Chronotropic incompetence in Chagas disease: usefulness of dual sensor pacemaker based on volume minute and accelerometer

1International Board Heart Rhythm Examiners Certified Cardiac Device Specialist. Director of Pacemaker Service of Instituto Dante Pazzanese de Cardiologia (IDPC), Sao Paulo, SP, Brazil. E-mail: pachon@usp.br Chagas disease or American trypanosomiasis is a chronic parasitosis affecting most Latin American countries where an estimated 8 million people are infected. Current assessments have shown that even in the United States there is a total of 300,000 infected individuals, essentially all of whom are immigrants from the endemic countries. It is a tropical parasitic disease caused by the protozoan Trypanosoma cruzi that is transmitted to humans by blood-sucking triatomine bugs, known as “Kissing Bug”, and via blood transfusion, mother-to-baby or organ transplant. This protozoan causes an acute systemic inflammatory illness that usually progresses to chronic myocarditis and autonomic disease leading to electrical and/or severe dilated cardiomyopathy. Myocardial damage is disseminated throughout the heart. The outcome may present cardiac arrhythmias, life-threatening heart failure, thromboembolism, stroke and sudden death. The latter is sometimes the first manifestation of the disease, even in the structurally normal heart (latent phase). In many patients, a chronic immunologic process may feed the inflammatory phenomenon even without the parasite. As a rule, extensive involvement of the autonomic nervous system and the cardiac conduction system results in a huge variety of supraventricular and ventricular cardiac arrhythmias. As a corollary, in approximately 60% of cases, the sinus node is injured, developing a more or less extensive sick sinus syndrome. Additionally, many patients have to be treated for heart failure and cardiac arrhythmias. Thanks to a coordinated multi-country program in the Southern Cone countries, the transmission of Chagas disease by vectors and via blood transfusion was interrupted in Uruguay in 1997, in Chile in 1999 and Brazil in 2006. For this reason, the incidence of new infections by T. cruzi across the South American continent has decreased by 70%. The natural course of the disease and the very common pharmacological requirement for treating numerous arrhythmias cause a high sick sinus node syndrome prevalence. One frequent expression of this condition is the “Chronotropic Incompetence” (CI).