Clinical diagnosis and pathogenesis of myocardial infarction complicated by hypertrophic cardiomyopathy: review of eight cases

Among 144 patients with hypertrophic cardiomyopathy, eight (58.3 +/- 7.0 years, M:F = 7:1) had complicating myocardial infarction, which was diagnosed clinically and by elevated cardiac enzymes or new Q-waves on electrocardiography. Coronary occlusion or stenosis evidenced by coronary angiography and nuclear cardiological findings were investigated. In six of the eight patients, coronary atherosclerosis caused infarction. These patients had many coronary risk factors compared to the other two patients. Sixteen of the 144 patients (11%) with hypertrophic cardiomyopathy had coronary atherosclerosis, the rate of which is reportedly 10 to 20%. Two of the eight patients had no coronary atherosclerosis. One patient had a diffusely spastic diathesis provoked by the intravenous administration of ergonovine maleate during coronary angiography, suggesting that coronary spasm caused myocardial infarction. The other patient had recurrent episodes of supraventricular tachyarrhythmia and no evidence of spasm during coronary angiography, suggesting coronary embolism as a cause of myocardial infarction. Myocardial infarction in patients with hypertrophic cardiomyopathy and normal coronary arteries as advocated by Maron et al. may have such pathogenesis. We conclude that coronary angiography may be mandatory in patients with hypertrophic cardiomyopathy, especially those who have many coronary risk factors and anginal symptoms. In these patients, ST-T changes and abnormal Q-waves on electrocardiography sometimes may be misleading when diagnosing the occurrence of acute myocardial infarction by electrocardiography alone. In such cases, infarct-avid scintigraphy with 99 m-Tc pyrophosphate is preferable.     

肥厚梗阻型心肌病化学消融术中、术后严重并发症及防治

目的 :报告经皮室间隔心肌化学消融术治疗肥厚梗阻型心肌病术中、术后出现的严重并发症 ,探讨其原因和机制 ,总结经验、教训 ,以期减少其发生。方法 :2 0例肥厚梗阻型心肌病患者用Sigwart法行化学消融术 ,观察术中、术后出现的严重并发症。结果 :2 0例患者中合并下壁急性心肌梗死 2例 ,前壁心肌梗死 1例 ;术后心室颤动 1例 ;永久性Ⅲ度房室传导阻滞 1例 ;术后严重血流动力学障碍 1例 ;术中左冠状动脉回旋支栓塞 1例。结论 :肥厚梗阻型心肌病化学消融术中及术后可发生多种严重并发症 ,明确靶血管与消融心肌之间的关系、选择恰当的一支或多支间隔支动脉行化学消融 ,是减少并发症的关键     

Echocardiographic mitral systolic motion in left ventricular aneurysm.

An abnormal, convex systolic anterior motion of the mitral valve, somewhat similar to that seen in idiopathic hypertrophic subaortic stenosis (hypertrophic obstructive cardiomyopathy) and occasionally in atrial septal defect, was found on the echocardiogram in 8 out of 9 patients with angiographically (7 patients) and/or clinically (2 patients) diagnosed left ventricular aneurysm secondary to myocardial infarction. The only patient whose echocardiogram failed to demonstrate convex systolic anterior motion was the only patient who had an inferior wall aneurysm; the rest of the group had anterior and/or apical aneurysms. In contrast to patients with typical idiopathic hypertrophic subaortic stenosis, the convex systolic anterior motion of the mitral valve observed in our patients tended to 'peak' rather than 'plateau'. Through the basis for this abnormal septal motion in our patients is uncertain, alterations in left vantricular configuration, plus a relatively vigorously contracting posterior left ventricular wall in the presence of abnormal interventricular septal motion, are probable contributory factors. Though non specific, in the proper clinical and echocardiographic setting convex systolic anterior motion of the mitral valve may be another sign of left ventricular aneurysm.     

