This trend was not seen in patients with ICDs, likely reflecting the "significant impact of ICD therapy on sudden cardiac death and the difficulty in further decreasing event rates," they add.
The authors note that patients treated with beta blockers were younger, had higher EF rates, higher rates of recent angina, and more recent heart attacks.
A limitation of the study was the inability to randomize the use of beta blockers because the administration of this therapy was left to the discretion of the referring physicians. Another drawback was that the effects of beta blockers in patients who received antiarrhythmic drugs may be obscured because several of these drugs possess some beta blocker activity.
Even so, the significant decrease in the overall death rate of these high-risk patients taking beta blockers and who hadn't had a recent heart attack combined with previous similar evidence lead the authors' to conclude "it is appropriate to prescribe these drugs in patients with the characteristics of those enrolled in the MUSTT trial."