PubMed Health⌕ Search

Biomedical subjects

M Hakimi

Publications and source records attributed to M Hakimi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Steroid-eluting epicardial pacing electrodes: six year experience of pacing thresholds in a growing pediatric population.

Indications for pacemaker implantation in the pediatric population often include sinus or atrioventricular node dysfunction following surgery for congenital heart defects. However, patient size, cardiac defects, and vascular and valvular concerns may limit transvenous lead utilization. Since the epicardial surface of these patients often exhibits variable degrees of fibrosis from scar tissue formation or pericardial adhesions, chronic low output (2.5/1.6 V, 0.3 ms) epicardial pacing from implant is not currently recommended in children due to frequent threshold changes and electrode exit block. As a result, pacing in children is often viewed as a less efficient system than in adults. The addition of steroid combined with newer low threshold electrode designs however stabilizes the electrode-tissue interface and eliminates postimplant changes seen with standard smooth surface electrodes potentially permitting efficient chronic pacemaker application to all patient ages. The stability of chronic low output epicardial pacing with steroid-eluting electrodes was prospectively studied in 22 patients (ages 2 days-18.5 years, median 3.5 years) for up to 6 years. Chronic pulse width thresholds were compared according to implant site and association of prior cardiac surgery. A total of 26 pacing leads were implanted. The acute implant mean pulse width threshold (2.5 V) for all the electrodes studied was 0.10 ms +/- 0.05 ms. Stable low thresholds were maintained for up to 6 years without significant variation from implant. Mean ventricular pulse width thresholds (0.12 ms +/- 0.05 ms) were significantly higher (P < 0.001) than atrial thresholds (0.06 ms +/- 0.03 ms) at implant and throughout the study period. The thresholds in the patients following cardiac surgery were comparable to those without previous cardiac surgery (P = NS). Stable low thresholds may be chronically maintained for up to 6 years for epicardial steroid-eluting electrodes irrespective of pacing site or associated cardiac surgery.

Adolescent↗
PubMed1997

The Ross procedure in children and young adults with congenital aortic valve disease.

METHODS: Thirty-three children and young adults with congenital aortic valve disease underwent pulmonary autograft replacement of the aortic valve between October 1993 and March 1997. There wer six females and 27 males; at operation, median age was 16 years (range: 3 to 41 years) and median body weight 60 kg (range: 14 to 121 kg). Fifteen patients (46%) had undergone one or more previous cardiac surgical procedures. A bicuspid aortic valve was present in 31 patients (94%); moderate to severe aortic stenosis and regurgitation was present in 10 (30%) and 26 (79%), respectively. RESULTS: All patients underwent the Ross procedure while in NYHA class I (64%) or class II (36%). A preoperative shortening fraction of 41 +/- 1.4% suggested well-preserved systolic function, but the mean left ventricular end-diastolic pressure of 16.6 +/- 1.3 mmHg was consistent with preoperative left ventricular pressure and volume overload. The aortic root was replaced using an interrupted suture technique in two patients and with three separate running sutures in 31. The right ventricular outflow tract was reconstructed in all classes with a cryopreserved pulmonary homograft valved conduit (median diameter 23 mm; range 19 to 30 mm). Intraoperative complications included transient atrioventricular dissociation (one), permanent atrioventricular dissociation (one), and left coronary artery distortion relieved by shortening the distal ascending aorta (one). Postoperatively, postpericardiotomy syndrome developed in six patients (18%), supraventricular tachycardia in three (9%), and ventricular tachycardia in one (3%). At three days after surgery, one patient developed ischemic left ventricular dysfunction requiring repositioning of the distorted left coronary artery higher on the neo-aortic root. Hospital survival rate was 100%. During a median follow-up of 17 months (range: 1 to 41 months) one patient suffered a non-cardiac death due to blunt trauma. there has been a significant postoperative improvement in NYHA class among surviving patients (class I, 94%; class II, 6%; p = 0.004 versus preoperative). Postoperative aortic regurgitation was absent or trivial in 17 (60%) and mild in the remaining 11 (40%) patients for whom follow-up echocardiographic data are available. One patient required reoperation 16.5 months after the Ross procedure to replace a rapidly degenerating pulmonary homograft, and one with moderately severe homograft stenosis and five with mild homograft stenosis are being monitored. Postoperatively, a gradual early expansion in the diameter of the neo-aortic root and reduction in echocardiographic indices of left ventricular hypertrophy and dilatation occurred. CONCLUSIONS: Pulmonary autograft replacement of the aortic valve in young patients with congenital aortic valve disease has produced excellent short-term anatomic/physiologic results and symptomatic relief with no mortality. Indices of left ventricular dilatation and hypertrophy regress after repair when the Ross operation precedes important deterioration in preoperative ventricular function. Important technical considerations include: (i) the native distal ascending aorta should be sufficiently shortened before performing the distal aortic anastomosis; and (ii) the left coronary anastomosis should be positioned relatively high on the neo-aortic root with a slight amount of tension. Both of these maneuvers reduce the likelihood of coronary artery distortion. Rapid degeneration of the pulmonary homograft and the propensity towards progressive dilatation of the neo-aorta are important postoperative considerations. Until more is known about the etiology and natural history of these two potential complications, postoperative anti-inflammatory and/or immunosuppressive therapy and strict control of hypertension should be strongly considered.