Acute myocardial infarction with angiographically demonstrated normal coronary arteries in the presence of hypertrophic cardiomyopathy

A 51-year-old black woman with known, echocardiographically-documented hypertrophic cardiomyopathy was admitted to the hospital with an acute myocardial infarction diagnosed by both electrocardiographic and serum enzyme changes. Six weeks following discharge, the patient underwent left-sided heart catheterization, left ventriculography, and coronary arteriography, and she was found to have entirely normal coronary arteries. There are possible pathogenetic mechanisms of myocardial infarction in the presence of normal coronary arteries in patients with hypertrophic cardiomyopathy, and it is also possibly significant that myocardial infarction is seen in patients with hypertropic cardiomyopathy.     

Magnetic resonance imaging in familial hypertrophic cardiomyopathy associated with abnormal thallium perfusion and cardiac enzymes

Gated magnetic resonance imaging (MRI) was performed in 6 patients with familial hypertrophic cardiomyopathy associated with abnormal thallium perfusion, and 12 patients with ordinary hypertrophic cardiomyopathy. The patients with ordinary hypertrophic cardiomyopathy and abnormal thickening of the septal wall and normal left ventricular dimensions, while the patients with familial hypertrophic cardiomyopathy had focal wall thinning (usually involving the apical-septal wall) and dilated left ventricle in addition to hypertrophied heart. The quantitative measurement for cardiac dimensions using MRI was similar to that found on echocardiography in all cases. In addition, inhomogeneous signal intensities at left ventricular wall were observed in 3 cases of familial hypertrophic cardiomyopathy, which may suggest the existence of myocardial fibrosis. Gated MRI should be performed for early detection and follow-up of hypertrophic cardiomyopathy, since some patients will progress from hypertrophic cardiomyopathy to dilated cardiomyopathy.     

Echocardiographic mitral systolic motion in left ventricular aneurysm.

An abnormal, convex systolic anterior motion of the mitral valve, somewhat similar to that seen in idiopathic hypertrophic subaortic stenosis (hypertrophic obstructive cardiomyopathy) and occasionally in atrial septal defect, was found on the echocardiogram in 8 out of 9 patients with angiographically (7 patients) and/or clinically (2 patients) diagnosed left ventricular aneurysm secondary to myocardial infarction. The only patient whose echocardiogram failed to demonstrate convex systolic anterior motion was the only patient who had an inferior wall aneurysm; the rest of the group had anterior and/or apical aneurysms. In contrast to patients with typical idiopathic hypertrophic subaortic stenosis, the convex systolic anterior motion of the mitral valve observed in our patients tended to 'peak' rather than 'plateau'. Through the basis for this abnormal septal motion in our patients is uncertain, alterations in left vantricular configuration, plus a relatively vigorously contracting posterior left ventricular wall in the presence of abnormal interventricular septal motion, are probable contributory factors. Though non specific, in the proper clinical and echocardiographic setting convex systolic anterior motion of the mitral valve may be another sign of left ventricular aneurysm.     

经皮腔内室间隔心肌消融术治疗梗阻性肥厚型心肌病57例

目的探讨经皮腔内室间隔心肌消融术治疗梗阻性肥厚型心肌病的方法和疗效。方法自1999年9月至2005年1月利用Sigwart法为57例梗阻性肥厚型心肌病患者行经皮腔内室间隔心肌消融术治疗。在压力监测、超声应用、消融操作、疗效判定以及术后处理等方面做了一些改进。结果每例患者消融共用无水乙醇0.6~9.0mL,分别消融1~5根前间隔支血管;57例患者导管测压示左心室流出道压差(静息和激发)均较术前下降>50%。发射计算机体层摄影对照4例中2例出现室间隔心肌放射性缺损。随访2周到5年,54例患者晕厥、头晕、心绞痛、心悸、气喘等症状消失或较术前改善;2例症状复发,心脏超声各项指标接近术前;1例术后半年内症状及心脏超声各项指标改善满意,一年半后死于扩张型心肌病。症状改善的54例中术后43例进行了半年、34例进行了1年的心脏超声随访,各项指标较术后2周时进一步改善。术中部分患者出现一过性短暂阵发性室性心动过速、房室传导阻滞。4例心电图呈前间隔心肌梗死改变,其中1例伴下壁心肌梗死改变。结论经皮腔内室间隔心肌消融术治疗梗阻性肥厚型心肌病疗效显著。本研究对该疗法应用进行了探索,促使经皮腔内室间隔心肌消融术更趋完善。     

