Bidirectional cavopulmonary anastomosis: impact on diastolic ventricular function indices.

Systolic ventricular function has been demonstrated to remain unchanged following bidirectional cavopulmonary anastomosis (BCPA). The effects of BCPA on diastolic ventricular performance have not been critically assessed. The objective of this study was to evaluate the changes in diastolic ventricular function indices early after BCPA. Nineteen patients were enrolled prospectively. Transthoracic echocardiograms were performed at a median of 4 days prior to and 5 days subsequent to BCPA. Diastolic and systolic echocardiographic indices of ventricular performance were measured for the dominant ventricle. End diastolic volume decreased postoperatively (71.1 +/- 21.1 vs 68.08 +/- 17.9 ml/m2, p = 0.05). Tei index increased postoperatively (0.51 +/- 0.2 vs 0.62 +/- 0.1, p = 0.002), whereas inflow Doppler E velocity (70.3 +/- 13 vs 56.3 +/- 24.7 cm/sec, p = 0.04), E/A ratio (1.18 +/- 0.52 vs 0.84 +/- 0.2, p = 0.02), tissue Doppler E' velocity (9.5 +/- 2.5 vs 6.4 +/- 3.2 cm/sec, p = 0.03) and diastolic flow propagation velocity (56.5 +/- 12 vs 52.8 +/- 11 cm/sec, p = 0.04) all decreased. There was no change in ventricular mass, area change fraction, heart rate, or inflow Doppler A or tissue Doppler A' and S' velocities. This study demonstrated that diastolic indices of ventricular performance are altered indicating decreased diastolic function early following BCPA. Whether this observation is a result of a change in ventricular mass:volume ratio, loading conditions of the ventricle, ventricular geometry, or the effects of cardiopulmonary bypass remains to be determined.

Fetal cardiac function assessed by Doppler myocardial performance index (Tei Index).

OBJECTIVES: The Tei Index (TI) is a useful, non-invasive, Doppler-derived myocardial performance tool which can be used to assess aspects of systolic and diastolic function. The aim of this study was to determine normal values of fetal left ventricular (LV) TI in second- and third- trimester fetuses and to compare these to other values reported in the literature. METHODS: Doppler waveforms of the LV outflow tracts were obtained in 74 second- and early third-trimester fetuses. The LV isovolumic contraction time (ICT), isovolumic relaxation time (IRT) and ejection time (ET) were measured and the TI calculated using the formula (ICT + IRT)/ET. The literature on LV myocardial function in the fetus was also reviewed. RESULTS: The normal TI in second- and early third-trimester fetuses (18-31 weeks' gestation) was 0.53 +/- 0.13. The ICT was 43 +/- 14 ms, the ET was 173 +/- 16 ms and the IRT was 48 +/- 13 ms. CONCLUSION: The TI can be easily obtained in the fetus without the need for precise anatomic imaging. The TI may be a useful tool to explore fetal myocardial function in different clinical situations.

Electrocardiographic repolarization abnormalities in familial dysautonomia: an indicator of cardiac autonomic dysfunction.

