Doppler Systolic Signal Void in Hypertrophic Cardiomyopathy: Apical Aneurysm and Severe Obstruction without Elevated Intraventricular Velocities.

BACKGROUND: In patients with hypertrophic cardiomyopathy (HCM), akinetic apical aneurysms are associated with ventricular tachycardia, heart failure, apical thrombus, and mortality. The cause of apical aneurysms remains unresolved, and there is controversy about prevalence and significance of mid-left ventricular (LV) obstruction, often present in these patients. The aim of this study was to test the hypothesis that low velocities in patients with aneurysms are due to near complete cessation of mid-LV flow, characteristically marked by a Doppler signal void. METHODS: This was a retrospective analysis of 39 patients with HCM with segmental hypertrophy of the mid left ventricle and complete systolic emptying at the mid-LV level. The severity of dynamic obstruction was evaluated by measuring the time during which cross-sectional mid-LV cavity area was <1 cm(2). Presence or absence of an LV Doppler midsystolic signal void was determined. RESULTS: Akinetic apical aneurysms were present in 21 patients. The duration of two-dimensional mid-LV short-axis complete emptying was longer in patients with akinetic apical aneurysms (194 ± 45 vs 148 ± 63 msec, P = .013), nearly 50% of systole. Midsystolic signal voids were seen only in patients with akinetic apical aneurysms (P < .001), present in 86%. In patients with akinetic aneurysms, there was a strong correlation between the duration of the systolic signal void and the proportion of systole with complete emptying < 1 cm(2) (r = 0.704; P = .001). Complete emptying < 1 cm(2) for ≥ 38% of systole was associated with akinetic aneurysm (odds ratio, 9.35; P < .004). CONCLUSION: Patients with akinetic apical aneurysm HCM have near complete cessation of flow across severe dynamic mid-LV obstruction for nearly 50% of systole. This explains how the adverse effects of obstruction may occur without high velocities on echocardiography.

Echocardiography before and after resect-plicate-release surgical myectomy for obstructive hypertrophic cardiomyopathy.

BACKGROUND: Anatomic features of obstructive hypertrophic cardiomyopathy are septal hypertrophy, elongated mitral leaflets, and anterior displacement of the papillary muscles. In addition to extended myectomy, the resect-plicate-release operation adds horizontal plication of the anterior mitral leaflet (AML) and release of the anterolateral papillary muscle (APM) in selected patients. The aim of this study was to test the hypotheses that (1) preoperative findings would be associated with procedures applied, (2) anatomic corrections would be observable postoperatively, and (3) there would be consistently good physiologic outcomes. METHODS: A retrospective study was conducted of patients with obstructive hypertrophic cardiomyopathy who had adequate echocardiograms before and 9.5 ± 12 months after the resect-plicate-release operation was performed from 2006 to 2012. RESULTS: Seventy-seven patients underwent myectomy, 50 AML plication, and 50 APM release. Patients who underwent plication had longer AMLs (32 ± 4 vs 28 ± 4 mm; P < .004). Anterior extension of the APM was more common with papillary muscle release (86% vs 62%, P < .04). Twenty-seven (35%) had septal thickness ≤ 18 mm; mitral valve-sparing operations were possible because of plication in 19 patients (70%), papillary release in 21 (78%), and one or both in 96%. Patients who underwent plication had decreased AML length by 16%, residual leaflet length by 33%, and protrusion by 24%. After APM release, there was decreased distance from mitral coaptation to the posterior wall. Surgery abolished severe systolic anterior motion and resting gradients and reduced mitral regurgitation. CONCLUSIONS: Echocardiographic AML length and directly observed slack provides a basis to recommend performance of plication and define its extent; plication decreases AML protrusion and stiffens the leaflet. Anterior APM recommends release, which drops the coaptation point posteriorly. Systematic relief of all aspects of obstructive pathophysiology results in consistent outcomes.

Treatment of obstructive hypertrophic cardiomyopathy symptoms and gradient resistant to first-line therapy with ß-blockade or verapamil.

