Prognosis of Subjects With Unexplainable Precordial Deep T-wave Inversion Without Wall Thickness> 15mm

The investigators sought to evaluate the morphological and functional changes and prognosis of participants with unexplainable precordial deep T-wave inversion on ECG and with apical thickness less than 15mm. The conduction of this study was largely due to the increased clinical requirement, which reflected the increased awareness among physicians of missed AHCM.

Apical hypertrophic cardiomyopathy (AHCM) is a special form of non obstructive hypertrophic cardiomyopathy (HCM), in which the hypertrophy of myocardium predominantly involves the apex of the left ventricle (LV). Generally, patients with AHCM show obvious negative T waves on precordial leads on electrocardiogram (ECG). However, clinically some patients present dramatic T-wave inversion with the apical thickness less than the diagnostic criteria of AHCM. In order to get a moderate diagnosis, these participants may undergo lengthy investigation with implications for lifestyle modifications and increase the health care expenses. The investigators wonder they may share their fate with patients who have overt AHCM. Further study of these patients is needed for a proper diagnosis and treatment.

In conventional diagnostic criteria published by American heart association (AHA)/American college of cardiology foundation (ACCF) in 2011, or European society of cardiology (ESC) in 2014, the LV wall thickness≥15 mm is the unified diagnostic criteria of HCM. These guidelines, however, did not give additional regulations or instructions for the diagnosis of AHCM. It is suspected that these criteria may be too strict for AHCM, as the normal left ventricular wall thins towards the apex and the normal values are lower naturally in the apical versus the basal segments.

Comparing with echocardiography, the superior spatial and temporal resolution of CMR makes it more sensitive to diagnose AHCM at earlier stage, much earlier than the appearance of "ace-of-spades" configuration. In a previous study, only 60% of patients with apical segmental hypertrophy that were confirmed by CMR were diagnosed by echocardiography. Echocardiography has its technical limitations for assessing apex due to the limited regional spatial resolution. Additionally, CMR can offer prognostic features, such as apical scar and apical aneurysms.

The investigators thus sought to evaluate the morphorage and functional changes and prognosis of participants with unexplainable precordial deep T-wave inversion on ECG and with apical thickness less than 15mm.The conduction of this study was largely due to the increased clinical requirement, which reflected the increased awareness among physicians of missed AHCM.

Eligibility Criteria:
Inclusion Criteria:

* Standard 12-lead electrocardiography showing deep T-wave inversion, most prominent in the anterolateral leads (V3-V5 leads) with the negative T wave voltage ≥5mm.
* Without evidence of coronary artery disease, or diameter stenosis ≥50% in one or more coronary vessels.
* Asymmetrical LV hypertrophy confined to the LV apex below the papillary muscle level; end-diastolic apical wall thickness \<15mm with the apical to basal posterior wall thickness ratio \<1.5.

Exclusion Criteria:

* Subjects who were not in sinus rhythm;
* Patients with T-wave inversion in ≤ 2 contiguous leads, concomitant bundle branch block or QRS\>80 ms or QTC\>440 ms were excluded.
* Blood pressure ≥140/90mmHg.
* Severe valvular lesion, pericardial disease, cardiac tumor, immunological or metabolic disease involving heart.
* History of cardiac surgery.