Nathan Roguin

High prevalence of muscular ventricular septal defect in neonates

OBJECTIVES This study sought to use echocardiography to evaluate the prevalence of muscular ventricular septal defect in neonates. BACKGROUND Ventricular septal defect is usually asymptomatic and closes spontaneously. An increase in its prevalence has been noted recently. One reason is the improved detection of small defects, especially with the increased used of echocardiography. Therefore, one would expect a higher prevalence in neonates on the basis of echocardiographic screening. METHODS Color Doppler echocardiography was performed in 1,053 consecutive neonates 6 to 170 h old at Western Galilee Hospital, Israel. Data on the neonates, parents and family were obtained to analyze the influencing factors. The identified patients were followed up for 1 to 10 months or until ventricular septal defect closure. RESULTS Muscular ventricular septal defect was found in 56 (25 male, 31 female) of the 1,053 neonates, a prevalence of 53.2/1,000 live births. All neonates were asymptomatic. Six had a systolic murmur. Electrocardiographic findings were normal in 44 (97.8%) of 45 neonates followed up, and left ventricular hypertrophy occurred in 1 (2.2%). By echocardiography, 50 ventricular septal defects (89.3%) were single and 6 (10.7%) were multiple. The defects (range 1 to 5 mm in diameter, mean [+/- SD] 2.3 +/- 0.8) occurred anywhere along the muscular septum; 43 (76.8%) were detectable only on color Doppler imaging. The left atrium and left ventricle were mildly dilated. Of 45 neonates who were followed up for 6 to 10 months or until closure of the defects, 40 (88.9%) had defects that closed spontaneously. The risk of ventricular septal defect was not significantly associated with gestational age, birth weight, birth order, maternal age, diabetes, smoking, exposure to drugs or infection, paternal age, familial congenital heart disease, religion or consanguinity. CONCLUSIONS There is a prevalence of muscular ventricular septal defect in neonates of 53.2/1,000 live births. The patients were asymptomatic, and 88.9% had defects that closed spontaneously within 1 to 10 months. These defects may be caused by environmental factors. In many cases, muscular ventricular septal defect may also result from delayed physiologic development.

Pulmonary hypertension in patients with thalassemia major

To evaluate the pulmonary artery pressure in patients with thalassemia major, Doppler echocardiography was performed in 33 patients with thalassemia major (aged 2 to 24 years) and 33 normal controls. Pulmonary artery pressure was estimated by (1) measuring the systolic transtricuspid gradient from tricuspid regurgitation and adding it to the right atrial pressure, estimated by the response of the inferior vena cava to deep inspiration, and (2) measuring the time to peak velocity of pulmonary flow. The results showed that of 33 patients, 28 had tricuspid regurgitation with a pulmonary systolic pressure ranging from 18 to 94 mm Hg (47 +/- 15 mm Hg). Pulmonary systolic pressure was > 30 mm Hg in all 22 patients > 10 years old and in four of six patients < 10 years old. Pressure correlated with left ventricular ejection fraction (r = -0.74), the ratio of mitral peak early diastolic flow velocity and peak velocity during the atrial contraction (r = 0.52), age (r = 0.56), and total blood transfusion units (r = 0.59). The pulmonary time to peak velocity was shortened compared with controls (p < 0.05). We concluded that pulmonary hypertension, as another cardiovascular complication of multiple factors of cause, seems to occur more frequently and at an early stage of the cardiac involvement in patients with thalassemia major.