Fatal myocardial embolus after myectomy

Coronary embolism is an infrequent phenomenon. A 56-year-old man with hypertrophic obstructive cardiomyopathy and severe mitral regurgitation who underwent left ventricular septal myectomy and mitral valve annular repair is presented. The patient had a cardiac arrest 36 h after surgery. Cardiac standstill, tamponade and a left ventricular rupture were noted when the chest was opened during attempted resuscitation. Autopsy revealed an occlusive embolus of myocardium in the proximal left anterior descending coronary artery. It showed pathological features of hypertrophic cardiomyopathy. There was an extensive acute transmural anteroseptal left ventricular myocardial infarction with rupture of the anterior free wall. Embolism of myocardium - to the coronary arteries, the systemic circulation or the pulmonary circulation - is a rare event, with only nine other cases reported in the literature in the past 30 years. This is the first reported case of myocardial embolus to a coronary artery in a patient with hypertrophic obstructive cardiomyopathy following septal myectomy.     

Percutaneous septal ablation for hypertrophic cardiomyopathy and mid-ventricular obstruction.

AIMS: Percutaneous transluminal septal myocardial ablation by alcohol-induced septal branch occlusion is a new treatment option in symptomatic patients with hypertrophic cardiomyopathy and subaortic, SAM-associated obstruction. We report on a patient with mid-ventricular obstruction and echocardiographic-guided reduction of septal hypertrophy. METHODS AND RESULTS: A 52-year-old woman with NYHA class III and recurrent exercise-induced syncope suffered from hypertrophic cardiomyopathy with mid-ventricular obstruction. She had a systolic gradient of 71 mmHg at rest and 153 mmHg post-extrasystole, and diastolic inflow gradient of 20 mmHg. Echo-guided percutaneous transluminal septal myocardial ablation with occlusion of the fourth septal branch resulted in acute reduction and final elimination of systolic, as well as diastolic resting and provocable gradients. Complications were not seen. At 3 months' follow-up the patient was asymptomatic and without further syncopes. CONCLUSIONS: Echocardiographic-guided percutaneous transluminal septal myocardial ablation is able to reduce gradients in hypertrophic cardiomyopathy and mid-ventricular obstruction with consecutive improvement of symptoms.     

Anterior QRS loop in hypertrophic cardiomyopathy.

Frank vectorcardiograms (VCGs) were reviewed in 45 patients with hypertrophic cardiomyopathy (HCM), 26 with obstruction and 19 without obstruction. Twelve of the 19 patients without obstruction and five of the 26 patients with obstruction were found to have predominantly anterior QRS loops. Fourteen patients had a large left anterior QRS loop with increased anterior and leftward force; the posterior and terminal rightward force were within the normal range, and the T loops were displaced posteriorly and to the right opposite to the QRS loop. Asymmetric septal and apical hypertrophy were noted echocardiographically and/or angiographically. Increased electrical force from the asymmetric hypertrophy of the septal and apical area is proposed to explain this large left anterior loop. Three patients had a QRS loop located anteriorly and to the right with electrocardiograms (ECGs) resembling those of posterolateral myocardial infarction or right ventricular hypertrophy. These finding suggest that (1) hypertrophic cardiomyopathy may be another cause of an anterior QRS loop; (2) the recognition of the large left anterior loop in the VCG in patients with a left ventricular hypertrophy pattern in the ECG is helpful in the diagnosis of HCM, especially the nonobstructive form; and (3) hypertrophic cardiomyopathy should be considered in the differential diagnosis of myocardial infarction or right ventricular hypertrophy.     

