Surgical treatment of atrial fibrillation with bipolar radiofrequency ablation: mid-term results in one hundred consecutive patients.

AIM: The Cox-Maze procedure was introduced nearly two decades ago for the surgical treatment of atrial fibrillation (AF). Recently, our group has replaced most of the incisions of the Cox-Maze procedure with bipolar radiofrequency (RF) ablations (Cox-Maze IV procedure). The purpose of this study was to examine our midterm results with the Cox-Maze procedure using bipolar RF ablation. METHODS: From January 2002 to October 2005, 100 consecutive patients underwent a modified Cox-Maze procedure with bipolar RF ablation for AF; 32 were lone operations, and 68 were concomitant procedures. Follow-up was performed at 1, 3, 6, and 12 months, and then annually thereafter. Heart rhythm was confirmed by electrocardiography. RESULTS: The mean age of patients was 62+/-13 years; 57% were male. Duration of AF was 6.3+/-7.6 years (0.1 to 40 years), 59% had paroxysmal AF, and 34% had permanent AF. Follow-up was complete for all patients with a mean follow-up of 13+/-10 months. At 12-month follow-up, 91% (49/54) of patients were free of AF. Cross-clamp time in the lone Cox-Maze IV procedure patients was 42+/-15 minutes, while it was 101+/-29 minutes for the Cox-Maze IV with a concomitant procedure (compared to 93+/-34 minutes and 122+/-37 minutes for the traditional procedure, P<0.05). There were four operative deaths. CONCLUSIONS: The Cox-Maze IV procedure had good mid-term efficacy. The use of bipolar RF energy significantly decreased operative time and simplified the procedure compared to the traditional Cox-Maze procedure, potentially increasing utilization of the procedure among cardiac surgeons.

The beneficial hemodynamic effects of selective patent vertical vein following repair of obstructed total anomalous pulmonary venous drainage in infants.

OBJECTIVES: Postoperative low cardiac output may persist after repair of total anomalous pulmonary venous drainage (TAPVD) because of a relatively small and non-compliant left atrium and left ventricle. We examined the effects of selective vertical vein patency on postoperative hemodynamics. METHODS: Thirty-four patients less than 3 months of age with TAPVD were operated from July 1993 to June 2000. The mean age at operation was 21+/-8 days (range, 3-62 days) and the mean weight was 3+/-0.2 kg (range, 2-4.1 kg). Supracardiac type drainage was found in 12 (35%), cardiac in three (9%), mixed in one (3%), and infracardiac in 18 (53%) patients. Twenty-two patients (65%) had obstructed venous drainage. All operations were performed with deep hypothermic circulatory arrest. Supracardiac, mixed and infracardiac types were repaired through a posterior approach, whereas, in the cardiac type, the coronary sinus was unroofed and the atrial septal defect was patched. The decision whether to keep the vertical vein open was made at the end of the operation and was based on the hemodynamic state of the patient. RESULTS: There were no operative deaths. The suture on the vertical vein was released in 22 patients who had obstructed pulmonary venous drainage (infracardiac type, n=18; supracardiac type, n=3; and mixed type, n=1), resulting in a significant drop in the left atrial pressure from 19+/-2 to 12+/-2 mmHg (P<0.05), and in the mean pulmonary artery pressure from 42+/-6 to 35+/-3 mmHg (P<0.05), associated with an immediate increase in the mean arterial blood pressure from a mean of 46+/-3 to 60+/-4 mmHg (P<0.05). During a mean follow-up of 38+/-6 months (range, 8-71 months), there were no late deaths. Follow-up, two-dimensional echocardiography with Doppler studies demonstrated good left ventricular function and trivial or no left to right shunt through the vertical vein in those patients in whom the snare was released. CONCLUSIONS: Maintaining the vertical vein patent in a selective group of patients with infracardiac total anomalous venous drainage contributes to a favorable outcome following surgery.

Congenital bilateral pulmonary venous stenosis in an adult:: diagnosis by Echo-Doppler.

A 22-year-old man with life-long exertional fatigue and dyspnea was diagnosed as having bilateral congenital pulmonary venous stenosis by echocardiography with color Doppler examination. Fibrous membranes overlying the entrances of the veins to left atrium were the cause of obstruction and were easily resected.

Surgical management of tetralogy of Fallot in the first year of life.

