Relationship between atrial fibrillation and blunted hyperemic myocardial blood flow in patients with hypertrophic cardiomyopathy.
BACKGROUND
Atrial fibrillation (AF) and coronary microvascular dysfunction (CMD) are common in hypertrophic cardiomyopathy (HCM), but whether they are associated is unclear. We assessed the relationship between AF and CMD in HCM.


RESULTS
Global hyperemic myocardial blood flow (hMBF) was measured in 95 HCM patients (16 with, 79 without paroxysmal or chronic AF) by N-13 ammonia positron emission tomography (PET) after dipyridamole infusion. AF patients were older (50.5 +/- 13.4 vs. 38.7 +/- 14.9 years, P < .0005), had larger left atrial diameter (49.8 +/- 7.4 vs 38.6 +/- 5.7 mm, P < .00001), and left ventricular end-systolic diameter (30.4 +/- 6.7 vs 25.5 +/- 5.3 mm, P < .005) compared with those in stable sinus rhythm. In patients with AF, hMBF was significantly lower (1.23 +/- 0.44 vs 1.87 +/- 0.90 mL/min/g, P < 0.0001). In multivariate logistic regression analysis, hMBF, left atrial diameter, and age were independently associated with AF (P < .05 for all).


CONCLUSIONS
HCM patients with paroxysmal or chronic AF have lower hMBF than those in stable sinus rhythm. The association between CMD and AF is independent of other known predictors of AF, suggesting a causal link between these two features.
Sciagrà
Roberto
R
Nuclear Medicine Unit, Department of Clinical Physiopathology, University of Florence, Viale Morgagni 85, 50134, Florence, Italy. r.sciagra@dfc.unifi.it
Sotgia
Barbara
B
Olivotto
Iacopo
I
Cecchi
Franco
F
Nistri
Stefano
S
Camici
Paolo G
PG
Pupi
Alberto
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D002648:Child; D015897:Comorbidity; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015994:Incidence; D007558:Italy; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D055815:Young Adult