Zeev Rotstein

Transvaginal echocardiographic examination of the fetal heart between 13 and 15 weeks' gestation in a low-risk population.

The object of our investigation was to evaluate the potential of transvaginal echocardiography for a complete anatomic study of the fetal heart, and for detection of congenital heart diseases in low‐risk pregnant patients between 13 and 15 weeks gestation. High‐frequency (6.5 MHz and 7.5 MHz) transvaginal probes were employed for fetal echocardiographic assessment. Six hundred and sixty patients considered at low risk for congenital heart disease underwent in utero ultrasonographic studies, neonatal records, postnatal imaging studies, and pathologic examination. The four‐chamber view was obtained in 100% of the fetuses, while the extended fetal heart examination was completed in 98%. Six fetuses with cardiac defects were diagnosed during the study: three had major heart defects (aortic atresia, tetralogy of Fallot, and persistent truncus arteriosus), all detected at the early transvaginal scan; three cardiac anomalies escaped our early diagnosis; two fetuses had a minor ventricular septal defect diagnosed only postnatally; and one had multiple cardiac rhabdomyoma diagnosed in the third trimester. Our results demonstrate that between 13 and 15 weeks gestation transvaginal echocardiographic assessment of the fetal heart in the low‐risk population is feasible. Moreover, some severe anomalies may be detected at such an early gestational age.

Percutaneous Multielectrode Endocardial Mapping During Ventricular Tachycardia in the Swine Model

BACKGROUNDnIdentification of critical areas within the ventricular tachycardia circuit is a prerequisite for catheter ablation. Currently, mapping during ventricular tachycardia, usually performed with standard catheters, is difficult and time-consuming and can be used only in patients with hemodynamically stable tachycardia.nnnMETHODS AND RESULTSnA total of 43 pigs underwent closed-chest induction of myocardial infarction. A basket-shaped catheter carrying 64 electrodes was deployed in the left ventricle during normal sinus rhythm. Unipolar pacing at 3 mA was successful in 78% of the basket catheter electrodes, demonstrating good electrode-tissue contact. Hemodynamic and echocardiographic measurements did not reveal any significant interference with myocardial or valvular function during or after catheter deployment. One hundred eighteen episodes of monomorphic ventricular tachycardia were induced in 28 pigs through right ventricular stimulation, 81 of which were mapped and analyzed. Ventricular tachycardia mapping was rapid, requiring only several beats and < 10 seconds to complete. Presystolic potentials, a possible target for ablation, were identified in 58% of the tachycardia episodes mapped. Pathological examination revealed only minor valvular and endocardial catheter-induced lesions immediately after mapping and none a month later.nnnCONCLUSIONSnThe multielectrode catheter enables rapid and safe percutaneous endocardial mapping of ventricular tachycardia in the swine model. Exploration of the clinical potential of the multielectrode catheter seems warranted.

Absence of tachycardia during tilt test predicts failure of β-blocker therapy in patients with neurocardiogenic syncope

Not all patients with neurocardiogenic syncope respond to beta-blockers. To determine whether differences in heart rate response to head-up tilt test with and without isoproterenol may predict drug efficacy, we evaluated 32 consecutive patients with a history of syncope, who were treated with beta-blockers after a positive tilt test. During the tilt test 21 patients (group A) with a baseline heart rate of 72 +/- 15 beats/min had tachycardia (mean 131 +/- 15) during tilt, before syncope, whereas 11 patients (group B) with a baseline heart rate of 68 +/- 13 beats/min did not (mean 86 +/- 13; p < 0.001). There were no significant differences between groups with regard to demographic and clinical characteristics or mean heart rate and mean arterial pressure in the supine position and during syncope. However, the proportion of patients requiring isoproterenol for provocation of syncope was significantly higher in group A compared with group B (15 of 21 vs 1 of 11; p < 0.001). All patients were treated with beta-blockers (propranolol or metoprolol). During a follow-up period of 18 +/- 6 months only one patient in group A had syncope and a positive tilt test compared with six patients in group B (9% vs 54%; p < 0.01). Development of tachycardia was a better predictor of drug efficacy than an isoproterenol-induced positive tilt test. The six nonresponders from group B were subsequently treated with disopyramide. During a mean follow-up period of 9 +/- 3 months, only one patient had syncope and another had a positive response to tilt test.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcutaneous multielectrode basket catheter for endocardial mapping and ablation of ventricular tachycardia in the pig

