Evaluation of Left Ventricular Longitudinal, Radial, and Circumferential Strains in Subjects with Normal Variations of Coronary Dominance: A Preliminary Comparative Study.

BACKGROUND: The aim of this study was to evaluate the contractile function of the left ventricular muscles in subjects with normal coronary artery and normal variations of coronary dominance. METHODS: This study was performed on 90 adult subjects with normal results of coronary arteries angiography, echocardiography, and electrocardiography. The participants were categorized into 3 groups of 30 with right-dominant, left-dominant, and codominant variations. Two-dimensional transthoracic echocardiography was performed with apical 2-, 3-, and 4-chamber views and parasternal basal, mid, and apical short-axis views. Then, images were analyzed offline using the velocity vector imaging method. In all studied groups, the mean and standard deviation of left ventricle coronary territorial longitudinal, circumferential, radial strains, and left ventricle global strains were determined. They were compared in 3 layers of sub-endocardial, myocardium, and sub-epicardial. RESULTS: In terms of longitudinal and circumferential strains, there were significant differences in the most coronary territories and global strain among the right-dominant, left-dominant and codominant groups (P < .05). No significant differences in terms of territorial and global radial strains were observed among the study groups (P > .05). CONCLUSION: Strain level decreased from endocardium to epicardium in all studied groups. Territorial and global contractile functions (longitudinal and circumferential strains) of the left ventricle vary depending on the variations of coronary arteries.

Role of electrophysiological study in patients with syncope and bundle branch block.

BACKGROUND: The finding of bundle branch block (BBB) in patients with syncope suggests that paroxysmal atrioventricular block (AVB) or ventricular tachyarrhythmia (VT) may be the cause of syncope. Guidelines for cardiac pacing and cardiac resynchronization therapy have been recommended to perform electrophysiological study (EPS) for confirming main cause of syncope. Therefore, the aim of our study was to evaluate the role of EPS in patients with syncope and BBB. MATERIALS AND METHODS: We evaluated 133 patients (mean age 63 ± 13.8 years) with past history of syncope and BBB from April 2002 to December 2010 who referred to Arrhythmia clinic in two tertiary care centers. All patients underwent EPS on admission time. The frequency distributions of AVB and VT in patients were determined. RESULTS: Left bundle branch block was diagnosed in 184 (82.1%) patients. 133 of them had preserved left ventricular ejection fraction (LVEF ≥45%) that in 91 (68.4%) of those, EPS finding was normal. In 41 (30.8%) patients AVB was reported. In 2 (1.5%) patients VT and atrioventricular nodal reentrant tachycardia were seen. Coronary artery disease was more common in patients with AVB and abnormal EPS finding (P = 0.02). CONCLUSION: Ventricular tachyarrhythmia was a rare electrophysiological finding in those with syncope, bifascicular block, and preserved LVEF. Considering cost-effect benefit, pacemaker or implantable loop recorder implantation is suggested; however, EPS may not be necessary to perform before permanent pacemaker implantation.

Comparison between QT Interval Parameters in Type 2 Diabetic and Nondiabetic Patients with Non-ST Elevation Myocardial Infarction.

BACKGROUND: QT interval parameters have been suggested as a predictor of lethal arrhythmia and mortality in patients with myocardial infarction. The aim of the present study was to compare the value of QT interval indices in patients presenting with non-ST-segment elevation myocardial infarction (NSTEMI) between a group of patients with type 2 diabetes mellitus and a nondiabetic group of patients. METHODS: This case-control study evaluated QT interval parameters in 115 patients (47 diabetic and 68 nondiabetic patients) diagnosed with NSTEMI between September 2011 and July 2012. The following QT interval indices were analyzed: maximum (max) and minimum (min) QT interval; max and min corrected QT interval (QTc); QT dispersion (QTd); and corrected QT dispersion (QTcd). All the patients were observed for ventricular arrhythmia during their hospital course and underwent coronary angiography. They were selected to undergo coronary artery bypass surgery (CABG) or percutaneous coronary angioplasty (PCI) based on their coronary anatomy. RESULTS: The mean age of the patients was 60.8 ± 11.4 years. The patients were 40.0% female and 60.0% male. There were no significant differences in clinical characters between type 2 diabetic and nondiabetic patients with NSTEMI. Compared with post-myocardial infarction patients without diabetes, those with type 2 diabetes had higher QTc max, QTd and QTcd (p value < 0.05). There was a significant difference in QTd and QTcd in the patients needing coronary revascularization with diabetes as opposed to the nondiabetics (p value = 0.035 and p value = 0.025, respectively) as well as those who had ventricular arrhythmia with diabetes (p value = 0.018 and p value = 0.003, respectively). QTcd was higher in the patients who had higher in-hospital mortality (p value = 0.047). The QTc max, QTd and QTcd were significantly (all p values < 0.05) associated with ventricular arrhythmia, QTcd with need for revascularization and QTc max with in-hospital mortality in the diabetic patients. CONCLUSION: Based on the findings of this study, it seems that type 2 diabetics with NSTEMI have greater QTc max, QTd, and QTcd and these QT parameters may have a relationship with worse cardiac outcomes and poorer prognoses.

