Increased atrial contraction contribution to left ventricular filling during early septic shock.

PURPOSE: To assess the atrial systolic function and the contribution of atrial contraction to left ventricular (LV) filling in septic shock patients as compared with healthy volunteers. METHODS: Twenty-seven septic patients evaluated during first 48 h of ICU admission and compared with 27 healthy volunteers. Left atrial (LA) contraction contribution to LV filling was calculated as the active emptying atrial volume/LV end-diastolic volume. Atrial systolic function was evaluated with the atrial kinetic force [LAKE = 0.5 × blood density × LVVactive × (peak A velocity)2] and atrial ejection force [LASF = 0.5 × blood density × mitral annulus area × (peak A velocity)2]. RESULTS: LV ejection fraction was lower in septic patients than in control group: 51 ±â€¯14%vs 60 ±â€¯6% (p < 0.01). Contribution of LA contraction to LV preload was greater in septic patients than in normal subjects (26.7 ±â€¯11.3% vs 15.9 ±â€¯5.9%, p < 0.001), even if adjusted for age (0.49 ±â€¯0.19 vs 0.35 ±â€¯0.13, p = 0.004). LAKE and LASF were also significantly larger in septic patients than in normal subjects (21.8 ±â€¯9.1 vs 7.3 ±â€¯3 kdynes·cm, p < 0.001; 16.1 ±â€¯11.7 vs 9.8 ±â€¯4.3 kdynes, p = 0.048, respectively), and remained unchanged during the next 48 h. CONCLUSION: In septic shock patients, LA systolic function increased and greatly contributed to support LV filling. These results highlight the role of preserving atrial contraction on the hemodynamic resuscitation in early septic shock.

Invasive assessment of coronary microvascular dysfunction in hypertrophic cardiomyopathy: the index of microvascular resistance.

We present a review of microvascular dysfunction in hypertrophic cardiomyopathy (HCM) and an interesting case of a symptomatic familial HCM patient with inducible ischemia by single photon emission computed tomography. Coronary angiography revealed normal epicardial arteries. Pressure wire measurements of fractional flow reserve (FFR), coronary flow reserve (CFR) and index of microvascular resistance (IMR) demonstrated a significant microcirculatory dysfunction. This is the first such case that documents this abnormality invasively using the IMR. The measurement of IMR, a novel marker of microcirculatory dysfunction, provides novel insights into the pathophysiology of this condition.