ABSTRACT
OBJECTIVE: Although chronotropic incompetence (CI) represents an independent predictor of mortality and incidence of coronary artery disease, its pathophysiological mechanisms remain unknown. The purpose of this investigation was to evaluate wall motion abnormalities of the left ventricle and location of coronary arterial lesions in patients with and without CI. METHODS: After exclusion of confounding factors, 610 patients (mean age of 58.4 +/- 11 years; 275 men) with ischaemia who underwent exercise echocardiography were studied. Based on heart rate (HR) reached in treadmill testing, patients were divided into two groups: Chl (97 patients who did not reach 85% of maximum HR recommended for age) and ChC (513 patients who achieved 85% of the maximum age-predicted HR). RESULTS: There was a higher frequency of dyspnoea (5.2% vs. 0.6%, P = 0.003), systemic hypertension (69.1% vs. 57.3%, P = 0.031) and obesity (38.1% vs. 22.6%, P = 0.001), and a lower tolerance to effort (dyspnoea as limitation of physical effort: 36.1% vs. 8.0%, P < 0.0001; duration of treadmill test: 4.4 +/- 2.2 vs. 7.2 +/- 2.8, P < 0.0001; METs: 6.0 +/- 2.6 vs. 8.4 +/- 2.9, P = 0.002) in Chl compared to ChC. The wall motion score index (WMSI) was higher in Chl than in ChC, both at rest (1.15 +/- 0.29 vs. 1.07 +/- 0.19, P = 0.011) and after exercise (1.24 +/- 0.29 vs. 1.15 +/- 0.19, P = 0.002). Systolic function, which was evaluated in peak exercise through WMSI, was significantly more altered in the Chl group. The presence of severe injuries in right coronary was independently associated with CI (adjusted OR = 3.57, CI 95%: 1.86-6.87). CONCLUSION: Chronotropic incompetence is associated with ventricular dysfunction in peak exercise and critical right coronary artery lesions.
Subject(s)
Coronary Artery Disease/physiopathology , Heart Rate/physiology , Ventricular Dysfunction/physiopathology , Coronary Angiography , Dyspnea/complications , Echocardiography , Electrocardiography , Exercise Tolerance/physiology , Female , Hemodynamics , Humans , Hypertension/complications , Male , Middle Aged , Obesity/complications , Regression AnalysisABSTRACT
Introdução: Objetivo: Avaliar a influência da utilização de betabloqueador em pacientes com incompetência cronotrópica, submetidos à Ecocardiografia sob Estresse. Método: Estudo observacional, transversal e retrospectivo, realizado entre janeiro/2001 e outubro/2008. Após exclusão de pacientes com precordialgia típica, com doença arterial coronariana estabelecida e que não usavam betabloqueador, foram avaliados 635 pacientes que faziam uso regular desta droga, suspensa 3 dias antes da execução do exame. A amostra foi dividida em 2 grupos: G1 e G2 (com e sem incompetência cronotrópica), que foram comparados quanto à características clínicas, hemodinâmicas, eletrocardiográficas e ecocardiográficas . Resultados: O G1 constituiu-se de 81 pacientes (13 por cento); o G2 de 554 pacientes (87 por cento). Quanto às características, os pacientes do G1 eram idosos (p=0,002), apresentavam mais precordialgia atípica (p=0,013, mais dispnéia durante o exame (p=0,001) e eram sintomáticos (p=0,009). Do ponto de vista ecocardiográfico, não foi possível diferenciar os dois grupos, quanto ao diagnóstico de isquemia miocárdica induzida pelo esforço (p=0,140) e, também quanto ao índice de escore de motilidade do ventrículo esquerdo durante o exercício (p=0,223). Todavia, G1 demonstrou maior índice de massa do ventrículo esquerdo (p=0,001). Conclusão: Isquemia miocárdica investigada com ecocardiografia sob estresse físico foi senelhante nos grupos estudados.