Latent Left Ventricular Outflow Tract Obstruction Research Articles

Unmasking Obstruction in Hypertrophic Cardiomyopathy With Postprandial Resting and Treadmill Stress Echocardiography

Latent left ventricular outflow tract obstruction (LVOTO) is an important cause of symptoms in patients with hypertrophic cardiomyopathy (HCM) but can be challenging to provoke. To examine the value of postprandial resting and stress echocardiography and utilization of invasive or enhanced drug therapies (surgical myectomy, alcohol septal ablation, disopyramide, and mavacamten) in patients with postprandial LVOTO. Consecutive HCM patients without LVOTO underwent routine and postprandial echocardiography at rest, with provocation (Valsalva and standing) and after symptom-limited treadmill stress. Among 252 patients (mean age, 58years, 39% women), postprandial LVOT gradients were higher compared with routine echocardiography at rest (median, 9.0 [0-38.0] vs 0 [0-14.0] mm Hg; P<.0001) and with provocation (18.5 [0-70.3] vs 1.5 [0-41.0] mm Hg; P<.0001). Postprandial exercise stress echocardiogram (PPXSE) gradients were higher in a subset of 44 patients who underwent both postprandial and fasting stress echocardiography (47.0 [5.3-81.0] vs 17.5 [0-46.0] mm Hg; P<.0001). In total, 49 (19.5%) patients achieved the ≥50mm Hg threshold under routine conditions (rest/provocation); 90 (35.7%) additional patients achieved postprandial gradients ≥50mm Hg (rest/provocation/exercise), 38 (15.1%) with PPXSE alone. A total of 71 patients were treated with 91 invasive or enhanced drug therapies, 32 (45.1%) of whom had gradients ≥50mm Hg only after eating (rest/provocation) and 8 (11.3%) only with PPXSE, with symptom relief in the majority. Postprandial echocardiography was useful at unmasking LVOTO in more than one-third of patients who did not have high gradients otherwise. Eating before echocardiography is a powerful provocative tool in the evaluation of patients with HCM.

Exaggerated myocardial torsion may contribute to dynamic left ventricular outflow tract obstruction in hypertrophic cardiomyopathy.

Dynamic left ventricular (LV) outflow tract obstruction (LVOTO) is associated with symptoms and increased risk of developing heart failure in hypertrophic cardiomyopathy (HCM). The association of LVOTO and LV twist mechanics has not been well studied in HCM. The aim of the study was to compare the pattern of LV twist in patients with HCM associated with asymmetrical septal hypertrophy with and without LVOTO. Echocardiography (including speckle tracking) was performed in 212 patients with HCM, divided according to the absence (n = 130) or presence (n = 82) of LVOTO (defined as peak pressure gradient ≥30 mmHg either at rest and/or with Valsalva manoeuvre). Patients with LVOTO were older, had smaller LV dimensions, a higher LV ejection fraction (LVEF), a longer anterior mitral valve leaflet length, and a higher early transmitral pulsed wave to septal tissue Doppler velocity ratio (E/E'). A univariate analysis showed that peak twist was significantly higher in patients with LVOTO compared with patients without LVOTO (19.7 ± 7.3 vs. 15.7 ± 6.0, P = 0.00015). Peak twist was similarly enhanced in patients with LVOTO, manifesting only during Valsalva (19.2 ± 5.6, P = 0.007) and patients with resting LVOTO (19.9 ± 8.0, P = 0.00004) compared with patients without LVOTO (15.7 ± 6.0). A stepwise forward logistic regression analysis showed that LVEF, LV end-systolic dimension indexed to body surface area, anterior mitral valve leaflet length, E/E', and peak twist were all independently associated with LVOTO. This study demonstrates that increased peak LV twist is independently associated with LVOTO in patients with HCM. Peak twist was similarly exaggerated in patients with only latent LVOTO, suggesting that it may play a contributory role to LVOTO in HCM.