BACKGROUND: There is controversy about preferred methods to relieve obstruction in hypertrophic cardiomyopathy patients still symptomatic after ß-blockade or verapamil. METHODS AND RESULTS: Of 737 patients prospectively registered at our institution, 299 (41%) required further therapy for obstruction for limiting symptoms, rest gradient 61 ± 45, provoked gradient 115 ± 49 mm Hg, and followed up for 4.8 years. Disopyramide was added in 221 (74%) patients and pharmacological control of symptoms was achieved in 141 (64%) patients. Overall, 138 (46%) patients had surgical relief of obstruction (91% myectomy) and 6 (2%) alcohol septal ablation. At follow-up, resting gradients in the 299 patients had decreased from 61 ± 44 to 10 ± 25 mm Hg (P<0.0001); New York Heart Association class decreased from 2.7 ± 0.7 to 1.8 ± 0.5 (P<0.0001). Kaplan-Meier survival at 10 years in the 299 advanced-care patients was 88% and did not differ from nonobstructed patients (P=0.28). Only 1 patient had sudden death, a low annual rate of 0.06%/y. Kaplan-Meier survival at 10 years in the advanced-care patients did not differ from that expected in a matched cohort of the US population (P=0.90). CONCLUSIONS: Patients with obstruction and symptoms resistant to initial pharmacological therapy with ß-blockade or verapamil may realize meaningful symptom relief and low mortality through stepped management, adding disopyramide in appropriately selected patients, and when needed, by surgical myectomy.

Antihypertensive therapy in hypertrophic cardiomyopathy.

Patients with coexisting hypertrophic cardiomyopathy (HC) and hypertension present diagnostic and therapeutic dilemmas. A retrospective cohort study of patients with HC with coexisting hypertension referred to a specialized HC program was conducted. HC and hypertension were confirmed by strict criteria. Echocardiographic data were reviewed for peak instantaneous left ventricular outflow tract gradients, at rest and with provocation. Symptom control, left ventricular outflow tract gradients, and hypertension control were compared between the first and last visits. One hundred fifteen patients (94 obstructed and 21 nonobstructed) met the eligibility criteria for the study and were included in the analysis, with the mean follow-up duration of 36 months. Because of the treatment strategy, there was a significant decrease in the number of patients treated with direct vasodilators and an increase in the use of ß blockers and disopyramide. Twenty-one obstructed patients (22%) required septal reduction therapy. Overall, in obstructed patients, peak instantaneous left ventricular outflow tract gradient at rest decreased from 48 to 14 mm Hg (p <0.01), which was accompanied by significant improvement in functional class (2.4 vs 1.8, p <0.01). The prevalence of uncontrolled hypertension decreased from 56% at the initial visit to 37% at the last visit (p = 0.01). The cohort had a low rate of adverse cardiovascular outcomes such as death, acute coronary syndromes, and stroke. In conclusion, the present study demonstrates that stepwise, symptom-oriented therapy is feasible and effective in patients with coexisting HC and hypertension.

Role of mitral valve plication in the surgical management of hypertrophic cardiomyopathy.

BACKGROUND: We have previously reported our 3-step repair for obstructive hypertrophic cardiomyopathy (HCM) consisting of resection of the septum, horizontal plication of the anterior mitral leaflet (AML), and release of abnormal papillary muscle attachments. This article reviews our complete experience with surgical management of HCM to better understand the role and relevance of mitral plication. METHODS: From 1997 to 2011, 132 patients with HCM underwent surgical treatment at our institution. Eighty-two patients (62%) received AML plication based on selection criteria and were classified as group A; patients in group B did not receive plication. All patients underwent preoperative and postoperative echocardiography. Long-term clinical follow-up was obtained by review of scheduled echocardiograms and direct patient interview. RESULTS: The average age of all patients was 55.5 years. Operative mortality was 0%. The mean left ventricular outflow tract (LVOT) gradient decreased from 118±41 mm Hg to 6±13 mm Hg (p<0.0001). Mean mitral regurgitation improved from 2.4±1.0 to 0.5±0.7 (p<0.0001). Postoperatively, 96.2% of patients had no residual systolic anterior motion (SAM). Significant improvements in heart failure classification and quality of life scores were noted for all patients. Comparison of groups A and B showed no statistically significant differences in outcomes, complications, or survival. Survival at 1, 5, and 10 years was 98%, 98%, and 92%, respectively. CONCLUSIONS: The heterogeneity of the pathologic process in HCM supports detailed analysis of the septum, mitral leaflets, and subvalvular apparatus. Surgical management of HCM that includes horizontal plication of a lax and elongated AML is safe and results in durable clinical and echocardiographic improvement.

Standing and exercise Doppler echocardiography in obstructive hypertrophic cardiomyopathy: the range of gradients with upright activity.