BACKGROUND: The surgical approach to tetralogy of Fallot (TOF) continues to evolve and now many centers favor early repair for TOF. METHODS: Our experience includes 82 consecutive patients less than 1 year old with TOF (n = 74) and TOF with pulmonary atresia (n = 8) who were operated on between January 1992 and March 1998. Mean age at repair was 5.2 +/- 1.2 months and mean weight was 4.5 +/- 0.4 kg. Seven patients (anomalous left anterior descending artery [n = 1], pulmonary atresia with hypoplastic pulmonary arteries [n = 6]), underwent palliative procedures in the neonatal period followed by complete repair. Forty-nine patients (59%) were symptomatic (severe cyanosis or hypoxic spells), and 33 patients (41%) were asymptomatic. A combined transatrial-transpulmonary approach was employed in 28 patients (34%), and transannular patch or conduit for reconstruction of the right ventricular outflow tract (RVOT) was required in 54 patients (66%). The mean Nakata index was 160 +/- 25 mm2/m2. RESULTS: There were no hospital deaths. Mean post-repair peak right ventricular/systemic pressure ratio was 0.48 +/- 0.1. There were no late deaths or reoperations during a mean follow-up of 23 +/- 5 months. All patients are currently asymptomatic and in New York Heart Association class 1. Postoperative evaluation by two-dimensional and Doppler echocardiography or cardiac catheterization showed minimal pulmonary artery stenosis with a mean pressure gradient of 15 +/- 6 mm Hg across the RVOT. CONCLUSIONS: Our experience suggests that early repair of TOF can yield excellent results and initial palliation does not preclude early complete repair.

Fatty acid block of the transient outward current in adult human atrium.

Fatty acids represent an essential source of fuel for the heart and play an important role in the mechanical, electrical, and synthetic activities of cardiac cells. Under pathological conditions, such as ischemia followed by reperfusion, the myocardium is exposed to very high levels of fatty acids, in particular the monounsaturated fatty acid, oleic acid. Elevated plasma fatty acids have been linked to an increased risk for cardiac arrhythmias. In other species, fatty acids have been shown to modulate several cardiac ion channels, most notably potassium channels. Virtually nothing is known about the actions of oleic acid on potassium channels in human heart. We therefore characterized the effects of oleic acid on the transient outward current, sustained current, and inwardly rectifying current, some of the major potassium channels present in human atrium, using the whole-cell patch clamp method. Exposure of cells to oleic acid (5 microM) reduced the transient outward potassium current to 3.7 +/- 0.8 pA/pF (n = 4) compared with 7.0 +/- 0.7 pA/pF (n = 4) (P <. 05) for cells not exposed. In contrast, oleic acid had little effect on either the sustained current (4.3 +/- 0.3 pA/pF, n = 4 for oleic acid versus 4.8 +/- 0.5, n = 5 for control) present after the decay of the transient outward current or on the amplitude of IK1 measured at -100 mV (1.4 +/- 0.4 pA/pF, n = 4 for oleic acid versus 1.3 +/- 0. 4 pA/pF, n = 6 for control). In addition, oleic acid significantly slowed the rate of recovery of the transient outward current, which is predicted to result in a use-dependent reduction in current amplitude in the beating heart. These results suggest a possible contributing role for oleic acid block of the transient outward current in the pathological consequences of myocardial ischemia.

Abdominal apoplexy.

We describe the case of a patient with abdominal apoplexy, the spontaneous rupture of a visceral vessel. Laparotomy revealed a hematoma arising from a ruptured gastroepiploic artery. We report the usefulness of preoperative abdominal computed tomography and transgastric ultrasonography and discuss the condition of abdominal apoplexy. An increased awareness of the condition is perhaps the most valuable aspect of the early preoperative diagnosis of this potentially fatal condition.

Carbon dioxide field flooding minimizes residual intracardiac air after open heart operations.

Transesophageal echocardiographic studies were used to monitor the presence of air bubbles in the heart after open heart operations. After cardiac valvular procedures all 22 patients managed with careful deairing procedures had persistence of air bubbles for at least 30 minutes and usually for 45 minutes. In 56 patients with CO2 field flooding, all foam disappeared in less than 1 minute in 48 patients and the remaining 8 had complete disappearance in 1 to 24 minutes. These observations demonstrate the ineffectiveness of the usual deairing maneuvers and the effectiveness of CO2 field flooding in displacing air.

Nonfunctioning cystic neuroendocrine neoplasms of the pancreas.