Midterm results of latent outflow tract obstruction in hypertrophic cardiomyopathy after septal myectomy: A propensity score-matched study.

The midterm clinical outcomes of patients with latent left ventricular outflow tract (LVOT) obstruction who undergo septal myectomy are unclear. Therefore, this study aimed to evaluate the clinical outcomes of patients with latent LVOT obstruction who underwent septal myectomy. We studied 34 patients with hypertrophic cardiomyopathy (HCM) and latent LVOT obstruction who underwent septal myectomy in 2011-2019 at Anzhen Hospital. After 2:1 propensity score matching, the study cohort included 34 patients with latent LVOT obstruction and 68 patients with resting LVOT obstruction. Compared to patients with resting LVOT obstruction, patients with latent LVOT obstruction had a thinner interventricular septal thickness (18.2 ± 3.2 mm vs. 20.4 ± 5.6 mm; p = .01), while the proportion of moderate or severe mitral regurgitation was significantly higher (26.5% vs. 5.9%; p = .003). Moreover, the proportion of mitral valve procedures (26.5% vs. 5.9%; p = .004) was significantly higher in patients with latent LVOT obstruction. However, there was no intergroup difference in cardiovascular death (5.9% vs. 1.5%, p = .26). Furthermore, the 5-year survival rates after sudden cardiac death (100.0% vs. 91.7%; p = .26) and cardiovascular death (95.5% vs. 89.0%; p = .32) were similar between HCM patients with latent versus resting LVOT obstruction. Midterm clinical outcomes were similar and excellent in a matched cohort of HCM patients with latent versus resting LVOT obstruction after septal myectomy.

Hypertrophic cardiomyopathy with latent obstruction: Clinical characteristics and surgical results

BackgroundThe role of mitral subvalvular anomalies in the etiology of latent left ventricular outflow tract (LVOT) obstruction has rarely been reported; and the results of surgical treatment for latent LVOT obstruction have been infrequently reported as a separate group by other medical centers other than Mayo clinic. MethodsAmong 292 eligible patients, 45 with resting gradients <30 mmHg had provoked obstruction. Their clinical characteristics and surgical results were compared with those of 247 patients with resting LVOT obstruction. The patients were followed up for a median of 13 months. ResultsComparatively, patients with latent obstruction were younger (51.6±12.1 years vs. 57.2±11.6 years, p=0.003) and had higher prevalence of mitral subvalvular abnormalities (73.3% vs. 16.2%, p<0.001) and basal variant of hypertrophic cardiomyopathy (84.5% vs. 62.0%, p=0.014), less marked septal thickness (16.9±2.8 mm vs. 18.6±3.8 mm, p=0.005), lower resting gradients (22.2±5.7 mmHg vs. 93.0±25.7 mmHg, p < 0.001), and lower mitral regurgitation severity (median, 2.0 vs. 3.0, p<0.001). After surgery, no surgical death occurred in patients with latent LVOT obstruction. Only one (2.2%) patient from the latent group developed complete atrioventricular block. No follow-up death or reoperation was recorded with a significant improvement in New York Heart Association functional status in either group. The provoked LVOT gradients of patients with latent obstruction decreased sharply from the preoperative value (11.8±3.7 mmHg vs. 89.8±16.4 mmHg, p < 0.001), with no occurrence of residual obstruction. ConclusionsSymptomatic patients with latent LVOT obstruction may have a higher prevalence of mitral subvalvular abnormalities and have less marked septal hypertrophy; and concomitant mitral management during myectomy for the treatment of this patient group achieved excellent results.

