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QRS Width (qr + width)
Selected AbstractsBaseline Characteristics of Patients Randomized in the Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction (REVERSE) StudyCONGESTIVE HEART FAILURE, Issue 2 2008Cecilia Linde MD The Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction (REVERSE) study is a randomized controlled trial currently assessing the safety and efficacy of cardiac resynchronization therapy in patients with asymptomatic left ventricular (LV) dysfunction with previous symptoms of mild heart failure. This paper describes the baseline characteristics of randomized patients; 610 patients with New York Heart Association (NYHA) class II (82.3%) heart failure or asymptomatic (NYHA class I) LV dysfunction with previous symptoms (17.7%) were randomized in 73 centers. The mean age was 62.5±11.0 years, the mean LV ejection fraction was 26.7%±7.0%, and the mean LV end-diastolic diameter was 66.9±8.9 mm. A total of 97% of patients were taking angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and 95.1% were taking ,-blockers, which were at the target dose in 35.1% of patients. Compared with previous randomized cardiac resynchronization therapy trials, REVERSE patients are on better pharmacologic treatment, are younger, and have a narrower QRS width despite similar LV dysfunction. [source] Diagnostic Value of Flecainide Testing in Unmasking SCN5A-Related Brugada SyndromeJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2006PAOLA G. MEREGALLI M.D. Introduction: Provocation tests with sodium channel blockers are often required to unmask ECG abnormalities in Brugada syndrome (BrS). However, their diagnostic value is only partially established, while life-threatening ventricular arrhythmias during these tests were reported. We aimed to establish sensitivity, specificity, and safety of flecainide testing, and to predict a positive test outcome from the baseline ECG. Methods and Results: We performed 160 tests with flecainide in subjects determined to be at risk for BrS. P wave width, PQ duration, QRS width, S wave amplitude and duration in leads II-III, in addition to ST morphology and J point elevation in V1-V3 were measured before and after flecainide administration. Moreover, leads were positioned over the third intercostal space (V1IC3 -V2IC3). Flecainide tests were considered positive if criteria from the First Consensus Report on BrS were fulfilled. In 64 cases, the test was positive, while 95 were negative (1 test was prematurely interrupted). The sensitivity and specificity, calculated in SCN5A-positive probands and their family members, were 77% and 80%, respectively. Baseline ECGs exhibited significant group differences in P, PQ, and QRS duration, J point elevation (leads V1-V2 and V1IC3 -V2IC3), and S duration in II, but an attempt to predict the outcome of flecainide testing from these baseline ECG parameters failed. No malignant arrhythmias were observed. Conclusion: Flecainide testing is a valid and safe tool to identify SCN5A-related BrS patients. Baseline ECGs do not predict test outcomes, but point to conduction slowing as a core mechanism in BrS. [source] A Clinical Risk Score to Predict the Time to First Appropriate Device Therapy in Recipients of Implantable Cardioverter DefibrillatorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2007HAITHAM HREYBE M.D. Background:To develop a risk score to predict the occurrence of appropriate defibrillator [implantable cardioverter-defibrillator (ICD)] therapies. A simple clinical score predicting the risk of appropriate ICD therapy is lacking. Methods:A Cox regression model was developed from a database of ICD patients at a single tertiary center to predict the time to appropriate ICD therapy defined as shock or antitachycardia pacing. A risk score was derived from this model using half of the database and was validated using the other half. Results:A total of 399 patients were entered into the database between July 2001 and February 2004. There were no statistically significant differences between the derivation (n = 200) and validation (n = 199) groups in any of the demographic or clinical variables recorded. The risk score included three independent variables: indication for ICD implantation (P = 0.03), serum creatinine level (P = 0.015), and QRS width (P = 0.028). The observed risk scores were highly predictive of time to ICD therapy in the validation group (P = 0.02). Conclusion:We describe a new clinical risk score that predicts the time to appropriate device therapy in ICD recipients of a single tertiary center hospital. The performance of this risk score needs to be investigated prospectively in a larger patient population. [source] Is the Left Ventricular Lateral Wall the Best Lead Implantation Site for Cardiac Resynchronization Therapy?PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p2 2003MAURIZIO GASPARINI GASPARINI, M., et al.: Is the Left Ventricular Lateral Wall the Best Lead Implantation Site for Cardiac Resynchronization Therapy?Short-term hemodynamic studies consistently report greater effects of cardiac resynchronization therapy (CRT) in patients stimulated from a LV lateral coronary sinus tributary (CST) compared to a septal site. The aim of the study was to compare the long-term efficacy of CRT when performed from different LV stimulation sites. From October 1999 to April 2002, 158 patients (mean age 65 years, mean LVEF 0.29, mean QRS width 174 ms) underwent successful CRT, from the anterior (A) CST in 21 patients, the anterolateral (AL) CST in 37 patients, the lateral (L) CST in 57 patients, the posterolateral (PL) CST in 40 patients, and the middle cardiac vein (MCV) CST in 3 patients. NYHA functional class, 6-minute walk test, and echocardiographic measurements were examined at baseline, and at 3, 6, and 12 months. Comparisons were made among all pacing sites or between lateral and septal sites by grouping AL + L + PL CST as lateral site (134 patients, 85%) and A + MC CST as septal site (24 patients, 15%). In patients stimulated from lateral sites, LVEF increased from 0.30 to 0.39(P < 0.0001), 6-minute walk test from 323 to 458 m(P < 0.0001), and the proportion of NYHA Class III,IV patients decreased from 82% to 10%(P < 0.0001). In patients stimulated from septal sites, LVEF increased from 0.28 to 0.41(P < 0.0001), 6-minute walk test from 314 to 494 m(P < 0.0001), and the proportion of NYHA Class III,IV patients decreased from 75% to 23%(P < 0.0001). A significant improvement in cardiac function and increase in exercise capacity were observed over time regardless of the LV stimulation sites, either considered singly or grouped as lateral versus septal sites. (PACE 2003; 26[Pt. II]:162,168) [source] Correlation of Electrical and Mechanical Reverse Remodeling after Cardiac Resynchronization TherapyANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2009Swapna Kamireddy M.D. Background: Cardiac resynchronization therapy (CRT) improves clinical outcome in many patients with refractory heart failure (HF). This study examined whether CRT is associated with reverse electrical remodeling by surface electrocardiogram (ECG). Methods: Consecutive CRT recipients at the University of Pittsburgh Medical Center with >90 days of follow-up were included in this analysis. ECG data were abstracted from medical records. Subjects with a relative increase of ,15% in left ventricular ejection fraction (LVEF) after CRT were considered responders. Results: A total of 113 patients (age 69 ± 11 years, men 70%, white 92%) were followed for a mean duration of 407 ± 290 (92,1439) days. Overall, LVEF increased after CRT (29 ± 13% vs 24 ± 9%; P < 0.01) and 50% of patients were responders. The mean native QRS interval among responders was higher than in nonresponders (163 ± 32 ms vs 148 ± 29 ms; P < 0.01). More than 3 months after CRT, there was no change in the paced QRS duration compared to baseline. Paced QRS duration, however, decreased among responders and increased among nonresponders and was significantly different by response status (P < 0.001). There was a significant correlation between increase in LVEF and decrease in paced QRS width in the overall population (r =,0.3; P < 0.01). Conclusions: Among responders to CRT, the paced QRS width decreases significantly, whereas it increases among nonresponders. Given the paced nature of the QRS, the improved conduction probably reflects enhanced cell-to-cell coupling after CRT as opposed to improved conduction within the His-Purkinje system. These findings have significant implications as to the mechanisms of benefit from CRT. [source] | ||||||||||