Clinical and echocardiographic evaluation of neonates with heart murmurs

Abstract In this study, 116 neonates (58M, 58F), aged 12h to 14d, with heart murmurs were examined by echocardiography: 26 were preterm and 90 full‐term neonates. The clinical diagnosis was classified into definite heart disease, possible heart disease and innocent murmur. The final diagnosis was based on echocardiography and, in some cases, cardiac catheterization or surgery. The results showed that 97 (84%) neonates had heart diseases; 19(16%) had a normal heart, including 7 with tricuspid regurgitation and 9 with physiological peripheral pulmonic stenosis. Out of 88 neonates with clinically definite heart disease, the final diagnosis was changed to normal heart in 9 (10%) cases and the lesion‐specific diagnosis was changed in 9 (10%) neonates. In four cases, the clinical diagnosis of ventricular septal defect or pulmonary stenosis was changed to double‐outlet right ventricle, single ventricle, hypoplastic left heart syndrome or tetralogy of Fallot. The clinical diagnosis was correct in 77–85% for varying simple lesions. In 5 of 21 neonates with clinically possible heart disease, the diagnosis was changed to normal heart. In one of six neonates with clinically innocent murmurs, the diagnosis was changed to small muscular ventricular septal defect. We concluded that 84% of heart murmurs in neonates were due to heart diseases and only 16% were innocent murmurs. Although clinical evaluation could determine the presence or absence of heart disease in most neonates, the lesion‐specific diagnosis was not quite satisfactory. Echocardiography is necessary for neonates with a clinically diagnosed heart disease or possible heart diseases, and may be unnecessary for those with innocent murmurs diagnosed by paediatricians.

Spontaneous closure of muscular ventricular septal defect identified by echocardiography in neonates

Muscular ventricular septal defects were diagnosed by echocardiography in 97 neonates within 7 days of birth. In 82 of the neonates (84.5%), the defect was solitary, while 15 had multiple defects. The solitary defects was located at mid-septal, apical, anterior and inlet locations in 42 (51.2%), 21 (25.6%), 14 (17.1%) and 5 (6.1%) neonates, respectively. Multiple defects occurred in the apical, anterior and mid-septal areas. The diameter of the solitary defects ranged from 1 to 6 mm (2.3 +/- 0.8 mm), while the multiple lesions were 1 to 4 mm in diameter (2.1 +/- 0.8 mm) in 28 instances in which they could measured. It proved possible to follow 79 of the patients for period of 10 to 13 months. The defects closed spontaneously in 56 (84.8%) of 66 patients with a single defect, and in 7 (53.8%) of 13 of those with multiple defects (P<0.05). For the solitary defects, the position and size were factors determining the likelihood and speed of closure. Defects located at the apical septum, or defects larger than 4 mm in diameter, closed slowly and at a later stage. Echocardiography is an useful technique in establishing of natural history of muscular ventricular septal defects encountered in neonates.

Power spectral analysis of heart rate variability during positive pressure pneumoperitoneum: the significance of increased cardiac sympathetic expression.

BackgroundPositive pressure pneumoperitoneum (PPP) effects on the autonomic nervous system (ANS) might be of clinical importance, as imbalance in the autonomic cardiac control might lead to serious consequences.MethodsFifteen healthy patients undergoing elective laparoscopic cholecystectomy were analyzed for cardiac autonomic nervous activity by spectral heart rate variability, during awake state, before and after intubation, during CO2 PPP (14 mmHg), and after CO2 evacuation. The very low, low, high and very high frequency (VLF, LF, HF, VHF respectively) bands of the spectral density of the heart rate variability (HRV) and their normalized values, as well as the LF/HF ratio, were obtained from the power spectra of R-R intervals, using the fast-Fourier transformation algorithm.ResultsUsing Friedman’s nonparametric test, only the difference between the power of LF during anesthesia (median 30.74) and the middle of PPP (median 195.66) was found to be significant (p<0.012). Such change was recorded in 14 patients (p=0.001, sign test).ConclusionsIncreased LF power reflects sympathetic cardiac activation. As the LF range accounts for regulation of blood pressure and baroreflex, several mechanisms may explain this activation. This in turn may predispose patients who suffer from cardiac disease to higher risk of developing ventricular arrhythmias, besides the possible adverse hemodynamic consequences of PPP.

High prevalence of muscular ventricular septal defect in preterm neonates

Isolated muscular ventricular septal defect was identified in 9 of 159 consecutive preterm neonates by color Doppler echocardiography, a prevalence of 56.6/1,000 live births. The neonates with ventricular septal defects appear clinically healthy, and in 87.5% of them the defect spontaneously closed within 6 to 11 months. The prevalence and rate of spontaneous closure are similar to those in full-term neonates.