OBJECTIVE: Electrocardiographic repolarization intervals were evaluated to determine the extent of cardiac autonomic dysfunction in patients with familial dysautonomia (FD) and to determine if any of these intervals could serve as a possible predictor of clinical symptoms. METHODS: Thirty-seven electrocardiograms of patients with FD were retrospectively evaluated. QT, JT, rate-corrected QT and JT intervals were calculated as well as QT and QTC dispersion. Results were compared to normative data and electrocardiograms of 20 age-matched control subjects. OBSERVATIONS: In the FD group, prolongation of QTC (>450 msec) was noted in 5/37 (13.5%) patients, as compared to 0/20 normal controls (p = NS), and prolongation of JTc (>340 msec) in 16/37 (43.3%) patients, as compared to 0/20 normal controls (p < 0.001). QT and QTC dispersion were abnormal in 3/37 (8.1%) and 5/37 (13.5%), respectively. In the 16 FD patients with prolonged JTc, six had a positive history of syncope, whereas none of the 21 with normal JTc had syncope or symptoms suggesting arrhythmia (p < 0.003). The positive predictive value of having syncope or symptoms suggestive of arrhythmia with an abnormal JTc is 37.5% (95% CI [15%, 65%]). The negative predictive value is 100% (95% CI [87%, 100%]). CONCLUSION: In the FD population, the electrocardiographic measure of repolarization that was most frequently abnormal was the JTc interval . Prolongation of the JTc interval was significantly more frequent than prolongation of the QTC interval (p < 0.001) QT and QTC dispersions were less significantly affected in the FD population, indicating uniform ventricular recovery time. These results suggest that a prolonged JTc interval may be a more sensitive indicator of abnormal ventricular repolarization and cardiac autonomic dysfunction. Due to the known sympathetic denervation inherent in patients with FD, they are at risk for unopposed parasympathetic predominance. FD patients, therefore, are more likely to have brady arrhythmias and asystole rather than polymorphic ventricular tachycardia. The increased incidence of syncope in patients with prolonged JTc suggests that this measure may serve as a helpful marker to predict which FD patients are at increased risk of serious clinical sequelae including bradyarrhythmias with asystole or sudden death.

Second-trimester molecular prenatal diagnosis of sporadic Apert syndrome following suspicious ultrasound findings.

Apert syndrome, an autosomal dominant disorder characterized by craniosynostosis, mid-facial malformations, symmetric bony syndactyly of hands and feet, and varying degrees of mental retardation, is most frequently caused by a de novo mutation. Two missense mutations in the fibroblast growth factor receptor 2 (FGFR2) gene have been found to account for the disorder in approximately 98% of affected patients. Seven cases of prenatal ultrasound diagnosis have been reported. Although one earlier diagnosis has been made in a familial case, sporadic cases have not been definitively diagnosed until the third trimester when craniosynostosis is usually detected. We report a second-trimester molecular diagnosis of a sporadic case, based on the ultrasound observation of fetal 'mitten hands' and craniosynostosis. We discuss the approach to such ultrasound features, given the current availability of molecular diagnosis for Apert syndrome.

MRI in the evaluation and management of a newborn infant with cardiac rhabdomyoma.

A newborn infant presented with a life-threatening cardiac arrhythmia. Echocardiography showed a large cardiac mass growing exophytically in the region of the left atrial appendage extending along the left ventricular wall but showed no clear tissue plane between the mass and the left ventricular wall. Based on the echocardiogram, surgical resection might damage the left ventricular wall. Magnetic resonance imaging demonstrated a clear plane of demarcation, making surgical resection a viable life-saving option.

Use of a free radial artery graft for correction of Bland-White-Garland syndrome.

A radial artery free graft was used to create a two-coronary artery system for a 15-month-old child with Bland-White-Garland syndrome. The anomalous left main coronary artery originated from the proximal right pulmonary artery.

Preliminary observations on the use of midodrine in treating orthostatic hypotension in familial dysautonomia.

Midodrine, a peripheral alpha-adrenergic agonist, was evaluated in 7 female and 2 male patients with familial dysautonomia (FD), a disorder characterized by decreased sympathetic innervation. Prior to and after three months of midodrine treatment, each patient's response to postural change was assessed by arteriosonde readings of blood pressure and heart rate, corrected QT-interval measurements, Doppler evaluation of renal blood flow and circulating atrial natriuretic peptide (ANP) levels. The initial midodrine dose (2.5 mg three times daily) was raised until subjective symptoms improved. Doses were reduced if patients felt jittery or developed erect hypertension (systolic > 180 mmHg or diastolic > 110 mmHg). Midodrine, at an average dose of 0.25 mg/kg per day, improved subjective symptoms in all patients. With treatment, magnitude of blood pressure responses was variable. Although mean erect blood pressure did not increase significantly for the aggregate, it did increase in six of nine patients. In addition, the QTc interval normalized and erect renal perfusion improved. Changes in supine mean blood pressure and supine circulating ANP correlated directly. We judge midodrine to be useful in management of orthostatic hypotension in patients with familial dysautonomia.