Adolescent↗
PubMed1996

Coronary sinus ostial atresia with persistent left superior vena cava.

BACKGROUND: Atresia of the coronary sinus orifice with a persistent left superior vena cava is an intrinsically benign cardiac anomaly with important surgical implications. METHODS: THe medical records of 5 patients with atresia of the coronary sinus orifice with a persistent left superior vena cava were reviewed retrospectively, and a computer search of the world literature describing this cardiac malformation was undertaken. RESULTS: The 5 patients ranged in age from 9 months to 5 years. In 2, the diagnosis was made preoperatively by angiocardiography, and in 3, the abnormality was found incidentally at the time of cardiotomy for repair of associated congenital heart disease. Four of the 5 patients underwent repair of associated cardiac lesions. During operation, care was taken to avoid disruption of left superior vena cava flow to prevent coronary venous obstruction. All patients survived and are doing well at follow-up. CONCLUSIONS: Atresia of the coronary sinus orifice with persistent left superior vena cava is, in itself, a benign anomaly without physiologic consequence. However, the recognition of this lesion during repair of associated cardiac lesions is of vital importance to the cardiac surgeon. Interruption of this sole route of coronary venous drainage can potentially lead to myocardial ischemia and necrosis.

Angiocardiography↗
PubMed1996

Repair of an unusual type of total anomalous pulmonary venous connection.

A 9-day-old, 4.5-kg female infant was diagnosed with total anomalous pulmonary venous connections by echocardiography. The unusual nature of the pulmonary veins and their connections led to cardiac catheterization and angiography. Angiography demonstrated the left-sided veins connected, via a retropulmonary artery vertical vein, to the left inominate vein whereas the right-sided pulmonary veins connected to the right superior vena cava. We repaired this lesion uneventfully by creating a neo-common pulmonary vein and anastomosing this confluence to the left atrium.

Cardiac Catheterization↗
PubMed1995

Pediatric cardiac surgical ECMO: multivariate analysis of risk factors for hospital death.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) has emerged as an effective technique for the mechanical support of many pediatric postcardiotomy patients with medically refractory cardiac failure. METHODS: We retrospectively reviewed the records of 73 pediatric patients with congenital heart disease who were placed on ECMO support between August 1984 and February 1994. The patients were divided into groups defined by the timing of ECMO cannulation relative to the time of operation. Group 1 patients (n = 7, 9.6%) were placed on ECMO preoperatively. Group 2 patients (n = 66, 90.4%) were a heterogeneous population placed on ECMO at any interval after cardiac repair. Subgroup 2A consisted of patients (n = 17, 25.8%) who could not be weaned from cardiopulmonary bypass and were converted directly to ECMO support immediately after repair. Subgroup 2B patients (n = 49, 74.2%) were cannulated postoperatively after an initial period of clinical stability. RESULTS: Hospital survival for all study patients (42/73) and for group 2 patients (38/66) was 58%. Only 4 group 2A patients (23.5%) survived their hospitalization compared with 34 group 2B patients (69.4%) (p = 0.001). Multivariate analysis identified elevated right atrial pressure after ECMO decannulation (p = 0.049) and, possibly, membership in group 2A (p = 0.061) as independent risk factors for hospital death. CONCLUSIONS: Extracorporeal membrane oxygenation is most effective in salvaging pediatric cardiac surgical patients who demonstrate medically refractory hemodynamic deterioration at some interval after being successfully weaned from cardiopulmonary bypass. The right atrial pressure after extracorporeal membrane oxygenation decannulation is an independent predictor of hospital death.

