Reliability of the first-trimester cardiac scan by ultrasound-trained obstetricians with high-frequency transabdominal probes in fetuses with increased nuchal translucency.

OBJECTIVE: To examine prospectively the reliability of ultrasound-trained obstetricians performing a first-trimester fetal cardiac scan with high-frequency transabdominal probes, by confirming normal or abnormal heart anatomy, in pregnancies referred for increased nuchal translucency thickness (NT). METHODS: Trained obstetric operators assessed the fetal heart in 133 fetuses with increased NT (> 95th centile) at 11-14 weeks of gestation. A high-frequency transabdominal probe was used to confirm or refute normal cardiac anatomy rather than to establish a specific diagnosis. Following this preliminary screening by the ultrasound-trained obstetrician, specialized fetal echocardiographers rescanned the fetal heart in order to confirm the accuracy of the obstetric operators' findings and to establish a diagnosis in abnormal cases. Fetal cardiologists repeated the examinations at 20 and 32 weeks of pregnancy. Postnatal follow-up lasted 2 years. Twelve fetuses with normal karyotype and normal anatomy were lost to follow-up. RESULTS: A total of 121 fetuses with increased NT between 11 and 14 weeks' gestation were studied. Congenital heart disease (CHD) was detected in 20/121 (16.5%) fetuses. In addition, there were three with mild ventricular disproportion, the right ventricle being larger than the left, considered as a minor non-specific cardiac abnormality. CHD was associated with chromosomal anomalies in 12/20 (60%) cases. Among the 121 fetuses, there was agreement between ultrasound-trained obstetricians and fetal cardiologists in 116 (95.9%) of the cases, and the ultrasound-trained obstetricians correctly identified 18 cases with major cardiac defects. However, there was disagreement in five cases: two with small ventricular septal defects and three with ventricular disproportion. CONCLUSIONS: Our results provide evidence that obstetricians, trained to study the heart in the second trimester, can also differentiate reliably between normal and abnormal heart findings in the first trimester, when using a high-frequency transabdominal ultrasound probe.

Respiration-dependent ventricular pacing compared with fixed ventricular and atrial-ventricular synchronous pacing: aerobic and hemodynamic variables.

A pacemaker that adapts heart rate in response to the patient's metabolic requirements has been developed. The pacemaker uses breathing frequency and tidal volume as the indicators of physiologic demand. Maximal physical work capacity, anaerobic threshold, oxygen uptake (16 patients) and hemodynamic variables (9 patients) were assessed with fixed rate (VVI), atrial synchronous (VDT/I) and respiration-dependent ventricular (VVI-RD) pacing. All subjects attained their anaerobic threshold in stress tests with VVI pacing. The maximal physical capacity (p less than 0.001), work time to attain the anaerobic threshold (p less than 0.01) and oxygen uptake (p less than 0.001) were significantly greater with VVI-RD than with VVI pacing. The transition from the supine to the standing position was characterized by a significant increase of cardiac index at rest with both VDT/I and VVI-RD pacing as compared with VVI pacing. Progressive increments in the cardiac index and average left ventricular stroke work index were significantly different at submaximal and maximal exercise when VVI and VVI-RD were compared. At maximal exercise, mean cardiac output was also significantly different: 10.21 +/- 2.5 (SD) liters/min with VVI, 11.2 +/- 0.8 liters/min with VDT/I (p less than 0.05) and 12.65 +/- 3.1 liters/min with VVI-RD (p less than 0.05) pacing. Maximal oxygen extraction values were greater with VVI and VVI-RD pacing than with VDT/I pacing. Pulmonary artery end-diastolic pressures at maximal exercise were within the normal range with the three different modes of pacing. In conclusion, there is a significant (25%) improvement in exercise performance with VVI-RD pacing as compared with VVI pacing.(ABSTRACT TRUNCATED AT 250 WORDS)

Sustained beneficial hemodynamic effects of low transdermal nitroglycerin doses compared with placebo in patients with congestive heart failure.

