Relation of QRS Duration to Response to Cardiac Resynchronization Therapy in Patients With Left Bundle Branch Block.

Left ventricular (LV) dyssynchrony (LVdys) is a necessary condition for successful cardiac resynchronization therapy (CRT). Despite left bundle branch block (LBBB) representing a reliable surrogate of LVdys, not all LBBB patients will respond to CRT. Our aim was to investigate the relation between QRS duration and LVdys in patients with LBBB who underwent CRT. We retrospectively studied 165 patients with LBBB who underwent CRT implantation according to the current guidelines. A 6-month reduction of LV end-systolic volume ≥15% identified responders to CRT. Baseline LVdys was defined as the delay between peak systolic velocities of the interventricular septum and lateral wall assessed by color-coded tissue Doppler imaging. Baseline characteristics of responders (61%) and nonresponders (39%) were comparable except for larger QRS complex (172 ± 24 vs 160 ± 16 ms, p <0.001) and lower degree of LVdys (46 ± 42 vs 72 ± 31 ms, p <0.001) in nonresponders. Receiver-operating characteristic curve analysis demonstrated that an optimal cut-off value of 3 for the ratio of QRS duration and LVdys (QRS/LVdys) yielded a sensitivity of 66% and specificity of 80% to predict nonresponsiveness to CRT; QRS/LVdys >3 remained an independent predictor at multivariate analysis. In patients with nonischemic origin of cardiomyopathy, the linear regression analysis documented a significant inverse relation between QRS duration and LVdys, as dyssynchrony progressively decreased as QRS widening increased (p = 0.006). This was not evident in patients with ischemic origin. In conclusion, in LBBB patients with nonischemic origin and marked QRS widening, the absence of LVdys may account for a lower response to CRT compared with patients with intermediate QRS widening.

[Chest pain in the emergency department: benefits of a management model modified from the ANMCO-SIMEU recommendations]. / Dolore toracico in Pronto Soccorso: utilità di un modello di gestione modificato rispetto alle indicazioni ANMCO-SIMEU.

BACKGROUND: The evaluation of chest pain patients in the emergency department remains a costly and difficult challenge, even though a large proportion of them do not suffer from an acute coronary syndrome. We adopted a clinical decision model, modified from the ANMCO-SIMEU recommendations, and tested its clinical usefulness by assessing: a) the rate of unnecessary hospital admissions, b) the rate of inappropriate discharges based on coronary events (unstable angina, myocardial infarction, death) at 6 months. METHODS: Our population included 511 consecutive patients with chest pain for a period of 6 months. On the basis of the chest pain score and individual risk factors, 383 patients with normal ECG and negative troponin were classified into four categories according to the probability of acute coronary syndrome, resulting in different lengths of hospital stay and planning of further diagnostic tests. Stress testing was mandatory within 72 h if 22 risk factors and typical angina were observed. RESULTS: Inappropriate discharges and unnecessary admissions were 1% and 9.5%, respectively. The clinical decision model based on the four categories of probability was correctly applied in 83% of cases. One hundred patients were diagnosed with acute coronary syndrome. After discharge, 6 patients underwent stress testing with subsequent revascularization (mean 34 days later) without experiencing new cardiac events. One patient was readmitted with unstable angina before completing non-invasive diagnostic tests. None of 297 patients with atypical chest pain, discharged without additional testing, had adverse cardiac events. CONCLUSIONS: Our clinical decision model resulted in a low rate of inappropriate discharges with a low risk of adverse events and a standard rate of unnecessary admissions. Although clinical judgment remains of paramount importance, a clinical decision model and the risk stratification of patients with chest pain lead to an improvement of quality of care.

Improved detection of left ventricular thrombi and spontaneous echocontrast by tissue harmonic imaging in patients with myocardial infarction.

BACKGROUND: Tissue harmonic imaging (THI) reduces near-field and side-lobe artifacts. This could improve recognition of cardiac masses, including thrombi and spontaneous echocontrast (SEC), a known thromboembolic risk factor. OBJECTIVES: We tested the hypothesis that THI improves detection of left ventricular (LV) thrombi and SEC compared with transthoracic fundamental imaging in patients with recent myocardial infarction. METHODS: In all, 118 consecutive patients with recent myocardial infarction were studied at predischarge. The echocardiographic examination was performed in both fundamental imaging and THI modality and evaluated by 3 skilled and 3 nonexperienced observers for recognition of LV thrombosis and SEC. RESULTS: THI increased LV thrombi diagnosis by 25% by skilled observers and by 50% by nonexperienced readers, reducing the number of false-positive diagnoses by 67%. Also, compared with fundamental imaging, THI improved recognition of LV SEC by both experienced and nonexperienced observers by 56% and 62%, respectively. CONCLUSIONS: The improved recognition of LV thrombosis and SEC by THI in patients with myocardial infarction is clinically relevant allowing appropriate treatment and prognostic stratification. Therefore, routine use of THI should be recommended when studying such patients in clinical practice.