A Detector for Premature Atrial and Ventricular Complexes

The relationship between premature atrial complexes (PACs) and atrial fibrillation (AF), stroke and myocardium degradation is unclear. Current PAC detectors are beat classifiers that attain low sensitivity on PAC detection. The lack of a proper PAC detector hinders the study of the implications of this event and its monitoring. In this work a PAC and ventricular detector is presented. Two PhysioNet open-source databases were used: the long-term ST database (LTSTDB) and the supraventricular arrhythmia database (SVDB). A combination of heart rate variability (HRV) and morphological features were used to classify beats. Morphological features were extracted from the ECG as well as on the 4th scale of the discrete wavelet transform (DWT). After feature selection, a random forest algorithm was trained for a binary classification of PAC (S) vs. others and for a multi-labels classification to discriminate between normal (N), S and ventricular (V) beats. The algorithm was tested in a 10-fold cross-validation following a patient-wise train-test division (i.e., no beats belonging to the same patient were included both in the test and train set). The resultant median sensitivity, specificity and positive predictive value (PPV) were 99.29, 99.54, and 100% for (N), 95.83, 99.39, and 35.68% for (S), 100, 99.90, and 79.63% for (V). The proposed method attains a greater PAC and ventricular beat sensitivity and PPV than the state-of-the-art classifiers.

Reproducibility of global electrical heterogeneity measurements on 12-lead ECG: The Multi-Ethnic Study of Atherosclerosis.

Objective: Vectorcardiographic (VCG) global electrical heterogeneity (GEH) metrics showed clinical usefulness. We aimed to assess the reproducibility of GEH metrics. Methods: GEH was measured on two 10-second 12-lead ECGs recorded on the same day in 4,316 participants of the Multi-Ethnic Study of Atherosclerosis (age 69.4 ± 9.4 y; 2317(54%) female, 1728 (40%) white, 1138(26%) African-American, 519(12%) Asian-American, 931(22%) Hispanic-American). GEH was measured on a median beat, comprised of the normal sinus (N), atrial fibrillation/flutter (S), and ventricular-paced (VP) beats. Spatial ventricular gradient's (SVG's) scalar was measured as sum absolute QRST integral (SAIQRST) and vector magnitude QT integral (VMQTi). Results: Two N ECGs with heart rate (HR) bias of -0.64 (95% limits of agreement [LOA] -5.68 to 5.21) showed spatial area QRS-T angle (aQRST) bias of -0.12 (95%LOA -14.8 to 14.5). Two S ECGs with HR bias of 0.20 (95%LOA -15.8 to 16.2) showed aQRST bias of 1.37 (95%LOA -33.2 to 35.9). Two VP ECGs with HR bias of 0.25 (95%LOA -3.0 to 3.5) showed aQRST bias of -1.03 (95%LOA -11.9 to 9.9). After excluding premature atrial or ventricular beat and two additional beats (before and after extrasystole), the number of cardiac beats included in a median beat did not affect the GEH reproducibility. Mean-centered log-transformed values of SAIQRST and VMQTi demonstrated perfect agreement (Bias 0; 95%LOA -0.092 to 0.092). Conclusion: GEH measurements on N, S, and VP median beats are reproducible. SVG's scalar can be measured as either SAIQRST or VMQTi. Significance: Satisfactory reproducibility of GEH metrics supports their implementation.

Clinical correlates and outcome of the patterns of premature ventricular beats in Olympic athletes: a long-term follow-up study

Background The pattern of premature ventricular beats, as a clue to site of origin, may help identify underlying cardiac diseases. Aim To assess the value of premature ventricular beat patterns in managing athletes with ventricular arrhythmias. Methods Athletes with 50 or more isolated premature ventricular beats/24 hours, and/or multifocal and/or repetitive premature ventricular beats at baseline, and/or exercise, and/or 24-hour electrocardiograms were selected for this analysis. Premature ventricular beats were defined as ‘common’ (outflow tract or fascicular origin), or ‘uncommon’ (other morphologies and/or multifocal or repetitive). Results From 4595 athletes consecutively examined, 205 (4%, 24.6 ± 6.9 years, 67% men) were included, 118 (58%) with uncommon and 87 (42%) with common premature ventricular beats. In particular, 81 (39%) showed complex patterns; 63 (31%) right/left ventricular outflow tract origin; 24 (12%) fascicular origin; 20 (10%) right bundle branch block pattern, intermediate/superior axis, wide QRS; and 17 (8%) left bundle branch block pattern, intermediate/superior axis. Uncommon premature ventricular beat patterns were predominant among men (62% vs. 38%; P < 0.001) but not among women. Uncommon premature ventricular beats were equally prevalent in endurance, mixed and skill disciplines, but lower in power sports. Cardiac diseases were detected in 11 (5%), 10 with uncommon patterns. Over a 6-year follow-up, cardiac diseases occurred in four (0.6%/year), all with uncommon patterns. Overall, cardiac diseases at baseline and during follow-up were detected in 14/118 athletes with uncommon versus one/87 with common premature ventricular beats ( P = 0.003). Conclusions Evaluation of premature ventricular beat patterns in Olympic athletes identified cardiac diseases, requiring disqualification and/or follow-up, in 12% with uncommon versus 1% with common patterns. This result suggests that athletes with uncommon premature ventricular beat patterns should undergo comprehensive cardiac evaluation and/or serial follow-up, irrespective of gender or sporting discipline.

Cardiac disorders in dogs infected with Babesia canis

The aim of this study was to assess cardiac disorders in dogs infected with B. canis. The study included 50 dogs with babesiosis and 20 healthy control animals. All the animals had haematological tests, ECG, echocardiography and serum troponin I and CK-MB levels checked. The haematology in the group of dogs with babesiosis confirmed thrombocytopaenia in 100% of dogs, decreased haematocrit in 52% and anaemia in 46%. The most common abnormalities in ECG and echocardiography in dogs infected with protozoa included: change in appearance and/or amplitude of the T-wave (34%), increased fractional shortening (24%), an increased sinus rhythm (14%) and heart axis deviation (10%). In 19 of the 50 dogs with babesiosis, the level of serum troponin I was elevated. In 2 dogs that died from babesiosis, the troponin level I was very high. The ECG confirmed sinus tachycardia and interpolated ventricular beat in these animals. In all dogs with babesiosis that were used in the study, the serum CK-MB was high or very high and was within limits of 23.17 U/L - 369.62 U/L. The highest kinase concentration (367.33 U/L and 369.62 U/L) was observed in dogs that died due to the disease. The presented results prove that cardiac changes are common in canine babesiosis, but that most changes are nonspecific and appear to have little clinical significance. Cardiovascular assessment should be based on the assessment of the level of troponin I and CK-MB in the serum of sick animals. High concentrations of these factors might be indicators of poor prognosis.

Epicardial ablation of premature ventricular beat from right ventricular outflow tract following ineffective endocardial ablation

A case of epicardial ablation of premature ventricular beat (PVB) originating in RVOT outflow tract in an 18-year old patient with frequent symptomatic drug-induced PVB after ineffective endocardial ablation is described. Multiple RF applications by using an irrigated catheter on the side of RVOT turned out ineffective. During epicardial mapping the source of PVB also was in the RVOT area, but with a greater relative and absolute lead. In the course of epicardial ablation, PVB tended to 'heat up', pass into ventricular tachycardia followed by the tatter's arrest and then disappear. At 12-month follow-up the patient showed no ventricular arrhythmias without any antiarrhythmic drugs.