A study on stability analysis of atrial repolarization variability using ARX model in sinus rhythm and atrial tachycardia ECGs

© 2016 Elsevier Ireland Ltd Background The interaction between the PTa and PP interval dynamics from the surface ECG is seldom explained. Mathematical modeling of these intervals is of interest in finding the relationship between the heart rate and repolarization variability. Objective The goal of this paper is to assess the bounded input bounded output (BIBO) stability in PTa interval (PTaI) dynamics using autoregressive exogenous (ARX) model and to investigate the reason for causing instability in the atrial repolarization process. Methods Twenty-five male subjects in normal sinus rhythm (NSR) and ten male subjects experiencing atrial tachycardia (AT) were included in this study. Five minute long, modified limb lead (MLL) ECGs were recorded with an EDAN SE-1010 PC ECG system. The number of minute ECGs with unstable segments (N us ) and the frequency of premature activation (PA) (i.e. atrial activation) were counted for each ECG recording and compared between AT and NSR subjects. Results The instability in PTaI dynamics was quantified by measuring the numbers of unstable segments in ECG data for each subject. The unstable segments in the PTaI dynamics were associated with the frequency of PA. The presence of PA is not the only factor causing the instability in PTaI dynamics in NSR subjects, and it is found that the cause of instability is mainly due to the heart rate variability (HRV). C onclusion The ARX model showed better prediction of PTa interval dynamics in both groups. The frequency of PA is significantly higher in AT patients than NSR subjects. A more complex model is needed to better identify and characterize healthy heart dynamics

Large free-floating left atrial thrombus with normal mitral valve

Left atrial thrombus in the presence of diseased mitral valve and atrial fibrillation is a well known entity. But it is very rare to occur in the presence of normal mitral valve apparatus. We report the case of a 36 year old female who presented with left atrial ball valve thrombus and normal mitral valve apparatus and underwent surgery. This patient with gangrene of right lower limb came for cardiac evaluation. She had infarct in left middle cerebral artery territory- ten months prior to this admission and was on treatment for infertility. She had atrial fibrillation. Emergency surgery to remove the thrombus should be considered given its potential life threatening embolic nature

Tenecteplase versus streptokinase thrombolytic therapy in patients with mitral prosthetic valve thrombosis

Objective: Prosthetic valve thrombosis (PVT) is a dreadful complication of mechanical prosthetic valves. Thrombolytic therapy (TT) for PVT is an alternative to surgery and currently making a leading role. This study compares TT with tenecteplase (TNK) and streptokinase (SK) head to head in patients with mitral PVT. Methods: In this single center, observational study, patients with mitral PVT diagnosed by clinical data, transthoracic echocardiography, transesophageal echocardiography, and fluoroscopy were included. After excluding patients with contraindications for thrombolysis, they were randomly assigned to receive either SK or TNK regimen. Patients were monitored for success or failure of TT and for any complications. Results: Among 52 episodes (47 patients with 5 recurrences) of mechanical mitral PVT, 40 patients were thrombolyzed with SK and 12 patients were thrombolyzed with TNK. Baseline characteristics including demographic profile, clinical and echocardiographic features, and valve types were not statistically significant between the groups. Complete success rate was 77.5% in SK group and 75% in TNK group (p = 0.88). Partial success rate, failure rate, and major complications were not statistically significant between the two groups. Within 12 h of therapy, TNK showed complete success in 33.3% of patients compared to 15% in SK group (p-value <0.02). Minor bleeding was more common in TNK group. Conclusion: Slow infusion of TNK is equally efficacious but more effective than SK in the management of mitral mechanical PVT. 75% to 77.5% of PVT patients completely recovered from TT and it should be the first line therapy where the immediate surgical options were remote. Keywords: Prosthetic valve thrombosis, Thrombolytic therapy, Tenecteplase, Streptokinas

An echocardiographic assessment of cardiovascular hemodynamics in patients with large pleural effusion

Background: The close relationship between pleural space and pericardial space and the dependence of their pressure kinetics are well known. This study evaluates the effects of increased intra pleural pressure due to pleural effusion on cardiovascular system. Methods: Forty patients above the age of 12 who had massive unilateral/bilateral pleural effusion due to non-cardiac etiology were included in the study. Therapeutic thoracocentesis was done for massive pleural effusion. The echocardiographic parameters measured before and after thoracocentesis were compared. Results: Mean age of the patients 46.6 years. Out of 40 patients 8 were females (20%). 7 patients had right atrial collapse on echo. 85% of patients had significant flow velocity changes across both tricuspid valve and mitral valve during phases of respiration.11 patients (47.82%) had IVC compressibility of <50% during inspiration. Mean flow velocity respiratory variations across tricuspid valve before thoracocentesis and after thoracocentesis E 45.04 ± 10.3,32 ± 11.3% (p value <0.001), A 53.71 ± 28%, 32.08 ± 12.5% (p < 0.001) across mitral valve E 32.30 ± 12%, 19.78 ± 7.8% (p < 0.001), A 26 ± 11.2%, 21 ± 9.3% (p 0.006) across pulmonary artery 42.63 ± 31.3%, 17.70 ± 6.2% (p < 0.001), across aorta 21.57 ± 11.4%, 14.08 ± 7.6% (p < 0.001). Conclusion: Large pleural effusion has a potential to cause adverse impact on the cardiovascular hemodynamics, which could manifest as tamponade physiology. Altered cardiac hemodynamics could be an important contributor in the mechanism of dyspnea in patients with large pleural effusion

Outcomes of ST Segment Elevation Myocardial Infarction without Standard Modifiable Cardiovascular Risk Factors – Newer Insights from a Prospective Registry in India

Objectives: Patients with ST elevation myocardial infarction (STEMI) without standard modifiable cardiovascular risk factors (SMuRFs; dyslipidaemia, hypertension, diabetes mellitus and smoking) are reported to have a worse clinical outcome compared to those with SMuRFs. However, robust prospective data and low-and middle-income country perspective are lacking. We aimed to study the patients with first STEMI and assess the influence of SMuRFs on clinical outcomes by comparing the patients with and without SMuRFs. Methods: We included all consecutive STEMI patients without prior coronary artery disease enrolled in the Madras Medical College STEMI Registry from September 2018 to October 2019. We collected baseline clinical characteristics, revascularisation strategies and clinical outcome. We analysed suboptimal self-reported sleep duration as a 5th extended SMuRF (eSMuRF). Primary outcome was in-hospital mortality. Secondary outcomes included in-hospital complications and one-year all-cause mortality. Results: Among 2,379 patients, 605 patients (25.4%) were SMuRF-less. More women were SMuRF-less than men (27.1% vs 22.1%; P = 0.012). SMuRF-less patients were older (57.44 ± 13.95 vs 55.68 ± 11.74; P < 0.001), more often former tobacco users (10.4% vs 5.0%; P < 0.001), with more anterior wall MI (62.6% vs 52.1%; P = 0.032). The primary outcome [in-hospital mortality (10.7% vs 11.3%; P = 0.72)] and secondary outcomes [in-hospital complications (29.1% vs 31.7%; P = 0.23) and one-year all-cause mortality (22.3% vs 22.7%; P = 0.85)] were similar in both groups. Addition of suboptimal self-reported sleep duration as a 5th eSMuRF yielded similar results. Conclusions: 25% of first STEMI patients were SMuRF-less. Clinical outcomes of patients without SMuRFs were similar to those with SMuRFs. Suboptimal sleep duration did not account for the risk associated with the SMuRF-less status