BACKGROUNDnEndocardial mapping using standard electrode catheters is often technically limited in ventricular tachycardia and constitutes a major obstacle to successful ablation. We wished to examine the utility of a basket-shaped multielectrode mapping catheter (MMC) in the mapping and ablation of ventricular tachycardia.nnnMETHODS AND RESULTSnThis study of sustained monomorphic ventricular tachycardia (SMVT) was conducted in two phases in the postinfarction pig model. In the first phase, the utility of the MMC in providing adequate localization of potential ablation site(s) of SMVT by different techniques (presystolic potentials, pace mapping, and concealed entrainment) was assessed in 21 pigs. In the second phase, ablation of induced SMVT was attempted in 10 pigs. Mapping of SMVT was performed after percutaneous introduction of the MMC to the LV. Comprehensive mapping was performed in 90 episodes of SMVT and required 2.0 to 25 seconds. Diastolic potentials were recorded during 86 episodes; good or identical pace maps (> or = 9 of 12 paced surface ECG leads identical to ventricular tachycardia surface ECG leads) were obtained in 25 of 31 maps, and entrainment was achieved during 28 of 42 SMVTs. In 10 pigs, 10 SMVTs were recorded at least twice and were considered for radiofrequency ablation. An 8-mm tip ablation catheter was advanced to potential ablation sites with a specially designed homing device, requiring a median time of 120 seconds. In these 10 pigs, either identical pace map (> or = 11 of 12, 6 SMVTs) or concealed entrainment (4 SMVTs) guided the ablation procedure. After ablation, 8 of 10 SMVTs were rendered noninducible, while 2 pigs died during energy application of degeneration of SMVT to ventricular fibrillation.nnnCONCLUSIONSnThe MMC allows rapid, comprehensive, and reliable endocardial mapping during SMVTs, which facilitates successful ablation in the porcine post-myocardial infarction model.

The development of the foetal thyroid: in utero ultrasonographic measurements

The early recognition of potentially treatable thyroid disease in the foetus frequently depends on the detection of abnormal growth of the foetal thyroid gland. We have therefore established nomograms for foetal thyroid transverse width and circumference from 14 weeks of gestation until term, using transvaginal and transabdominal high‐resolution ultrasound techniques.

Peripheral right pulmonary artery blood flow velocimetry: Doppler sonographic study of normal and abnormal fetuses.

The knowledge of fetal lung circulation in normal and abnormal human fetuses is limited. Our objectives were to assess normal values for flow velocity waveforms in the fetal pulmonic circulation and to test the hypothesis that Doppler velocimetry can predict lung hypoplasia. In a cross‐sectional study, peripheral right pulmonary artery flow velocimetry was investigated prospectively in 96 healthy fetuses between 14 and 37 weeks gestation and four fetuses with abnormalities known to induce lung hypoplasia. The pulsatility index was used to quantify the velocity waveforms. In normal fetuses the mean pulsatility index in the peripheral right pulmonary artery was low, being equivalent to that corresponding to 14 to 17 weeks gestation (2.89; confidence interval = 2.35 to 3.42), increasing at midgestation to 3.44, with a confidence interval of 3.04 to 3.83; P < 0.01. Thereafter, during the late second and third trimesters the mean pulsatility index did not change significantly with GA, being 3.66 (confidence interval = 3.04 to 4.04) at term. In fetuses with proven lung hypoplasia, the pulsatility index measurements were within the 95% confidence limits of those for normal fetuses. In a normal pregnancy, except for the early stages, a relatively stable high vascular resistance of the fetal pulmonary circulation was found. Our preliminary data suggest that the pulsatility index of the lung circulation cannot be used as an indicator of lung hypoplasia.

Effects of thrombolysis on the 12-lead signal-averaged ECG in the early postinfarction period.

