Does Sinus Rhythm Beget Sinus Rhythm? Effects of Prompt Cardioversion on the Frequency and Persistence of Recurrent Atrial Fibrillation

Recent clinical and experimental studies have demonstrated that atrial fibrillation (AF) alters the electrical and mechanical remodeling of the atrium, which subsequently promote the maintenance and recurrence of AF. If atrial remodeling can be prevented with prompt and repeated cardioversion, the likelihood of AF recurrence may be reduced. Recent clinical studies have demonstrated that the strategies of transesophageal echocardiography facilitated early cardioversion and early repeated cardioversion may be clinically valuable in some patients who have persistent AF and recurrence of arrhythmia after the initial cardioversion. Furthermore, the use an implantable atrial defibrillator (IAD) for early repeated device-based cardioversion to maintain sinus rhythm appears to be safe and clinically feasible. Early cardioversion by IAD reduces AF burden, reverses atrial remodeling and prevents subsequent AF recurrence in selected patients without structural heart disease implanted with this device, indicating possible "sinus rhythm begets sinus rhythm". Despite encouraging initial observations, further long-term clinical studies in a larger patient population are needed to confirm this finding. Furthermore, whether the use of IAD in the fully automatic mode to provide immediate termination of AF episodes could intensify the potential beneficial effect and the clinical efficacy of this approach in patients with structural heart disease needs to be evaluated.     

CD4-T-cell antigen receptor complexes on human leukemia T cells.

CD4 and T-cell antigen receptor (TCR) comodulate from the surface of human and murine T cells following exposure to monoclonal anti-CD4 or anti-TCR. This comodulation may occur because expression of CD4 and TCR is regulated by similar transmembrane signals or because CD4 and TCR are physically associated. To study multimolecular assemblies on the plasma membrane, we developed a flow cytometric method for detecting singlet-singlet energy transfer between fluorescein isothiocyanate (FITC)- and tetramethylrhodamine isothiocyanate (TRITC)-conjugated monoclonal antibodies as sensitized TRITC emission on intact, single cells. Using this procedure, we detected CD4-TCR complexes on the surface of the transformed human leukemia T cells, HPB-ALL, in the absence of stimulation. More than one CD4 were found in association with one TCR. CD4-TCR complexes were not in rapid equilibrium with free CD4 and free TCR, and they were not induced by the dye-labeled anti-CD4 or anti-TCR.     

Thoracic Aortic Frontier: Review of Current Applications and Directions of Thoracic Endovascular Aortic Repair (TEVAR)

Thoracic endovascular aortic repair, a minimally invasive technique is replacing the maximally invasive gold standard of thoracotomy and replacement of the descending thoracic aorta. With experience, indications have expanded to encroach on the arch and even ascending aorta. This review highlights the current state of technology, discusses controversies, and takes the perspective of a forward-thinking review to describe novel, innovative techniques that might make the entire thoracic aorta amenable to minimally invasive repair.     

Visit-to-visit blood pressure variability as a prognostic marker in patients with cardiovascular and cerebrovascular diseases – Relationships and comparisons with vascular markers of atherosclerosis

Background

Visit-to-visit blood pressure variability (BPV) is a simple surrogate marker for the development of atherosclerotic diseases, cardiovascular and all-cause mortality. Nevertheless, the relative prognostic value of BPV in comparison with other established vascular assessments remain uncertain.

Methods

We prospectively followed-up 656 high-risk patients with diabetes or established cardiovascular or cerebrovascular diseases for the occurrence of major adverse cardiovascular events (MACEs). Baseline brachial endothelial function, carotid intima-media thickness (IMT) and plaque burden, ankle-brachial index and arterial stiffness were determined. Visit-to-visit BPV were recorded during a mean 18 ± 9 outpatient clinic visits.

Results

After a mean 81 ± 12 month's follow-up, 123 patients (19%) developed MACEs. Patients who developed a MACE had significantly higher systolic BPV, more severe endothelial function, arterial stiffness and systemic atherosclerotic burden compared to patients who did not develop a MACE (all P < 0.01). BPV significantly correlated with all of the vascular assessments (P < 0.01). A high carotid IMT had the greatest prognostic value in predicting development of a MACE (area under receiver operating characteristic curve (AUC) 0.69 ± 0.03, P < 0.01). A high BPV also had moderate prognostic value in prediction of MACE (AUC 0.65 ± 0.03, P < 0.01). After adjustment of confounding factors, a high BPV remained a significant independent predictor of MACE (hazards ratio 1.67, 95% confidence interval 1.14-2.43, P < 0.01).

Conclusions

Compared with established surrogate markers of atherosclerosis, visit-to-visit BPV provides similar prognostic information and may represent a new and simple marker for adverse outcomes in patients with vascular diseases.     

The CHADS2 and CHA2DS2-VASc scores predict adverse vascular function,ischemic stroke and cardiovascular death in high-risk patients without atrial fibrillation: Role of incorporating PR prolongation

Objectives

To investigate whether the CHADS₂ and CHA₂DS₂-VASc scores have clinical utility for prediction of adverse vascular function and vascular dysfunction-mediated incident cardiovascular (CV) events among high-risk patients without atrial fibrillation (AF), and the additional value of incorporating PR prolongation to the scores.

Methods

We analyzed 579 high-risk CV outpatients without clinical AF in a prospective cohort for new-onset ischemic stroke, myocardial infarction (MI), congestive heart failure (CHF), and CV death. Brachial flow-mediated dilation (FMD) and nitroglycerin-mediated dilatation (NMD), carotid intima-media thickness (IMT) and pulse wave velocity (PWV) were determined.

Results

Baseline CHADS₂ score was associated with lower FMD (Pearson r = −0.16, P < 0.001) and NMD (r = −0.17, P < 0.001), higher carotid IMT (r = 0.30, P < 0.001) and PWV (r = 0.35, P < 0.001; similar for CHA₂DS₂-VASc score: All P < 0.05). After follow-up of 63 ± 11 months, 82 patients (14.2%) developed combined CV endpoint. ROC curve analysis showed that both CHADS₂ and CHA₂DS₂-VASc scores were predictors for ischemic stroke (C-Statistic: CHADS₂ 0.70, P = 0.004; CHA₂DS₂-VASc 0.68, P = 0.010), MI (CHADS₂ 0.63, P = 0.030; CHA₂DS₂-VASc 0.70, P = 0.001), and CV death (CHADS₂ 0.63, P = 0.022; CHA₂DS₂-VASc 0.65, P = 0.011). Higher CHADS₂ score was associated with reduced event-free survival from combined CV endpoints (log-rank = 16.7, P < 0.001) with differences potentiated if stratified by CHA₂DS₂-VASc score (log-rank = 29.2, P < 0.001). Incorporating PR prolongation, the CHA₂DS₂-VASc-PR score achieved the highest C-Statistic for CV death prediction (0.70, P < 0.001) superior to the CHADS₂ score (chi-square: 12.1, P = 0.0005).

Conclusions

The CHADS₂ and CHA₂DS₂-VASc predict vascular dysfunction and cardiovascular events in high-risk CV patients without clinical AF, with further improved performance incorporating PR prolongation.