Prediction of Paroxysmal Atrial Fibrillation From Complexity Analysis of the Sinus Rhythm ECG: A Retrospective Case/Control Pilot Study.

Paroxysmal atrial fibrillation (PAF) is the most common cardiac arrhythmia, conveying a stroke risk comparable to persistent AF. It poses a significant diagnostic challenge given its intermittency and potential brevity, and absence of symptoms in most patients. This pilot study introduces a novel biomarker for early PAF detection, based upon analysis of sinus rhythm ECG waveform complexity. Sinus rhythm ECG recordings were made from 52 patients with (n = 28) or without (n = 24) a subsequent diagnosis of PAF. Subjects used a handheld ECG monitor to record 28-second periods, twice-daily for at least 3 weeks. Two independent ECG complexity indices were calculated using a Lempel-Ziv algorithm: R-wave interval variability (beat detection, BD) and complexity of the entire ECG waveform (threshold crossing, TC). TC, but not BD, complexity scores were significantly greater in PAF patients, but TC complexity alone did not identify satisfactorily individual PAF cases. However, a composite complexity score (h-score) based on within-patient BD and TC variability scores was devised. The h-score allowed correct identification of PAF patients with 85% sensitivity and 83% specificity. This powerful but simple approach to identify PAF sufferers from analysis of brief periods of sinus-rhythm ECGs using hand-held monitors should enable easy and low-cost screening for PAF with the potential to reduce stroke occurrence.

MicroRNA 8059 as a marker for the presence and extent of coronary artery calcification.

Objective: MicroRNAs (miRNAs) may serve as potential biomarkers in a variety of pathologies. The aim of this study was to determine whether miRNAs could serve as blood-based markers of isolated coronary artery calcification (CAC) defined as CAC in the absence of an underlying metabolic abnormality. Methods: 24 age-matched and sex-matched patients who had been referred for elective CT coronary calcium score and angiography as part of investigation for cardiac chest pain were recruited. Peripheral venesection was performed and an Agatston calcium score was derived from the CT coronary angiogram using default software. RNA was extracted using the LeukoLOCK Total RNA Isolation System for Toray's microarray analysis and quantitative reverse transcription PCR (qRT-PCR). Results: The patients were well matched for age, sex and conventional risk factors for coronary artery disease. Microarray analysis identified lower expression of miRNA-138-2-3p, miRNA-1181, miRNA-6816-3p and miRNA-8059 in patients with coronary artery calcium score (CACS)=0 vs CACS>100. qRT-PCR confirmed significant downregulation of miRNA-8059 in patients with CACS>100 (CACS=0 vs CACS>100; P=0.03). Conclusion: miRNA-8059 may serve as a peripheral blood-based biomarker for the presence of CAC, as well as provide a platform for studying the pathophysiological basis of isolated CAC. Trial registration number: NCT01992848; Results.