Revisit to the Prognostic Value of Premature Atrial Contraction Burden in 24-h Holter Electrocardiography for Predicting Undiagnosed Atrial Fibrillation　- A Propensity Score-Matched Study.

BACKGROUND: The optimum cut-off value of premature atrial contraction (PAC) burden (CV-PACb) in 24-h Holter electrocardiography (24-h ECG) for predicting atrial fibrillation (AF) is debatable, with few validation data.Methods and Results:We retrospectively analyzed 61 patients already diagnosed with AF (AD-AF) and 147 patients never diagnosed with AF (ND-AF), aged ≥50 years, free of heart disease, and who had undergone 24-h ECG and transthoracic echocardiography (TTE). Receiver operating characteristic analysis demonstrated that 0.4% was the optimal CV-PACb differentiating AD-AF from ND-AF, with 69% sensitivity and 72% specificity (area under the curve [AUC] 0.72; 95% confidence interval [CI] 0.65-0.79); however, the left atrial volume index was not significant (AUC 0.60; 95% CI 0.51-0.68). To verify the CV-PACb, new propensity-matched cohorts (i.e., subjects with a PAC burden ≥0.4% and <0.4%; n=69 in each group) were compared based on new detection of AF at a median follow-up of 50 months (interquartile range 12-60 months) Multivariable Cox regression analysis revealed that among 24-h ECG and TTE findings, only PAC burden ≥0.4% was independently associated with incident AF (hazard ratio 5.28; 95% CI 1.28-26.11; P=0.023). CONCLUSIONS: A high PAC burden (≥0.4%) in 24-h ECG was a reliable indicator to identify undiagnosed AF, whereas TTE parameters did not show any predictive value.

Novel Device-Based Algorithm Provides Optimal Hemodynamics During Exercise in Patients With Cardiac Resynchronization Therapy.

BACKGROUND: An adaptive cardiac resynchronization therapy (aCRT) algorithm has been described for synchronized left ventricular (LV) pacing and continuous optimization of cardiac resynchronization therapy (CRT). However, there are few algorithmic data on the effect of changes during exercise.Methods and Results:We enrolled 27 patients with availability of the aCRT algorithm. Eligible patients were manually programmed to optimal atrioventricular (AV) and interventricular (VV) delays by using echocardiograms at rest or during 2 stages of supine bicycle exercise. We compared the maximum cardiac output between manual echo-optimization and aCRT-on during each phase. After initiating exercise, the optimal AV delay progressively shortened (P<0.05) with incremental exercise levels. The manual-optimized settings and aCRT resulted in similar cardiac performance, as demonstrated by a high concordance correlation coefficient between the LV outflow tract velocity time integral (LVOT-VTI) during each exercise stage (Ex.1: r=0.94 P<0.0008, Ex.2: r=0.88 P<0.001, respectively). Synchronized LV-only pacing in patients with normal AV conduction could provide a higher LVOT-VTI as compared with manual-optimized conventional biventricular pacing at peak exercise (P<0.05). CONCLUSIONS: The aCRT algorithm was physiologically sound during exercise by patients.

Severity of myocardial fatty acid dysmetabolism induced by coronary spasm does not differ with Thrombolysis in Myocardial Infarction (TIMI) grade during intracoronary acetylcholine provocation tests.

Whether additional intracoronary acetylcholine (ACH) injections are required for severe coronary spasm without limited coronary flow in the ACH provocation test remains unclear. We used (123)I-ß-methyl-iodophenyl pentadecanoic acid ((123)I-BMIPP) to identify myocardial ischemic memory to compare the severity of myocardial fatty acid dysmetabolism among Thrombolysis in Myocardial Infarction (TIMI) grade flow.Thirteen hypertensive volunteers (mean age, 69.5 years) and 37 patients with VSA (mean age, 62.8 years) were enrolled. The patients with VSA were stratified according to TIMI flow grades of 3 (90% luminal narrowing; n = 12) or TIMI 0-2 (≥ 99% or total occlusion; n = 25) during ACH provocation tests. Two weeks after cardiac catheterization, (123)I-BMIPP myocardial scintigraphic images were obtained at 15 minutes (early) and at 4 hours (delayed) after tracer injection. The heart-to-mediastinum (H/M) ratio and washout rates (WR) were calculated from planar images.The TIMI 3 and TIMI 0-2 groups had significantly lower early and delayed H/M ratios than controls but the difference did not reach significance between the two groups (Early: 2.7 ± 0.5 versus 2.3 ± 0.4 and 2.2 ± 0.3, P = 0.024; Delayed: 2.4 ± 0.4 versus 1.8 ± 0.3 and 1.8 ± 0.3, P = 0.001). The washout rate was greater for TIMI 0-2 than the controls.The severity of myocardial fatty acid dysmetabolism did not differ between TIMI 3 and TIMI 0-2 coronary spasms. Additional ACH might not be required considering safety and the severity of coronary spams with TIMI 3 grade flow.

Polymorphic Ventricular Tachycardia with QT Interval Prolongation Due to a Brain Tumor.

We herein report the case of a 20-year-old man with a history of epilepsy who presented with frequent transient loss of consciousness (T-LOC) and polymorphic ventricular tachycardia (VT) with QT interval prolongation. Blood investigations revealed panhypopituitarism. Following a biopsy, he was diagnosed with brain germinoma. During the biopsy, he had an episode of polymorphous VT with QT prolongation. There was no recurrence of T-LOC following chemotherapy and hormone replacement therapy. This case indicates the importance of checking the QT interval in patients with T-LOC, including those with seizures and brain tumors, to ensure appropriate treatment.