BACKGROUND: Three types (functioning solid, nonfunctioning solid, and functioning cystic) of neuroendocrine neoplasms (benign and malignant) of the pancreas have been reported. PATIENTS: We report three patients with nonfunctioning neuroendocrine neoplasms of the pancreas with cystic components, a type of neoplasm not previously reported. One of the neoplasms we report was benign; the other two were malignant. The patients were admitted with abdominal pain. In each case an abdominal computed tomography scan defined a large multicystic pancreatic mass. RESULTS: In all instances, immunochemical staining was positive for neuroendocrine markers, confirming the neuroendocrine nature of the tumors. The nonfunctional nature of the neoplasms was confirmed by (1) the absence of clinical symptoms traditionally attributed to neuroendocrine secretagogues and (2) the lack of gastroenteropancreatic peptide serum levels. CONCLUSIONS: Two of these three cases represent another subset of pancreatic neuroendocrine pathology: a nonfunctional cystic neoplasm. Increased clinical awareness, appropriate operation, and better immunohistochemical staining techniques may yield more, heretofore unrecognized, subtypes. These cases reemphasize the need for proper surgical exploration and biopsy of all unexplained pancreatic cystic lesions, particularly if they are multicystic.

Norepinephrine increases the economy of pressure development in isolated canine hearts.

To test for oxygen wasting by norepinephrine (NE) without relying on normalization by measures of performance such as the pressure-volume area, myocardial oxygen consumption (MVO2) was determined for isovolumic beats at five different left ventricular (LV) end-diastolic volumes (EDV) in nine isolated cross-perfused canine hearts in each of three states: a basal anesthetic state (B); after depression with halothane (H); and after adding NE to increase contractility back to the B state (H+NE). The end-diastolic and peak systolic pressure-volume lines were identical for B and H+NE. The R2 for a linear regression of MVO2 per beat for B vs. H+NE for beats originating at the same EDV and developing similar (within 10%) peak isovolumic pressures for all hearts was 0.85. The slope and intercept were 0.83 and 0.01, which are significantly less than one (P less than 0.001) and greater than zero (P less than 0.001), respectively. These data suggest that NE increases both the economy of pressure development as well as activation energy of an isovolumically contracting LV.

Protection of the hypertrophied myocardium by crystalloid cardioplegia.

Patients with left ventricular hypertrophy (LVH) have a worse outcome after cardiac surgery than those without hypertrophy. We studied protection of hearts with LVH in an isolated rat heart model using multidose, cold, oxygenated cardioplegia. LVH was produced by banding the abdominal aorta in young rats. Six weeks after banding, this produced a 31% increase in the left ventricular dry weight/body weight ratio compared to two age-matched control groups comprising sham-operated and nonoperated animals. The recovery of cardiac output after arrest was higher in LVH (82 +/- 4% of prearrest) than in sham-operated (69 +/- 4%) or nonoperated (66 +/- 3%) control groups. The improved functional recovery in LVH occurred although there were no differences among the groups in myocardial adenosine triphosphate (ATP) and phosphocreatine (PCr) prior to arrest, at the end of arrest, or after reperfusion. Glycogen levels were also similar among the three groups prior to arrest and after reperfusion but were highest in LVH after arrest. Myocardial oxygen consumption (MVO2) and efficiency, expressed as cardiac output/MVO2, were similar among the groups prior to arrest. Myocardial efficiency after reperfusion declined in all groups but was best preserved in LVH. We also compared the sensitivity of hypertrophied and control hearts to the deleterious effects of calcium in cardioplegia. Calcium in the cardioplegia increased myocardial lactate production during arrest in a dose-related fashion and depressed myocardial levels of ATP, PCr, and glycogen at end arrest in all groups. Cardiac output recovery was also depressed by calcium but was still best in LVH. We conclude that the hypertrophied myocardium is well protected by standard cardioplegia and that calcium in cardioplegia does not preferentially depress recovery in LVH.

Hip disarticulation: factors affecting outcome.

