ABSTRACT
[Figure: see text].
Subject(s)
Blood Pressure/physiology , Cardiovascular Diseases/mortality , Heart Rate/physiology , Adult , Age Factors , Aged , Cardiovascular Diseases/physiopathology , Exercise Test , Female , Humans , Male , Middle Aged , Reference Values , Retrospective Studies , Sex FactorsABSTRACT
BACKGROUND: Functional aerobic capacity (FAC) determined by treadmill exercise testing (TMET) is associated with cardiovascular (CV) disease mortality independent of traditional CV risk factors and is a potentially underutilized tool. The purpose of this study was to determine added prognostic value of reduced FAC and other exercise test abnormalities beyond CV risk factors for predicting total and CV mortality. METHODS: The TMET database was queried for Minnesota patients (≥30â¯years) without baseline CV disease from September 21, 1993, through December 20, 2010. Risk factors and exercise abnormalities including low FAC (<80% predicted), abnormal heart rate recovery (<13â¯bpm), and abnormal electrocardiogram (ST depression ≥1â¯mm regardless of baseline) were extracted. Mortality data were obtained through February 2016. Patients were divided into 9 groups by abnormality number (0, 1, or ≥2) and risk factors (0, 1, or ≥2). Cox regression was used to determine mortality risk according to exercise abnormalities/CV risk factors, adjusted for age and sex. RESULTS: 19,551 patients met inclusion criteria; 1271 (6.5%) died over 12.4⯱â¯5.0â¯years' follow-up (405 [32%] CV deaths). Exercise abnormalities significantly modified risk for every number of CV risk factors. Hazard ratios (95% CI) for total mortality (0 vs ≥2 abnormalities) were 2.4 (1.9-2.9; Pâ¯<â¯.001) for 0 CV risk factors; 2.7 (2.2-3.3; Pâ¯<â¯.001), 1 risk factor; and 6.1 (4.8-7.7; Pâ¯<â¯.001), ≥2 risk factors. Similar results were noted for CV disease mortality. CONCLUSIONS: Exercise test abnormalities strongly predict mortality beyond traditional CV risk factors. Our results indicate that TMET should be considered for CV risk assessment.
Subject(s)
Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/physiopathology , Exercise Test/methods , Exercise Tolerance/physiology , Adult , Cardiovascular Diseases/mortality , Cohort Studies , Exercise Test/mortality , Female , Follow-Up Studies , Humans , Male , Middle Aged , Retrospective Studies , Risk Assessment/methods , Risk Factors , Survival Rate/trendsABSTRACT
BACKGROUND: Spontaneous second-degree atrioventricular block induced by exercise (Ex2AVB) is rare, but it can cause profound exercise intolerance. OBJECTIVE: We sought to determine the frequency of Ex2AVB in our exercise testing practice and to describe characteristics of patients with Ex2AVB. We hypothesized that the number of patients would be small, but they would require invasive treatment. METHODS: We reviewed the Mayo Clinic Integrated Stress Center database for nonimaging tests performed from 2006 through 2010. All exercise tests coded as "second-degree atrioventricular block" were captured and reviewed. Tests were excluded if results showed evidence of second-degree atrioventricular block at rest. RESULTS: From 40,715 tests performed, definite Ex2AVB was found in only 19 patients (0.05%; 5 women and 14 men). Ex2AVB occurred as a Mobitz type II block in 4 patients and as a Mobitz type I block in 15. In 3 patients, Ex2AVB occurred only in recovery. Ex2AVB was intermittent in 11 patients and persistent in 8. Mean peak heart rate was higher with intermittent Ex2AVB than with persistent Ex2AVB (126⯱â¯39 vs 88⯱â¯28â¯bpm, Pâ¯<â¯.01), as was mean functional aerobic capacity (87%⯱â¯20% vs 59%⯱â¯14%, Pâ¯<â¯.01). Seven patients with persistent Ex2AVB received a permanent pacemaker; 1 underwent pacemaker adjustment. CONCLUSION: Ex2AVB is uncommon but can cause exercise intolerance that requires pacemaker implantation. Structural or ischemic heart disease and resting conduction abnormalities are common findings in patients with Ex2AVB. Intervention is seldom required for intermittent Ex2AVB.