BACKGROUND: The ideal provocative maneuver in patients with hypertrophic cardiomyopathy (HCM) is a subject of ongoing investigation. Standing is a fundamental activity of daily life. This study examined acquisition of standing, Valsalva, and post-exercise left ventricular outflow tract gradients in HCM. METHODS: Rest supine, standing, and post-Valsalva gradients were measured in 98 consecutive patients with HCM who were referred for outpatient echocardiography. In 53 (54%) of the 98 patients, symptom-limited treadmill exercise was also performed, with gradients measured immediately after in the supine position. RESULTS: Fifty-six (57%) of the 98 patients had resting gradient<30 mm Hg and would thus be characterized as nonobstructive at rest. In the 98 patients, median gradients were 25 mm Hg at rest (range 0-205 mm Hg), increasing to 44 mm Hg after standing (range 0-309 mm Hg), an increase of 76%, and were again higher after Valsalva, 64 mm Hg (range 0-256 mm Hg) (P<.001). In the 53 patients who had gradient assessed after exercise, they were higher still, 100 mm Hg (range 0-256 mm Hg) (P<.001). In 29 patients (30%), standing provoked a higher gradient than Valsalva. CONCLUSION: Although standing increased gradients by 76%, it is not as potent a provocative maneuver as Valsalva or treadmill exercise. Nevertheless, standing is recommended as a physiologic provocative maneuver. In some patients standing may guide therapy; in others, the standing and exercise gradient provide a correct appreciation of the range of physiologically experienced gradients during daily upright activity.

Severe symptoms in mid and apical hypertrophic cardiomyopathy.

BACKGROUND: We analyzed the clinical and quantitative echocardiographic characteristics of patients with sub-basal hypertrophic cardiomyopathy (HCM) to define the characteristics of patients (pts) with severe symptoms. METHODS: Of 444 pts in a referral-based HCM program, 22 (5%) had midventricular or apical HCM. Quality of life (QoL) questionnaire was administered as an independent confirmer of symptomatic state. RESULTS: Ten pts were NYHA III and IV, and 12 pts were NYHA I and II; QoL scores (41 +/- 26 vs. 10 +/- 13, P = 0.001) confirmed a priori division of two groups based on NYHA classification. Pts with more severe symptoms were more likely female (70% vs. 25%, P = 0.001) with atrial fibrillation (40% vs. 0%, P = 0.02). They more frequently had midventricular HCM 60% versus 8% (P = 0.01) (mid-LV thickness 17 +/- 6 vs. 12 +/- 2 mm, P = 0.03) and had much smaller LV diastolic volumes 68 +/- 12 versus 102 +/- 22 ml (39 +/- 4 vs. 53 +/- 12 ml/m(2), P = 0.001). Septal E/E' was higher in the severely symptomatic pts (15 +/- 5 vs. 7 +/- 3, P = 0.001) indicating higher estimated LV filling pressure. Midobstruction with apical akinetic chamber was noted in 4/10 pts who developed refractory symptoms. Cardiac mortality was higher in the severely symptomatic patients, 4/10 who had midventricular HCM as compared to 0/12 in the mildly symptomatic apical HCM group (P = 0.03). CONCLUSIONS: In subbasal HCM, pts with severe symptoms have midventricular hypertrophy, with encroachment of the LV cavity and consequent very small LV volumes that may be complicated by mid-LV obstruction. Pts with mid-LV hypertrophy are more symptomatic than those with apical HCM, are often refractory to therapy, and have higher mortality.

Resection-plication-release for hypertrophic cardiomyopathy: clinical and echocardiographic follow-up.