Echocardiographic Characteristics of Severe Left Ventricular Outflow Tract Obstruction in Hypertrophic Cardiomyopathy

It is important to diagnose severe left ventricular outflow tract (LVOT) obstruction in symptomatic patients with hypertrophic cardiomyopathy (HCM) to determine who might benefit from septal reduction therapy. Due to its dynamic nature, LVOT obstruction may not be present at rest, 1 Maron M.S. Olivotto I. Betocchi S. Casey S.A. Lesser J.R. Losi M.A. et al. Effect of left ventricular outflow tract obstruction on clinical outcome in hypertrophic cardiomyopathy. New Engl J Med. 2003; 348: 295-303 Crossref PubMed Scopus (1012) Google Scholar , 2 Maron M.S. Olivotto I. Zenovich A.G. Link M.S. Pandian N.G. Kuvin J.T. et al. Hypertrophic cardiomyopathy is predominantly a disease of left ventricular outflow tract obstruction. Circulation. 2006; 114: 2232-2239 Crossref PubMed Scopus (650) Google Scholar , 3 Ayoub C. Geske J.B. Larsen C.M. Scott C.G. Klarich K.W. Pellikka P.A. Comparison of Valsalva maneuver, amyl nitrite, and exercise echocardiography to demonstrate latent left ventricular outflow obstruction in hypertrophic cardiomyopathy. Am J Cardiol. 2017; 120: 2265-2271 Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar and it is then necessary to “search for obstruction” with further provocative testing. 4 Ommen S.R. Mital S. Burke M.A. Day S.M. Deswal A. Elliott P. et al. 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol. 2020; 76: e159-e240 Crossref PubMed Scopus (76) Google Scholar , 5 Geske J.B. Sorajja P. Ommen S.R. Nishimura R.A. Left ventricular outflow tract gradient variability in hypertrophic cardiomyopathy. Clin Cardiol. 2009; 32: 397-402 Crossref PubMed Scopus (54) Google Scholar , 6 Nishimura R.A. Ommen S.R. Hypertrophic cardiomyopathy: the search for obstruction. Circulation. 2006; 114: 2200-2202 Crossref PubMed Scopus (41) Google Scholar We sought to determine whether there are resting echocardiographic characteristics associated with latent LVOT obstruction.

Latent outflow tract obstruction in hypertrophic cardiomyopathy: Clinical characteristics and outcomes of septal myectomy

ObjectiveThis investigation analyzed clinical characteristics of patients with hypertrophic cardiomyopathy (HCM) and latent left ventricular outflow tract (LVOT) and outcomes following septal myectomy. MethodsWe reviewed patients with HCM and LVOT obstruction undergoing septal myectomy from 2001 to 2016 at our center. Follow-up data on functional status were obtained through mailed survey questionnaires. ResultsThere were 629 (31.8%) patients with latent obstruction (resting LVOT gradient <30 mm Hg, provoked gradient >30 mm Hg) among 1981 patients undergoing septal myectomy. Patients with latent obstruction were more likely to be male (65.7% vs 51.8%, P < .001), but there were no important differences in other clinical characteristics. The New York Heart Association functional classes and measured/predicted maximal oxygen consumption (62 [51, 72] vs 60 [48, 72], P = .158) in cardiopulmonary exercise tests were comparable between the 2 groups. Patients with latent obstruction had both lower septal thickness and lower posterior wall thickness. Median intraoperative provoked pressure gradient decreased from 96 (68, 126) mm Hg to 0 (0, 6) mm Hg after myectomy (P < .001). There was no difference in early (<30 days) deaths (3/629 vs 5/1352, P = .726) and long-term survival between patients with latent obstruction and resting obstruction. In follow-up, both general health status and New York Heart Association functional class were significantly improved following septal myectomy. ConclusionsPatients with HCM and latent LVOT obstruction generally have milder left ventricular hypertrophy but similarly impaired functional capacity compared to those with resting obstruction. Septal myectomy improves functional capacity and symptoms.

Manifestation of Latent Left Ventricular Outflow Tract Obstruction in the Acute Phase of Takotsubo Cardiomyopathy.

