Individual hemodynamic data in both baseline and post-PVC conditions are listed in Table 1 for OCM, in Tables 2 and 3 for the whole group of WAS, and in Table 3 for the subgroup of nonsevere WAS. Collective data of OCM and VAS series of patients are shown in Table 4. Comparisons are made between OCM and the whole group of WAS (ie, severe + nonsevere WAS) and between OCM and the subgroup of nonsevere WAS, which have a similar basal gradient. Left ventricular ejection fraction (EF) was significantly higher for OCM than for WAS (OCM, 83.2 ± 6.4, range 71 to 92 percent vs WAS, 65.9 ± 16.1, range 32 to 82 percent; p<0.01).
Patients with OCM show a post-PVC LVOT gradient (109 ±41 mm Hg) similar to post-PVC LVOT gradient of patients with WAS (110 ±50 mm Hg). However, the latter are departing from much higher basal gradients (Table 4). When comparing OCM to nonsevere WAS patients (similar basal gradients), the post-PVC LVOT gradient is higher in the OCM group (109 ±41 vs 63±32; p<0.05) (Table 4). All OCM patients show a relative post-PVC LVOT gradient increment >75 percent, while only three (8 percent) of the patients of the whole group with WAS and two (14 percent) of the subgroup with nonsevere WAS do have such an increment (p<0.01).
When analyzing the behavior of arterial pressure in the post-PVC beat, there is a striking incidence of arterial peak ASP decrement in all groups: 14 (100 percent) of OCM cases, 28 (77 percent) of VAS cases, and 11 (73 percent) of nonsevere VAS cases (Table 4). The post-PVC aortic PP decreased in 13 (92 percent) of the OCM cases, in 12 (33 percent) of the VAS cases (nonsignificant) and three (20 percent) of nonsevere VAS cases (p<0.05) (Table 4). The statistical difference between dynamic and fixed obstruction is enhanced if only arterial PP decrements >5 mm Hg are considered: 12 (85 percent) of the cases with OCM, six (17 percent) of the cases with \AS (LVEF 62.0±14.0) (p<0.05), and one (7 percent) of the cases with nonsevere VAS (LVEF 66.2 ±16.6); nonsignificant vs the whole group of VAS (p<0.01) (Table 4).
The post-PVC behavior of LVOT gradient, AS? and PP in both groups is illustrated in Figure 1. Figure 2 displays the relationship between the degree of prematurity assessed by the post-PVC RR increment (since all PVCs were followed by a full compensatory pause) and the induced relative increment in LVOT gradient. It illustrates the absence of any relationship between post-PVC RR increment and LVOT gradient increment for any degree of PVC prematurity in both types of diseases, OCM and VAS.
Figure 1. Postextrasystolic behavior of peak-to-peak left ventricular aortic gradient, systolic aortic pressure, and aortic pulse pressure in valvular aortic stenosis (VAS) and in obstructive cardiomyopathy (OCM). Much higher increment of gradient in OCM and failure to increase aortic systolic pressure in VAS.
Figure 2. Relationship between degree of prematurity assessed by the post-PVC RR increment (since all PVC are followed by full compensatory pause) and induced relative increment in LVOT gradient. Absence of any relationship between prematurity of PVC and relative gradient increment in both types of diseases, OCM and VAS. For any degree of prematurity gradient, increment is always higher for OCM than for VAS.