Cardiac resynchronization therapy-induced acute shortening of QRS duration predicts long-term mortality only in patients with left bundle branch block.

AIMS: QRS narrowing with initiation of biventricular pacing might be an acute electrocardiographic indicator of correction of left bundle branch block (LBBB)-induced depolarization delay and asynchrony. However, its impact on prognosis remains controversial, especially in non-LBBB patients. Our goal was to evaluate the impact of QRS narrowing on long-term mortality and morbidity in a large cohort of patients undergoing cardiac resynchronization therapy (CRT) with different pre-implantation QRS types: LBBB, non-LBBB, and permanent right ventricular pacing. METHODS AND RESULTS: This study included consecutive patients who underwent CRT device implantation. Study endpoints: death from any cause or urgent heart transplantation and death from any cause/urgent heart transplantation or hospital admission for heart failure. All pre- and post-implantation electrocardiograms were analysed using digital callipers, high-amplitude augmentation, 100 mm/s paper speed, and global QRS duration measurement method. A total of 552 CRT patients entered the survival analysis. During the 9 years observation period, 232 (42.0%) and 292 (52.9%) patients met primary and secondary endpoints, respectively. QRS narrowing predicted survival in the Kaplan-Meier analysis only in patients with LBBB. Multivariate Cox regression model showed that QRS narrowing was the major determinant of both study endpoints, with hazard ratios of 0.46 and 0.43, respectively. There was a strong relationship between mortality risk and shortening/widening of the QRS, albeit only in the LBBB group. Patients with non-LBBB morphologies had unfavourable prognosis similar to that in LBBB patients without QRS narrowing. CONCLUSION: Acute QRS narrowing in patients with LBBB might be a desirable endpoint of CRT device implantation.

Specificity of wide QRS complex tachycardia criteria and algorithms in patients with ventricular preexcitation.

BACKGROUND: Despite substantial progress in the field of differentiation between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) with wide QRS complexes, differentiation between VT and preexcited SVT remains largely unresolved due to significant overlap in QRS morphology. Our aim was to assess the specificities of various single ECG criteria and sets of criteria (Brugada algorithm, aVR algorithm, Steurer algorithm, and the VT score) for diagnosis of VT in a sizable cohort of patients with preexcitation. METHODS: We performed a retrospective study of consecutive accessory pathway ablation procedures to identify preexcited tachycardias. Among 670 accessory pathway ablation procedures, 329 cases with good quality ECG with either bona fide preexcited SVT (n = 30) or a surrogate preexcited SVT (fast paced atrial rhythm with full preexcitation, n = 299) were identified. ECGs were analyzed with the use of wide QRS complex algorithms/criteria to determine specificities of these methods. RESULTS: The Steurer algorithm and VT score (≥3 points), with specificities of 97.6% and 96.1%, respectively, were significantly (p < .01) more specific for the diagnosis of VT than Brugada algorithm, aVR algorithm, and Pava criterion with specificities of 31%, 11.6%, and 57.1%, respectively. The first step of the Brugada algorithm and the first step of the aVR algorithm had also high specificities of 93.3% and 96.0%, respectively. CONCLUSION: There are sufficient electrocardiographical differences between VT and preexcited SVT to allow electrocardiographic differentiation. VT score, Steurer algorithm, and some single criteria do not overdiagnose VT in patients with preexcitation.

Comparison of four LBBB definitions for predicting mortality in patients receiving cardiac resynchronization therapy.

BACKGROUND: Left bundle branch block (LBBB) is considered an important prognostic parameter in cardiac resynchronization therapy (CRT). We aimed to evaluate, in a sizeable cohort of patients with CRT, long-term mortality, and morbidity according to four different electrocardiographic definitions of LBBB. METHODS: This longitudinal cohort study included consecutive patients who underwent CRT device implantation in our institution in years 2006-2014. Two endpoints were assessed: (a) death from any cause or urgent heart transplantation, and (b) death from any cause or heart failure admission. All preimplantation ECGs were analyzed by three physicians blinded to outcome and categorized as LBBB or non-LBBB according to four definitions. RESULTS: A total of 552 CRT patients entered survival analysis. According to the conventional definition, 350 (63.4%) patients had LBBB, and the Marriott, WHO/AHA, and Strauss definitions identified LBBB in 254 (46.0%), 218 (39.5%) and 226 (40.9%) patients, respectively. During the 9 years of observation, 232 patients died, the combined endpoint was met by 292 patients. The Strauss LBBB definition was significantly better to the other definitions in predicting survival (Kaplan-Meier analysis with comparison of C-statistics). Multivariate Cox regression model showed that LBBB was the major determinant of all-cause mortality with the Strauss definition having the lowest hazard ratio (0.51) of the four studied definitions. CONCLUSIONS: Criteria included in various definitions of LBBB result in a diagnosis of LBBB in divergent groups of patients. Differences in LBBB definitions have clinical consequences, as patients without 'complete/true' LBBB probably get no mortality benefit from CRT.

New ECG markers for predicting long-term mortality and morbidity in patients receiving cardiac resynchronization therapy.