Acute myocardial infarction with diminutive right coronary artery and obstructive hypertrophic cardiomyopathy without significant coronary stenoses

Focal tissue abnormalities consistent with regional ischemia have been reported in patients with hypertrophic cardiomyopathy (HCM). Coronary microvascular dysfunction has been also reported to be present in patients with HCM despite normal epicardial coronary arteries. Moreover, it has been demonstrated that in the case of HCM and idiopathic left ventricular hypertrophy, hypoplastic coronary arteries as diminutive vessels are present and that obstructive hypertrophic cardiomyopathy is associated with enhanced thrombin generation and platelet activation. Previously, it has been described an acute myocardial infarction in a young athlete with non-obstructive hypertrophic cardiomyopathy and normal coronary arteries. We present a case of an acute myocardial infarction with diminutive right coronary artery and obstructive hypertrophic cardiomyopathy without significant coronary stenoses. To our knowledge, this is the first report of an acute myocardial infarction with diminutive right coronary artery and obstructive hypertrophic cardiomyopathy without significant coronary stenoses.     

Hypertrophic cardiomyopathy and transmural myocardial infarction without significant atherosclerosis of the extramural coronary arteries

Clinical and morphologic features of transmural myocardial infarction (associated with insignificant or absent atherosclerosis of the extramural coronary arteries) are described in seven patients with hypertrophic cardiomyopathy. Marked chronic congestive heart failure associated with supraventricular arrhythmias occurred in six of the seven patients, each of whom had no or mild left ventricular outflow tract obstruction under basal conditions. No patient had typical angina pectoris, and only one patient had clinically evident acute myocardial infarction. Infarction may have caused cardiac arrest in one other patient, but was “silent” in the remaining five patients.

At necropsy, six of the seven patients had extensive myocardial scarring involving the ventricular septum, left ventricular free wall and one or both left ventricular papillary muscles; in four patients portions of the right ventricular wall were also scarred. Six patients had dilated ventricular cavities, including two who were known to have nondilated ventricular cavities earlier in their clinical course.

It is concluded that transmural myocardial infarction in the absence of significant coronary atherosclerosis is a not uncommon finding (prevalence rate 15 percent) in a population of patients who had died from hypertrophic cardiomyopathy. Although transmural infarction is possibly a secondary event, it more likely contributes causally to the clinical deterioration of some patients with hypertrophic cardiomyopathy, leading to ventricular dilatation and progressive fatal cardiac failure.     

Q waves and QS complexes

A Q wave or a QS complex on the electrocardiogram (ECG) is usually considered as the sign of an old myocardial infarction. While this is often true, the physician should not forget that other possibilities may exist, particularly in the elderly, for example, left ventricular hypertrophy (LVH) (including hypertrophic obstructive cardiomyopathy [HOCM]), cardiac amyloidosis, left intraventricular conduction disturbance, aberrant ventricular activation (WPW pre-excitation pattern). A QS complex in the limb leads or a Q wave in the precordial leads are sometimes the result of mistaken positioning of the electrodes. Furthermore, a Q wave in the inferior limb leads can sometimes disappear on deep inspiration. Similar changes may rarely be seen in normal subjects.     

A computer model of myocardial disarray in simulating ECG features of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) was simulated with a computer heart model having a realistic shape and rotating fiber orientation in order to elucidate possible mechanisms for abnormal ECG findings. The disarray of myocardial muscle in HCM was simulated by assigning random fiber direction and isotropic electrophysiologic properties to abnormal hypertrophic regions, in contrast to the anisotropic modeling for normal myocardium. With these models, main ECG features including abnormal Q wave and QS pattern were reproduced and were comparable with clinical findings. This study suggests that the change in anisotropy in the hypertrophic myocardium is likely to be the main factor responsible to the ECG features of HCM.     

Clinical and angiographic profile and follow-up of myocardial bridges: a study of 21 cases

