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CASE REPORT
Year : 2022 | Volume
: 11
| Issue : 3 | Page : 89-90
Sawtooth cardiomyopathy
Zahra Ansari, Sedigheh Saedi, Nahid Rezaeian
Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
Correspondence Address:
Dr. Sedigheh Saedi
Rajaie Cardiovascular Medical and Research Center, Vali-Asr Ave, Adjacent to Mellat Park, Tehran
Iran
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/rcm.rcm_14_22
Sawtooth cardiomyopathy (STC) is a kind of left ventricular (LV) dysplasia which was falsely classified as a variant of LV noncompaction. Here, we report a young man case with presyncope and dyspnea during exercise. Echocardiographic and cardiac magnetic resonance features showed multiple ridge-like projections of compacted myocardium in the inferior and lateral wall which was compatible with diagnosis of STC.
Keywords: Cardiomyopathy, CMR, left ventricle dysplasia, noncompaction left ventricle, sawtooth
In 2009, a 2-month-old male infant was reported as the first case of sawtooth cardiomyopathy (STC). In imaging, echocardiography (echo), and cardiac magnetic resonance (CMR), the myocardium appeared compacted with too many cross-bridging muscular projections in the left ventricle (LV) and normal right ventricle (RV) which was not compatible with noncompacted LV (NCLV)[1] due to the absence of deep recesses and myocardial compaction.[2] After that, few cases of STC was diagnosed and they all were reported as case reports, although it may be underdiagnosed because careful imaging evaluation is needed for separating these two identities. STC is a rare kind of LV dysplasia,[3] although some primary reports falsely categorized it as a kind of NCLV.[4] In some reported cases, genetic testing was done for evaluation of genetic bases of STC.
Case ReportAn 18-year-old male referred due to presyncope during exercise 2 months before presentation. He reported dyspnea on exertion with a New York Heart Association Functional Class of II.
He did not report any other symptoms, and also, he had no remarkable medical history. No history of congenital heart disease or different kinds of cardiomyopathies was reported in the first-degree family members.
The initial echo showed numerous ridge-like projections of compacted myocardium from the inferior and lateral segments of the LV into the LV cavity, in favor of STC [Figure 1]. The LV size was normal with mildly reduced systolic function (systolic function = 45%–50%) with no regional wall motion abnormality and no significant valvular heart disease, while the RV size and function were normal. Electrocardiography showed ST-T changes in the inferior and precordial leads [Figure 2]. 48-h rhythm Holter monitoring was done due to suspicious history of presyncope, and it was normal. Electrophysiology study recommended to the patient. For better anatomic evaluation, the patient referred for cardiovascular magnetic resonance (CMR). CMR showed evidence of course indentation of the myocardial wall that confirmed the diagnosis of STC [Figure 3]. Hence, heart failure medical treatment began for the patient with beta-blocker, angiotensin-converting enzyme inhibitors, and aldosterone receptor antagonist. Our patient was visited after 4 months and 1 year after beginning of medical treatment with standard therapies for heart failure, but LV systolic function was not changed. Due to genetic base of this cardiomyopathy, family check-up recommended to the patient.
Figure 1: Echocardiography of sawtooth cardiomyopathy case. Ridge-like projections of myocardium mimics the pattern of sawtooth
Figure 2: Electrocardiography of sawtooth cardiomyopathy case. You can see diffuse ST-T changes
Figure 3: CMR sequences depict evidence of saw-tooth cardiomyopathy. (a) Two-chamber, (b) four-chamber and (c) three-chamber cine functions showing evidence of course indentations of the myocardial wall, especially in two-chamber. (d) Two-chamber, (e) four-chamber, and (f) three-chamber late gadolinium enhancement images demonstrating confirmation of myocardial indentations, which should not be misdiagnosed as fibrosis Discussion STC is a rare and unusual kind of cardiomyopathy which was initially classified as a type of NCLV; however, in other investigations, it was shown that sawtooth cases do not meet LVNC criteria. Hence, STC is known as a rare form of LV dysplasia with multiple compacted myocardial projections from the inferior and lateral walls into the LV cavity.[1],[3]
Report of this abnormality in a 2-month-old male infant with heart failure symptoms brings up the probability of genetic basis of this cardiomyopathy.[1]
Same as our case, in most of saw tooth reports, the cases were male, and so, some authors have raised the possibility of x-linked disease.[5] Proukhnitzky et al. did an interesting survey on their sawtooth case and provided data regarding family history and genetic testing. After analysis, no familial disease and no genetic abnormalities were found in large panel genetics testing to be responsible for this model of cardiomyopathy,[6],[7] and interestingly, in sawtooth cases, there was no mutation in genes which are responsible for left ventricular noncompaction cardiomyopathy (LVNC).[7] Since the etiology and the prognosis of STC are still unknown, further studies are necessary.
In CMR of STC patient against NCLV cases, normal compaction of LV and absence of hypertrabeculation can be seen.[7] STC mainly affects lateral and inferior walls of the LV, and cross-bridging muscular projections of compacted myocardium may falsely resemble crypts or deep recesses in echo or CMR.[6],[7]
At last, we should mention that, to the best of our knowledge about STC, the clinical approach to these cases should be similar to LVNC cases with periodic cardiac evaluation and follow-up.
Our patient was visited after 4 months of medical treatment with standard therapies for heart failure. However, LV systolic function was not changed.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Ethical clearance
Institutional ethics committee approved of the study protocol (committee's reference number: 01024).
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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