Biventricular pacing found to be better in atrioventricular block

cardiac pacing


A study published in the latest issue of the New England Journal of Medicine has found that in patients suffering from atrioventricular block with depressed left ventricular ejection fraction, biventricular pacing gives better results compared to the standard right ventricular pacing. The study was led by Anne Curtis from the University of Buffalo, New York, along with her colleagues.
The study was undertaken as it was seen that the conventional right ventricular pacing in patients with atrioventricular block led to left ventricular systolic dysfunction in a large percentage of patients. The researchers tried to evaluate the effect of biventricular pacing on the mortality and morbidity of such patients.
The researchers selected 691 patients with New York Heart Association (NYHA) class I, II, or III heart failure with a left ventricular ejection fraction of 50% or less, who were ideal candidates for pacing. The average age of the patients was 73 years. The patients were both given pacemakers or ICDs, and then divided randomly into two groups. The first group was assigned right ventricular pacing while the second group was assigned biventricular pacing. All the patients were followed up for an average duration of 37 months.
The primary outcome of the study was measured as:
the time to death from any cause 
an urgent care visit for heart failure that required intravenous therapy 
15% or more increase in the left ventricular end-systolic volume index.
The researchers observed primary outcome in 55.6% (190 out of 342 patients) who were assigned right ventricular pacing. This percentage was reduced to 45.8% (160 out of 349 patients) in those who were assigned biventricular pacing. The incidence of primary outcome was significantly lower over time in patients who received biventricular pacing compared to those who were given right ventricular pacing. The results were similar in patients who were given a pacemaker and those who were given an ICD. Serious side effects were seen in 4.9% of the patients within 6 months of getting the implants. These included lead dislodgement, pacing failure, infection, etc.
On the basis of these results, the researchers have concluded that biventricular pacing is a better option in patients with atrioventricular block and left ventricular systolic dysfunction with NYHA class I, II, or III heart failure. 
Editor: Dr. Bimal Rajalingam MBBS DNB (Resp Med)


Friday, October 3, 2014
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