In an attempt to resolve some of the controversies concerning the dose requirements and duration of effects of transdermal nitroglycerin (NTG) in patients with heart failure (CHF), the short-term hemodynamic responses to transdermal NTG, in a 20 cm2 self-adhesive patch (10 mg/24 h), were evaluated in 10 patients with severe chronic CHF using a randomized, within-patient, double-blind, placebo-controlled cross-over trial. Serial hemodynamic measurements over 24 h revealed sustained effects that began 1 h after the application of nitroglycerin patch and fully persisted throughout the study. The peak effect occurred at 4 h with the pulmonary capillary wedge pressure decreasing from 33.7 +/- 8.4 to 21.4 +/- 9 mmHg (mean +/- SD) (p less than 0.05) and the cardiac index increasing from 2.5 +/- 0.6 to 3 +/- 0.6 l/min/m2 (p less than 0.01). Transdermal nitroglycerin also significantly reduced pulmonary arterial and right atrial pressures (from 43.5 +/- 9.5 to 31 +/- 11.4 and from 7.4 +/- 6.6 to 3.8 +/- 4.7 at peak effect, respectively) as well as pulmonary and systemic vascular resistances (from 10.7 +/- 6.6 to 6.5 +/- 3.2 and from 26.2 +/- 5.1 to 22.5 +/- 5.7, respectively). There was no change in heart rate or systemic arterial pressure. These beneficial hemodynamic responses persisted for 24 h. No rebound deterioration occurred upon withdrawal of the nitroglycerin. No significant hemodynamic changes occurred during placebo treatment period. Thus, low doses (10 mg/24 h) of transdermal nitroglycerin induce significant hemodynamic benefit that is sustained for 24 h in patients with heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

[Automatic method for the evaluation of the extent of myocardial infarct from the serum of CPK curve]. / Sistema automatico per valutare l'estensione dell'infarto miocardico dalla curva del CPK serico.

An off-line system for calculating the extent of infarct from serial serum CPK determinations based on Sobel et al.'s compartmental model is presented. Results in 40 patients with acute infarct in a coronary unit showed that the index of infarct extent had an appreciable prognostic significance. Employment of the MB isoenzyme in the calculation could, it is felt improve the sensitivity of the method.

[Termination of ventricular tachycardia by noninvasive methods]. / Interruzione di una tachicardia ventricolare con metodiche non invasive.

Present paper reports on a patient referred for sustained, hemodynamically well tolerated, ventricular tachycardia, terminated by noninvasive temporary pacing. The tachycardia was refractory to chest tump and intravenous standard drugs (lidocaine and propafenone). Demonstration of spontaneous atrioventricular dissociation and ventricular capture during transesophageal atrial pacing allowed rapid and correct diagnosis. Overdrive with external noninvasive ventricular pacing proved effective in terminating ventricular tachycardia and converting it to sinus rhythm. These observations suggest that noninvasive approach to hemodynamically stable ventricular tachycardia can provide a safe and effective alternative to more aggressive medical management.

[Ventricular pre-excitation in old age associated with severe troubles of a-v conduction (author's transl)]. / Preeccitazione ventricolare emergente in eta' avanzata associata a gravi turbe della conduzione a-v.

The Authors describe two cases of old people with syncopal crises in which the appearance of ventricular pre-excitement (WPW) is a new phenomenon associated with the progressing of severe troubles in A-V conduction, sometimes only shown by endocavitary electrophysiologic test. The appearance of accessory pathways latent or functionally dumb up to that time might be a substitutive mechanism in the attempt of counterbalacing serious deficiences of A-V conduction. In these patients special care is necessary in the use of antiarrhythmic drugs and in the interpretation of syncopal troubles in order to prescribe a correct therapy.

[The control of the atrio-ventricular reciprocating tachyarrhythmias. A preliminary electrophysiological study and comparison between amiodarone and verapamil (author's transl)]. / Il problema del controllo delle tachiaritmie reciprocanti atrio-ventricolari. Studio elettrofisiologico preliminare e comparativo tra amiodarone e verapamil.