Comparison of patients with acute myocardial infarction with and without ventricular fibrillation.

Among 1,590 patients with acute myocardial infarction from 1990 to 1994, the rate of primary ventricular fibrillation was 3.6%. The prevalence of smoking, complete left bundle branch block, hypokalemia, and decreased left ventricular function was higher in patients with ventricular fibrillation while those on thrombolytic therapy and those with non-Q-wave myocardial infarction were significantly lower.

Power spectral analysis of heart rate variability during helium pneumoperitoneum: The mechanism of increased cardiac sympathetic activity and its clinical significance

BackgroundCarbon dioxide pneumoperitoneum (PP) is known to induce increased cardiac sympathetic expression. The role of the insufflated gas involved in this mechanism should be elucidated in an attempt to eliminate its possible serious consequences.MethodsTwenty-five patients undergoing elective laparoscopic cholecystectomy were prospectively analyzed for cardiac autonomic nervous activity by spectral heart rate variability. In 15 patients, helium was used as CO2 substitution for abdominal insufflation (study group). Four frequency bands of interest were obtained from the power spectrum of R-R intervals, as well as the ratio between the low and high frequency (LF/HF), using the fast Fourier transformation algorithm to characterize the synergy of both autonomic branches during PP.ResultsSignificantly increased values of the power spectrum related to the LF and VLF bands (from 130 to 377 msec2/Hz and from 145 to 516 msec2/Hz, respectively) were inspected during CO2 PP, as well as increased LF/LH ratio (2.1). Using helium as CO2 substitution has eliminated the significant changes in the power spectrum that reflect increased cardiac sympathetic activity.ConclusionsThe elimination of sympathetic predominance by helium PP indicates the central role of CO2 in establishing this phenomena. Considering this information and its other known advantages, helium should be considered for use during prolonged laparoscopic procedures for high-risk patients.

Red cell filterability in cigarette smokers and its relations to cardiac hypertrophy

The relationship among daily cigarette consumption, washed and non-washed RBC filterability time (FT) as an indicator of erythrocyte deformability and echocardiographic left ventricular mass (LVM) were examined in 25 clinically healthy smokers and in 25 non-smoking controls matched for sex and age. FT of non-washed RBC was significantly higher in smokers than in non-smokers (25.2 +/- 3.6 vs. 16.8 +/- 2.2 min, P < 0.001). A highly significant linear correlation between number of cigarette consumption and FT was found. These differences were not observed when RBC were washed three times with isotonic saline. LVM was significantly greater in smokers (85.5 +/- 13.4 g/m2) than in controls (61.8 +/- 6.7 g/m2, P < 0.001). A linear correlation between daily cigarette consumption and LVM was observed. A positive relationship between LVM and FT of non-washed RBC was also found. These results demonstrated that LVM is significantly elevated in smokers and is linearly correlated with both cigarette consumption and RBC filtratibility. The increased deformability found in smokers may be a determinant to the cardiac hypertrophy. The association of both elevated LVM and rheological impairment may indicate unfavourable prognosis.

The physiological impact of intermittent sequential pneumatic compression (ISPC) leg sleeves on cardiac activity

BACKGROUND Pneumatic sleeves are widely used in surgery to prevent venous stasis and to improve cardiac function. The aim of this study was to assess the underlying cardiovascular mechanism induced by the activation of intermittent sequential pneumatic compression (ISPC) in healthy volunteers. METHODS Twenty male subjects underwent transthoracic echocardiographic and tissue Doppler imaging evaluation before and during the activation ISPC devices. Each patient served as his own control. RESULTS Following ISPC activation, there were significant increases in cardiac output (from 5.1 to 5.5 L/min, P < .05) and stroke volume (from 72 to 78 mL, P < .002), as well as ejection fraction, the velocity-time integral of aortic flow, and fractional shortening of the left ventricle. There was no increase in heart rate. Tissue Doppler imaging was compatible with normal cardiac responses. Total peripheral resistance was significantly reduced during ISPC activation. CONCLUSIONS The activation of ISPC devices in normal volunteers augmented cardiac output because of increased preload as well as decreased afterload.