Publications

OBJECTIVES

The purpose of this study was to evaluate mechanical dyssynchrony in patients with acute onset cardiomyopathy with narrow QRS interval, and its association with improvements in left ventricular (LV) function.

BACKGROUND

LV dyssynchrony has been usually studied in patients with chronic heart failure and wide QRS in the context of cardiac resynchronization therapy.

METHODS

We studied 201 patients enrolled in the IMAC-2 (Inflammatory Mediators in Acute Cardiomyopathy) trial with recent onset nonischemic cardiomyopathy and ejection fraction <40%. Dyssynchrony was assessed using speckle-tracking velocity vector imaging. Diastolic function was assessed by mitral inflow E and mitral E' annular velocities (E/E'). A normal control group of 15 normal volunteers was studied for comparison.

RESULTS

Although mean QRS was narrow (98 ± 21 ms), 108 (54%) acute cardiomyopathy patients had significant LV dyssynchrony at presentation: opposing wall delay 89 ± 51 ms, versus 35 ± 11 ms in controls, and 12-site standard deviation 43 ± 23, versus 24 ± 8 ms in controls (p < 0.001). Patients with dyssynchrony had greater degrees of diastolic dysfunction: E/E' 15 ± 8 versus 12 ± 6 (p < 0.05). At 6 months, group mean ejection fraction improved from 23 ± 8% to 40 ± 12% and E/E' improved from 14 ± 7 to 9 ± 5 (both p < 0.001). Dyssynchrony improved from 89 ± 51 ms to 52 ± 35 ms in maximum opposing wall delay, and 43 ± 23 ms to 32 ± 19 ms in 12-site standard deviation, and the prevalence of dyssynchrony decreased to 12% after 6 months (p < 0.001 vs. baseline).

CONCLUSIONS

Mechanical dyssynchrony was observed in a significant number of patients with acute onset cardiomyopathy, despite having a narrow QRS interval. Resolution of dyssynchrony associated with improvements in LV function occurred in the large majority of these patients.

BACKGROUND

Renal dysfunction is common before mechanical circulatory support (MCS). Mechanical circulatory support frequently improves renal function, but the impact of pre-MCS renal dysfunction on renal function after cardiac transplantation (CTX) is unknown.

METHODS

Patients with MCS from January 1995 until April 2008 at a single center were included if their MCS duration was at least 60 days and they underwent successful CTX. Patients were followed for 1 year after CTX.

RESULTS

A total of 116 patients were included in the study. Mechanical circulatory support was biventricular assist device in 28% and left ventricular assist device in 72% (continuous flow left ventricular assist device, 14%). Mean duration of MCS was 124 days. Patients were grouped according to tertiles of pre-MCS creatinine clearance (CrCl): group 1, CrCl less than 45 mL/min; group 2, CrCl between 45 and 65 mL/min inclusive; and group 3, CrCl more than 65 mL/min. Group 3 had the best renal outcomes both after MCS and 1 year after CTX. Regardless of group, patients who had a CrCl of at least 60 mL/min before CTX had similar 1-year posttransplant CrCl (55 versus 53 versus 56 mL/min for groups 1 through 3, respectively; not significantly different). However, the ability to achieve this level of renal function after MCS was less likely in those with the worst renal function before the initiation of MCS (53% versus 74% versus 90% for groups 1 through 3, respectively; p=0.001).

CONCLUSIONS

The use of MCS leads to improvements in renal function in patients after MCS. However, the renal outcomes after CTX seem to be more dependent on the level of renal function achieved during MCS than on the level of renal function before MCS.