Myocardial Perfusion in Nonischemic Dilated Cardiomyopathy With and Without Atrial Fibrillation

Abstract

Recent studies have shown that idiopathic atrial fibrillation (AF) is associated with diminished myocardial perfusion and perfusion reserve, which are also impaired in various forms of cardiomyopathies. In many cases, AF develops during progression of dilated cardiomyopathy (DCM) and may aggravate heart failure. This study compared myocardial perfusion between patients with nonischemic DCM with and without AF. Methods: Twelve men (age 6 SD, 55 6 12 y) who had DCM and persistent AF were compared with a group of 18 men (mean age, 43 6 15 y, P 5 not statistically significant) who had DCM and sinus rhythm and with 22 healthy controls (mean age, 47 6 13 y, P 5 not statistically significant). Myocardial blood flow (MBF) was noninvasively quantified at rest and during adenosine infusion using PET and radioactive-labeled water (H 2 15 O PET). Results: Compared with controls, DCM patients without AF showed impaired hyperemic perfusion (2.52 6 1.29 vs. 3.57 6 0.88 mL/min/mL, P 5 0.014) and perfusion reserve (2.10 6 1.01 vs. 3.37 6 0.97, P 5 0.003). However, compared with DCM patients without AF, DCM patients with AF showed an additional impairment in resting perfusion (0.82 6 0.31 mL/min/mL, P 5 0.010) and hyperemic perfusion (1.32 6 0.93 mL/min/mL, P 5 0.022), and compared with controls, DCM patients with AF showed a further diminishment of perfusion reserve (1.68 6 0.94 vs. 3.37 6 0.97, P , 0.001) accompanied by the highest coronary vascular resistance of all groups. Conclusion: Compared with patients with sinus rhythm, patients with AF have significantly reduced myocardial perfusion reserve and increased coronary resistance in nonischemic DCM. Further studies on the underlying pathomechanisms are warranted.

Clinical Profile and Angiographic Findings among Patients with Atrial Fibrillation Presenting for Selective Coronary Angiography

“…Other studies indicated that acute AF causes a decline in diastolic coronary flow and promotes sub-endocardial ischemia [31]. Similar changes have been shown among AF patients with hypertrophic cardiomyopathy [32], and dilated cardiomyopathy [33], proving that AF may be a causative factor and not merely a bystander. AF patients are more likely to have positive SPECT finding for ischemia, yet have a lower yield of significant CAD by SCAG (15% for AF patients vs. 67% in n-AF; p=0.006) [34].…”

[11C]Acetate rest–stress protocol to assess myocardial perfusion and oxygen consumption reserve in a model of congestive heart failure in rats

“…In this paper we describe a rest/stress [ 11 C]acetate PET imaging protocol that can effectively yield measurement of the myocardial blood flow [3,4,6,[24][25][26] [30]. Another approach was to use [ 13 N]ammonia with dipyridamole to investigate the effect of long-terms inhibition of the angiotensin converting enzyme or Beta blocker [31].…”

Documentation of impaired coronary blood flow by TIMI frame count method in patients with atrial fibrillation

“…However, myocardial ischaemia and/or impairment of myocardial microcirculation have been shown in patients with AF despite normal epicardial coronary arteries. Various methods have been used to measure coronary flow in AF patients, including intracoronary Doppler flow wire [3], position emission tomography (PET) [4][5][6] and single-photon emission computed tomography (SPECT) [1,[7][8][9], and it has been reported that impaired coronary blood flow is associated with unfavorable outcomes in patients with AF [7,8].…”