Effective prediction of response to cardiac resynchronization therapy using a novel program of gated myocardial perfusion single photon emission computed tomography.

Aims: The limitation of QRS duration as a surrogate measure for left ventricular (LV) mechanical dyssynchrony (LVMD) in cardiac resynchronization therapy (CRT) patient selection encourages seeking alternatives to QRS duration. Exploring the potential of an analysis program of electrocardiographically gated myocardial perfusion single photon emission computed tomography (SPECT) (GMPS) for the estimation of LVMD to predict CRT response.

Methods And Results: Twenty-four patients undergoing CRT for advanced heart failure caused by non-ischaemic cardiomyopathy were studied.

The role of echocardiography in predicting responders to cardiac resynchronization therapy.

Background: This multicenter prospective cohort study aimed to identify both ability of echocardiographic parameters to detect cardiac resynchronization therapy (CRT) volume responders and relation of these parameters with clinical outcomes.

Methods And Results: CRT responder was defined as ≥ 15% reduction of left ventricular (LV) end-systolic volume at 6 months. Seven echocardiographic dyssynchrony parameters were evaluated.

Difference in percentage of ventricular pacing between two algorithms for minimizing ventricular pacing: results of the IDEAL RVP (Identify the Best Algorithm for Reducing Unnecessary Right Ventricular Pacing) study.

Aims: Managed ventricular pacing (MVP) and Search AV+ are representative dual-chamber pacing algorithms for minimizing ventricular pacing (VP). This randomized, crossover study aimed to examine the difference in ability to reduce percentage of VP (%VP) between these two algorithms.

Methods And Results: Symptomatic bradyarrhythmia patients implanted with a pacemaker equipped with both algorithms (Adapta DR, Medtronic) were enrolled.

Quantitative assessment of dyssynchrony using ECG-gated SPECT myocardial perfusion imaging prior to and following cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) assists patients with advanced heart failure (HF) by improving left ventricular (LV) dyssynchrony, but there are significant numbers of non-responders, 1 reason being that the QRS duration is used as the only surrogate determinant of mechanical dyssynchrony, so an effective indicator of LV dyssynchrony is required. The present patient, who had HF, underwent CRT and showed clinical improvement with marked LV reverse remodeling. The regional contraction timing in the LV was assessed with software developed in an application on ECG-gated SPECT myocardial perfusion imaging that depicts the time-volume relationship of the segmented ventricular myocardium and the dispersion of time to end-systole as an expression of dyssynchrony.

Noninvasive risk stratification of subjects with a Brugada-type electrocardiogram and no history of cardiac arrest.

Background: Recent studies suggest that the Brugada-type electrocardiogram (ECG) is much more prevalent than the manifest Brugada syndrome. Although invasive electrophysiologic investigations have been proposed as a risk stratifier, their value is controversial, and alternative noninvasive techniques may be preferred. We sought a noninvasive strategy to detect a high-risk group in a long-term follow-up study of subjects with a Brugada-type ECG, and no history of cardiac arrest.

Relationship between ST-segment morphology and conduction disturbances detected by signal-averaged electrocardiography in Brugada syndrome.

Background: Although arrhythmogenesis of Brugada syndrome is still unknown, it has been reported to be associated with conduction disturbances. Two ST-segment morphologies (coved and saddle-back patterns) have been described in this syndrome. No study has sought to determine which morphology has stronger conduction disturbances, thereby associating with life-threatening events.

Time course for resolution of left atrial appendage stunning after catheter ablation of chronic atrial flutter.

Objectives: This study assessed the time course of resolution of left atrial appendage (LAA) stunning after catheter ablation of chronic atrial flutter (AFL).

Background: Although the presence of LAA stunning after ablation of chronic AFL calls for anticoagulation in the post-cardioversion period, limited information has been obtained, particularly regarding its duration.

Methods: Sixteen patients who underwent ablation of chronic, pure AFL were studied, only five of whom had structural heart disease and one of whom had a reduced left ventricular ejection fraction.

Evaluation of bi-atrial pacing and single site right atrial pacing for the prevention of atrial fibrillation.

Atrial resynchronization resulting from simultaneous pacing of the atria may adjust inter- or intra-atrial asynchrony and prevent atrial fibrillation (AF). The purpose of this study was to assess the efficacy of bi-atrial pacing (BAP) in preventing AF, and the safety of this system. The effect of BAP was compared with single site right atrial pacing (RAP) in 6 patients with sick sinus syndrome and paroxysmal AF in a prospective switchover trial.