Predictors of local venous complications resulting from electrophysiological procedures.

BACKGROUND: Thromboembolic complications resulting from radiofrequency catheter ablation (RFCA) have an overall incidence of 0.6%. Multiple intracardiac catheters are often necessary for electrophysiological study and RFCA therapy. Therefore, the placement of multiple venous sheaths in one femoral vein is always required for multiple intracardiac catheter insertion. The safety of the placement of multiple separate venous sheaths has been studied previously in a non-randomized study, but the placement of multiple sheaths via one venous line has not been fully studied. METHODS AND RESULTS: A randomized clinical trial was conducted with a total of 200 patients. We studied the safety of placing multiple sheaths via one venous line, and the effect of heparin on deep vein thrombosis (DVT) and on in situ thrombosis. DVT was not seen in our patients. We observed a significant decrease in the rate of in situ thrombosis in patients who received heparin during the procedure (28% vs 11%, p = 0.04). The type of cannulation changed the in situ thrombosis rate independently of the heparinization protocol. The rate of in situ thrombosis was higher when placing sheaths via one venous line regardless of the heparinization protocol used (16% vs 6%, p = 0.1 for the group on heparin, and 38% vs 18%, p = 0.04 for the other group). In the group cannulated with only one venous line (100 patients), heparinization significantly decreased the rate of in situ thrombosis (16% vs 38%, p = 0.023), but there was an insignificant decrease in the separate cannulation group (6% vs 18%, p = 0.12). Advanced age had no effect on thrombosis. Surprisingly, there was a significantly greater rate of in situ thrombosis (not DVT) among women than among men (26% vs 11%, p = 0.01), regardless of the heparinization protocolor the type of cannulation. CONCLUSIONS: Given the local venous complications and DVT after electrophysiological procedures, heparinization is not necessary for right-sided electrophysiological procedures. In situ thrombosis is a minor complication that can be reduced by heparinization in patients undergoing one-line cannulation and in women during longer procedures.

Induction and aggravation of atrioventricular valve regurgitation in the course of chronic right ventricular apical pacing.

AIMS: Valvular regurgitation, especially on the right side of the heart, is a common finding even in patients without endocardial pacing leads. The severity of valvular regurgitation can change after permanent pacemaker (PPM) implantation. Ventricular pacing has been shown to cause ventricular dysfunction. The purpose of this study was to evaluate the mid-term effects of right ventricular (RV) apical pacing on atrioventricular (AV) valvular regurgitation in patients with a normal left ventricular function before PPM implantation. METHODS AND RESULTS: Patients who required dual-chamber pacemakers due to a high-degree AV block were enrolled in the study. Initial echocardiography was performed before PPM implantation and re-evaluation by echocardiography was performed every 24 months thereafter. A total of 125 patients (61 male; mean age: 66.57 ± 6.45 years) were included in the study, and 115 pacemaker-dependent patients were followed up (mean ± SD; 4.08 ± 0.8 years). Echocardiography demonstrated mild tricuspid regurgitation (TR) and mitral regurgitation (MR) in 70 (60.1%) and 34 (29.6%) patients before PPM implantation, respectively. Moderate TR and MR were detected in 10 (8.7%) and 1 (0.9%) patients, respectively. Thirty-six (31.6%) patients showed moderate-to-severe TR at long-term follow-up, compared with the 10 (8.7%) patients, who had the same degree of TR before RV apical pacing (P < 0.001). Mild and moderate MR were detected in 54 (47%) and 8 (7%) patients after PPM implantation on the last echocardiography(P < 0.001). Baseline systolic pulmonary artery pressure (PAP) was 29.24 ± 8.45 mmHg, which increased to 36 ± 11 mmHg on the last echocardiography (P < 0.001). CONCLUSION: Considering the haemodynamic effects at mid-term follow-up, left ventricular dysfunction is rare in patients with RV apical pacing and normal baseline left ventricular function. Right ventricular apical pacing is associated with a significant increase in the prevalence and severity of TR and MR.