The effects of amiodarone (2.5 mg/Kg i.v.) and of verapamil (0.1 mg/Kg i.v.) on refractory periods and on conduction of structures interested in the reciprocating circuit, as well as on the possible echo zones, were comparatively evaluated through electrophysiological test in 8 patients, four of which with W.P.W. from Kent bundle, and four with double A-V pass with reciprocating supraventricular tachicardia (RST) documented crises. None of the two drugs seems to have the theorical requirements of balanced effect to be chosen for the antiarrhythmic prophylaxis in patients with ventricular pre-excitement. In patients with double A-V pass, while both drugs have a sufficiently balanced and regular action on refractory periods and on conduction the irregularity of their effects on echo zones appears to restrict their validity in chronical therapy. According to the Authors, the only useful criteria for the choice of an antiarrhythmic drug for the prophilaxis of R.S.T. to be derived through extrapolation from these electrophysiological tests are: 1) the functional suppression of a circuit structure; 2) the evaluation of effects on echo zones; 3) the possibility or not the evoking R.S.T.

Restriction fragment length polymorphism analysis of the kappa-casein locus in cattle.

The two common genetic variants (A and B) of bovine kappa-casein originate from two point mutations in the codons for the aminoacids in position 136 and 148. These mutations give rise to polymorphic sites for the restriction endonucleases Hin dIII, AluI, HinfI, Mbo II and TaqI. We have examined DNAs of several Italian Friesian cows and bulls of known and unknown genotype by Southern analyses using kappa-casein cDNA probes. Restriction fragment length polymorphisms (RFLPs) specific for the A and B alleles were identified for each of the above enzymes, except for AluI, which has a non-polymorphic site 12bp away from the polymorphic one. We have also found two new polymorphic sites for MboII and TaqI in the non-coding regions. These sites differentiate the A allele into two new variants, named A1 and A2. The RFLP analysis permits the characterization of kappa-casein alleles even in the absence of their expression. This should facilitate selective breeding programmes aimed at increasing the frequency of the kappa-casein B allele whose product improves the cheesemaking properties of milk.

Permanent physiological pacing.

Ideal physiological form of pacing responds to body's needs for varying cardiac output indipendent of the requirement to synchronize with atrial activity. The atrial synchronous pacemakers are superior to the ventricular inhibited fixed rate pacing mode. Alternative methods of sensing physiological demands with single chamber ventricular pacing that produce a physiological rate response to exercise are described. System based on QT sensing and pacing system responsive to changes in respiratory rate have undergone successful clinical trials. Hemodynamics of rate responsive pacing are described. The highest cardiac performance during stress test in rate responsive pacing was achieved with the respiratory dependent pacemaker.

[Blood bunaphthine during dynamic physical exercise and anti-arrhythmic action]. / La bunaftinemia durante esercizio fisico dinamico e azione antiaritmica

The course of bunaphtinemia during submaximal exercise was studied. To 5 patients showing the appearance or the increase of extrasystole, both ventricular and supraventricular, during ergometric test on the bicycle ergometer, bunaphtine was administered by the following method: a first dose of 0.5 mg/kg was injected endovenously in 2 minutes followed by a constant endovenous infusion at the speed of 2.5 mg/min, throughout the exercise. Doses were calculated referring to a pharmacocynetic pattern with two compartments and supposing an apparent distribution volume of 3 l/k. Resulting bunaphtinemia curves showed a steady state and were completely above the minimum effective standard throughout the test. In all patients the drug prevented ventricular arrhythmias and compared to the standard reduced the supraventricular arrhythmias by 80%.

[Experience in primary prevention of cardiovascular risk factors in children]. / Esperienze di prevenzione primaria sui fattori di rischio cardio-vascolare nei bambini.