Objective Left ventricular outflow tract (LVOT) obstruction is a complication in 15-25% of patients with Takotsubo cardiomyopathy and sometimes leads to catastrophic outcomes, such as cardiogenic shock or cardiac rupture. However, the underlying mechanisms have not been clarified. Methods and Results We experienced 22 cases of Takotsubo cardiomyopathy during 3 years, and 4 of these 22 cases were complicated with LVOT obstruction in the acute phase (mean age 79±5 years, 1 man, 21 women). The LVOT pressure gradient in the acute phase was 100±17 mmHg. Transthoracic echocardiogram (TTE) revealed left ventricular hypertrophy (LVH) in one case and sigmoid-shaped septum without LVH in three cases. The complete resolution of the LVOT obstruction was achieved in a few days with normalization of the left ventricular wall motion following administration of beta-blockers. A dobutamine provocation test after normalization of the left ventricular wall motion reproduced the LVOT obstruction in all cases and revealed the presence of latent LVOT obstruction. Conclusion The manifestation of latent LVOT obstruction in the acute phase of Takotsubo cardiomyopathy is one potential reason for the complication of LVOT obstruction with Takotsubo cardiomyopathy.

Manifestation of latent left ventricular outflow tract obstruction caused by acute myocardial infarction: An important complication of acute myocardial infarction

BackgroundAlthough transient left ventricular outflow tract (LVOT) obstruction is reported as a complication with acute myocardial infarction (AMI), the mechanisms and features of LVOT obstruction in AMI are unclear. Methods and resultsHerein, we present two cases of transient LVOT obstruction with anteroseptal AMI. The features of these two cases were one-vessel disease (1-VD) of the left anterior descending artery (LAD) and maintenance of blood flow to the major septal branch (SB). Moreover, LVOT obstruction was revealed after dobutamine infusion in the chronic phase and the aorto-septal angle was low in these two cases, meaning that latent LVOT obstruction was due to sigmoid-shaped septum. ConclusionsLatent LVOT obstruction would be manifested in the acute phase of AMI. 1-VD of LAD and the maintenance of major SB blood flow are important factors with respect to the manifestation of latent LVOT obstruction.

Major determinants and possible mechanism of dobutamine-induced left ventricular outflow tract obstruction in patients with a sigmoid ventricular septum

BackgroundA sigmoid ventricular septum (SVS) may be related to normal aging, but some people with an SVS develop a left ventricular outflow tract (LVOT) obstruction (defined as a gradient of >30mmHg). Therefore, we investigated the association of LVOT obstructions with an SVS by dobutamine stress echocardiography (DSE) and assessed the possible mechanism of the latent LVOT obstruction. Methods and resultsDSE was performed in 64 subjects with SVS (mean age: 73.3±7.7 years; 36 women) without an LVOT obstruction. In 40 of the 64 subjects, an LVOT obstruction occurred during the DSE (defined as latent obstruction). At rest, the subjects with a latent obstruction had a shorter end-systolic mitral leaflet tethering distance (“α” distance, i.e. the distance between the tip of the posterior papillary muscle and the contralateral anterior mitral annulus) than those without one (29.9±4.2mm versus 35.2±4.6mm), as well as a smaller end-systolic LVOT diameter (13.4±2.7mm versus 16.1±3.4mm) and larger ejection fraction (72.0±5.0% versus 67.8±5.9%) (all p<0.05). They also had a higher LV outflow velocity at rest (1.23±0.24m/s versus 1.03±0.24m/s) and during the Valsalva maneuver (1.31±0.27m/s versus 1.03±0.27m/s) (both p<0.05). After adjusting for these parameters, the resting end-systolic “α” distance and LV outflow velocity at rest remained independent predictors of a latent obstruction. ConclusionA short leaflet tethering distance (“α”) was the major determinant of a latent obstruction, suggesting that a mitral leaflet displacement/redundancy caused by a short “α” distance contributes to the LVOT obstruction.