Myocardial bridging describes an angiographic entity, which is any degree of systolic narrowing of a coronary artery observed in at least one angiographic projection. Among the cineangiograms of 3200 patients reviewed, there were 21 cases (19 males) of myocardial bridges--incidence of 0.6 percent. Of these, seven had hypertrophic cardiomyopathy, six had atherosclerotic coronary artery disease and remaining eight had no evidence of either. All 21 patients had myocardial bridges in proximal or mid left anterior descending coronary artery. In addition, one case of hypertrophic cardiomyopathy had whole posterior descending coronary artery under a myocardial bridge. Another case of hypertrophic cardiomyopathy had a short normal segment of 5 mm inside a long myocardial bridge of 35 mm (tandem myocardial bridges). The length of the bridges varied from 10 to 35 mm (mean 24.5 +/- 4.5 mm) and diameter stenosis during systole varied from 40-90 percent (mean 70 +/- 8%). Two patients had large saccular coronary aneurysms proximal to the muscle bridge. Four of the eight patients who had neither hypertrophic cardiomyopathy nor coronary artery disease presented with acute anterior wall myocardial infarction and three of them had regional wall motion abnormality of left descending territory. Of the six patients who had coronary artery disease, one had 60 percent left descending artery lesion and two had recanalized segments proximal to the bridge. Five of the above six patients had significant stenosis of other coronary vessels. Four patients were lost to follow-up (mean period 3.4 +/- 2 years). In the coronary artery disease group, one patient underwent coronary artery bypass graft surgery for 3-vessel disease including graft to left descending artery and one developed inferior wall myocardial infarction. The patients in the hypertrophic cardiomyopathy group and "no hypertrophic cardiomyopathy-no coronary artery disease" group were free of events at last follow-up. Long-term prognosis of isolated myocardial bridges appears to be excellent. Degree of systolic narrowing or length of myocardial bridge does not correlate with event rates on follow-up.     

Myocardial metabolic, hemodynamic, and electrocardiographic significance of reversible thallium-201 abnormalities in hypertrophic cardiomyopathy

BACKGROUND. Exercise-induced abnormalities during thallium-201 scintigraphy that normalize at rest frequently occur in patients with hypertrophic cardiomyopathy. However, it is not known whether these abnormalities are indicative of myocardial ischemia. METHODS AND RESULTS. Fifty patients with hypertrophic cardiomyopathy underwent exercise 201Tl scintigraphy and, during the same week, measurement of myocardial lactate metabolism and hemodynamics during pacing stress. Thirty-seven patients (74%) had one or more 201Tl abnormalities that completely normalized after 3 hours of rest; 26 had regional myocardial 201Tl defects, and 26 had apparent left ventricular cavity dilatation with exercise, with 15 having coexistence of these abnormal findings. Of the 37 patients with reversible 201Tl abnormalities, 27 (73%) had metabolic evidence of myocardial ischemia during rapid atrial pacing (myocardial lactate extraction of 0 mmol/l or less) compared with four of 13 patients (31%) with normal 201Tl scans (p less than 0.01). Eleven patients had apparent cavity dilatation as their only 201Tl abnormality; their mean postpacing left ventricular end-diastolic pressure was significantly higher than that of the 13 patients with normal 201Tl studies (33 +/- 5 versus 21 +/- 10 mm Hg, p less than 0.001). There was no correlation between the angiographic presence of systolic septal or epicardial coronary arterial compression and the presence or distribution of 201Tl abnormalities. Patients with ischemic ST segment responses to exercise had an 80% prevalence rate of reversible 201Tl abnormalities and a 70% prevalence rate of pacing-induced ischemia. However, 69% of patients with nonischemic ST segment responses had reversible 201Tl abnormalities, and 55% had pacing-induced ischemia. CONCLUSIONS. Reversible 201Tl abnormalities during exercise stress are markers of myocardial ischemia in hypertrophic cardiomyopathy and most likely identify relatively underperfused myocardium. In contrast, ST segment changes with exercise and systolic compression of coronary arteries on angiography are unreliable markers of inducible myocardial ischemia in hypertrophic cardiomyopathy. Apparent cavity dilatation during 201Tl scintigraphy may indicate ischemia-related changes in left ventricular filling, with elevation in diastolic pressures and endocardial compression.     

Cardiogenic shock due to dynamic left ventricular outflow tract obstruction as a mechanical complication of acute myocardial infarction

We report the clinical case of a 77-years-old woman with cardiogenic shock caused by dynamic left ventricular outflow tract (LVOT) obstruction that appeared after anterior acute myocardial infarction. Dynamic LVOT obstruction has been reported in various circumstances aside from hypertrophic obstructive cardiomyopathy, such as acute myocardial infarction. In a patient with cardiogenic shock and a heart murmur after acute myocardial infarction, an acute mechanical complication, ventricular septal defect, and acute mitral regurgitation must be ruled out because the treatment of these conditions differs completely. We describe the diagnostic and therapeutic measures used in the diagnosis and treatment of this complication.     

