Selective catheter ablation of the tachycardia focus in patients with nonreentrant junctional tachycardia

We describe a technique for ablation of junctional tachycardia focus by means of examining the earliest atrial activation sequence during tachycardia. The procedure was successful in 7 of 9 patients, and 1 developed complete atrioventricular block.

Combined alpha-beta blockade (doxazosin plus metoprolol) compared with beta blockade alone in chronic congestive heart failure

There has been growing evidence for the benefits of beta blockers, but alpha blockers have not shown sustained benefits in chronic congestive heart failure (CHF). Thirty patients with moderate to severe CHF (New York Heart Association class II to IV) were sequentially assigned to receive metoprolol 6.25 mg with the alpha-1 antagonist doxazosin 4 mg/day or metoprolol alone. The dose of metoprolol was gradually increased to a target dose of 50 mg orally twice daily. Hemodynamic measurements were obtained before drug therapy, 2 hours after the first dose of combined alpha-beta therapy or metoprolol alone, and after 3 months of continuous treatment. Nuclear ejection fraction, plasma norepinephrine, and submaximal and maximal exercise capacity were also measured before and after chronic therapy. With initial combined drug administration, mean arterial pressure, left ventricular filling pressure, and systemic vascular resistance decreased significantly compared with results after metoprolol alone. However, after 3 months of continuous therapy, both treatment groups showed similar and significant reductions in systemic vascular resistance and heart rate, with significant increases in cardiac index, stroke volume index, stroke work index, ejection fraction, and exercise capacity. Furthermore, the next dose of chronic combined medication no longer showed vasodilating effects. Chronic therapy with fixed-dose doxazosin and increasing doses of metoprolol produced identical effects as those seen in patients receiving metoprolol alone.

Safety and efficacy of beta blockade in patients with chronic congestive heart failure awaiting transplantation

BACKGROUND

Donor availability remains a limiting factor for heart transplantation while transplant waiting time entails significant morbidity and mortality. This study was designed to assess the efficacy and safety of long-term beta blockade as optimization of therapy in patients with severe congestive heart failure already receiving digoxin, diuretics, and converting enzyme inhibitors awaiting transplantation.

METHODS

The beta-1 antagonist metoprolol was given to 19 patients with moderate to severe congestive heart failure. Hemodynamic, clinical, and neurohormonal measurements were obtained before drug therapy and after 3 months of treatment. Patients initially received 6.25 mg of metoprolol orally twice daily which was increased to a target dose of 50 mg twice daily over several weeks.

RESULTS

Metoprolol produced significant clinical, exercise, and hemodynamic benefits. Long-term therapy was associated with improvements in New York Heart Association class, ejection fraction, 6-minute walk, and peak maximal oxygen consumption. There were significant decreases in heart rate, pulmonary arterial systolic pressure, and left ventricular filling pressure with significant increases in stroke volume index and stroke work index. Four patients were removed from the transplant list after improving to New York Heart Association I. Only one patient required hospitalization during the first 6 months of therapy. There were no deaths caused by progressive heart failure; however, one patient died suddenly.

CONCLUSIONS

Beta blockade with metoprolol can be safely administered to patients awaiting heart transplantation producing clinical, exercise, and hemodynamic improvements. Thus, beta blockade may prove to be a safe and cost-effective bridge to transplantation.

A feminist perspective on the study of home birth. Application of a midwifery care framework

Studies of home birth have compared it with hospital birth, with a focus on perinatal outcomes. Although such studies have established the safety of midwife-attended home births, this narrow view does not include all of the concepts represented in a proposed midwifery care framework derived from the philosophy of the American College of Nurse-Midwives. In this essay, the authors recommend the employment of qualitative research with a feminist perspective as a method to elucidate other concepts in the midwifery care framework, and suggest that future home birth research should explore the recognition and validation of the woman and her experiences, appropriate use of technology, and the influences of the birth environment.

Radiofrequency catheter ablation of tachyarrhythmias--adult and paediatric experience

BACKGROUND AND AIMS

Until recently, curative therapy for supraventricular tachycardia (SVT) was possible only with map-guided cardiac surgery. The ability to ablate permanently the reentrant circuit responsible for tachycardia using radiofrequency electrical current (RF) delivered through a catheter has now allowed cure of SVT by non-surgical means. We present our initial experience with this technique in both adult and paediatric patients.

METHODS

In 53 patients of median age 32 years, 56 radiofrequency catheter ablation procedures were performed for control of tachyarrhythmias. Fourteen patients were aged 18 years or less. Indications for RF ablation were SVT due to an accessory pathway (n = 27), SVT due to atrioventricular junctional reentry (AVJRT) (n = 22), incessant SVT (n = 2), ventricular tachycardia (n = 2), and uncontrolled atrial fibrillation (n = 3). General anaesthesia was used in 88% of procedures. Ablation was preceded by electrophysiological testing to confirm tachycardia mechanism in all cases.

RESULTS

The ablation procedure was completely successful in 49/56 cases (87.5%) and partially successful in another two cases. Only five procedures (9%) failed. Median procedure time was two hours, median fluoroscopy time was 24 min, and the median number of RF applications was four. There were no major differences in results comparing adult and paediatric patients. A transient ulnar nerve palsy was the only major complication observed. After a follow-up of one to 15 months, tachycardia has recurred in two patients (4%). Of the total 53 patients, 90.5% are currently asymptomatic and off all cardiac drug therapy. RF catheter ablation appears to be an effective, curative, and relatively safe alternative to long term drug therapy in the management of troublesome SVT.