Basic Echocardiographic Features of Patients With Latent Left Ventricular Outflow Tract Obstruction Without Left Ventricular Hypertrophy

Left ventricular outflow tract obstruction (LVOTO) is commonly observed in patients with hypertrophic cardiomyopathy (HCM) or left ventricular hypertrophy (LVH). While some patients develop LVOTO at rest, it can also be provoked by physical exertion, and hence termed latent LVOTO (L-LVOTO). Recent reports demonstrated that L-LVOTO develops not only in LVH patients, but also in patients without LVH (non-LVH). However, the prevalence and clinical prognosis of non-LVH patients with L-LVOTO are not yet elucidated. In this study, we retrospectively investigated the echocardiographic features of patients with malignancy who underwent dobutamine stress echocardiography (DSE) to evaluate preoperative cardiac risk. One hundred ninety-nine patients were found not to have LVH or coronary artery disease. Among them, 106 patients exhibited L-LVOTO after DSE. We next compared the baseline echocardiographic features of L-LVOTO (+) patients with those of L-LVOTO (-) patients, and identified the left ventricular outflow tract (LVOT) ratio (systolic LVOT diameter/diastolic LVOT diameter) as a significant predictor of L-LVOTO. An LVOT ratio ≤ 0.83 was the best cutoff value to detect the presence of L-LVOTO, with a sensitivity of 81.1% and specificity of 80.6%. Overall, L-LVOTO was found to develop in almost half of non-LVH patients with malignancy. In addition, the baseline LVOT ratio was strongly related to the presence of L-LVOTO in non-LVH patients. Therefore, patients with dynamic LVOT narrowing may benefit from DSE to detect the presence of L-LVOTO.

Provokation einer dynamischen Obstruktion des linksventrikulären Ausflußtrakts bei sekundärer Myokardhypertrophie

The effect of the Valsalva manoeuvre before and after sublingual administration of 1.6 mg nitroglycerin on maximal velocity (Vmax), acceleration time (AT) and ejection time (ET) of left-ventricular outflow was measured by Doppler echocardiography in 49 patients (28 men and 21 women; mean age 65 [48-84] years) with secondary left-heart hypertrophy, and in 8 controls. Changes in flow profile typical of dynamic obstruction in the left-ventricular outflow tract (LVOT) occurred in 30 of the patients, Vmax increasing from a mean of 137 to 302 cm/s. Latent LVOT obstruction was associated with a thickened posterior wall, an accelerated left-ventricular outflow even at rest and systolic anterior motion of the anterior mitral leaflet (SAM phenomenon). The size of the provoked LVOT gradient correlated significantly with Vmax or the AT/ET ratio at rest. Obstruction of the LVOT is apparently a non-specific phenomenon which also occurs in secondary left-heart hypertrophy. These findings may have therapeutic consequences.

Reproducible (latent) obstruction of the left ventricular outflow tract

Left ventricular outflow tract obstruction (LVOTO) with flow acceleration in late systole (Vmax > or = 2.0 m/s and acceleration/ejection time [AT/ET] > or = 0.5) is often present in a latent form in left ventricular hypertrophy; it can be unmasked by administration of glyceryl trinitrate or with the Valsalva manoeuvre (preload reduction). It was investigated prospectively whether latent LVOTO also occurs on ergometric exercise. 61 patients (19 female, 42 male, mean age 55.5 +/- 12.9 years) with left ventricular hypertrophy at rest were examined by Doppler echocardiography at rest, under provocation with glyceryl trinitrate and the Valsalva manoeuvre, and during bicycle ergometry. Manifest LVOTO was already present before the test in 3 patients. In 24 patients LVOTO occurred during the provocation (Vmax rose from 1.38 +/- 0.25 to 2.93 +/- 0.53 m/s; AT/ET rose from 0.47 +/- 0.16 to 0.68 +/- 0.09). In 19 of these 24 patients LVOTO also occurred during the ergometry. In four additional patients changes were marginal (AT/ET > or = 0.5; Vmax = 1.8 and 1.9 m/s, respectively). There was a highly significant correlation between provocation and ergometry with regard to Vmax, as well as AT/ET (with r = 0.84 and 0.76, respectively). These findings show that provokable LVOT gradients are likely to occur during exercise to a similar degree as those on preload reduction. Thus, course of disease could possibly be influenced by early treatment in patients with left ventricular hypertrophy.