Cardiopulmonary Bypass↗
PubMed1994

Delayed sternal closure after neonatal cardiac operations.

We retrospectively compared the use of primary elective open sternum coupled with delayed sternal closure with the use of primary sternal closure in neonates after cardiac operations. Primary elective open sternum/delayed sternal closure was selectively used in patients who demonstrated hemodynamic or respiratory deterioration, or both, during an intraoperative trial of sternal closure; otherwise primary sternal closure was used. Primary elective open sternum was used in 55 (61.8%) and primary sternal closure in 34 (38.2%) of the 89 patients studied. Eleven (20%) patients having primary elective open sternum died compared with 5 (14.7%) patients having primary sternal closure (p = 0.6). Six (10.9%) of the patients with primary elective open sternum died before delayed sternal closure; the remaining 49 patients comprise the primary elective open sternum/delayed sternal closure group. The durations of mechanical ventilation (9.7 +/- 0.9 days [mean plus or minus standard error of the mean], median 7.7 versus 9.9 +/- 3.4 days, median 4.9; p = 0.0005) and hospital stay (21.1 +/- 1.4 days, median 17.7 versus 19.6 +/- 4.1 days, median 12.9; p = 0.004) were shorter in the primary sternal closure group. The overall morbidity and duration of inotropic support were not significantly different between the two groups, although seven (20.6%) of the patients with primary sternal closure did have to undergo delayed sternal reopening for refractory postoperative low cardiac output. There was one superficial wound infection in the primary elective open sternum/delayed sternal closure group. Primary elective open sternum/delayed sternal closure is an effective treatment for postoperative neonatal mediastinal compression for the following reasons: (1) the morbidity is low; (2) the mortality of the critically ill group of neonates in whom primary elective open sternum/delayed sternal closure was used was similar to that of the less critically ill primary sternal closure group; and (3) 20.6% of the primary sternal closure group eventually had to undergo delayed sternal reopening to treat refractory postoperative low cardiac output.

Cardiac Surgical Procedures↗
PubMed1993

Congenital coronary artery fistulae: a review of 18 cases with special emphasis on spontaneous closure.

Between 1972 and 1990, 18 patients (median age 3 years, range 0.1-14 years) with coronary artery fistulae (CAF) were seen at this institution. Of the 16 patients without associated heart defects, two patients presented with congestive heart failure and the remaining 14 were asymptomatic. Fifteen patients had normal origin of two coronary arteries. Two patients had atresia of the proximal right coronary artery and, in one patient, the right coronary artery originated from the left main coronary artery. The QP/QS ranged between 1.0 and 2.8, with a mean of 1.4. Fifteen patients underwent operative closure without any deaths. One patient is being followed medically at present. Two patients showed spontaneous clinical improvement of CAF (complete closure in one and near complete in the other) and remained asymptomatic during a decade of follow-up. Review of the literature suggests operative closure of symptomatic and asymptomatic small CAF during childhood. However, the natural history of minute CAF remains unclear. In addition, symptoms from CAF may spontaneously improve with time.

Arterio-Arterial Fistula↗
PubMed1993

Conjunctival impression cytology as an indicator of vitamin A status in lactating Indonesian women.

Conjunctival impression cytology (CIC) has been used to assess the vitamin A status of children but not women. We used CIC in a randomized controlled trial of high-dose vitamin A supplementation in Indonesian women. We report its association with biochemical indicators and evaluate its usefulness for several assessment functions, using two definitions for abnormal CIC. Serum retinol concentrations of all women and milk vitamin A concentrations of unsupplemented women decreased with worsening CIC category. CIC indicated risk of low milk vitamin A and low infant serum retinol with low sensitivity and high specificity. CIC did not identify women who benefited from supplementation. The usefulness of CIC to measure response to supplementation was limited by the low prevalence of abnormal status in these women. CIC may be a useful indicator of vitamin A deficiency in women or their breast-fed infants, or to measure response to supplementation, when a more sensitive cutoff point for abnormal status is used.

