Does the presence of Q waves on the EKG accurately predict prior myocardial infarction when compared to cardiac magnetic resonance using late gadolinium enhancement? A cross-population study of noninfarct vs infarct patients.

BACKGROUND: We hypothesize that infarct detection by electrocardiogram (EKG) is inaccurate as compared with detection by magnetic resonance imaging and is potentially independent of infarct vs noninfarct status. This might have implications for societies in which initial cardiovascular testing is uniformly EKG. OBJECTIVE: This study aimed to relate EKG-defined scar to cardiovascular magnetic resonance imaging (CMR)-defined scar independent of the underlying myocardial pathology. METHODS: A total of 235 consecutive patients who underwent CMR-late gadolinium enhancement (LGE) with simultaneous EKG were screened for Q waves and compared with patients with a positive LGE pattern. The patients were divided into 3 groups: (1) patients with a positive infarct LGE pattern (LGE+/+; herein defined as LGE+), (2) patients with a noninfarct LGE pattern (LGE+/-), and (3) patients with a negative LGE pattern (LGE-). RESULTS: While 139 of 235 patients (59%) were either LGE+ or LGE+/-, pathological Q waves were present in only 74 of 235 patients (31%). However, of these LGE+ or LGE+/- patients, only 76 (32%) had an infarct LGE pattern representing little overlap between the presence of LGE+ and Q waves. EKG sensitivity and specificity to detect infarct: 66% and 85%, respectively. However, of 24 of 74 patients (32%) with Q waves on the EKG, 66% were LGE+/- and 34% were LGE-. Importantly, 3-dimensional volume of myocardial scar was far more predictive of a Q wave than of scar transmurality. CONCLUSION: EKG-defined scar, while ubiquitous for an infarct, has low sensitivity than CMR-LGE-defined scar. Unexpectedly, a significant number of pathological Q waves had absent infarct etiology, indicating high false positivity. Similarly, underrecognition of bona fide myocardial infarction frequently occurs, while 3-dimensional CMR volume of myocardial scar is far more predictive of a Q wave than of scar transmurality. This suggests that the well-regarded EKG may be a disservice when applied on a population basis, leading to inappropriate over or under downstream testing with wide socioeconomic implications.

Is left ventricular hypertrophy regression important? Does the tool used to detect it matter?

Left ventricular hypertrophy (LVH) has been demonstrated to define an adverse cardiovascular prognosis. However, due to poor noninvasive tools in which to accurately define LVH, the clinical manifestations dictate an inexact manner in which to either initiate therapy or to gauge the success of LVH regression. Herein, the authors define the current state of imaging modalities available to interrogate LVH and its regression, but concentrating chiefly on the "gold standard" of cardiovascular magnetic resonance imaging (CMR). The authors review the data demonstrating the importance of LVH regression. Additionally, they highlight the strengths and weaknesses of CMR via several pinnacle studies that demonstrate the ease, efficiency, and accuracy of this new noninvasive reproducible and available tool to relatively inexpensively delineate LVH. Finally, upon pharmacologic administration of an antihypertensive regimen, the authors, for the first time, define a goal of left ventricular mass reduction (in grams) for echocardiography and CMR based in part on Framingham data aiming at improving cardiovascular risk.

Silent aortic dissection presenting as transient locked-in syndrome.

Acute aortic dissection is a medical emergency. Without prompt recognition and treatment, the mortality rate is high. An atypical presentation makes timely diagnosis difficult, especially if the patient is experiencing no characteristic pain. Many patients with aortic dissection are reported to have presented with various neurologic manifestations, but none with only a presentation of transient locked-in syndrome.Herein, we report a case of completely painless aortic dissection in a woman who presented with a transient episode of anarthria, quadriplegia, and preserved consciousness. On physical examination, she had a 40-point difference in blood pressure between her left and right arms, and a loud diastolic murmur. The diagnosis of acute aortic dissection was reached via a combination of radiography, computed tomography, echocardiography, and a high index of clinical suspicion. The patient underwent emergency surgery and ultimately experienced a successful outcome.To our knowledge, this is the 1st report of aortic dissection that presented solely as locked-in syndrome. We suggest that silent aortic dissection be added to the differential diagnosis for transient locked-in syndrome.