Prolongation of the QT interval and the sudden infant death syndrome.

BACKGROUND: The sudden infant death syndrome (SIDS) is multifactorial in origin, but its causes remain unknown. We previously proposed that prolongation of the QT interval on the electrocardiogram, possibly resulting from a developmental abnormality in cardiac sympathetic innervation, may increase the risk of life-threatening ventricular arrhythmias and contribute to this devastating disorder. We prospectively tested this hypothesis. METHODS: Between 1976 and 1994, we recorded electrocardiograms on the third or fourth day of life in 34,442 newborns and followed them prospectively for one year. The QT interval was analyzed with and without correction for the heart rate. RESULTS: One-year follow-up data were available for 33,034 of the infants. There were 34 deaths, of which 24 were due to SIDS. The infants who died of SIDS had a longer corrected QT interval (QTc) than did the survivors (mean [+/-SD], 435+/-45 vs. 400+/-20 msec, P<0.01) and the infants who died from causes other than SIDS (393+/-24 msec, P<0.05). Moreover, 12 of the 24 SIDS victims but none of the other infants had a prolonged QTc (defined as a QTc greater than 440 msec). When the absolute QT interval was determined for similar cardiac-cycle lengths, it was found that 12 of the 24 infants who died of SIDS had a QT value exceeding the 97.5th percentile for the study group as a whole. The odds ratio for SIDS in infants with a prolonged QTc was 41.3 (95 percent confidence interval, 17.3 to 98.4). CONCLUSIONS: Prolongation of the QT interval in the first week of life is strongly associated with SIDS. Neonatal electrocardiographic screening may permit the early identification of a substantial percentage of infants at risk for SIDS, and the institution of preventive measures may therefore be possible.

[Factors limiting adaptation to exercise after the Fontan operation: role of altered pulmonary function]. / Fattori limitanti l'adattamento allo sforzo dopo intervento di Fontan: ruolo di eventuali anomalie polmonari.

BACKGROUNDS: The abnormal adaptation to exercise after Fontan operation, is primarily due to a suboptimal increase in cardiac output. We postulated that abnormal pulmonary function could cooperate in reducing effort tolerance of these patients (pts). METHODS: We have evaluated 10 pts, mean age 15 +/- 8 yrs, with a mean postoperative follow-up of 6 +/- 2 yrs. Seven pts were asymptomatic while 3 had mildly decreased effort tolerance. These pts were evaluated with echocardiogram, cycle ergometer stress test, basal and effort spirometry and perfusion lungs scanning. RESULTS: Basal ejection fraction was normal in 9 pts and mildly depressed in 1 pt. Basal cardiac index was 1.8 + 2.2 l/min/m2 and increased to 4.8 + 5 l/min/m2 during exercise. Effort tolerance was 73% +/- 21% of predicted values, with maximal O2 consumption of 60% +/- 13% of predicted. Basal spirometry showed a mild restrictive pattern in 7 pts with a decrease in total pulmonary capacity and in forced vital capacity (mean values respectively 79% +/- 14% and 75% +/- 18% of predicted), otherwise respiratory reserve resulted normal in all pts. Carbon monoxide diffusion was impaired in all pts with a mean value of 49% +/- 10% of predicted. O2 saturation near normal in basal condition decrease during exercise (mean value 96% +/- 2% and 91% +/- 7%). The VE/VO2 and Vd/Vt ratio were both abnormally increased (respectively 111% +/- 28% and 186% +/- 39% of predicted). Lung scanning was abnormal in 6 pts with defects of perfusion localized prevalently in left lung (5/6) especially in upper lobe (4/6). CONCLUSIONS: After Fontan operation exercise tolerance is reduced as consequence of 1) a suboptimal increase in cardiac output and 2) abnormal gas diffusion probably due to a damage of alveolo-capillary membrane and/or to a ventilation/perfusion mismatch as showed by abnormalities in lungs perfusion and by increase Vd/Vt ratio.

Color Doppler echocardiographic assessment of atrial septal defect size: correlation with surgical measurements.