Muscle fiber disarray in patients without hypertrophic cardiomyopathy

Muscle fiber disarray (MFD) has been described as the histologic feature of hypertrophic cardiomyopathy (HC), but it was also found in normal and other abnormal conditions. Its distribution related to the topography of the myocardium has not been described. In this paper, the incidence of MFD in hearts free from HC, the frequency of the histologic disorganization and the affected muscles involved were studied at autopsy. 29 hearts with acute myocardial infarction and 1 with suppurated myocarditis were employed. Macroslides containing the point of maximum septal enlargement were selected for histological examination. The areas of MFD were measured by a polar planimeter and correlated with the involved wall, the total slice area, parietal widths and involved muscles. 27 patients (90%) presented with MFD; hypertrophic ventricular walls were observed in 10, 8 of which had MFD. The remaining 20 patients with nonhypertrophic ventricular walls had MFD in 19 instances. There was septal posterior involvement in 26 cases (p less than 0.0005). 12 patients (44.4%) had only one wall involved. Only 1 patient presented more than 5% of MFD in regard to the total area. The septal wall was the most affected (p less than 0.0005). The most commonly affected muscle was the deep-sinospiral, either alone or combined with other muscles (p less than 0.01). Greater MFD was found (23/30) in patients with septum/posterior wall ratio less than 1.3 cm. It is concluded that MFD may affect up to 10% of the septum in patients free from HC, and that secondary hypertrophy is not a prerequisite for MFD.(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of chest pain in hypertrophic cardiomyopathy using exercise thallium-201 myocardial scintigraphy.

Exercise thallium-201 myocardial scintigraphy was performed in 23 patients with hypertrophic cardiomyopathy. Eighteen patients presented with chest pain which was a persistent symptom in 11. Selective coronary arteriography was performed in 16 patients and showed normal coronary arteries in 15 and insignificant luminal irregularities in one patient. Eighteen patients had abnormal scintigrams. Three had an abnormal distribution of tracer entirely attributable to asymmetric septal hypertrophy, whereas 15 had discrete tracer uptake defects which could not be explained solely by myocardial hypertrophy. In this latter group of patients three scintigraphic patterns were identified: (1) in 10 patients defects were seen in scintigrams immediately after exercise but not in delayed images obtained four to six hours later. Eight of these patients had chest pain. (2) Four patients had uptake defects seen in both initial and delayed images. One patient had chest pain. (3) In three patients, one of whom had chest pain, tracer defects were seen only in delayed images and were not apparent in the initial scintigrams. Chest pain occurred in eight out of 10 patients with scintigraphic evidence of myocardial ischaemia but was present in only three out of 13 patients with non-ischaemic scintigrams. The value of exercise thallium-201 myocardial imaging as a diagnostic technique in hypertrophic cardiomyopathy appears limited. Scintigraphic evidence of regional myocardial ischaemia in the absence of significant coronary artery disease, however, contributes to an understanding of the mechanism of angina production in patients with hypertrophic cardiomyopathy.     

Apical hypertrophic cardiomyopathy mimicking acute coronary syndrome: a case report and review of the literature

Apical hypertrophic cardiomyopathy is a form of hypertrophic cardiomyopathy localized to the left ventricular apex. It is common in Japanese and other Asian populations, where it is generally considered relatively benign. However, its presence has also been recognized, though less commonly, in non-Asian patients. In these patients, the electrocardiographic changes and symptoms associated with apical hypertrophic cardiomyopathy often mimic acute coronary syndromes. Invasive or noninvasive evaluation of the left ventricular cavity confirms the diagnosis, with the "ace-of-spades" sign on left ventriculography being pathognomonic. Its prognosis is relatively benign in terms of cardiovascular mortality; however, morbid sequelae, such as diastolic dysfunction, left atrial enlargement, apical thrombi, ventricular aneurysms, and myocardial infarction, are not uncommon. The authors present a case of apical hypertrophic cardiomyopathy in a Caucasian patient who presented with findings suggestive of acute coronary syndrome and review the literature on apical hypertrophic cardiomyopathy.