BACKGROUND: Abnormal positioning and size of the mitral valve contribute to the systolic anterior motion and mitral-septal contact that are important components of obstructive hypertrophic cardiomyopathy (HCM). The RPR repair (resection of the septum, plication of the anterior leaflet, and release of papillary muscle attachments) addresses all aspects of this complex pathology. This study reports outcomes regarding effectiveness of the RPR repair. METHODS: Fifty consecutive unselected patients (average age, 55.8 years) undergoing RPR repair for obstructive HCM from 1997 to 2007 were studied. Each patient underwent preoperative and postoperative transthoracic echocardiograms to document gradient, ejection fraction, degree of mitral regurgitation, and systolic anterior motion. Intraoperative transesophageal echocardiogram was used to guide all surgical repairs. Clinical follow-up included patient interviews to determine New York Heart Association (NYHA) status. RESULTS: Concomitant operations were performed in 25 patients (50%). Postoperative mortality was 0%. Average mean left ventricular outflow tract gradients decreased from 134 +/- 40 to 2.8 +/- 8.0. Mitral regurgitation improved from a mean of 2.5 to 0.1 (p < 0.001). Average length of stay was 6.9 +/- 2.7 days. NYHA class improved from 3.0 +/- 0.6 to 1.2 +/- 0.5. Follow-up was 100%, with a mean of 2.5 +/- 1.8 years. Average mitral regurgitation at follow-up was 0.9, with no residual systolic anterior motion. CONCLUSIONS: The RPR repair is safe and effective for symptomatic obstructive HCM. Our data support repair of the mitral valve that results in good intermediate outcomes with respect to gradient, mitral regurgitation, and clinical status.

Effect of obstruction on longitudinal left ventricular shortening in hypertrophic cardiomyopathy.

OBJECTIVES: We investigated the cause of the midsystolic drop (MSD) in left ventricular (LV) ejection velocities that are observed with hypertrophic cardiomyopathy (HCM) and severe obstruction. BACKGROUND: Dynamic obstruction is an important determinant of symptoms and adverse outcome. The MSD in velocity and flow occurs in patients with gradients >60 mm Hg. The nadir velocity in the LV occurs simultaneously with peak gradient. METHODS: We studied 36 patients with obstructive HCM and an MSD and compared them with 15 patients with HCM and no obstruction and with 25 age-matched normal control subjects. We measured LV ejection velocity proximal and distal to LV obstruction as well as tissue Doppler velocities and time intervals. RESULTS: The duration of contraction of both the septum and lateral wall is shorter in obstructed patients with the MSD than in nonobstructed HCM patients: septal contraction 203 +/- 68 ms vs. 271 +/- 41 ms (p < 0.001). Parallel reduction in the length of shortening was noted: 1.2 +/- 0.6 cm vs. 1.9 +/- 0.4 cm (p < 0.001). The ejection velocity nadir follows the septal and lateral peak velocities by 100 ms and 60 ms, respectively. The velocity nadir occurs as both walls rapidly decelerate to their premature termination: septal deceleration 79 +/- 35 cm/s2 vs. 48 +/- 21 cm/s2 (p < 0.001). With medical abolition of obstruction the MSD disappears and the duration and length of contraction normalizes. CONCLUSIONS: These data indicate that the MSD is caused by premature termination of LV segmental shortening and is a manifestation of systolic dysfunction.

Beyond extended myectomy for hypertrophic cardiomyopathy: the resection-plication-release (RPR) repair.

BACKGROUND: Extended myectomy for left ventricular outflow tract obstruction (LVOTO) due to hypertrophic cardiomyopathy (HCM) has good long-term results. In addition to the midseptal resection (R) for HCM, our group has introduced a novel variation in anterior leaflet plication (P) and release (R) of papillary muscle attachments. We sought to investigate the medium-term success of this three-step repair that addresses all aspects of complex HCM pathology. METHODS: Nineteen patients underwent resection-plication-release repair for complex HCM pathology. Transesophageal echocardiography was performed on all patients preoperatively and postoperatively to assess adequacy of resection, left ventricular outflow tract gradients, and mitral valve function. All patients underwent transthoracic outpatient echocardiography at a mean follow-up of 2.4 +/- 2.1 years (range, 0.5 to 6). RESULTS: The average age of the patients was 57 +/- 14 years. The preoperative peak LVOTO was 137 +/- 45 mm Hg. The average degree of mitral regurgitation was 3.1. The average length of stay was 7.5 +/- 3.3 days. There were no readmissions or deaths in the group. Initial postoperative transesophageal echocardiography demonstrated marked reduction in LVOTO to 10 +/- 17 mm Hg (p < 0.0001) and significant improvement in mitral regurgitation to 0.2 (p < 0.0001). In follow-up, the LVOT gradient remained low at 6 +/- 14 (p > 0.0001) and mitral regurgitation remained insignificant at 0.4 (p < 0.0001). CONCLUSIONS: Anterior leaflet plication and papillary muscle release are logical adjuncts to septal resection in the treatment of the complicated pathophysiology of obstructive HCM. Durable long-term results can be achieved with an aggressive approach to mitral valve pathology in conjunction with extended myectomy.