Prevalence, Incidence, and Impact on Mortality of Conduction System Disease in Transthyretin Cardiac Amyloidosis

Am J Cardiol. 2020 Aug 1;128:140-146. doi: 10.1016/j.amjcard.2020.05.021. Epub 2020 May 16.


Transthyretin cardiac amyloidosis (ATTR-CA) is an increasingly recognized infiltrative cardiomyopathy in which conduction system disease is common. The aim of our study was to define the incidence and prevalence of high-grade atrioventricular (AV) block requiring pacemaker implantation in our quaternary referral center. This was a single-center retrospective cohort study of 369 consecutive patients with ATTR-CA who underwent 12-lead electrocardiogram at the time of ATTR-CA diagnosis. During a mean follow-up of 28 months, serial ECGs and the electronic medical record were examined for the development of high-grade AV block and pacemaker implantation. Wild-type ATTR-CA (wtATTR-CA) was diagnosed in 261 patients and 108 had hereditary ATTR-CA (hATTR-CA). A total of 35 (9.5%) had high-grade AV block requiring pacemaker implantation at the time of diagnosis of ATTR-CA. The most common conduction abnormalities evident on the baseline ECG were a wide QRS complex, present in 51% with wtATTR-CA and 48% with hATTR-CA (p = 0.62), followed by first-degree AV block, which was present in 49% with wtATTR-CA and 43% with hATTR-CA (p = 0.31). During follow-up, high-grade AV block developed in 10% of those with hATTR-CA and 12% of patients with wtATTR-CA (p = 0.64). On multivariable models, high-grade AV block was not significantly associated with increased mortality. More advanced ATTR-CA stage and a history of obstructive coronary artery disease were associated with increased mortality on multivariable models. In conclusion, the incidence and prevalence of high-grade AV block is high in patients with ATTR-CA. Patients with ATTR-CA require close monitoring during follow-up for the development of conduction system disease.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Amyloid Neuropathies, Familial / complications
  • Amyloid Neuropathies, Familial / genetics
  • Amyloid Neuropathies, Familial / physiopathology*
  • Amyloidosis / complications
  • Amyloidosis / physiopathology
  • Atrioventricular Block / epidemiology*
  • Atrioventricular Block / etiology
  • Atrioventricular Block / therapy
  • Bundle-Branch Block / epidemiology
  • Bundle-Branch Block / etiology
  • Cardiac Pacing, Artificial
  • Cardiomyopathies / complications
  • Cardiomyopathies / genetics
  • Cardiomyopathies / physiopathology*
  • Cohort Studies
  • Electrocardiography
  • Female
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Mortality*
  • Mutation
  • Pacemaker, Artificial
  • Prealbumin / genetics
  • Prevalence
  • Proportional Hazards Models
  • Retrospective Studies
  • Severity of Illness Index
  • Sick Sinus Syndrome / epidemiology
  • Sick Sinus Syndrome / etiology


  • Prealbumin
  • TTR protein, human

Supplementary concepts

  • Amyloidosis, Hereditary, Transthyretin-Related