Double jeopardy in the echocardiography laboratory: coexistence of two distinct cardiomyopathies?

BACKGROUND: In our Hypertrophic Cardiomyopathy (HCM) Center, we identified 6 patients each with what appeared to be the occurrence of 2 rare diseases that prompted investigation for a common derivative. METHODS: We reviewed our database, searching for all patients with a diagnosis of HCM, amyloid heart disease and left ventricular noncompaction (LVNC). RESULTS: Using transthoracic echocardiography and magnetic resonance imaging, we identified 6 patients with apical hypertrabeculations and myocardium suggestive of LVNC; 4 of the patients had HCM and 2 of the patients had cardiac amyloidosis. CONCLUSIONS: The significance of these possible concomitant cardiomyopathies is not presently well understood. We did not identify a common derivative when looking for a genetic link, but it is most likely hidden in the genetic substrate, yet to be identified.

Myocardial mechanics: understanding and applying three-dimensional speckle tracking echocardiography in clinical practice.

Speckle tracking echocardiography (STE) is an emerging tool to characterize and quantify myocardial segmental and rotational mechanics. This literature review is aimed at clinical and academic cardiologists to provide: (1) a conceptual framework of STE to initiate understanding of myocardial mechanics; (2) evidence that three-dimensional (3D) STE overcomes the problems of time-consuming data acquisition and postprocessing seen with two-dimensional STE; and (3) illustrative clinical cases with analysis of myocardial mechanics via 3D STE to show the incremental value of strain in clinical decision making.

Intravenous magnesium sulfate enhances the ability of intravenous ibutilide to successfully convert atrial fibrillation or flutter.

BACKGROUND: A previous randomized trial found that adjunctive use of intravenous magnesium (a total of 4 grams) can attenuate the corrected QT interval (QTc) prolongation associated with ibutilide, but its impact on ibutilide efficacy has not been elucidated. METHODS: This was a cohort evaluation of 229 consecutive patients who received ibutilide in the presence or absence of intravenous magnesium. Multivariate logistic regression analysis was used to determine the impact of magnesium on ibutilide efficacy as well as the impact of magnesium dosing intensity on ibutilide efficacy. RESULTS: The overall chemical conversion rate with ibutilide in the presence or absence of magnesium was 59.8%. The concurrent administration of magnesium (n = 141) was associated with a 78% increased odds of successful chemical conversion (adjusted odds ratio, AOR; 1.78 [95% confidence intervals,CI 1.02-3.09]) compared to those who did not receive magnesium (n = 88). Magnesium dosing intensity appeared to be an important determinant of ibutilide efficacy, with the 4 grams dose associated with a threefold increase in the odds of successful chemical conversion (AOR; 2.98 [95% CI 1.46-6.11). The 1 to 3 grams subgroup was associated with only a trend toward an improvement. There was only one case of Torsade de Pointes (TdP) which occurred in the no adjunctive magnesium group. CONCLUSIONS: Concurrent use of magnesium enhanced the ability of ibutilide to successfully convert atrial fibrillation (AF) or flutter (AFl). The 4 grams magnesium dose appeared to provide the greatest benefit.