A comparison of the clinical efficacy of echocardiography and magnetic resonance for chronic aortic regurgitation.

AIMS: Timing surgery in chronic aortic regurgitation (AR) relies mostly on echocardiography. However, cardiac magnetic resonance (CMR) may be more accurate for quantifying regurgitation and left ventricular (LV) remodelling. We aimed to compare the technical and clinical efficacies of echocardiography and CMR to account for the severity of the disease, the degree of LV remodelling, and predict AR-related outcomes. METHODS AND RESULTS: We studied 263 consecutive patients with isolated AR undergoing echocardiography and CMR. After a median follow-up of 33 months, 76 out of 197 initially asymptomatic patients reached the primary endpoint of AR-related events: 6 patients (3%) were admitted for heart failure, and 70 (36%) underwent surgery. Adjusted survival models based on CMR improved the predictions of the primary endpoint based on echocardiography: R2 = 0.37 vs. 0.22, χ2 = 97 vs. 49 (P < 0.0001), and C-index = 0.80 vs. 0.70 (P < 0.001). This resulted in a net classification index of 0.23 (0.00-0.46, P = 0.046) and an integrated discrimination improvement of 0.12 (95% confidence interval 0.08-0.58, P = 0.02). CMR-derived regurgitant fraction (<28, 28-37, or >37%) and LV end-diastolic volume (<83, 183-236, or >236 mL) adequately stratified patients with normal EF. The agreement between techniques for grading AR severity and assessing LV dilatation was poor, and CMR showed better reproducibility. CONCLUSIONS: CMR improves the clinical efficacy of ultrasound for predicting outcomes of patients with AR. This is due to its better reproducibility and accuracy for grading the severity of the disease and its impact on the LV. Regurgitant fraction, LV ejection fraction, and end-diastolic volume obtained by CMR most adequately predict AR-related events.

Systemic vascular load in calcific degenerative aortic valve stenosis: insight from percutaneous valve replacement.

BACKGROUND: Systemic arterial load impacts the symptomatic status and outcome of patients with calcific degenerative aortic stenosis (AS). However, assessing vascular properties is challenging because the arterial tree's behavior could be influenced by the valvular obstruction. OBJECTIVES: This study sought to characterize the interaction between valvular and vascular functions in patients with AS by using transcatheter aortic valve replacement (TAVR) as a clinical model of isolated intervention. METHODS: Aortic pressure and flow were measured simultaneously using high-fidelity sensors in 23 patients (mean 79 ± 7 years of age) before and after TAVR. Blood pressure and clinical response were registered at 6-month follow-up. RESULTS: Systolic and pulse arterial pressures, as well as indices of vascular function (vascular resistance, aortic input impedance, compliance, and arterial elastance), were significantly modified by TAVR, exhibiting stiffer vascular behavior post-intervention (all, p < 0.05). Peak left ventricular pressure decreased after TAVR (186 ± 36 mm Hg vs. 162 ± 23 mm Hg, respectively; p = 0.003) but remained at >140 mm Hg in 70% of patients. Wave intensity analysis showed abnormally low forward and backward compression waves at baseline, increasing significantly after TAVR. Stroke volume decreased (-21 ± 19%; p < 0.001) and correlated with continuous and pulsatile indices of arterial load. In the 48 h following TAVR, a hypertensive response was observed in 12 patients (52%), and after 6-month follow-up, 5 patients required further intensification of discharge antihypertensive therapy. CONCLUSIONS: Vascular function in calcific degenerative AS is conditioned by the upstream valvular obstruction that dampens forward and backward compression waves in the arterial tree. An increase in vascular load after TAVR limits the procedure's acute afterload relief.

Bloqueo de rama dependiente de la frecuencia: no solo existe la fase 3 / Rate-Dependent Bundle Branch Block: Not Only Phase 3 Exists

Los bloqueos de rama dependientes de la frecuencia suelen estar relacionados con el aumento de la frecuencia cardíaca (bloqueo de rama taquicárdico-dependiente o en fase 3). Menos comúnmente, son causados por la reducción de la frecuencia cardíaca (bloqueo de rama bradicárdico-dependiente o en fase 4). El bloqueo en fase 3 es la presentación más frecuente de los trastornos de la conducción intraventricular paroxísticos, documentada en varias publicaciones. Sin embargo, no son tan numerosos los artículos que describen el bloqueo de rama en fase 4 y, raras veces, ambos mecanismos coexisten en el mismo paciente. En esta presentación se describe el caso de un paciente ingresado con un infarto agudo de miocardio en el que se detectaron trastornos de la conducción intraventricular paroxísticos, tanto taquicárdico-dependientes como bradicárdico-dependientes.

Rate-dependent bundle branch blocks are often related with increased heart rate (tachycardia-dependent or phase 3 bundle branch block). Less often, they are caused by heart rate reduction (bradycardia-dependent or phase 4 bundle branch block). Phase 3 block is the most common type of paroxysmal intraventricular conduction disturbances documented in several publications. However, few articles describe phase 4 bundle branch block, and both mechanisms rarely coexist in the same patient. We report the case of a patient admitted with acute myocardial infarction, presenting with both tachycardia- and bradycardia-dependent paroxysmal intraventricular conduction disturbances.