In patients with atrial septal defect (ASD), color flow Doppler echocardiography provides visualization of the transseptal jet, the maximal dimension of which can be assumed to correspond to the maximal dimension of the true orifice. To test whether color flow Doppler echocardiography can provide an alternative method for measurement of ASD size, we studied 63 consecutive patients with echocardiographic evidence of ASD. In 48 patients the maximal dimension of the jet was measured in the parasternal, apical, or subcostal four-chamber view or in the parasternal short-axis view. In the remaining 15 patients transesophageal echocardiography was performed because of transthoracic views were inadequate. The transesophageal studies also measured, from two-dimensional images, the maximal transverse discontinuity in the atrial septum. All patients underwent surgical repair, during which the surgeon directly measured the maximal dimension of ASD. Linear regression equations were performed to compare transthoracic and transesophageal dimensions to those measured at operation. Correlation coefficients were as follows for transthoracic versus surgical measurements: r = 0.745, standard error = 4.35, p less than 0.001. Transesophageal measurements derived from both two-dimensional images and echocardiographic jet width showed similar excellent correlation with surgical measurements (n = 0.91, standard error = 4.33, p less than 0.001; and r = 0.919, standard error = 4.42, p less than 0.001, respectively). We conclude that ASD size derived from color flow Doppler echocardiography shows a good correlation with the anatomic maximal dimension observed at operation. Both transesophageal color flow Doppler echocardiography of jet width and direct surgical measurement of the defect provide an accurate estimation of ASD size.

[The follow-up in adulthood of subjects with progressive rheumatic disease in childhood. Considerations of secondary prevention]. / Controllo in età adulta di soggetti con pregressa malattia reumatica nell' infanzia. Considerazioni sulla profilassi secondaria.

We reviewed 57 patients who had previously suffered from rheumatic fever (RF) after an average period of 7.2 (+/- 2.8) years without penicillin prophylaxis. In 24 cases (42%) RF began with carditis and in 9 patients valvular damage remained after hospital discharge. Prophylaxis with retard penicillin every four week was carried out for 5.5 +/- 1.8 years. At present the patients are all asymptomatic. There was in 7 cases mild valvular damage without clinical and instrumental involvement. There was not recurrency after the end of prophylaxis, except for a doubtful case, analysed in the Discussion. Although our cases are not numerous, we believe that a regular prophylactic treatment over 5 or 6 years is sufficient to avoid any recurrency in patients with previous RF. After this period of treatment, only subjects with valvular damage should have further extensive treatment until their 20th year and always for a period not shorter than ten years.

[Fontan's operation: results, immediate and long-term postoperative complications]. / Intervento di Fontan. Risultati, complicanze postoperatorie e a distanza.

The Fontan operation and its modifications can be relatively safely performed in the treatment of many complex congenital heart diseases, such as univentricular heart and tricuspid atresia. The main postoperative complications following the Fontan procedure and the incremental risk factors involved in their development are investigated. Between January 1984 and January 1988 eleven patients (6 females and 5 males), ranging in age from 2 to 15 years (mean age: 7.3 +/- 3.7) and in weight from 10.8 to 50 Kg (mean weight 22.3 +/- 12.7) underwent the Fontan operation in our Department. No hospital death occurred. The mean postoperative stay in the Intensive Care Unit was 6.3 +/- 3.9 days. There were two surgical re-entries for the same patient: cardiac tamponade (the day of operation) and residual atrial septal defect (2 days following the operation). Eight patients had significant signs of venous stasis, with severe hepatomegaly and pleural effusion. The 11 patients discharged were followed-up for a period of between 3 and 48 months (mean follow-up: 26.4 +/- 18). There were 2 cases of recurrent pleural effusion, 10 to 15 days after discharge. One late death occurred 2 years after the Fontan procedure (massive pulmonary embolism after re-operation). Short and medium-term rate of complications is related to increased post-operative values of mean right atrial pressure (greater than 15 mmHg). Mean right atrial pressures greater than 15 mmHg appear to be correlated with Nakata index values less than 250 mm2/m2. The experience reviewed confirms the excellent results of the Fontan operation, as regards survival and functional recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

[Defects of the interatrial septum: surgical correction without the hemodynamic test. Analysis of 145 cases operated on]. / Difetti del setto interatriale: correzione chirurgica senza esame emodinamico. Analisi su 145 casi operati.