Signal-averaged ECG has been used to identify patients at risk for ventricular tachycardia and sudden death after myocardial infarction. The goals of this prospective study were to examine the effects of reperfusion achieved with thrombolytic therapy on the 12-lead signal-averaged ECG and on ventricular arrhythmias in the early period after acute myocardial infarction (AMI). A total of 190 consecutive patients with AMI who fulfilled the inclusion criteria were enrolled. Thrombolysis was attempted in 80 patients and was considered successful in 57 (group I) and unsuccessful in 23 (group II); 110 patients were not treated with thrombolytic agents (group III). Signal averaging of 12 ECG leads was performed within 2 days in all patients and between 7 and 10 days after admission in 163 patients. The filtered QRS complex duration (QRSD) was significantly shorter in group I compared to group III in 7 of 12 ECG leads at 2 days and in 10 of 12 leads at 7 to 10 days. The root mean square voltage of the terminal 40 msec of the QRS complex (RMS40) did not change between the two signal-averaged ECG recordings in group I, whereas it became lower in three ECG leads in group II and in seven ECG leads in group III. There was no correlation between infarct site and significant changes in infarct-related signal-averaged ECG leads. The occurrence of complex ventricular arrhythmias was not significantly different among the three groups. We conclude that successful reperfusion, compared with failed and nonattempted reperfusion, is associated with fewer abnormalities in the 12-lead signal-averaged ECG in the early period after AMI.(ABSTRACT TRUNCATED AT 250 WORDS)

Superior mesenteric artery blood flow velocimetry: cross-sectional Doppler sonographic study in normal fetuses.

Our objectives were to describe the flow velocity waveform of the fetal superior mesenteric artery and to establish a nomogram for its pulsatility index. In a cross‐sectional study using color Doppler ultrasonography, superior mesenteric artery flow velocimetry was investigated prospectively in 96 healthy fetuses of between 14 and 37 weeks of gestation. In normal fetuses the pulsatility index measurements showed a slight but insignificant increase over the course of gestation (r = 0.26; P > 0.5). The lowest mean +/‐ standard deviation for pulsatility index in the superior mesenteric artery was 1.86 +/‐ 0.45 (95% confidence interval 1.67‐2.06), recorded between 18 and 21 weeks gestation. Thereafter the pulsatility index increased to 1.94 +/‐ 6.4 (95% confidence interval 1.74‐2.8) at 22 to 25 weeks, and from weeks 26 to 29 it increased to 2.18 +/‐ 0.52 (95% confidence interval 1.91‐2.46). During the third trimester and at term, the mean pulsatility index of 2.23 +/‐ 0.32 (95% confidence interval 1.43‐3.03) did not change significantly with gestational age. In normal fetuses, except for the early stages, a relatively stable vascular resistance of the intestinal circulation was found. The application of this nomogram in clinical practice may facilitate evaluation of intestinal perfusion in compromised fetuses with blood flow centralization.

Fetomaternal haemorrhage discovered after trauma and treated by fetal intravascular transfusion

Fetomaternal haemorrhage can occur spontaneously, or after abdominal trauma. We describe a case of fetomaternal haemorrhage diagnosed at 27 weeks gestation after blunt trauma. The Kleihauer-Betke smear on admission and during the first week was positive, ranging between 3% and 5%. Cordocentesis revealed a fetal haemoglobin of 8.8 gm/dl. An intravascular fetal transfusion was performed. The weeks until delivery and the neonatal period were unremarkable. Fetal anaemia can be a serious complication of fetomaternal haemorrhage, however, intravascular fetal transfusion is an effective treatment when this occurs. The Kleihauer-Betke test should be performed in every patient with a history of abdominal trauma during pregnancy.

Intermittent, dose-related fluctuations of pain and ST elevation during infusion of recombinant tissue plasminogen activator during acute myocardial infarction

Abstract Reocclusion of reperfused coronary arteries is a major setback that erodes the initial gain obtained by thrombolytic therapy in patients with acute myocardial infarction (AMI). 1 After thrombolysis with recombinant tissue-type plasminogen activator (rt-PA), early in-hospital reocclusion is observed in 20 to 45% of successfully treated patients. 2 Although maintenance infusion of rt-PA reduces the incidence of reocclusion during the in-hospital period, 3 very early reocclusions immediately after 4 or even during continuous rt-PA infusion can occur. 5,6 We describe 15 patients among 190 patients with AM1 treated with rt-PA in whom initial clinical signs of reperfusion were followed by clinical and electrocardiographic evidence of rt-PA dose-related reocclusion-reperfusion cycles.