Outflow Acceleration Assessed by Continuous-Wave Doppler Echocardiography in Left Ventricular Hypertrophy: An Analysis of 103 Consecutive Cases

Abstract

The effect of provocation on left ventricular (LV) outflow was studied by continuous-wave Doppler echocardiography in 103 nonselected, consecutively enrolled patients with LV hypertrophy (LVH), either due to pressure overload (97 patients) or hypertrophic cardiomyopathy (HCM, 6 patients). In 34 patients with LVH, outflow acceleration (gradients ranging from 18 to 122 mm Hg) was induced or accentuated by the Valsalva maneuver after 1.6 mg nitroglycerine sublingually independent of LVH etiology. Factors associated with LV outflow acceleration were female sex, small body surface area and LV cavity size, increased relative wall thickness, LV contractility, and resting LV outflow velocity, mitral anulus calcifications and systolic anterior movement of the mitral valve. It is concluded that dynamic, intracavity LV gradients are a nonspecific flow abnormality that merit consideration because they can be frequently found in LVH patients.

Prevalence of exercise-induced left ventricular outflow tract obstruction in symptomatic patients with non-obstructive hypertrophic cardiomyopathy

“…This was not explained by more vigorous exercise in the latent cohort as work-rates were similar to those patients with non-obstructive HCM. A more likely explanation for the higher peak VO 2 is that, in comparison with patients who have no obstruction, those with latent obstruction have a higher cardiac output at peak exercise (perhaps reflecting more severe diastolic dysfunction in the non-obstructive cohort) 12 23 24. This hypothesis is supported by the higher peak exercise blood pressure in the latent obstruction group.…”

“…The term labile obstruction has been used to describe the spontaneous appearance and disappearance of obstruction and latent obstruction to describe gradients that only appear with provocation 2. The most commonly used techniques used to provoke obstruction have been inhalation of amyl nitrate,11 the Valsalva manoeuvre12 and intravenous inotropes 13 14. The problem with all such methods is that, unlike upright exercise stress testing, they do not reliably reproduce the physiological circumstances in which latent obstruction is likely to occur1 22; consequently, gradients produced during such manoeuvres correlate poorly with gradients induced during exercise 23…”

“…In some cases, obstruction only appears during a haemodynamic challenge2 10 such as inhalation of amyl nitrite,11 Valsalva manoeuvre12 and infusion of positive inotropes 13 14. However, the clinical significance of outflow tract gradients provoked by such techniques remains controversial as these manoeuvres are difficult to standardise in routine clinical practice and do not reproduce the physiological conditions in which obstruction occurs during daily life.…”

Gender Differences in the Presentation of Adult Obstructive Hypertrophic Cardiomyopathy With Resting Gradient

“…24 Patiemts can even present with left ventricular outflow obstructions similar to that seen in HCM. 25,26 But most believe that hypertension is not the primary cause of HCM although it may coexist with or aggravate HCM. 24,27,28 In our study, the high prevalence of hypertension among female patients maybe due to one, 2 or all of aforementioned factors.…”

Clinical research Comparison of sublingual isosorbide dinitrate and Valsalva maneuver for detection of obstruction in hypertrophic cardiomyopathy

“…It is considered controversial and is not recommended. Currently we have a variety of other obstruction provoking tests, such as the VM [ 13 ], the upright position [ 14 ], a post-extrasystolic measurement, and inhalation of amyl nitrite [ 15 ]. They are mentioned in the guidelines for the diagnosis and treatment of hypertrophic cardiomyopathy [ 16 ].…”