Pulmonary Right Ventricular Resynchronization in Congenital Heart Disease: Acute Improvement in Right Ventricular Mechanics and Contraction Efficiency.

BACKGROUND: Electromechanical discoordination may contribute to long-term pulmonary right ventricular (RV) dysfunction in patients after surgery for congenital heart disease. We sought to evaluate changes in RV function after temporary RV cardiac resynchronization therapy. METHODS AND RESULTS: Twenty-five patients aged median 12.0 years after repair of tetralogy of Fallot and similar lesions were studied echocardiographically (n=23) and by cardiac catheterization (n=5) after primary repair (n=4) or after surgical RV revalvulation for significant pulmonary regurgitation (n=21). Temporary RV cardiac resynchronization therapy was applied in the presence of complete right bundle branch block by atrial-synchronized RV free wall pacing in complete fusion with spontaneous ventricular depolarization using temporary electrodes. The q-RV interval at the RV free wall pacing site (mean 77.2% of baseline QRS duration) confirmed pacing from a late activated RV area. RV cardiac resynchronization therapy carried significant decrease in QRS duration (P<0.001) along with elimination of the right bundle branch block QRS morphology, increase in RV filling time (P=0.002), pulmonary artery velocity time integral (P=0.006), and RV maximum +dP/dt (P<0.001), and decrease in RV index of myocardial performance (P=0.006). RV mechanical synchrony improved: septal-to-lateral RV mechanical delay decreased (P<0.001) and signs of RV dyssynchrony pattern were significantly abolished. RV systolic stretch fraction reflecting the ratio of myocardial stretching and contraction during systole diminished (P=0.001). CONCLUSIONS: In patients with congenital heart disease and right bundle branch block, RV cardiac resynchronization therapy carried multiple positive effects on RV mechanics, synchrony, and contraction efficiency.

Prevalence and predictors of right ventricular diastolic dysfunction in peripartum cardiomyopathy.

BACKGROUND: This study aimed to assess the prevalence of right ventricular diastolic dysfunction (RVDD) and its potential predictors in peripartum cardiomyopathy (PPCM) patients. METHODS: This was a cross-sectional study carried out in Nigeria. RVDD was defined and graded using Doppler filling and myocardial tissue Doppler velocities obtained at tricuspid annular level. RESULTS: Forty-three subjects with PPCM and mean age of 26.6 ± 7.0 years were recruited over 6 months. RVDD was found in 30 (69.8 %) subjects, of whom 16 (53.3 %) had grade I, 12 (40.0 %) had grade II and 2 (6.7 %) had grade III severity. RV systolic dysfunction (RVSD), defined as RV fractional area change <35 %, was found in 88.4 %, while combined RVSD and RVDD was found in 58.1 % of patients. Subjects with RVDD had significantly higher tricuspid E/e' ratio (5.1 ± 2.8 versus 3.5 ± 1.0, p = 0.012) and prevalence of pulmonary hypertension (76.7 versus 46.2 %; p < 0.05), and lower serum selenium concentration (55.6 ± 12.1 versus 72.5 ± 12.0 µg/L, p = 0.001) than those with preserved RV diastolic function. Regression analyses showed serum selenium [odds ratio (OR) = 1.14; 95 % confidence interval (CI) = 1.0-1.3; p = 0.049] and combined RVSD and pulmonary hypertension (OR = 79.2; CI = 3.9-1593.7; p = 0.004) as the only predictors of RVDD, and serum selenium <70 µg/L increased the odds of RVDD by 6.67-fold (CI = 1.18-37.78; p = 0.032). CONCLUSIONS: Both RVDD and RVSD were common in PPCM patients. Selenium deficiency and combined RVSD and pulmonary hypertension seemed to be the only determinants of RVDD in this small cohort, a finding that needs verification in a larger sample of patients.

Alternative endocardial sites for artificial cardiac stimulation.

The conventional right ventricular stimulation can be associated with deleterious effects on cardiac function. The need for a more physiological artificial cardiac stimulation is undoubtedly one of the most important points in the area of cardiac electrotherapy. The programming algorithms for the maintenance of adequate atrioventricular conduction, the stimulation of alternative endocardial sites and the cardiac resynchronization therapy are used with the objective of attaining these goals. The stimulation of the bundle of His and the septal stimulation have been studied as alternative endocardial sites for the positioning of the electrode on the right ventricle. The septal stimulation represents a simple and practical alternative, with no additional costs involved and with potential benefits in decreasing the deleterious effects of the right ventricular stimulation. However, this alternative site involves a heterogeneous group of patients and presents conflicting results regarding its long-term clinical benefit. This article reviews the scientific evidence on the alternative sites for right ventricular stimulation, with emphasis on the safety of the procedure, the measurement of the electrophysiological parameters, assessment of the left ventricular function and the clinical follow-up of patients.

Evaluation of 107 patients with sickle cell anemia through tissue Doppler and myocardial performance index.

BACKGROUND: Sickle-cell anemia (SCA) is associated with elevated cardiac output and cardiomegaly, as demonstrated in many studies. Recently, diastolic dysfunction and pulmonary hypertension have been shown to have poor prognoses in patients with SCA. New indexes of systolic and diastolic evaluation should be used to give more information on both the adult and the pediatric populations. The objectives of this study were to determine the systolic and diastolic function of both ventricles using load-independent parameters and to evaluate cardiac findings due to transfusion or chelation therapy in patients with SCA. METHODS: We evaluated 107 patients with SCA, aged 3 to 18 years (mean age, 10.1 +/- 4.7 years). Physical exams, electrocardiography, and Doppler echocardiography were performed in all patients. These patients were compared with 70 normal children and adolescents. RESULTS: Combined systolic and diastolic function of both ventricles was evaluated by the myocardial performance index (MPI). MPI values were higher both in the left ventricles (P = .00) and in the right ventricles (P = .00) of patients with SCA compared with controls. Diastolic function was evaluated by diastolic mitral valve flow and by tissue Doppler echocardiography. E-wave deceleration time was higher in patients than in controls. Patients were divided into 2 groups: group 1 consisted of 95 nontransfused patients and group 2 of 12 patients on chronic transfusion therapy. Group 1 patients demonstrated significantly larger left ventricular mass than those in group 2. Systolic and diastolic function did not differ between patients when an 8 g/dL cutoff value of hemoglobin was used. CONCLUSION: This Doppler echocardiographic study showed that early abnormalities in systolic and diastolic function can occur at an early age in SCA, even among children and adolescents in New York Heart Association functional classes I and II.