients with normal ventricular function.