Weeranun D. Bode

Prominent R wave in ECG lead V1 predicts improvement of left ventricular ejection fraction after cardiac resynchronization therapy in patients with or without left bundle branch block.

BACKGROUND QRS morphology on postprocedural ECG indicating posterolateral left ventricular pacing may be predictive of response to cardiac resynchronization therapy (CRT). OBJECTIVE The purpose of this study was to assess whether a positive vector in V1 and/or negative vector in lead I on the first postprocedural ECG, suggesting posterolateral capture from CRT, correlates with improvement in left ventricular ejection fraction (LVEF). METHODS A retrospective chart review was conducted on all patients who underwent CRT implantation at our institution between April 2008 and December 2011. Biventricular (BiV) paced QRS morphology was defined as R/S ≥1 in V1 and/or R/S ≤ 1 in lead I. The primary outcome was improvement of LVEF ≥7.5%. The χ(2) and t tests were used for analysis. RESULTS Of 68 patients, 49 (72%) met our BiV paced QRS morphology criteria. Thirty-four of these 49 patients (69%) had improvement in LVEF. Of the 19 patients who did not meet our criteria, 17 (89%) did not have an improvement in LVEF (sensitivity 94%, specificity 53%, χ(2) = 19.04, P < .0001). The average LVEF improvement in patients who met our BiV paced QRS morphology criteria was significantly greater than in those who did not (14.27% vs 2.63%, P = .0001). Preprocedural left bundle branch block was not a predictor of echocardiographic response. CONCLUSION Our results highlight the importance of periprocedural ECG analysis to optimize response to CRT. Moreover, patients without left bundle branch block still benefited from CRT if they met our BiV paced morphology criteria. This suggests that postprocedural left ventricular activation as reflected on the ECG may supersede the baseline conduction delay.

Current Approaches to Antiarrhythmic Therapy in Heart Failure

Atrial fibrillation (AF) is exceedingly common in patients with heart failure (HF), as they share common risk factors. Rate control is the cornerstone of treatment for AF; however, restoration of sinus rhythm should be considered when more than minimal symptoms are present. Life-threatening ventricular arrhythmias are responsible for the primary mode of death in patients with NYHA I, II, or III HF. Although implantable cardioverter defibrillators protect against sudden cardiac arrest, many patients will present with VT or ICD shocks. Antiarrhythmic drug therapy beyond beta-blocker therapy remains fundamental to the termination of acute VT and the prevention of ICD shocks.

The factor Xa inhibitor rivaroxaban reduces cardiac dysfunction in a mouse model of myocardial infarction

INTRODUCTION Rivaroxaban selectively inhibits factor Xa (FXa), which plays a central role in blood coagulation. In addition, FXa activates protease-activated receptor-2 (PAR-2). We have shown that PAR-2-/- mice exhibit less cardiac dysfunction after cardiac injury. MATERIAL AND METHODS Wild-type (WT) and PAR-2-/- mice were subjected to left anterior descending artery (LAD) ligation to induce cardiac injury and heart failure. Mice received either placebo or rivaroxaban chow either starting at the time of surgery or 3 days after surgery and continued up to 28 days. Cardiac function was measured by echocardiography pre-surgery and 3, 7 and 28 days after LAD ligation. We also measured anticoagulation, intravascular thrombi, infarct size, cardiac hypertrophy and inflammation at various times. RESULTS Rivaroxaban increased the prothrombin time and inhibited the formation of intravascular thrombi in mice subjected to LAD ligation. WT mice receiving rivaroxaban immediately after surgery had similar infarct sizes at day 1 as controls but exhibited significantly less impairment of cardiac function at day 3 and beyond compared to the placebo group. Rivaroxaban also inhibited the expansion of the infarct at day 28. Rivaroxaban did not significantly affect the expression of inflammatory mediators or a neutrophil marker at day 2 after LAD ligation. Delaying the start of rivaroxaban administration until 3 days after surgery failed to preserve cardiac function. In addition, rivaroxaban did not reduce cardiac dysfunction in PAR-2-/- mice. CONCLUSIONS Early administration of rivaroxaban preserves cardiac function in mice after LAD ligation.

Simvastatin effects on skeletal muscle: study design and validity.

We read with great interest the report by Larsen et al. ([1][1]). In their paper, they addressed a potential mechanism for statin-induced myositis. This is a topic of clinical importance because muscle pain is a common symptom for patients taking statins and the pain often limits statin usage ([2][2