Atrial function in the Fontan circulation: comparison with invasively assessed systemic ventricular filling pressure.

Abnormal atrial mechanics in biventricular circulations have been associated with elevated left heart filling pressures. Similar associations in the Fontan circulation are unknown. The aim of this study was to examine the relationship between atrial mechanics and invasively assessed hemodynamic parameters late after the Fontan operation. Thirty-nine Fontan patients with echocardiographic and invasive hemodynamic studies done within 48 h were included and were compared to 40 age-matched healthy controls. Atrial and ventricular strain measurements were measured offline using 2-dimensional speckle-tracking. Mean age was 10.2 ± 6.7 years and 24 (62%) were male. Atrial strain measures were lower in Fontan patients compared to healthy controls. There was no significant association between atrial strain measurements and Fontan systemic ventricular filling pressures (SVFP) as indicated by pulmonary artery occlusion pressures, direct left atrial pressure or systemic ventricular end-diastolic pressure. Global atrial strain was not correlated with segmental atrial strain in the pulmonary venous atrium. Global atrial reservoir strain was positively correlated with pulmonary vascular resistance (r = 0.508, p = 0.045). Global atrial conduit strain was positively correlated with E/A ratio of the AV valve inflow (r = 0.555, p = 0.002). Atrial and ventricular strain measurements were not significantly correlated. In patients with a Fontan, global atrial function is significantly depressed, and is uncoupled from segmental left lateral atrial function. Global as well as segmental atrial mechanics are not significantly associated with SVFPs in Fontan patients. Instead, global atrial reservoir function appears to parallel pulmonary vascular resistance.

Cavitation phenomenon in mechanical prosthetic valves: Not only microbubbles.

INTRODUCTION: Microbubbles (MBs) or cavitation is high-velocity, echo-bright findings present during the closing or opening of a mechanical valve (MVP). Cavitation bubble growth or gas emboli are less frequently described. We evaluated the hemodynamic parameters involved in the formation of gas emboli and the impact of gas emboli on requests for additional investigations. METHODS AND RESULTS: Transthoracic echocardiographic studies (TTE) of 57 patients (31 males, mean age 46.8 ± 13.8 years) with gas emboli were evaluated after heart valve replacement surgery. The majority (72%, n = 42) had a mitral or combined mitral/aortic MVP, with 28% (n = 16) an aortic MVP. The last TTE with and without gas emboli were considered for the same patient and the no emboli group was the control group (42 patients). The patient's blood pressure (BP) and heart rate (HR) were available for each TTE. Comparing the two TTEs, the systolic and diastolic BP, transmitral and aortic gradients, and left ventricular ejection fraction were similar but the HR (80.9 ± 18.7 vs 72.5 ± 13.9 bpm, P = .02) was significantly higher in the group with gas emboli. A TEE was performed 52 times in 27 patients, due to gas emboli, with one case positive for thrombus/vegetation. For 19 patients, a brain CT was requested. In two patients, the indication for the brain CT was gas emboli but the result was negative. CONCLUSION: Gas emboli are frequently present and associated to an increased HR. They can cause the misdiagnosis of endocarditis or thrombus formation with significant additional requests for diagnostic examinations.

Subcutaneous Implantable Cardioverter Defibrillators Implantation Without Defibrillation Threshold Testing: A Single Center Experience.

BACKGROUND: Subcutaneous implantable cardioverter defibrillator (S-ICD) system has been proven to be an effective therapy for prevention of sudden cardiac death (SCD) in selected patients. Although the Shockless IMPLant Evaluation (SIMPLE) trial has shown that defibrillation threshold (DFT) testing is not necessary for transvenous ICD (TV-ICD) systems, it is still recommended for S-ICD systems. We aimed to study the efficacy and safety of S-ICD implantation without DFT in our Heart Center with the comparison of S-ICD patients' outcome to those with a single chamber TV-ICD without DFT in the same period. METHODS: A retrospective analysis of patients underwent S-ICD without DFT from December 2014 to May 2016 with the comparison to single chamber TV-ICD patients implanted during the same period. RESULTS: Thirty consecutive patients (23 males (76.7%); mean age 41 ± 13 years; mean left ventricular ejection fraction 30±12%) received a S-ICD for primary (25 patients, 83.3%) or secondary prevention (five patients, 16.7%) of SCD. During a mean follow-up of 710.6 ± 190 days, three patients received 38 appropriate ICD shocks (90.5%), and two patients received four inappropriate shocks (9.5%). There were two mortalities (6.7%): one cardiac and one non-cardiac. When compared to 30 consecutive who received a single chamber TV-ICD during the same period, there was no significant difference in mortality. CONCLUSIONS: Implantation of S-ICD using intermuscular approach without DFT seems to be safe and effective. Data from large S-ICD registries with long-term follow-up, and preferably randomized controlled studies, are needed to confirm this finding.