Conjunctiva↗
PubMed1993

Evaluation of indicators for use in vitamin A intervention trials targeted at women.

This paper examines the ability of three indicators to detect changes in women's vitamin A status. Serum retinol concentration, milk vitamin A concentration, and milk vitamin A per gram milk fat were used to assess the vitamin A status of mildly deficient Indonesian women before and after supplementation in a randomized intervention trial. Choice of indicator made a fourfold difference in the sample size required to measure a statistically significant change in vitamin A status. Milk vitamin A per gram milk fat was the best indicator of response, milk vitamin A concentration was intermediate, and serum retinol concentration performed most poorly. Serum retinol concentration was equally responsive across the range of vitamin A status in this population. The milk indicators were more responsive among women of lower status than women of higher status. Milk vitamin A is an efficient indicator for monitoring the effects of vitamin A interventions in women.

Adult↗
PubMed1993

High dose vitamin A supplementation of breast-feeding Indonesian mothers: effects on the vitamin A status of mother and infant.

For regions where vitamin A deficiency is common, high dose vitamin A supplementation of lactating mothers is currently recommended, but the effects of this intervention have not been carefully evaluated. We conducted a randomized, double-blind trial in which 153 Indonesian mothers 1-3 wk postpartum received either a capsule containing 312 mumol of vitamin A as retinyl palmitate or a placebo. Mothers' serum retinol concentrations in the vitamin A group tended to be lower than in the placebo group at baseline but higher at 3 mo postpartum (1.39 vs. 1.24 mumol/L, P = 0.03) and 6 mo postpartum (1.23 vs. 1.08 mumol/L, P < 0.01). The milk retinol concentrations of the vitamin A group were higher than those of the placebo group by 0.48 to 1.18 mumol/L at 1-8 mo postpartum (P < 0.05). Among the infants at 6 mo of age, the prevalences of low serum retinol concentration (< 0.52 mumol/L) were 36 and 15% in the placebo and vitamin A groups, respectively (P < 0.005), and the prevalences of low vitamin A stores (assessed by relative dose response) were 23 and 10%, respectively (P < 0.03). High dose vitamin A supplementation of lactating mothers is an efficacious way to improve the vitamin A status of both mother and breast-fed infant.

Adolescent↗
PubMed1992

Improved chronic epicardial pacing in children: steroid contribution to porous platinized electrodes.

Although new "low threshold" epicardial electrodes combine steroid with a porous, platinized-platinum surface, the actual contribution of steroid elution has not been established. We evaluated this new electrode surface design with and without steroid in 13 children, ages 1-22 years. Both electrodes are unipolar and of similar surface area. The Medtronic Model 4951-P is a barb design for epimyocardial insertion without steroid while the Model 10295A is a steroid eluting, epicardial disk-shaped design. Both electrodes were implanted for atrial and ventricular pacing. At implant, sensed P and R waves, and pacing impedances were comparable between both electrodes. There were no significant differences between initial measured pulse width or calculated energy thresholds for the first 2 months following implant. Strength-duration curves for both electrodes at 1 month were comparable to implant values. After 2 months, the threshold of the nonsteroid electrode peaked and stabilized at a significantly higher (P less than 0.05) level than the more constant steroid eluting electrode. This difference continued for the first year following implant. We conclude that the new porous, platinized-platinum electrode design intrinsically limits initial electrode-tissue interface reactivity in children and improves epicardial pacing with low chronic threshold values. Steroid elution augments these intrinsic qualities by maintaining fibrous capsule stability with more constant low thresholds over time.

Bradycardia↗
PubMed1990

Down's syndrome, complete atrioventricular canal, and pulmonary vascular obstructive disease.

