Atrial fibrillation in patients with idiopathic hypertrophic subaortic stenosis

Abstract

Atrial fibrillation occurred in 16 (10%) of 167 patients with idiopathic hypertrophic subaortic stenosis. The clinical and haemodynamic findings in these 16 patients are presented. Atrial fibrillation appeared late in the course of the disease, and its occurrence did not seem to be related to the severity of left ventricular outflow obstruction or to the amount of associated mitral regurgitation. In each patient the onset of the arrhythmia was accompanied by severe clinical deterioration, which often necessitated urgent medical treatment. Digitalis was administered to all 16 patients with subsequent clinical improvement in 15. Electrical cardioversion was uniformly successful in restoring sinus rhythm, but atrial fibrillation usually recurred. In each of 8 patients catheterized during atrial fibrillation, cardiac output was strikingly low (average, 1.9 l./min./m.(2)), whereas it was normal in 10 of 13 patients studied in sinus rhythm. The duration of follow-up from the onset of atrial fibrillation has averaged 5 years, and 3 of the 16 patients have died of causes related to their heart disease. Four have suffered cerebral emboli. Only 5 patients are now in stable sinus rhythm; in general, they are less symptomatic than the patients in whom atrial fibrillation has recurred.The unusually severe clinical deterioration at the onset of atrial fibrillation and the low cardiac output measured during catheterization are thought to be related to the loss of the important contribution to ventricular filling of atrial systole in patients with poorly compliant ventricles, and to the effect of an irregular ventricular rhythm on the variable nature of the outflow obstruction.

Impact of Atrial Fibrillation on the Clinical Course of Hypertrophic Cardiomyopathy

“…6 -11 Early observational studies (confined largely to patients with obstruction) emphasized the association of AF onset with severe acute clinical deterioration. 6,7 Conversely, a more recent study reported no difference in mortality among patients with AF compared with an HCM control group in sinus rhythm. 10 However, the latter investigation was based largely on highly selected patients at a tertiary referral center, 4,5 and the deleterious impact of AF may have been obscured by the low survival rate in control patients with sinus rhythm.…”

“…Although the more severe consequences associated with development of AF in younger HCM patients have not been explained satisfactorily, AF may represent a marker of generally more aggressive disease. 7 In addition, the combination of AF and basal outflow obstruction proved to be particularly adverse, 6 suggesting that obstructive patients may rely on LA contraction for LV filling more than nonobstructive patients and thus may be more prone to long-term deterioration after development of AF. 19,20 …”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] However, studies regarding long-term prognosis of AF in HCM patients have been sparse and often conflicting, with some reports suggesting a generally unfavorable prognosis associated with this arrhythmia [5][6][7][8][9] and others indicating a relatively benign course. 10,11 Thus, many crucial issues regarding the determinants and clinical impact of AF on HCM patients remain unresolved; therefore, the present investigation was undertaken in our community-based population, including the largest series of HCM patients with AF assembled to date.…”

Clinical Impact of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy Results From Kochi RYOMA Study

“…The impact of AF on major morbidity with cardioembolic events and HF admission was again highlighted, as in the previous limited number of existing studies on AF in HCM populations. [12][13][14][15][16][17] …”

Association of elevated plasma B-type natriuretic peptide levels with paroxysmal atrial fibrillation in patients with nonobstructive hypertrophic cardiomyopathy

“…AF is a common complication of hypertrophic cardiomyopathy (HCM), with an incidence ranging between 10 and 40% [16][17][18][19]. AF causes deterioration in hemodynamic conditions, progression of heart failure and increased risk of thromboembolism in HCM [20,21].…”