Pathologic studies have shown that atherosclerosis may already be present in childhood as reversible fatty streaks in the aortic intima. These findings are directly related to total serum cholesterol and inversely related to serum HDL cholesterol. This study was aimed at screening children and young adolescents of Novara for cardiovascular risk factors and achieving a specific health educational program. We screened a sample of 2560 children and young adolescents aged 10 to 16 years (mean 12) for known family history of cardiovascular diseases and hyperlipidemia, blood pressure values, serum cholesterol fractions and triglycerides. Of the 2560 children, 786 were considered at risk according to pre-defined cutoff points for systolic BP (> 120 mmHg) 10.6%, diastolic BP (> 80 mmHg) 3.4%, total serum cholesterol (= > 160 mg/dl) 18.7%, serum HDL cholesterol (< 40 mg/dl) 49.5%, total serum cholesterol/HDL ratio (> 4) 28.0%, and triglycerides (> 150 mg/dl) 3.7%. Parents were invited to change family lifestyle according to a specific health educational program, which included advice about diet and physical activity. All children at risk were re-examined 1 year later. Mean values of total serum cholesterol (129 +/- 26 vs 143 +/- 30, p < 0.001), triglycerides (86 +/- 28 vs 91 +/- 32, p < 0.01) and total serum cholesterol/HDL ratio (3.7 vs 3.8, p NS) were found to be lower than at index evaluation. The distribution of total cholesterol curve shifted to the left, and the high risk cases (total serum cholesterol > 200 mg/dl) lowered from 56 to 24 at the follow-up evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Spatial velocity profile changes along the cord in normal human fetuses: can these affect Doppler measurements of venous umbilical blood flow?

OBJECTIVE: Several studies have assumed a parabolic velocity profile through the umbilical vein (UV) to derive the mean spatial velocity that is indispensable for flow rate calculations. However, the structure and arrangement of the umbilical cord suggest that velocity profiles may vary. The aim of this study was to evaluate UV spatial flow velocity profiles at different sites along the umbilical cord. METHODS: Ten singleton pregnancies with a gestational age between 26 and 34 weeks were included in the study. Ultrasound equipment with an inbuilt function for analysis of the spatial velocity profile along a line located in a fixed plane was used to obtain UV velocity profiles. Velocity profiles were obtained at the placental insertion and in a free intra-amniotic loop of the cord. Two-dimensional (2D) velocity distribution coefficients were evaluated as ratios between mean and maximum velocities along the investigated lines. RESULTS: 2D velocity distribution coefficients at the placental insertion (0.85 +/- 0.03) were significantly higher (P < 0.00001) than those obtained from a free loop of cord (0.76 +/- 0.03). Values indicated that velocity profiles are approximately flat at the placental insertion and become more parabolic moving downstream. Moreover, profiles become skewed in association with cord curvature and show peculiar biphasic shapes immediately downstream from the placenta. CONCLUSIONS: Flow velocity profiles in the UV are not perfectly parabolic and modify along the cord. These characteristics may affect the evaluation of UV blood flow rate.

Respiration as a reliable physiological sensor for controlling cardiac pacing rate.

A study was carried out to determine whether variations in the respiration rate during physical exercise could be used as a physiological variable in controlling the rate of an implanted pacemaker. The relation between respiration rate and heart rate was significantly correlated in 73 patients (19 with normal lung function, four with restrictive pulmonary disease, and 50 with obstructive airways disease) during repeated calibrated ergometric tests; no significant differences were found between the subgroups. An external computerised programmable system with algorithm control activated by a radio frequency system was used to vary the cardiac stimulation rate in relation to respiration rate in 11 patients implanted with ventricular inhibited pacemakers. In addition, a prototype programmable pacemaker dependent on respiration rate was implanted in two patients. Maximum values of oxygen uptake, minute ventilation, and work time were increased during the exercise stress tests when the variable cardiac pacing rate was used. Thus respiration rate appears to be a valid and stable physiological variable for controlling the cardiac stimulation rate in order to improve cardiac output in patients dependent on pacemakers.

Respiratory-dependent atrial pacing, management of sinus node disease.

