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Background: The contribution of atrial and ventricular function in neurocardiogenic syncope (NCS) pathophysiology is elusive. Hypothesis: We assessed the influence of echocardiographic properties to the age of presentation and NCS recurrences. Methods: We assigned 124 patients with symptoms suggesting NCS, to those with syncope initiation at age <35 (group A, n = 56) and >35 years (group B, n = 68). Echocardiographic indices were measured before head‐up tilt test (HUTT). Results: A total of 55 had positive HUTT (44%) with a trend favoring group A (p =.08). Group A exhibited lower left atrial (LA) volume index (17 ± 6 vs. 22 ± 11 ml/m2, p =.015), higher LA ejection fraction (69 ± 10 vs. 63 ± 11%, p =.008), LA peak strain (reservoir phase 41 ± 13 vs. 31 ± 14%, p =.001, contraction phase 27 ± 11 vs. 15 ± 10%, p <.001) and LA peak strain rate (reservoir phase 1.83 ± 1.04 vs. 1.36 ± 0.96 1/s, p =.012, conduit phase 2.36 ± 1.25 vs. 1.36 ± 0.78 1/s, p =.001). Group A showed smaller minimum right atrial (RA) volume, better RA systolic function, superior left ventricular diastolic indices, and lower filling pressures. Group A patients were more likely to have >3 recurrences (82.0% vs. 50.1%, p <.05). Conclusions: Patients with younger age of NCS onset and more syncopal recurrences manifest smaller LA and RA dimensions with distinct patterns of systolic and diastolic function and better LA reservoir and contraction properties. These findings may indicate an increased susceptibility to preload reduction, thereby triggering the NCS mechanism. [ABSTRACT FROM AUTHOR]

To evaluate right atrial (RA) contractile performance in patients with myocardial infarction, we validated a cineangiographic method of RA volume measurement, and investigated RA volume change in ‘normal’ individuals and patients with a previous myocardial infarction. Sixteen silicone rubber RA casts made from human cadavers were filmed in the postero-anterior and left lateral projections. The cast volumes calculated following Simpson's rule were in good agreement with those measured by water replacement (r=0.992, P<.001). At cardiac catheterization, biplane RA cineangiography was performed in 19 ‘normal’ individuals (N group), in 14 patients with a previous antero-septal infarction (AM1 group) and in seven patients with aprevious inferior infarction (IMI group). The RA volume-time curve was constructed at 20–40 ms intervals for one cardiac cycle. RA volume at the beginning of the atrial contraction (RAVd), which was defined as the ‘preload’ of the RA, tended to be larger in both the AMI and IMI groups compared with ‘normal’ individuals. The RA ejection volume was significantly larger in both the AMI (18.4 ± 2.1 ml. m, P <0.01) and IMI groups (l9.4±2.8, P<0.01) than in the N group (14.5±1.9), even for a comparable level of RAVd (range from 26 to 36ml.m) (18.6±2.1, P<0.01, 18.2±2.0, P<0.01, 14.7±1.9, respectively). These results suggest that RA contraction increases in patients with myocardial infarction by increasing both the ‘preload’ and ‘contractility’ of the RA. [ABSTRACT FROM PUBLISHER]