Surgical correction of ostium secundum atrial septal defects may be performed, in most cases, without cardiac catheterization, on the ground of clinical and two-dimensional echocardiographic (2D echo) findings. Consequently it's useful to identify the reliability of 2D echo and the indications for angiography in these patients (pts). One hundred forty-five patients operated in "A. De Gasperis" Division of Cardiac Surgery in Milan from January 1982 to December 1986 are reviewed. Patients with ostium primum atrial septal defects or subjected to cardiac catheterization and angiography in other institutions are excluded. Altogether two-dimensional echocardiography was performed in 131 pts, cardiac catheterization in 78. Sixty-four pts were studied with both 2D echo and angiography. In 35 pts (with only 2D echo examination) radionuclide angiocardiography was performed. The results of the different techniques were compared with intra-operative findings, defining sensitivity and specificity in relation to detection of the site of the defect and of the pulmonary venous return. There were no statistically significative differences between echo 2D and cardiac catheterization (Figs. 1 and 2). Two-dimensional echocardiography confirms its cost effective and psychological advantages, especially in younger patients. Hemodynamic and angiographic assessment should be performed as follows: 1) when associated anomalies are suspected; 2) in cases of non-satisfying quality of the 2D echo examination; 3) when diagnostic incoherence between clinical and instrumental data is present; 4) in patients with pulmonary hypertension.

[Amiodarone therapy in childhood: efficacy and side effects]. / La terapia con amiodarone in età pediatrica: efficacia ed effetti collaterali.

In the adult, Amiodarone is a very effective drug in the treatment of ventricular and supraventricular arrhythmias. The presence of severe side effects such as some alterations in the thyroid function and/or pulmonary fibrosis have restricted the use in children. Nevertheless, research has shown that there is a low incidence of collateral side effects and this therapy in infancy can be very effective. For this reason we evaluated a group of 27 children with supraventricular (19 patients) and ventricular (8 patients) arrhythmias. The mean age of patients treated was 6 +/- 5 years (2 days-13 years). The follow-up period was of 13 +/- 10 months. Amiodarone has been used in 9 patients intravenously, with the loading dose of 5 mg/Kg followed by an infusion of 10 mg/Kg/day. In 18 patients we administered the drug orally with a loading dose of 10 mg/Kg/day for a period of 10 days, thereafter the maintenance was of 5-7 mg/Kg/day for 5 days every week. The patients were all checked for thyroid function and Holter monitoring quarterly; they were given an ophthalmologic examination (every 6 months) and a chest-x-ray and echocardiography annually. The efficacy of intravenous treatment was judged successful in 56% of patients, partially successful in 22% and ineffective in the remaining 22%. The oral treatment was completely effective in 77% of children, partially in 5% and ineffective in 18%. In one case we had to suspend the therapy because we found high values of T3 and T4. During the treatment, in 86% of cases, we had blood level fluctuations of T3 and T4, however these did not exceed the normal ranges. The most important side effect observed has been the photosensitivity found in 22% of children. Moreover we observed a reduction of sinusal automatism, which was more marked in patients less than year old. In 4 cases an A/V block of first degree appeared. In all patients we found changes of ventricular repolarization, while corneal deposits appeared in only one child after a year of therapy and did not cause an impairment of visual acuity. In conclusion we can assert that Amiodarone is a very effective drug in children, specially in small babies, where it can safety be used as a first choice drug.

[beta-Blocking therapy in obstructive hypertrophic cardiomyopathy. Long term results (author's transl)]. / Risultati a distanza della terapia betabloccante nella cardiomiopatia ipertrofica ostruttiva.

34 patients have been controlled after beta-blocking therapy, for a mean period of 5 years. Symptoms and evolution: syncope disappeared, angoy passed from 47% to 23%, dyspnea from 65% to 47%, dizziness from 70% to 54%, weakness from 30% to 37%. A systolic murmur was present in 75% of the cases. Two patients died by heart failure. Phonocardiogram: the systolic murmur was unchanged, like the carotid pulse. Paradoxical splitting of the 2 degrees sound was more frequent, atrial sound unimodified, isometric contraction shortened (60%) and the Q-1 degree sound interval prolonged (90%). Electrocardiogram: 1 degree A/V block appeared in 24% of the cases, complete A/V block in 9%, atrial fibrillation in 3%. Left atrial enlargement was more frequent; left ventricular hypertrophy unchanged. Heart catheterization (10 cases, after a mean period of 5.5 years): left ventricular pressure gradient passed from 80% to 90%; a low cardiac index from 20% to 30%; telediastolic pressure of left ventricle was unmmodified in 10% of cases, more elevated in 50%, less elevated in 40%. Chest X ray: cardiac size was unchanged in 65% of cases, enlarged in 32%; smaller in 3%. In conclusion, symptoms improved in most of the patients; no case of sudden death was observed. Some data however show that the evolution of the myocardiopathy goes on to congestive heart failure and arise doubts on the real usefullness of beta-blocking drugs in the disease.