2.1 Finalist criteria
This study is a retrospective observational study. To analyze the clinical data of 215 cases of myocardial ischemia diagnosed in our hospital from 2006 to 2018 due to the presence of GNT on the electrocardiogram. After careful observation, combined with angiography and echocardiography, 11 cases of clinical data with the characteristics of Papillary muscle deformity downward movement(Male: female = 9: 2, age 46-73 years old), the average age is (59.5 ± 13.5) years old(Table 1).
Inclusion criteria: (1) According to the 2014 ESC ”Diagnostic and Treatment Guidelines for Hypertrophic Cardiomyopathy”. ECG examination: T wave asymmetry, of which 9 cases are: anterior myocardial ischemia, and the patient has a 6-14 mm T wave inversion in leads V4-V6 (Figure 1-a/b). There are 2 cases of inferior wall ischemia. ECG tips: sinus rhythm, normal ECG axis, 6-10mm T wave inversion (Figure 1-c/d), no abnormal angiography, echocardiography shows left ventricular wall structure, exercise, and left ventricular ejection fraction Within normal range. (2) Coronary angiography results were normal. (3) Result of left ventriculography: the left ventricle nipple is grossly deformed, and its position is down. Echocardiography showed that the base of the anterolateral papillary muscles(Figure 2)originated from the top third of the left ventricle. At the same time, the combined medial papillary deformity and downward movement showed a huge negative T wave, corresponding to leads II, III, and Arterial vessel fistula. Eleven patients had different degrees of discomfort in the precardiac area, normal exercise tolerance, and left ventricular wall motion and left ventricle ejection fraction were within normal ranges. The patient’s age ranged from 1-73 years, with an average age of (59.5 ± 13.5) years. The patient had no risk factors for coronary artery disease such as hypertension, diabetes, and obesity, nor had a history of other cardiovascular diseases, and was not given medication. Eleven patients had normal physical examination, blood pressure remained within the normal range of 70-90 / 110-125 mmHg, and the chest was not deformed.The exclusion criteria are: (1) There are other heart diseases; (2) The spectrum of the heart cannot be accurately detected; (3) In multiple examinations, the highest values ​​of ECG, echocardiography, coronary angiography and cardiac CT / MRI values ​​are The difference of the lowest value is greater than 3.
This study was approved by the Medical Ethics Committee of Liaoning Provincial People’s Hospital of China Medical University.
2.2 Detection method:
Careful analysis of the medical history, laboratory data, electrocardiogram, echocardiography, coronary angiography and cardiac CT / MRI of 11 patients. After further examination, blood lipids, blood sugar, treadmill exercise test (spring games), 24-hour dynamic electrocardiogram, coronary angiography were not abnormal, echocardiography showed that the papillary muscles were close to the apex (Figure 3). Echocardiographic evaluation: In this study, GE Vivid E9 line echocardiography was used for general ultrasound and Sonove sonography. Observe the levels of the apical four-chamber heart, apical three-chamber heart, left ventricle and short-axis apical segment, and at the same time try to avoid the short contraction of the left ventricle in the horizontal section of the apical four-chamber. Echocardiography showed that the base of the anterolateral papillary muscles originated from the top third of the left ventricle(figure4). At the same time, the medial papillary deformity and downward movement after the merger showed a GNT, corresponding to leads II, III, and Arterial vessel fistula. All 11 patients had varying degrees of precordial discomfort, normal exercise tolerance, and left ventricular wall motion and left ventricle ejection fraction were within the normal range. For the papillary muscles of healthy subjects, the left ventricular papillary muscle is a tapered meat column that extends from the left ventricular wall into the chamber. It is the muscle part of the mitral valve device, which is always thick and paired, divided into The two groups are located in the middle of the left ventricular cavity, in which the anterolateral papillary muscles are located at the junction of the anterior wall and the lateral wall of the left ventricle, and the posterior medial papillary muscles are located in the posterior wall of the left ventricle. The papillary muscles form a parallel arrangement and no hypertrophy. We found that the number, shape, shape, and position of the papillary muscles vary considerably. The position of the papillary muscles has moved down. American studies have pointed out that GNT is not a specific manifestation of apical hypertrophic cardiomyopathy. In this study, the abnormal manifestation of papillary muscles is position shift to the apex. Apically displaced papillary muscle is defined as the papillary muscle originating from the apical four-chamber view of the left ventricle near the apical segment of the third, regardless of whether it is associated with hypertrophy of the apical segment. Under normal circumstances, myocardial cell repolarization is from the epicardium to the endocardium. The obvious T-wave inversion may represent physiological changes during rapid ventricular repolarization. On the other hand, the T-wave inversion may be due to hereditary heart muscle disease or it may be normal variation2. According to Victor and Nayak’s research, in the anterior-lateral group of papillary muscles, only 1.5% of the papillary muscles originate from the middle and lower third. In the papillary muscles of healthy subjects, there are usually two sets of anterolateral and posteromedial muscles of equal size in the left ventricular cavity (Figure5). However, in this study, echocardiography showed that 11 cases of anterolateral papillary muscle base originated from 1/3 of the apex(Figure6), and 2 cases of posterior internal papillary muscle base originated from the posterior and medial apex of the left ventricle 1/3 (Figure 7) and some patients have morphological variations in the papillary muscles, divided into multiple groups (Figure8). The results showed that the position of the displaced, thick, and grouped papillary muscles was consistent with the corresponding lead changes of the conventional 12-lead ECG, and the corresponding rate was more than 90%. After 5 years of follow-up, the patient’s ECG and echocardiogram showed no abnormal changes and no cardiovascular events occurred. The presence of GNT in the differential diagnosis of electrocardiogram GNT may indicate that the patient has apical hypertrophy, especially when GNT is difficult to interpret, it must be taken into account, and has certain predictive value. Apical hypertrophic cardiomyopathy is a subtype of hypertrophic cardiomyopathy, which is limited to the apex of the heart, and Japan accounts for about 24% [5,6]. Apical hypertrophy is defined as the thickest part of the apical part ≥15mm, and the ratio of the thickest part to the posterior wall ≥1.5. This is the characteristic [7] of echocardiography in clinically suspected apical hypertrophy [8]. Kobashi [9]and others believe that papillary muscle hypertrophy is an early form of hypertrophic cardiomyopathy. GNT can exist in single papillary muscle hypertrophy [10,11]. Papillary muscle hypertrophy is defined as at least one group of papillary muscles with a diameter ≥ 1.1 cm. Echocardiography is the main method of diagnosing the disease, with a specificity of 90%, but in our study, we found that two-dimensional echocardiography did not show evidence of left ventricular hypertrophy. At the same time, we know that the clinical manifestations depend on the onset of emergency, mitral regurgitation, and primary disease. Mild papillary muscle insufficiency that occurs gradually can be asymptomatic due to its small effect on hemodynamics. In severe cases, palpitations, shortness of breath, cough, fatigue, etc. may appear.
The purpose of this study was to compare the evaluation of myocardial ischemia with 12-lead ECG and the evaluation of early myocardial ischemia by combining multiple ultrasound imaging methods.