Efficacy and safety of atrial fibrillation ablation in heart failure patients with left ventricular ejection fraction less than 50

INTRODUCTION

The efficacy of catheter ablation in patients with low cardiac function has been previously reported; however, only a few studies have included mid-range ejection fraction (mrEF). This study aimed to evaluate the efficacy and safety of atrial fibrillation (AF) ablation in patients with left ventricular ejection fraction (LVEF) < 50%.

METHODS

This study retrospectively analyzed 79 patients (reduced ejection fraction [rEF]/mrEF, 38/41; paroxysmal/persistent, 37/42; heart failure hospitalizations within one year before ablation, 36 [45.6%]) who underwent the first ablation procedure at our hospital from April 2017 to December 2021. Radiofrequency ablation and cryoablation were performed for 69 and 10 patients, respectively.

RESULTS

Complications included pacemaker implantation for postoperative sick sinus syndrome in one patient and inguinal hematoma in one patient. Regarding efficacy, there were significant postoperative improvements in echocardiographic data, blood test values, and diuretic use. After a mean follow-up of 60 months, 86.1% patients had no AF recurrence. There were 9 heart failure hospitalizations (11.4%) and 5 all-cause deaths (6.3%); no significant differences were found between the rEF and mrEF groups. No significant predictors of AF recurrence were found in preoperative patient characteristics.

CONCLUSION

AF ablation in patients with LVEF <50% significantly improved cardiac and renal functions with few complications, resulting in a high non-recurrence rate and reduced heart failure.

One-step isolation of lactoferrin using immobilized monoclonal antibodies

Immunoaffinity columns made with monoclonal antibodies to either human or bovine lactoferrins were prepared to isolate human lactoferrin or bovine lactoferrin from milks by a single chromatographic step. Recoveries of human lactoferrin and bovine lactoferrin were 98 and 97%, respectively. The human lactoferrin recovered from defatted human colostrum was 98% pure with 93% iron-binding capacity. Amount of recovered bovine lactoferrin, as well as purity and iron-binding capacity, varied widely depending on the source of bovine milks and pretreatments (particularly pasteurization temperature). The best source to isolate bovine lactoferrin was raw skim milk yielding a protein 97% pure and with a 99% iron-binding capacity. Thus, immunoaffinity chromatography provides an effective one-pass isolation of highly pure human or bovine lactoferrin with reasonable recovery and iron-binding capacity.

IgA specific helper factor (alpha HF) in human colostrum

Induction of immunoglobulin secretion by human colostrum was investigated using human peripheral blood lymphocytes (PBL) and Epstein-Barr virus transformed human B lymphoblastoid cells. Stimulation of the cells with colostrum induced IgA plaque forming cells but neither IgG nor IgM plaque forming cells, indicating the occurrence of IgA specific helper factor (alpha HF) in human colostrum. alpha HF activity was eluted into fractions with an apparent molecular weight of about 80 kD by gel filtration, and with a PI range of 5.8 to 6.2 by chromatofocusing. IgA secreted by PBL stimulated with alpha HF had a similar molecular weight distribution to that of IgA in human colostrum. From these results a hypothesis is proposed; IgA-committed B cells in the mammary gland differentiate to plasma cells producing dimeric IgA after stimulation by alpha HF so that the dominant immunoglobulin in human colostrum is IgA.

[Pulsed Doppler evaluation of left ventricular pressure and pressure difference in hypertrophic obstructive cardiomyopathy]

To assess the patho-physiological severity of hypertrophic obstructive cardiomyopathy (HOCM), the systolic pressure differences caused by the functional stenosis across the outflow tract of the left ventricle must be evaluated. The present study explored and proposed a non-invasive method predicting the pressure difference across the intraventricular obstruction and the pressure proximal to the obstruction by using pulsed Doppler technique, guided by simultaneous two-dimensional echocardiography. The ultrasonic equipment recently developed in our laboratory was used. It consisted of a 3.0 MHz pulsed ultrasonic transducer with a 4.4 KHz repetition rate and a mechanical sector scanner equipped with a single concave transducer 1.3 cm in diameter having a 70 mm radius of curvature. The sample volume was approximately 3 X 3 X 3 mm. Doppler signals obtained were subjected to a real-time analyzer with a fast Fourier transformer, and were simultaneously recorded on a thermal recorder as a spectral display together with an M-mode echocardiogram, lead II ECG, phonocardiogram and mechanocardiogram. Ten adults with HOCM were the subjects in the present study. For six of the 10, good pressure tracings were obtained. The pressure differences estimated by the maximum velocity as measured from the Doppler signals at the left ventricular (LV) outflow tract and the pressure gradients as obtained by cardiac catheterization were subjected to correlative analysis. Prior to investigating the pressure differences, the site and mechanism of the outflow obstruction in HOCM were studied in two cases using two-dimensional echocardiography in the longitudinal- and short-axis views. The obstruction was produced during systole by posteroinferior displacement of the hypertrophied interventricular septum and by abnormal anterosuperior movement of the hypertrophied, and elongated anterior or posterior papillary muscles. Thus, a concentric and centripetal narrowing was formed at the midportion of the outflow tract. In some cases, a bottle-shaped chamber was clearly observed in the apical area. Ultrasonic Doppler examinations were performed by the apical approach. Flow velocity patterns in the apical region or proximal to the obstruction had two peaks with a narrow spectrum in systole. At the distal portion or downstream the obstruction had a pattern with a narrow spectrum and a sharp single peak. To measure the maximum flow velocity, Doppler velocity patterns recorded immediately distal to the obstruction were used.(ABSTRACT TRUNCATED AT 400 WORDS)

Non-invasive estimation by cross sectional echocardiography of myocardial damage in cardiomyopathy

Retrospective and prospective studies of high resolution cross sectional echocardiograms were undertaken in order to establish an ultrasonic method for the non-invasive estimation of degeneration and fibrosis of the endomyocardium in cases of cardiomyopathy. When the echocardiograms of the ventricular wall were compared with the histological specimens intense abnormal echoes were seen at the sites of myocardial degeneration and fibrosis of the ventricular wall. The abnormal echoes classified into five types: types I, II, III-1, III-2, and III-3. Type I and type III-1 echoes were the strongest followed by those of types II and III-2, and then those of type III-3. The intensity of the abnormal echoes was 5-20 decibels stronger than that from intact tissue and was closely related to the consistency and density of the diseased tissue. These findings strongly suggest that the boundary between degeneration or fibrosis and the intact normal myocardium was the source of the abnormal myocardial echoes and that the extent and the pattern of the distribution of the sites of degeneration and fibrosis in the myocardium were reflected in the echo patterns. Thus the tissue characteristics of the sites of degeneration or fibrosis of the myocardium may be determined non-invasively by measuring the echo intensity.

Isolation and characterization of human renin substrate

Human renin substrate (angiotensinogen) was purified from outdated bank plasma. Purification procedures included ammonium sulfate precipitation, DEAE-cellulose column chromatography, concanavalin A-Sepharose column chromatography, Hydroxylapatite column chromatography preparative isoelectric focusing and Ultrogel AcA 44 gel filtration. The final recovery was 10% and the specific angiotensin I content of 10.5 micrograms/mg of protein was obtained. Polyacrylamide gel and SDS-polyacrylamide gel electrophoresis and analytical ultracentrifugal analyses showed the homogeneity of the purified renin substrate. The molecular weight of 60900 was determined by sedimentation equilibrium studies. Human renin substrate was a glycoprotein containing 13% carbohydrate. Cystine could not be detected on amino acid analysis. The purified renin substrate showed the isoelectric point heterogeneity (pI, 4.6 and 4.9).