The role of the fragmented QRS complexes on a routine 12-lead ECG in predicting non-responsiveness to cardiac resynchronization therapy.

OBJECTIVE: Cardiac resynchronization therapy (CRT) is introduced as a promising therapeutic option in heart failure (HF) patients with ventricular dyssynchrony.The challenge, however, is identifying the patients who are suitable candidates for this procedure. Fragmented QRS (fQRS) is associated with subendocardial fibrosis and myocardial scars. In this study, we aimed to evaluate the role of fragmented QRS complex on a routine 12-lead ECG as a predictor of response to CRT. METHODS: Sixty-five consecutive patients with HF who underwent CRT, were studied. Patients' resting 12-lead ECGs were analyzed to find presence of fQRS by a cardiologist. Echocardiographic response to CRT was defined as ≥15% decrease in left ventricular end-systolic volume (LVESV) after CRT implantation. Response to CRT was compared between patients with and without fQRS. RESULTS: The study group included 27 women (41.5%) and 38 men (58.5%) with a mean (±SD) age of 62±12 years. 27 patients (41.5%) had fQRS in their basal ECGs. Totally 46 patients (70.8%) responded to CRT in a way that the mean left ventricular ejection fraction (%) significantly increased, and left ventricular end diastolic volume (LVEDV) significantly decreased after CRT (p<0.001 and p=0.001 respectively). In multivariate logistic analysis, lack of fQRS was found to be a predictor of response to CRT (OR: 4.553, 95% CI: 1.345-15.418, p=0.015). CONCLUSION: We showed that the fQRS complex, as a sign of myocardial scar, predicts non-responsiveness to CRT. Therefore, fQRS may help selecting of CRT candidates.

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.

Signal-averaged electrocardiography in patients with advanced heart failure: a better indicator of left ventricular enlargement compared with conventional electrocardiography.

BACKGROUND: The signal-averaged electrocardiography is a noninvasive method to evaluate the presence of the potentials generated by tissues activated later than their usual timing in the cardiac cycle. The purpose of this study was to demonstrate the correlation between the filtered QRS duration obtained via the signal-averaged electrocardiography and left ventricular dimensions and volumes and then to compare it with the standard electrocardiography. METHODS: We included patients with advanced systolic left ventricular dysfunction (ejection fraction ≤ 35%). All the patients underwent surface twelve-lead electrocardiography, signal-averaged electrocardiography, and echocardiography. RESULTS: The study included 86 patients with a mean age of 54.66 ± 13.23 years. The mean left ventricular ejection fraction was 18.31 ± 5.49%; the mean QRS duration was 0.14 ± 0.02 sec; and 52% of the patients had left bundle branch block. The mean filtered QRS duration was 145.87 ± 24.89 ms. Our data showed a significant linear relation between the filtered QRS duration and left ventricular end-systolic volume, left ventricular end-diastolic volume, left ventricular end-systolic diameter, and left ventricular end-diastolic diameter; the correlation coefficient was, however, not good. There was no significant correlation between the QRS duration and left ventricular diameters and volumes. CONCLUSION: The filtered QRS duration has a better correlation with left ventricular dimensions and volumes than does the QRS duration in the standard electrocardiography.

Significance of signal averaged electrocardiography in patients with advanced heart failure and intraventricular conduction delay.

AIMS: Signal averaged electrocardiography is a noninvasive method to evaluate the presence of the potentials that are generated by tissues, activated later than their usual timing in the cardiac cycle. The purpose of this study was to demonstrate the correlation of data obtained via signal averaged electrocardiography and left ventricular dyssynchrony. METHODS: We included the patients with advanced systolic left ventricular dysfunction (ejection fraction

Prediction of response to cardiac resynchronization therapy using simple electrocardiographic and echocardiographic tools.

