Abstract 2996: The Relationship of Heart Rate in the Early Post Myocardial Infarction Period and Long Term Outcome: Results From the VALsartan in Acute Myocardial iNfarcTion (VALIANT) Trial
Background and aims: Increased heart rate (HR) in the acute phase of myocardial infarction (MI) has been shown to be related to mortality. We assessed whether higher HR in stable survivors of high risk MI is also associated with worse long term outcome.
Methods: In VALIANT 14,703 patients with left ventricular dysfunction and/or heart failure (HF) following MI were randomized to captopril, valsartan or their combination. We performed a landmark analysis in patients free from HF or recurrent MI at 30 days following randomization. To assess the relationship between HR and the risk of death (and the combined endpoint of death, MI or HF), Cox proportional hazards models were generated using a stepwise selection procedure from more than 50 covariates. These included baseline risk factors, characteristics of the index MI, baseline and 30-day clinical characteristics, such as HR, blood pressure, diabetes, eGFR, NYHA class and use of beta and calcium channel blockers (Table⇓ footnote). A subgroup analysis was also performed restricted to patients treated with beta-blockers at 30 days.
Results: The study population comprised 12,741 patients. HR was significantly lower at 30 days compared to randomization (71±11 vs. 76±12 bpm; p=<0.0001). At 30 days, there were 9,429 (74%) patients treated with beta-blockers and had a lower HR than those who were not on beta-blockers (70±11 vs. 76±11 bpm; p=0.0001). After adjustment for the 50 covariates, higher HR at 30 days was associated with increased hazard for mortality (10% increased hazard per 10 bpm) and the combined end point of death, MI or HF (7% increased hazard per 10 bpm). Similar results were found the group of patients on beta-blockers (Table⇓).
Conclusions: In stable post-MI survivors, increased HR in the early follow up period is predictive of worse outcome even with background beta-blocker therapy. This observation provides additional rationale for testing HR reducing agents. Adjusting for: Baseline risk factors: Age, height, weight, race, sex, history of hypertension, diabetes, dyslipidemia, smoking, angina, myocardial infarction, transient ischemic attack/stroke, peripheral vascular disease, atrial fibrillation, renal insufficiency, chronic obstructive pulmonary disease, alcohol abuse, cancer, coronary artery bypass graft (CABG) surgery. Clinical characteristics at the time of MI: Killip class, location and type of the MI, new left bundle branch block, NYHA class, HR, systolic and diastolic blood pressure, eGFR, use of beta-blockers, calcium channel blockers, thrombolytic therapy or percutaneous coronary intervention (PCI) at time of the MI; Need for PCI or CABG, pacemaker, implantable cardioverter-defibrillator, intra-aortic balloon pump following the MI; development of angina, atrial fibrillation, ventricular fibrillation or tachycardia, renal insufficiency, dyslipidemia, diabetes following the MI. 30-day clinical characteristics: Systolic and diastolic blood pressure, NYHA class, use of beta-blockers and calcium channel blockers.