Evaluation of cardiac arrhythmia in pediatric patients with Left Ventricular Assist Device (L-VAD)

OBJECTIVE

Pediatric heart failure is an important cause of morbidity and mortality in childhood. Left ventricular assist devices (L-VAD) are used for bridging to transplantation in patients with indications for heart transplantation.

PATIENTS AND METHODS

The children included in the study were patients who underwent implantation of an L-VAD due to advanced heart failure at Ege University Faculty of Medicine Hospital between January 2009 and January 2023.

RESULTS

Of the 33 patients who underwent L-VAD implantation, 16 (48.5%) were female and 17 (51.5%) were male. The median age at surgery was 13 years (IQR, 9.5-15). The median weight was 44 kg (IQR, 25.65-52), the median height was 158 cm (IQR, 134.5-168.5), and the median body surface area was 1.37 m2 (IQR, 0.95-1.51). All patients who underwent L-VAD implantation had an echocardiographic diagnosis of dilated cardiomyopathy. The patients underwent a median of 16 (IQR, 9-21) ECGs, and the median number of 24-hour Holter ECGs obtained was 3 (IQR, 2-5). Arrhythmias that occurred after L-VAD implantation were classified as atrial and ventricular. Ventricular arrhythmia included ventricular tachycardia (VT) lasting for more than 30 seconds (sustained VT), VT lasting for less than 30 seconds (nonsustained VT), and ventricular fibrillation. Atrial arrhythmias included atrial flutter, atrial fibrillation, supraventricular tachycardia, and atrial ectopic tachycardia. During the follow-up, atrial or ventricular arrhythmias were observed in 11 (33%) patients. The most common rhythm disturbances before L-VAD implantation were ventricular arrhythmias, while after the surgery, atrial arrhythmias were found to be the most frequent. A total of 5 patients underwent cardioversion (n=2) or defibrillation (n=3) due to arrhythmia.

CONCLUSIONS

In patients undergoing L-VAD implantation, rhythm disorders that could normally lead to hemodynamic instability are frequently encountered. In these rhythm disorders, medical therapy should be attempted before resorting to cardioversion or defibrillation, and subsequently, more aggressive treatment methods should be considered.

Effects of basic fibroblast factor (bFGF) on MMP-2, TIMP-2, and type-I collagen levels in human lung carcinoma fibroblasts

Matrix metalloproteinases (MMP's) and tissue inhibitors of metalloproteinases (TIMP's) possess a preponderant role in the metabolism of the major extracellular matrix protein, collagen, and are thought to be important in the mechanism of tumor invasion. Lung cancer occupies the first position in mortality and the second position in incidence, among all cancers. In the present investigation, we studied the effect of basic fibroblast growth factor (bFGF) on collagen, matrix metalloproteinase-2 (MMP-2), and tissue metalloproteinase inhibitor-2 (TIMP-2) levels in normal and carcinoma lung tissue fibroblast cultures. MMP-2 was selected because of its high specificity in the degradation of type IV collagen, major component of the basal membrane. The effect of bFGF on MMP-2, TIMP-2, total collagen, and type I collagen levels of normal and carcinoma lung fibroblast cultures was investigated at 0, 10, and 100 ng/ml. Statistical analysis was carried out using the Mann-Whitney-U test and possible correlations were searched using the Spearman correlation analysis method. MMP-2, TIMP-2, total collagen, and type-1 collagen levels based on cell counts (10(3) cells) showed no statistically significant differences between the carcinoma and normal fibroblast cultures. However, positive correlations were found between MMP-2 and TIMP-2 in normal (P = 0.016) and carcinoma (P = 0.001) tissue fibroblast cultures. Positive correlations were also found between total collagen and TIMP-2 levels in normal and carcinoma tissue fibroblast cultures (P = 0.002 and P = 0.032). Total collagen and TIMP-2 levels also showed positive and strong correlations in all cultures except in 100 ng/ml bFGF concentrations. In addition, type I collagen and MMP-2 levels showed positive significant correlations only in normal and carcinoma control cultures, while type I collagen and TIMP-2 levels showed positive correlations in all cultures except carcinoma fibroblasts at 100 ng/ml bFGF. It may be concluded that bFGF does not affect MMP-2, TIMP-2, total collagen, and type-1 collagen levels in fibroblast cultures grown from human carcinoma and normal lung tissues. However, bFGF was noted, in vitro, to disturb the equilibrium which normally exists between the four parameters, both in normal and carcinoma tissue fibroblasts.