Elevated circulating tumor necrosis factor levels in Alzheimer's disease

Recent investigations have demonstrated a local inflammatory response in Alzheimer's disease (AD), including microglia and cytokines. Levels of the cytokine tumor necrosis factor alpha (TNF-alpha) in sera from patients with AD and age-matched controls were measured by an enzyme-linked immunoassay and a cytotoxicity bioassay. Significantly elevated levels of TNF were found in AD sera compared to controls. Elevated circulating TNF may be derived from the local CNS inflammatory reaction in AD, and may account for some systemic manifestations of AD such as weight loss. Future studies may determine if, in the absence of complicating disorders which may elevate TNF, circulating TNF could be a marker of AD inflammatory activity.

Elevated circulating levels of tumor necrosis factor in severe chronic heart failure

BACKGROUND AND METHODS

Although cachexia often accompanies advanced heart failure, little is known about the causes of the cachectic state. To assess the potential role of tumor necrosis factor in the pathogenesis of cardiac cachexia, we measured serum levels of the factor in 33 patients with chronic heart failure, 33 age-matched healthy controls, and 9 patients with chronic renal failure.

RESULTS

Mean (+/- SEM) serum levels of tumor necrosis factor were higher in the patients with heart failure (115 +/- 25 U per milliliter) than in the healthy controls (9 +/- 3 U per milliliter; P less than 0.001). Nineteen of the patients with chronic heart failure had serum levels of tumor necrosis factor greater than or equal to 39 U per milliliter (greater than 2 SD above the mean value for the control group), whereas the remaining 14 patients had serum levels of tumor necrosis factor below this level. The patients with high levels of tumor necrosis factor were more cachectic than those with low levels (82 +/- 3 vs. 95 +/- 6 percent of ideal body weight, respectively; P less than 0.05) and had more advanced heart failure, as evidenced by their higher values for plasma renin activity (2.92 +/- 0.53 vs. 1.06 +/- 0.53 ng per liter per second [10.5 +/- 1.9 vs. 3.8 +/- 1.9 ng per milliliter per hour]; P less than 0.01) and lower serum sodium concentration (135 +/- 1 vs. 138 +/- 1 mmol per liter; P less than 0.05). The group with high levels of tumor necrosis factor also had lower hemoglobin levels (7.82 +/- 0.2 vs. 8.69 +/- 0.4 mmol per liter [12.6 +/- 0.4 vs. 14.0 +/- 0.6 g per deciliter]) and higher values for blood urea nitrogen (19.5 +/- 2.2 vs. 12.5 +/- 1.8 mmol per liter) than the group with low levels of tumor necrosis factor (P less than 0.05 for both). The high levels of tumor necrosis factor were not due solely to decreased renal clearance, however, since the levels in the patients with heart failure were considerably higher than those in the nine patients with chronic renal failure (115 +/- 25 vs. 45 +/- 25 U per milliliter; P less than 0.05).

CONCLUSIONS

These findings indicate that circulating levels of tumor necrosis factor are increased in cachectic patients with chronic heart failure and that this elevation is associated with the marked activation of the renin-angiotensin system seen in patients with end-stage cardiac disease.

Primary treatment of regional and disseminated pancreatic cancer with hexamethylmelamine, mitomycin C and 5-fluorouracil infusion

Hexamethylmelamine, mitomycin C and 5-fluorouracil infusion (HexMF) achieved a median survival of 9 months for the 45 patients with either metastatic stage III or unresectable stage II carcinoma of the pancreas. Fifteen percent survived 2 years. Of 32 patients with measurable tumors, 7 had partial and 3 had minor responses (31%); an additional 44% has stable disease for 3 months or more. Response was associated with a 17-month median survival. These findings are indications for further evaluation of both dosage-intensive 5-fluorouracil infusions alone and HexMF as an alternative to streptozotocin- or adriamycin-containing regimens. Patients with nonmeasurable disease are candidates for survival-oriented phase III studies.

Stimulation of prostacyclin formation by the platelet-derived growth factor--an important pathomechanism for atherogenesis?

The capacity of vascular tissue in generating PGI2 has been accepted to be a key property in hemostatic balancing at a local level. Earlier it has been shown that PDGF is able to enhance SMC-proliferation. As this process is associated with c-AMP changes which again are influenced by PGI2, the question arose, whether PDGF itself exerts an effect on PGI2-synthesis. Using normal and atherosclerotic human arterial tissue, animal arteries and cultured cells with and without addition of various PDGF-concentrations this question was answered by means of bioassay and RIA-determination in a static and a pulsatile perfusion chamber system as well. In general, between 10 and 50 ng PDGF/ml, a significant increase either in PGI2-formation or 6-oxo-PGF1 alpha can be seen. A similar dose dependent stimulation of PGI2-synthesis can be monitored for vascular tissue and cultured cells as well. Static incubation and perfusion chamber experiments reveal comparable findings of PDGF stimulatory capacity on PGI2-formation. In contrast, no such effect can be seen using human umbilical artery. The half-life of PGI2-formation in the perfusion chamber model is comparable in presence and absence of PDGF as well. The stimulatory effect of PDGF on atherosclerotic vascular tissue is significantly less pronounced than onto normal one. Concluding from our findings we speculate that PGI2 prevents PDGF-release from platelets, thus decreasing smooth muscle cell proliferation and improving cellular lipid metabolism; an insufficient response of vascular tissue onto PDGF to generate PGI2 might be a key event in the pathogenesis of early atherosclerosis favouring a negative vicious cycle.