We reviewed our experience over a 10-year period to determine whether children with Down's syndrome and complete atrioventricular canal develop pulmonary vascular obstructive disease earlier than children with normal chromosomes and this defect. Comparisons were made between Down's syndrome and normal chromosome children regarding (1) pulmonary blood flow and pulmonary vascular resistance at initial catheterization, (2) operability as related to elevation in pulmonary vascular resistance, and (3) age at diagnosis of fixed pulmonary vascular obstructive disease. The 45 patients with Down's syndrome catheterized under 1 year of age had a lower mean pulmonary blood flow (3.2 versus 5.7; p = 0.0001) and higher mean pulmonary vascular resistance (8.3 versus 4.6 Wood units.m2; p = 0.0003) than their 34 normal chromosome counterparts. When all ages were included, 38 of 81 (47%) of the children with Down's syndrome and 32 of 40 (80%) of the normal children were considered operable. Non-Down's syndrome patients who had operations had a higher pulmonary blood flow (5.8 versus 3.3; p = 0.004) and lower pulmonary vascular resistance (3.6 versus 6.0 Wood units.m2; p = 0.005) than Down's syndrome patients. Of the 34 patients who did not have operations because of pulmonary vascular obstructive disease, 31 had Down's syndrome. In 10 of 81 children with Down's syndrome, fixed pulmonary vascular obstructive disease was diagnosed before the age of 1 year, while this was found in none of 40 normal children. Our data demonstrate that Down's syndrome patients with complete atrioventricular canal have a greater degree of elevation of pulmonary vascular resistance in the first year of life and more rapid progression to fixed pulmonary vascular obstructive disease than children with normal chromosomes.

Adolescent↗
PubMed1988

Intracardiac teratoma in a newborn.

Primary tumors of the heart are infrequent at all ages. We present a newborn with hypoxia and a heart murmur, in whom an echocardiogram revealed a large tumor filling the right ventricle and the pulmonary annulus. To maintain pulmonary blood flow, the patency of the ductus arteriosus was achieved by infusion of prostaglandin E1. Successful surgical resection was accomplished. The pathological examination was characteristic of a benign teratoma. The patient remains asymptomatic and has shown no evidence of recurrence of the tumor during a follow-up period of 34 months. This represents the eleventh case of intracardiac teratoma and only the fourth case to undergo successful surgical resection.

Echocardiography↗
PubMed1988

Primary pulmonary artery sarcoma in two children.

The clinical and pathological features of primary pulmonary artery sarcoma in two children are reported. The first patient presented with right ventricular outflow obstruction and underwent successful surgical resection of his tumor. The second patient developed cardiac arrest following a relatively short period of symptoms of right heart failure and could not be revived. The pathological diagnosis in both patients was hemangiopericytoma. To the best of our knowledge, primary pulmonary artery sarcoma in children has not been previously reported.

Adolescent↗
PubMed1987

Surgical and medical results of complete atrioventricular canal: a ten year review.

The files of 121 patients who presented to Children's Hospital of Michigan over the last 10 years with complete atrioventricular (AV) canal were reviewed to evaluate long-term management and overall outcome. Of 121 patients, 70 underwent corrective surgery, 21 (30%) of whom died perioperatively. The surgical mortality rate was 13% when patients with hypoplastic left or right ventricle (n = 6), double-orifice mitral valve or extreme deficiency of mitral tissue (n = 5), and pulmonary vascular obstructive disease (n = 5) were excluded. Of the 49 patients who survived operation, 36 are in New York Heart Association class I, 1 patient requires a pacemaker and 3 died late. In 34 of the 51 patients (28%) who did not undergo operation, pulmonary vascular obstructive disease developed; it occurred within 12 months in 10 patients (8%). Eight other patients who did not undergo operation died before planned surgery (age 1 to 9 months). Although surgical prognosis in good candidates is acceptable, the overall prognosis for children with complete AV canal is guarded because of the risk of early death or early pulmonary vascular obstructive disease and frequently unfavorable anatomy.

Cardiac Catheterization↗
PubMed1986

Pulmonary hypertension postventricular septal defect repair treated by extracorporeal membrane oxygenation.

Severe pulmonary hypertension complicating the correction of congenital cardiac defects is an unusual cause of early postoperative mortality. We present a case of a nine-month-old infant who developed paroxysmal pulmonary hypertension associated with severe hypoxemia after the successful repair of a large perimembranous ventricular septal defect (VSD). The pulmonary hypertension was refractory to all medical and pharmacologic therapy but was successfully treated with extracorporeal membrane oxygenation (ECMO). On ECMO, pharmacologic support was removed, pulmonary artery pressure reduced, and ECMO support withdrawn. To date, ECMO has been applied to pulmonary hypertension of the newborn, neonatal respiratory insufficiency, and for primary cardiac pump failure. Our experience with this case leads us to believe it is an effective therapy for acute pulmonary hypertension occurring after the repair of congenital cardiac anomalies.

Heart Arrest↗