Atrial natriuretic peptide response to postural change and medication in familial dysautonomia.

Circulating atrial natriuretic peptide (ANP) was assayed before and after postural change and exercise in 54 patients with familial dysautonomia (FD) and 20 controls. ANP levels were compared with blood pressure, heart rate, plasma catecholamines and parameters of renal function. Compared with controls supine FD subjects had elevated blood pressures, heart rates and ANP levels (39 +/- 4 pg/ml vs. 23 +/- 3 pg/ml, p < 0.01). With the erect posture and exercise in FD subjects, blood pressure fell below control values, with ANP lowered. In FD subjects, blood pressure was correlated with ANP levels when supine and when erect and with heart rate post exercise. In controls, ANP levels did not correlate with other parameters. In FD patients on metoclopramide, supine and erect blood pressure and ANP levels were higher. FD subjects treated with fludrocortisone, had elevated supine and erect noradrenaline (p < 0.05 and p = 0.06); and those on diazepam had lower erect and post exercise noradrenaline (p < 0.05), but ANP levels were similar. In conclusion, sympathetic denervation may increase FD patients' responsiveness to other regulators of cardiovascular integrity, such as ANP. In addition, circulating ANP and catecholamines in FD subjects appear to be influenced by commonly used medications, such as metoclopramide.

Renal blood flow velocity in neonates with and without umbilical artery catheters.

We performed an observational prospective cohort study on the applicability of two-dimensional echocardiography with pulsed Doppler technique as a noninvasive modality to serially evaluate renal blood velocities in premature neonates with and without umbilical artery catheters. We also sought to determine the incidence of umbilical artery catheter-related thrombus formation in our neonatal intensive-care unit. We established normative values for renal artery blood flow velocities in premature neonates and postulate that this echo-Doppler technique is valid and can be used to evaluate renal developmental physiology in the neonatal population. In addition, we observed that even in the absence of clinical sequelae due to thrombus formation, the presence of a thrombus in the aorta caused abnormalities in renal hemodynamics.

Abnormalities of the corrected QT interval in familial dysautonomia: an indicator of autonomic dysfunction.

We report abnormalities in corrected QT intervals with changes in position and after exercise in patients with familial dysautonomia and confirm the previously reported finding of abnormal heart rate and blood pressure responses. Prolonged corrected QT intervals (> 440 msec) with lack of appropriate shortening with exercise is a noninvasive means of demonstrating an aberration in autonomic regulation of cardiac conduction.

The effects of postural change and exercise on renal haemodynamics in familial dysautonomia.

Cardiovascular instability is a prominent manifestation of familial dysautonomia [FD] while renal insufficiency occurs in a large number of adult FD patients. To determine if there was a causative relationship, renal artery blood flow velocity using Doppler technology, was recorded and the ratio of the peak systolic velocity (point A) to the end diastolic velocity (point B) was calculated. The A/B ratio was assessed in response to change of position and exercise, and was correlated with renal function, heart rate and systemic blood pressure. Studies were performed in 54 FD patients with a mean age of 24 years +/- 9.8 years, and 20 controls, with a mean age of 24.7 +/- 7.6 years. In the supine position, the mean A/B ratios were not significantly different, but FD subjects had a significantly higher mean blood pressure and heart rate than controls. When erect and post exercise, the mean A/B ratios in FD subjects were significantly higher than controls, p = 0.0004 and p = 0.0001, respectively. In contrast to controls, when FD subjects were standing erect and post exercise, mean blood pressure decreased significantly without a significant change in heart rate. When FD subjects were divided into two groups based on their creatinine clearance value, the group with the lower creatinine clearances had a significantly greater fall in diastolic pressure when they moved from the supine to the erect position. Our results indicate that noninvasive Doppler techniques are helpful in detecting changes in renal blood flow in subjects with familial dysautonomia.(ABSTRACT TRUNCATED AT 250 WORDS)