The recognition of muscular LVOT obstruction associated with fixed stenosis has therapeutic implications. Since a catheter within the left ventricular chamber can easily induce PVCs during left heart catheterization, the induction of this arrhythmia has been considered as the standard hemodynamic intervention for evaluation of LVOT gradients. In fact, post-PVC LVOT gradient increments (dynamic obstruction) were usually considered to be indicative of hypertrophic OCM. However, fixed stenosis in the LVOT, as in WAS, might also show a post-PVC gradient potentiation, even in the documented absence of OCM. Although post-PVC decrement of arterial pulse pressure (PP) and peak systolic aortic pressure are suggestive of OCM, some cases of \AS might also show such behavior. In view of these observations we prospectively evaluated the hemodynamic behavior of the post-PVC beat in patients with OCM and with WAS free of OCM. http://www.medicines-for-diabetes.com/
Material and Methods
Two groups of patients are defined. The first consisted of 14 patients with OCM; three males and 11 females, aged 23 to 65 years (mean age 52 years). The diagnosis was made by M-mode or twodimensional echocardiogram and left ventriculography classic criteria plus demonstration of subvalvular LVOT gradient (Table 1). All patients with OCM had a morphologically normal aortic valve, a septal to posterior wall thicknes ratio>1.5, presence of basal or postmaneuver systolic anterior motion of the mitral valve in the echocardiogram, and absence of valvular systolic aortic gradient in the hemodynamic study. Thus, associated \AS was ruled out.
In the second group were 36 patients with pure WAS, 20 males and 16 females, aged 13 to 70 years (mean age 51 years). Diagnosis was made by M-mode or two-dimensional echocardiogram, left ventriculography, and aortography plus demonstration of valvular LVOT gradient Thus, OCM and significant aortic regurgitation were ruled out Tables 2 and 3). None of the VAS patients showed echocardiographic, hemodynamic, or angiographic features of OCM. Septal-to-posterior wall thickness ratio was <1.3; systolic anterior motion of the mitral valve was not present in basal conditions and could not be induced with classic provocation maneuvers; subvalvular gradients were not detected; and systolic cavity obliteration was not present in the LV angiogram.
For basal gradient comparison with OCM, we used a subgroup of 15 patients (9 males and 6 females, aged 13 to 70 years, mean age 45 years) with nonsevere \AS (basal LVOT gradient [60 mm Hg) (Table 3). Significant coronary artery disease (stenosis 50 percent) was discarded by means of selective coronary arteriography performed in all patients with angina and in those older than 40 years.
Catheterization was performed after premedication with diazepam, 5 mg, and promethazine, 25 mg IM. Left heart catheterization was performed with an end-hole catheter suitable for LVOT gradient evaluation. In all patients, simultaneous LV and aortic pressure tracings were recorded with two Statham P23 Id transducers by means of a double-lumen catheter or transeptal and retrograde left heart catheterization. Informed consent was obtained from all patients.
The following parameters were analyzed in baseline and post-PVC conditions: RR interval, peak LVSI peak ASP, aortic PP, and peak systolic ^VG. All post-PVC parameters were analyzed in the first beat after one or two consecutive PVCs that followed at least four stable sinus beats, with a full compensatory pause. PVCs were induced with a catheter within the LV chamber. Statistical analysis was performed by means of Students t test for unpaired quantitative data and Fishers exact test and x2 test for comparison of proportions.
Table 1—Individual Hemodynamic Parameters in the Basal and Post-PVC Condition in Patients with OCM
Table 2—Individual Hemodynamic Parameters in the Basal and Post-PVC Condition in Patients with Severe VAS
Table 3—Individual Hemodynamic Parameters in the Basal and Post-PVC Condition in Patients with Nonsevere VAS
Table 4—Comparison of Collective Hemodynamic Parameters in the Basal and Post-PVC Conditions between the OCM Patients and Either the Whole Group of VAS and its Subgroup cf Nonsevere VAS
|Group||N||BasalRR||PVC RR||RR||BasalAVG||PVC AVG||AAVG(%)||AAVG>75%(%)||1 ASP(%)||J,PP 1(%)||i PP>5(%)|
|OCM||14||746 ±154||977 ±255||+231±132||24± 16||109 ±41||14 (100)||14 (100)||14 (100)||13 (92)||12 (85)|
|All VAS||36||699 ±126||1,018 ±189||+ 320 ± 125||72 ±30||110 ±50||33 (92)||3 (8)t||28 (77)||12 (33)||6 (17)§|
|NonsevereVAS||15||702 ±150||1,003 ±209||+301±138||39 ±17||63 ±32*||12 (80)||2 (14)4:||11 (73)||3 (20)t||1 (7) §|