We investigated prognostic value of four recently proposed ECG markers in patients with cardiac resynchronization therapy (CRT): 1./ pathological preimplantation QRS axis, 2./ increase in QRS amplitude in V3 during biventricular pacing, 3./ negative QRS in V1/V2 during left ventricular (LV)-only pacing, 4./ longer QRS duration during LV-only pacing. A longitudinal cohort study was performed (n = 552). RESULTS: During the 9-year observation period the primary endpoint (death from any cause or urgent heart transplantation) was met in 232 patients. The secondary endpoint of survival free of heart failure hospitalization was met in 292 patients. Long LV-paced QRS and pathological axis predicted unfavorable prognosis in Kaplan-Meier analysis. In multivariable Cox model (functional class, LV ejection fraction, LV end-diastolic dimension, permanent atrial fibrillation, age, gender, heart failure etiology, creatinine level, diabetes mellitus), LV-paced QRS duration remained a significant determinant of both endpoints. The other studied ECG markers lacked independent prognostic value.

[Diagnostic difficulties in amebic liver abscess].

Amebiasis is a widespread parasitic infection caused by the human-specific protozoan Entamoeba histolytica (E.- histolytica). Tropical and subtropical regions with poor socioeconomic and sanitary conditions belong to endemic areas. The highest rates of E. histolytica infection are observed in India, Mexico, Africa, some parts ofCentral and South America. Up to 90% of infections remain asymptomatic, about 10% of patients develop amebic colitis. About 10% of symptomatic individuals may present with an extraintestinal manifestation, mostly amebic liver abscess (ALA). Clinical symptoms of ALA appear within 5 months after an exposition to E. histolytica cysts. Anamnesis revealing a travel to endemic area plays a crucial role in a diagnostic process, which is further supported by an physical examination, radiological findings, serology and parasitology test. The following article presents the difficulties which may occur when the ALA is suspected in a patient traveling from endemic areas.

True left bundle branch block and long-term mortality in cardiac resynchronisation therapy patients.

BACKGROUND: Left bundle branch block (LBBB) is an important qualification criterion and determinant of prognosis in cardiac resynchronisation therapy (CRT) patients. AIM: Our goal was to investigate the long-term mortality and morbidity in a sizable cohort of patients with CRT with regard to the new strict LBBB definition proposed by Perrin. METHODS: We performed a longitudinal cohort study that included consecutive CRT patients. Primary endpoint (all-cause death) and secondary endpoint (all-cause death and hospitalisation for heart failure) were analysed. All preimplantation elec- trocardiograms were categorised as LBBB or non-LBBB according to the new definitions/criteria analysed. RESULTS: The survival analysis comprised 552 patients with CRT. The Perrin criteria, CRT guidelines class I indication criteria, and Strauss criteria were fulfilled in 38.9%, 79.4%, and 62.3% of all LBBB patients, respectively. During the nine-year study period, 232 patients died and the combined endpoint was met by 292 patients. The Perrin "true LBBB" definition criteria were inferior to the Strauss "complete" LBBB definition criteria in predicting survival as reflected by Kaplan-Meier survival curves (C-statistics). Multivariate Cox regression models showed that both LBBB definitions predicted mortality, however, the Perrin definition had a higher hazard ratio (HR 0.67) compared to the Strauss definition (HR 0.51). CONCLUSIONS: It seems that the Perrin "true LBBB" criteria are not well-suited for the selection of CRT candidates. Perhaps they do not reflect the presence of a true/complete LBBB or exclude too many patients who, despite some residual conduction in the left bundle branch, responded well to CRT.

Risk stratification in patients with cardiac resynchronisation therapy: the AL-FINE CRT risk score.

BACKGROUND: Mortality and morbidity in patients with cardiac resynchronisation therapy (CRT) remain very high. Prognostic evaluation of CRT candidates might be useful for the assessment of CRT indications, directing further therapy, counselling, etc. AIM: Our goal was to assess the prognostic value of various parameters in order to construct a risk score that could predict long-term mortality and morbidity during the initial evaluation of CRT candidates. METHODS: This was a retrospective, single-centre, large cohort study involving consecutive heart failure patients who underwent CRT device implantation. In order to build a prediction model, 28 parameters were analysed using uni- and multivariate Cox models and Kaplan-Meier survival curves. RESULTS: Data from 552 patients were used for the long-term outcome assessment. During nine years of follow-up, 232 patients met the primary endpoint of death and 128 patients were hospitalised for heart failure. The strongest and clinically most relevant predictors were selected as the final model. AL-FINE is the acronym for these six predictors: Age ( > 75 years), non-Left bundle branch block morphology (according to Strauss criteria), Furosemide dose ( > 80 mg), Ischaemic aetiology, New York Heart Association class ( > III), and left ventricular Ejection fraction ( < 20%). Depending on the number of AL-FINE score points, overall mortality at seven years was in the range of 28% (0-1 points) to 74% (3-6 points). CONCLUSIONS: A novel, multiparametric CRT risk score was constructed on the basis of simple and recognised clinical, electrocardiographic, and echocardiographic parameters that show a significant add-on effect on mortality in this specific population.