AIMS: To predict response to cardiac resynchronization therapy (CRT) in patients with heart failure (HF) and intraventricular conduction delay. METHODS AND RESULTS: The study population consisted of 82 consecutive HF patients with standard CRT indications. Patients were classified as responders, if they were alive without cardiac decompensation and experienced >or=15% decrease in left ventricular end-systolic volume. Sixty-eight percent of the enrolled patients responded to CRT. When compared with non-responders, responders had a wider baseline QRS width (P = 0.001), more marked QRS shortening (DeltaQRS) immediately after CRT (P = 0.001), and a better improvement in aortic velocity time integral (VTI) 24 h after CRT (P = 0.02). Moreover, there was a trend towards a greater baseline intraventricular dyssynchrony in the responder group (P = 0.07). By multivariable logistic regression, the baseline QRS width (OR: 0.95, 95% CI: 0.90-0.97, P = 0.001), DeltaQRS (OR: 1.038, 95% CI: 1.012-1.064, P = 0.003), and acute aortic VTI (OR: 0.81, 95% CI: 0.68-0.96, P = 0.017) emerged as independent predictors of response to CRT. Receiver operating characteristic curve analysis identified a QRS width >145 ms, DeltaQRS >20 ms, and aortic VTI >14 cm to predict responders. CONCLUSION: A positive response to CRT was observed in 68% of the patients. Cardiac resynchronization therapy response is predictable using simple electrocardiographic and echocardiographic data.

Effect of right ventricular lead location on response to cardiac resynchronization therapy in patients with end-stage heart failure.

AIMS: It is currently recommended to implant the left ventricular (LV) pacing lead at the lateral wall. However, the optimal right ventricular (RV) pacing lead location for cardiac resynchronization therapy (CRT) remains controversial. We sought to investigate whether optimizing the site for placement of the RV lead could further improve the long-term response to CRT in patients with advanced heart failure. METHODS AND RESULTS: Between October 2006 and December 2007, a total of 73 consecutive patients with standard indication for CRT were enrolled. The enrolled patients were divided into two groups based on the RV lead location. There were 50 patients in RV apex (RVA) group and 23 patients in RV high septum (RVHS). The primary study endpoint was a decrease in LV end-systolic volume (LVESV) by >15% at 6-month follow-up. The secondary endpoints were improvement in New York Heart Association (NYHA) class by >or=1 point and decrease in brain-type natriuretic peptide (BNP) levels by >50% after CRT. At 6-month follow-up, improvement in NYHA class by >or=1 point (RVA: 72% vs. RVHS: 74%, P = 0.76), decrease in LVESV by >or=15% (RVA: 65% vs. RVHS: 64%, P = 0.76), and decrease in BNP level by >50% (RVA: 70% vs. RVHS: 69%, P = 0.88) were observed in similar proportion of the two groups. When we separately assessed the significance of RV pacing site in three LV stimulation sites, there were no significant differences in terms of clinical improvement (62 vs. 64%, P = 0.74) and decrease in LVESV by >15% (63 vs. 62%, P = 0.78) between RVA and RVHS pacing when the LV stimulation site was lateral cardiac vein. In anterolateral vein pacing site, the RVA stimulation was associated with higher clinical (88 vs. 47%, P = 0.05), echocardiographic (75 vs. 32%, P = 0.02), and neurohormonal responses (80 vs. 50%, P = 0.04) compared with that in RVHS site. When LV was paced from posterolateral vein, RVHS pacing was superior to RVA in terms of the clinical improvement (85 vs. 35%, P = 0.01), echocardiographic response (72 vs. 30%, P = 0.01), and decrease in BNP levels (75 vs. 50%, P = 0.04). CONCLUSION: The present study did not show any difference between RVA and RVHS pacing sites in terms of overall improvement in clinical outcome and LV reverse remodelling following CRT. However, effect of RV lead location on CRT response varies depending on LV stimulation site.

Relationship between QRS complex notch and ventricular dyssynchrony in patients with heart failure and prolonged QRS duration.