Hip disarticulation, especially in patients with peripheral vascular disease, has been associated with high morbidity and mortality rates. This report describes patient characteristics that influence the clinical outcome of hip disarticulation. The medical records of all patients undergoing hip disarticulation from 1966 to 1989 were reviewed for surgical indication, perioperative wound complications, and postoperative deaths. Fifty-three patients underwent hip disarticulation for limb ischemia (10), infection (12), infection and ischemia (14), or tumor (17). The overall incidence of wound complications was 60%, and no significant differences were found among the groups. Prior above-knee amputation and urgent/emergent operations were significantly associated with increased wound complications (p less than 0.05). The overall mortality rate was 21%, ranging from 0% (tumor) to 50% (ischemia) and differed significantly among the groups (p less than 0.02). Mortality was significantly associated with urgent/emergent operations (p less than 0.01). Age, diabetes mellitus, and previous inflow procedures did not influence mortality rates. The presence of limb ischemia influenced mortality rates to a greater extent than did infection, and a history of cardiac disease was statistically predictive of death. Wound complications frequently accompanied hip disarticulation, regardless of operative indication, and were significantly increased by urgent/emergent operations and prior above-knee amputation. Hip disarticulation can be performed with low mortality rates in selected patients. Both limb ischemia and infection substantially increase operative mortality rates.

Oxygenated cardioplegia: the metabolic and functional effects of glucose and insulin.

Reports differ as to the efficacy of glucose and insulin as cardioplegic additives. Although deliberate oxygenation of crystalloid cardioplegic solutions improves myocardial protection, little is known about the protection afforded by glucose and insulin in such oxygenated solutions. In the isolated working rat heart, we studied the addition of oxygen, glucose, and insulin, separately and together, to a cardioplegic solution. The solution was equilibrated with O2 or N2, with glucose added as a substrate or sucrose as a nonmetabolizable osmotic control, with or without insulin. Hearts were arrested for 2 hours at 8 degrees C by multidose infusions. Oxygenation decreased lactate production and improved high-energy phosphate and glycogen preservation during arrest, prevented ischemic contracture, and improved functional recovery. The addition of glucose to the oxygenated solution increased the level of adenosine triphosphate at end-arrest from 10.5 +/- 0.5 to 13.9 +/- 0.6 nmol/mg dry weight and glycogen stores from 18.7 +/- 2.5 to 35.7 +/- 5.5 nmol/mg dry weight. The further addition of insulin did not better preserve these metabolites. Improvements in functional recovery due to glucose or insulin in the oxygenated solution attained statistical significance when both additives were included. Glucose increased lactate production significantly only when the solution was nitrogenated. Insulin added to the nitrogenated glucose-containing solution increased adenosine triphosphate and glycogen levels after 1 hour of arrest; and, although insulin did not prevent ischemic contracture from developing during the latter part of arrest with profound depletion of these metabolites, functional recovery was improved. The mechanism of improved functional recovery by insulin is not clear.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of hypothalamic opioid neurons: a combined immunocytochemical and [3H]thymidine autoradiographic study.

Using a combined technique of immunocytochemistry and [3H]thymidine autoradiography, we have determined the "birth-date" of opioid peptide containing neurons in three hypothalamic nuclei. These include proopiomelanocortin neurons (indicated by ACTH immunoreactivity) in the arcuate nucleus, dynorphin A neurons in the supraoptic nucleus, and [Leu]enkephalin neurons in the periventricular nucleus. Arcuate proopiomelanocortin neurons were born very early in embryonic development, with peak heavy [3H]thymidine nuclear labelling occurring on embryonic day E12. Supraoptic dynorphin A neurons were also labelled relatively early (peak at E13). By contrast, [Leu]enkephalin neurons in the periventricular nucleus exhibited peak heavy nuclear labelling on day E14. The results indicate a differential genesis of these three opioid peptide containing neuronal groups in three different hypothalamic nuclei.

Ontogeny of opioid and related peptides in the rat cns and pituitary: an immunocytochemical study.

The development of proopiomelanocortin (POMC) derived peptides was compared to that of leucine-enkephalin ([Leu]ENK) and dynorphin A (DYN-A) immunoreactivity (i.r.) in the rat CNS and pituitary gland. POMC i.r. appeared first in hypothalamic neurons on embryonic day E12, in pituitary anterior lobe (AL) cells on E15, in pituitary intermediate lobe (IL) cells on E16, and in perikarya of the nucleus tractus solitarius on E17. In the fetal stages (E19-22), all POMC systems appeared adult-like; however, peak i.r. occurred between postnatal days P21-28. The development of alpha-MSH (a-MSH) i.r. was dissimilar to that of other POMC peptides including beta-endorphin (B-End). In contrast, both [Leu]ENK and DYN-A i.r. appeared in later embryonic stages (E16-17), and their maturation lagged behind that of POMC peptides. Peak i.r. for these latter peptides also occurred between P21-28.