Abstract
The new European Society of Cardiology guideline for ST-segment elevation myocardial infarction recommends that left and right bundle branch block should be considered equal for recommending urgent angiography in patients with suspected myocardial infarction. This consideration is not taken into account in the management of patients with coronary syndrome without ST elevation (NSTEMI). We evaluate the evolution of patients with acute coronary syndrome and long-term bundle branch block.
Patients and methods
We included 8771 patients admitted to two tertiary hospitals between 2003 and 2017 with an acute coronary syndrome, 5673 NSTEMI (64.3%) and 3098 STEMI (35.7%). All patients had an ECG recorded immediately upon admission. Patients were classified as having right bundle branch block (RBBB), left bundle branch block (LBBB). Long-term follow-up was performed (median 55 months) to assess mortality.
Results
A total of 8771 patients were included with a mean age of 66.1 years, 72.5% males, 4.1% (362) with LBBB and 5% (440) with RBBB. Patients with BBB were older, with more previous history of myocardial infarction and coronary revascularization and higher prevalence of cardiovascular risk factors. Medical treatment was similar but they were less often submitted to angioplasty. During the acute phase, patients with RBBB and LBBB presented a higher rate of heart failure than those without branch block (4.8% vs 9.1% vs 3.5%, p=0.0001); higher mortality (8.4% vs 10.5% vs 3.0%, p=0.0001); higher stroke rate (2.5% vs 1.4% vs 0.8%, p=0.001); higher rate of renal failure (8.2% vs 9.7% vs 3.9%, p=0.0001) and higher rate of reinfarction (3.0% vs 4.1% vs 1.7%, p=0.001). Patients who had a RBBB or an LBBB had a worse prognosis throughout the follow-up. Heart failure was present in 17.7% of the group with RBBB, 29.6% of LBBB and 11% in the group without branch block (p=0.0001). Mortality during follow-up was 31% in RBBB, 40.6% in LBBB and 18.7% without branch block (p=0.0001). In multivariate analysis of Cox, both RBBB (HR 1.55, 95% CI 1.23–1.98, p=0.0001) and LBBB (HR 1.48, 95% CI 1.22–1.53, p=0.001) were an independent predictors of all-cause mortality (adjustment for GRACE score, gender, treatment with betablockers, angiotensin conversor enzym inhibitors, statin and coronary revascularization).
Cox regression model multivariate
Conclusions
The presence of RBBB or LBBB in the ECG of patients with an ACS is associated with a worse prognosis both during the hospital phase and in the long term. In addition, both bundle branch blocks are independent predictors of long-term mortality in patients with ACS.
Real-world impact of a quality improvement project to implement rapid rule out of acute coronary syndrome processes in eligible emergency department patients
