Prophylactic pacemaker implantation in familial amyloid polyneuropathy.

BACKGROUND: Familial amyloid polyneuropathy (FAP) is an autosomic dominant disease with a high rate of conduction disorders and increased risk of sudden death. Prophylactic cardiac pacing may be considered in asymptomatic patients with FAP. However, the potential benefits are unknown. OBJECTIVE: To document conduction disorders in a large series of FAP and the incidence of high-degree atrioventricular (AV) block in patients with prophylactic pacemaker (PM). METHODS: From January 1999 to January 2010, 262 patients with FAP were retrospectively evaluated. Prophylactic PM was implanted in patients with His-ventricular interval ≥ 70 ms, His-ventricular interval >55 ms associated with a fascicular block, a first-degree AV block, or a Wenckebach anterograde point ≤ 100 beats/min. The spontaneous AV conduction was then analyzed by temporarily inhibiting the PM. RESULTS: As compared with patients with prophylactic PM (n = 100) and patients implanted given a class I/IIa indication (n = 18), the patients who did not require PM (n = 144) were younger and displayed less severe cardiac involvement. Follow-up after prophylactic PM implantation was analyzed in 95 of the 100 patients over 45 ± 35 months, and a high-degree AV block was documented in 24 of the 95 patients (25%). The risk of high-degree AV block was higher in patients with first-degree AV block or Wenckebach anterograde point ≤ 100 beats/min (hazard ratio 3.5; 95% confidence interval 1.2-10) while microvoltage on surface electrocardiogram reduced the risk (hazard ratio 0.2; 95% confidence interval 0.1-0.7). CONCLUSION: In FAP with conduction disorders, prophylactic PM implantation prevented major cardiac events in 25% of the patients over a 45-month mean follow-up. It is suggested that prophylactic PM implantation prevented symptomatic bradycardia in these patients.

A hemodynamic study of pulmonary hypertension in sickle cell disease.

BACKGROUND: The prevalence and characteristics of pulmonary hypertension in adults with sickle cell disease have not been clearly established. METHODS: In this prospective study, we evaluated 398 outpatients with sickle cell disease (mean age, 34 years) at referral centers in France. All patients underwent Doppler echocardiography, with measurement of tricuspid-valve regurgitant jet velocity. Right heart catheterization was performed in 96 patients in whom pulmonary hypertension was suspected on the basis of a tricuspid regurgitant jet velocity of at least 2.5 m per second. Pulmonary hypertension was defined as a mean pulmonary arterial pressure of at least 25 mm Hg. RESULTS: The prevalence of a tricuspid regurgitant jet velocity of at least 2.5 m per second was 27%. In contrast, the prevalence of pulmonary hypertension as confirmed on catheterization was 6%. The positive predictive value of echocardiography for the detection of pulmonary hypertension was 25%. Among the 24 patients with confirmed pulmonary hypertension, the pulmonary-capillary wedge pressure was 15 mm Hg or less (indicating precapillary pulmonary hypertension) in 11 patients. Patients with confirmed pulmonary hypertension were older and had poorer functional capacity and higher levels of N-terminal pro-brain natriuretic peptide than other patients. In contrast, patients who had a tricuspid regurgitant jet velocity of at least 2.5 m per second without pulmonary hypertension and patients with a tricuspid regurgitant jet velocity of less than 2.5 m per second had similar clinical characteristics. CONCLUSIONS: In this study of adults with sickle cell disease, the prevalence of pulmonary hypertension as confirmed on right heart catheterization was 6%. Echocardiographic evaluation alone had a low positive predictive value for pulmonary hypertension. (Funded by the French Ministry of Health and Assistance Publique-Hôpitaux de Paris; ClinicalTrials.gov number, NCT00434902.).