Latent left ventricular outflow tract obstruction induced by abnormal hypertrophic papillary muscle caused myocardial ischemia

Left ventricular outflow tract (LVOT) obstruction is a typical recognized feature in hypertrophic cardiomyopathy. However, it has been shown in other clinical scenarios such as acute ischemia. In some patients, LVOT obstruction may only be detectable with provocation testing such as exercise stress. Accurate and timely diagnosis, therefore, relies on recognizing an echocardiographic substrate in which LVOT obstruction may occur, such as ventricular hypertrophy. This report describes the case of a patient presenting with effort ECG and signs of myocardial ischemia, with no significant narrowing of coronary arteries but with latent LVOT obstruction due to the presence of an abnormal hypertrophic papillary muscle instead of a typical ventricle hypertrophy.

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

Background:Resting left ventricular outflow tract obstruction (LVOTO) occurs in 25% of patients with hypertrophic cardiomyopathy (HCM) and is an important cause of symptoms and disease progression. The prevalence and clinical...

Acute Myocardial Ischemia Associated with Latent Left Ventricular Outflow Tract Obstruction in the Absence of Left Ventricular Hypertrophy

Left ventricular outflow tract obstruction (LVOTO) is a recognized feature in hypertrophic cardiomyopathy, but can occur in other clinical scenarios such as acute myocardial ischemia. In some patients, LVOTO may only be detectable with provocation testing such as exercise stress. Accurate and timely diagnosis, therefore, relies on recognizing an echocardiographic substrate in which LVOTO may occur, such as ventricular hypertrophy. The investigators describe two cases of latent LVOTO, presenting with acute myocardial ischemia in the absence of obstructive coronary artery disease, in which the diagnosis was delayed because of the absence of hypertrophy, or other recognizable substrate, on the resting echocardiographic study, but became evident during exercise echocardiography.

Use of Doppler Echocardiography and Amyl Nitrite Inhalation to Characterize Left Ventricular Outflow Obstruction in Hypertrophic Cardiomyopathy

The presence of left ventricular outflow tract obstruction (LVOTO) of either a resting or dynamic nature may have important therapeutic and prognostic implications in patients with hypertrophic cardiomyopathy (HCM). Doppler echocardiograms combined with amyl nitrite (Amyl) inhalation were performed in 333 consecutive patients referred for suspected HCM to diagnose and categorize the nature and severity of LVOTO. Hypertrophic cardiomyopathy was present by 2-D and M-mode criteria in 145/333 (44 percent) patients. Normal limits of resting and post-Amyl continuous wave Doppler peak left ventricular outflow tract velocities were established in 15 subjects with completely normal 2-D and Doppler echocardiograms. Based on these criteria, of the 145 patients with HCM, 63 (43 percent) were classified as having resting LVOTO, peak velocity 4.2 +/- 1.3 m/s. Among 82 patients with HCM without resting LVOTO, 47 (57 percent) received Amyl. Latent LVOTO was provoked in 25/47 (53 percent), peak post-Amyl velocity 4.5 +/- 1.2 m/s. The remaining 22 (47 percent) had nonobstructive HCM, as indicated by no significant increase in post-Amyl velocity. Among a total 62 subjects receiving Amyl, none experienced serious morbidity or mortality. Doppler echocardiography, in conjunction with Amyl inhalation in selected patients, is a useful noninvasive method to diagnose and categorize patients with HCM according to the nature and severity of LVOTO.