Effects of cardiac resynchronization therapy on mitral regurgitation in heart failure patients

Cardiac resynchronization therapy [CRT] has been introduced as a promising therapeutic choice in heart failure [HF] patients with ventricular dyssynchrony, shown with a wide QRS. In previous study, we showed a positive effect of CRT on ejection fraction. This study aimed to evaluate the effect of CRT on the severity of mitral regurgitation [MR] quantitatively using the volumetric Doppler method in HF patients. In this prospective before-after survey, 22 HF patients with wide QRS [>/=120 ms] and NYHA class III who were included. All patients were evaluated initially for QRS width, NYHA class, MR volume, MR fraction and mitral valve area [MV area]. Biventricular pacing was done through cardiac-resynchronization device along with three pacing leads and same evaluations were done after CRT. The mean [SD] QRS width and NYHA class were significantly decreased after CRT in HF patients [p<0.001]. Also MR volume [46.9 +/- 30.2 mL vs. 27.0 +/- 26.4 mL, p<0.001] and fraction [40.1 +/- 25.5% vs. 26.8 +/- 22.7%, p=0.002] were improved following CRT. The decrease of MV area after CRT was also significant [10.6 +/- 3.0 cm[2] vs. 8.6 +/- 2.6 cm[2], p<0.001]. As MR is associated with morbidity and mortality in HF patients and the standard surgical therapy may not be practical for a majority of them, this novel treatment may improve their disease condition significantly

Comparison between QT interval parameters in type 2 diabetic and nondiabetic patients with non-ST elevation myocardial infarction

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. 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. 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. 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

Evaluation of left ventricular systolic function after cardiac resynchronization therapy in heart failure patients

Cardiac resynchronization therapy [CRT] has introduced as new treatment strategy in heart failure [HF] patients and some of its effects have been investigated. The aim of this study was to study the effectiveness of CRT in the improvement of left ventricular systolic function indicated by left ventricular ejection fraction [LVEF] in HF patients. In our prospective study 22 HF patients with NYHA class III and above, QRS duration>120 ms and EF [ejection fraction]

Hyperglycemia-induced t-wave oversensing as a cause of cardiac resynchronization therapy [CRT] failure

T-wave overs ens ing occurs when the counter starts giving dual beeps for every cardiac cycle instead of one. This usually happens when the monitoring lead displays a tall T wave, which is also sharp. R wave sensing algorithms of the devices do not sense Twave because the slow rate of the Twave is much less than that of the R wave. But the slow rate of'T'waves may change with time and also because of parameters like potassium levels and hyperglycemia. We present a 67-year-old female who underwent the implantation of cardiac resynchronization therapy [cardiac resynchronization and implantable cardioverter defibrilator [CRT-D]] because of severe left ventricular systolic dysfunction and ventricular dyssynchrony experienced recurrent inappropriate implantable cardioveYter-defibrillator [ICD] shocks and CRT failure. Device analysis showed that the CRT failure was in consequence of T-wave oversensing due to hyperglycemia. Elimination of the T-wave oversensing after hyperglycemia control conferred good biventricular pacing and good response to CRT during a 6-month follow-up period

assessment of left ventricular time-varying radius using tissue doppler imaging

Left ventricular twist/torsion is believed to be a sensitive indicator of systolic and diastolic performance. To obtain circumferential rotation using tissue Doppler imaging, we need to estimate the time-varying radius of the left ventricle throughout the cardiac cycle to convert the tangential velocity into angular velocity. The aim of this study was to investigate accuracy of measured LV radius using tissue Doppler imaging throughout the cardiac cycle compared to two-dimensional [2D] imaging. A total of 35 subjects [47 +/- 12 years old] underwent transthoracic echocardiographic standard examinations. Left ventricular radius during complete cardiac cycle measured using tissue Doppler and 2D-imaging at basal and apical short axis / levels. For this reason, the 2D-images and velocity-time data derived and transferred to a personal computer for off-line analysis. 2D image frames analyzed via a program written in the MATLAB software. Velocity-time data from anteroseptal at basal level [or anterior wall at apical level] and posterior walls transferred to a spreadsheet Excel program for the radius calculations. Linear correlation and Bland-Altman analysis were calculated to assess the relationships and agreements between the tissue Doppler and 2D-measured radii throughout the cardiac cycle. There was significant correlation between tissue Doppler and 2D-measured radii and the Pearson correlation coefficients were 0.84 to 0.97 [P<0.05]. Bland-Altman analysis by constructing the 95% limits of agreement showed that the good agreements existed between the two methods. It can be concluded from our experience that the tissue Doppler imaging can reasonably estimate radius of the left ventricle throughout the cardiac cycle