The effectiveness of respiratory-dependent atrial pacing (AAI-RD) was assessed in 23 patients (11 male, 12 female; 68 +/- 10 years) with symptomatic isolated sinus node disease (SND). Follow-up was performed at 3 month intervals and included history taking, physical examination, ECG recording and 24-hour Holter monitoring. An incremental treadmill exercise test was performed in 21/23 patients before pacemaker implantation, in 23/23 patients after implantation (at least two tests with different programmed settings of respiratory rate/paced rate ratio); 21/23 patients underwent treadmill tests during both fixed rate 70 bpm and AAI-RD pacing. Physiological sensitivity of AAI-RD pacing was found excellent in 34 tests (85%) and fair in six (15%). Spontaneous heart rate was significantly higher after pacemaker implantation (bpm 115 +/- 20 vs 98 +/- 24, P less than 0.001). In 10/21 patients paced rate was significantly higher during AAI-RD vs AAI pacing (131 +/- 9 vs 106 +/- 16, P less than 0.001) with better total work time (min 9.9 +/- 4 AAI-RD vs 6.8 +/- 2.6 AAI, P less than or equal to 0.002), higher oxygen consumption at anaerobic threshold (ml/min 1137 +/- 406 AAI-RD vs 882 +/- 268 AAI-RD vs 5.5 +/- 2.6 AAI, P = 0.001). No significant difference was found in 7/21 patients (overlap between spontaneous and paced rate during both AAI-RD and AAI programming); 4/21 patients did not reach anaerobic threshold owing to osteomuscular limitations. AV block was detected in 1/23 patients, Biorate circuital failure in 1/23, sporadic undersensing in 5/23, short and symptom-free myopotential inhibitions in 10/23.(ABSTRACT TRUNCATED AT 250 WORDS)

Physiological sensitivity of respiratory-dependent cardiac pacing: four-year follow-up.

Clinical and physiological data on long-term follow-up of 143 patients with respiratory-dependent pacemakers (RDP3) are reported; 121 patients received ventricular (VVI-RD) and 22 patients atrial (AAI-RD) respiratory-dependent stimulation. Functional evaluation was based on the exercise testing (130 pts) with oxygen uptake VO2, ventilation, ECG and arterial pressure monitoring and the dynamic Holter electrocardiogram (95 pts). In each patient, the stimulation rate curve selected was that which produced the best work tolerance and moved the anaerobic threshold to the right. Respiratory levels were assessed by telemetry verifying proper sensing of tidal volume variations and absence of interference and artefacts. In patients with VVIR or AAIR stimulation, exercise tolerance, oxygen uptake and anaerobic threshold increased significantly in comparison with VVI or AAI pacing respectively. The physiological sensitivity of the stimulation system (i.e., a linear relationship of the pacing rate with metabolic requirements) was excellent (up to exhaustion) in 70%, very good (up to anaerobic threshold) in 20% and erratic (no relationship between pacing rate and VE/VO2) in 10% of patients. In dynamic electrocardiographic monitoring, the automatic pacing rate was always predominant during the night and during rest periods; the pacing rate increased properly with daily activity; myopotential inhibition (none longer than 3,500 ms) was observed in 38 patients, but without subjective complaints. The incidence of the RDP3 malfunction was less than 8%; it may have stemmed from the pacing system itself, or from other clinical conditions. Oversensing of impedance system pulses has not been recorded in the last 3 years. Partial respiration undersensing results from incorrect accessory lead position, pulmonary emphysema, marked obesity or other causes. Respiratory sensing becomes erratic at the anaerobic threshold point in such patients, but functions well at submaximum exercise levels. In patients with left ventricular failure, exercise tolerance was improved by setting a lower ratio between the pacing rate and respiration, which prevented the occurrence of excessive pacing rates.

Increasing cardiac rate by tracking the respiratory rate.

The rate responsive pacemaker using respiratory rate as a sensor was implanted in 22 patients, 19 patients for ventricular pacing and three for atrial pacing. The level of exercise achieved with this system was consistently higher than with a fixed ventricular pacing rate. In addition, no special chemical or mechanical sensors are required; the sensor itself is simple, long-lasting, and energy efficient. Thus, this system adapts easily to the individual patient.