BACKGROUND: Cardiac resynchronization therapy (CRT) has been accepted as an established therapy for advanced systolic heart failure. Electrical and mechanical dyssynchrony are usually evaluated to increase the percentage of CRT responders. We postulated that QRS notch can increase mechanical LV dyssynchrony independently of other known predictors such as left ventricular ejection fraction and QRS duration. METHODS: A total of 87 consecutive patients with advanced systolic heart failure and QRS duration more than 120 ms with an LBBB-like pattern in V1 were prospectively evaluated. Twelve-lead electrocardiogram was used for detection of QRS notch. Complete echocardiographic examination including tissue Doppler imaging, pulse wave Doppler and M-mode echocardiography were done for all patients. RESULTS: Eighty-seven patients, 65 male (75%) and 22 female (25%), with mean (SD) age of 56.7 (12.3) years were enrolled the study. Ischemic cardiomyopathy was the underlying heart disease in 58% of the subjects, and in the others it was idiopathic. Patients had a mean (SD) QRS duration of 155.13 (23.34) ms. QRS notch was seen in 49.4% of the patients in any of two precordial or limb leads. Interventricular mechanical delay was the only mechanical dyssynchrony index that was significantly longer in the group of patients with QRS notch. Multivariate analysis revealed that the observed association was actually caused by the effect of QRS duration, rather than the presence of notch per se. CONCLUSIONS: QRS notch was not an independent predictor of higher mechanical dyssynchrony indices in patients with wide QRS complex and symptomatic systolic heart failure; however, there was a borderline association between QRS notch and interventricular delay.

Early septal activation, successful lateral ablation.

The coronary sinus activation pattern is an important clue for the detection of arrhythmia mechanisms and/or localization of accessory pathways. Any change in this pattern during radiofrequency ablation should be evaluated carefully to recognize the presence of another accessory pathway or innocence of the accessory pathway during arrhythmia. Intra-atrial conduction block can change the coronary sinus activation pattern. Negligence regarding this phenomenon can cause irreversible complications. Here we describe a case with left lateral accessory pathway conduction in which intra-atrial conduction block completely reversed the coronary sinus activation pattern.

The effect of preoperative aspirin use on postoperative bleeding and perioperative myocardial infarction in patients undergoing coronary artery bypass surgery.

BACKGROUND: We tried to evaluate the clinical outcomes (mortality, postoperative bleeding and perioperative myocardial infarction) of patients who underwent first elective coronary artery bypass grafting and received aspirin during the preoperative period. METHODS: The study was a prospective, randomized and single-blinded clinical trial. Two hundred patients were included and divided into two groups. One group received aspirin 80-160 mg, while in the other aspirin was stopped at least seven days before surgery. The primary end-points of the study were in-hospital mortality and hemorrhage-related complications (postoperative blood loss in the intensive care unit, re-exploration for bleeding and red blood cell and non-red blood cell requirements). The secondary end-point was perioperative myocardial infarction. RESULTS: There were no differences in patient characteristics between the aspirin users and non-aspirin users. We found a significant difference between postoperative blood loss (608 +/- +/- 359.7 ml vs. 483 +/- 251.5 ml; p = 0.005) and red blood cell product requirements (1.32 +/- +/- 0.97 unit packed cell vs. 0.94 +/- 1.02 unit packed cell; p = 0.008). There was no significant difference between the two groups regarding platelet requirement and the rate of in-hospital mortality and re-exploration for bleeding. Similarly, we found no significant difference in the incidence of definite and probable perioperative myocardial infarction (p = 0.24 and p = 0.56 respectively) or in-hospital mortality between the two groups. CONCLUSION: Preoperative aspirin administration increased postoperative bleeding and red blood cell requirements with no effect on mortality, re-exploration rate and perioperative myocardial infarction. We recommend withdrawal of aspirin seven days prior to surgery. (Cardiol J 2007; 14: 453-457).

A patient with sick sinus syndrome, atrial flutter and bidirectional ventricular tachycardia: Coincident or concomitant presentations?

Channelopathies are among the major causes of syncope or sudden cardiac death in patients with structurally normal hearts. In these patients, the atrium, ventricle or both could be affected and reveal different presentations. In this case, we present a patient with an apparently structurally normal heart and recurrent syncope, presented as sick sinus syndrome with atrial flutter and bidirectional ventricular tachycardia. (Cardiol J 2007; 14: 585-588).