QRS duration and early hemodynamic instability after coronary revascularization surgery.

INTRODUCTION AND OBJECTIVES: The duration of the QRS interval measured by ECG is a marker of ventricular dysfunction and indicates a poor prognosis. Its value in patients undergoing coronary revascularization surgery has not been established. METHODS: The study involved 203 consecutive patients (age 64+/-9 years, 74% male) scheduled for elective coronary surgery. The maximum QRS duration measured on a preoperative 12-lead ECG was recorded. Hemodynamic instability was defined as the occurrence of cardiac death, heart failure, or a need for intravenous inotropic drugs or intra-aortic balloon counterpulsation during the postoperative period. RESULTS: The occurrence of hemodynamic instability (n=94, 46%) was associated with a longer preoperative QRS duration (97.5+/-21.14 ms vs 88.5+/-16.9 ms; P=.001). The QRS duration was also longer in patients who developed heart failure (n=23; 104.3+/-22.9 ms vs. 91.1+/-18.5 ms; P=.002), needed inotropic drugs (n=77; 96.5+/-20.5 ms vs. 90.1+/-18.2 ms; P=.007) or developed postoperative atrial fibrillation (n=58; 98.2+/-23.8 ms vs. 90.4+/-17.0 ms; P=.018). Bundle branch block was associated with a greater need for intra-aortic balloon counterpulsation (29% vs 12%; P=.012) or inotropic drugs (58% vs 35%; P=.014) and a higher incidence of hemodynamic instability (69% vs 42%; P=.006). Multivariate analysis identified the following independent predictors of hemodynamic instability: QRS duration (adjusted odds ratio [OR] per 10 ms=1.49; 95% confidence interval [CI], 1.11-2; P=.007), the lack of an arterial graft (OR=3.6; 95% CI, 1.14-11.6; P=.029) and extracorporeal circulation time (OR per min=1.013; 95% CI, 1.003-1.023; P=.013). CONCLUSIONS: The intraventricular conduction delay, or QRS duration, was associated with a higher risk of postoperative hemodynamic instability following coronary surgery.

[Usefulness of incremental atrial pacing for evaluating the effectiveness of the ablation of the slow perinodal pathway]. / Utilidad de la estimulación auricular progresiva para evaluar la efectividad de la ablación de la vía lenta perinodal.

INTRODUCTION AND OBJECTIVES: To study the usefulness of incremental atrial pacing for evaluating the effect of radiofrequency catheter ablation on slow pathway conduction in patients with atrioventricular (AV) nodal reentrant tachycardia. METHODS: A prospective study was carried out in patients either with (i.e., AV nodal reentrant tachycardia group) or without (i.e., control group) inducible AV nodal reentrant tachycardia who were referred for electrophysiologic study. Incremental atrial pacing involved gradually decreasing the pacing cycle length until the PR interval exceeded the R-R interval (i.e., PR>RR) or AV nodal block occurred. The presence of dual anterograde AV nodal physiology was assessed during programmed atrial stimulation using standard criteria. In the AV nodal reentrant tachycardia group, electrophysiologic study was repeated 30 minutes after successful catheter ablation. RESULTS: In the AV nodal reentrant tachycardia group (n=85), 52 patients (61%) exhibited dual AV nodal physiology during programmed atrial stimulation and 66 (78%) had a PR>RR during incremental atrial pacing. In the control group, the corresponding proportions were 10/56 (18%) and 7/56 (12%), respectively. After successful slow pathway catheter ablation (81/85), 37/81 exhibited dual AV nodal physiology during programmed atrial stimulation while 1/81 had a PR>RR during incremental atrial pacing. The positive predictive value of successful slow pathway ablation for the absence of a PR>RR was 98%. CONCLUSIONS: Incremental atrial pacing demonstrated that the PR interval exceeded the R-R interval in the majority of patients with inducible AV nodal reentrant tachycardia. This technique could provide a fast and simple way of evaluating the effect of radiofrequency catheter ablation on slow pathway conduction.

[Prognostic role of new biomarkers in off-pump coronary artery bypass surgery]. / Papel pronóstico de los nuevos biomarcadores en la cirugía coronaria sin circulación extracorpórea.

The value of biomarkers of myocardial damage or inflammation in off-pump coronary artery bypass (OPCAB) surgery has not yet been established. In a prospective study of 51 consecutive patients scheduled for elective OPCAB surgery, preoperative levels of troponin T, C-reactive protein, interleukin-6 and tumor necrosis factor-alpha were determined. The primary endpoint was the combination of cardiac death or acute myocardial infarction (AMI) within 30 days. Seven patients (14%) presented with an adverse event: three cardiac deaths and six AMIs. Univariate analysis identified the following adverse event predictors: renal failure (50% vs 11%, P=.028), left ventricular ejection fraction 0.10 ng/dL (43% vs 9%, P=.016), and EuroSCORE rating (7.6 [2.5] VS. 5.2 [2.6], P=.031). A preoperative troponin-T level > 0.10 ng/dL (P=.03) was the only independent adverse event predictor. No significant differences were found with biomarkers of inflammation (P.05). The presence of a preoperative troponin-T level > 0.10 ng/dL is associated with a higher risk of cardiac death or AMI in patients undergoing OPCAB surgery.

[Evolution of severe mitral regurgitation after optimization of pharmacological therapy in non-ischemic dilated cardiomyopathy]. / Evolución de la insuficiencia mitral severa tras optimización del tratamiento médico en la miocardiopatía dilatada no isquémica.

In dilated cardiomyopathy, severe functional mitral regurgitation (MR) is associated with a poor prognosis. In 112 consecutive clinically stable patients with non-ischemic dilated cardiomyopathy, echocardiography identified 15 (14%) patients who had severe MR (age, 53+/-12 years; 80% male; left ventricular ejection fraction, 26 +/- 8%). Existing medical treatment with ACE inhibitors and beta-blockers was increased up to the maximum tolerated doses. At 6 months, MR decreased by at least one grade in 13 (87%) patients (P =.001), as did the effective regurgitant orifice area (from 0.41 [0.05] mm2 to 0.20 [0.15] mm2; P.

[Usefulness of NTproBNP in the emergency management of patients with severe dyspnea and an uncertain heart failure diagnosis]. / Utilidad del NTproBNP en el manejo urgente del paciente con disnea severa y diagnóstico dudoso de insuficiencia cardíaca.

INTRODUCTION AND OBJECTIVES: Measurement of N-terminal pro-B-type natriuretic peptide (NTproBNP) helps in diagnosing heart failure (HF). The test's usefulness may be greatest in patients with severe dyspnea of uncertain origin. However, NTproBNP has not been evaluated specifically in this setting. PATIENTS AND METHOD: This prospective emergency department study included 70 patients with shortness of breath at rest as their chief complaint. In the attending physician's opinion, both HF and a non-cardiac cause were equally probable. Blinded NTproBNP measurement was carried out in blood samples collected on admission. Patients were monitored and their final diagnoses were based on clinical findings, therapeutic responses, and cardiac and noncardiac tests performed during hospitalization. RESULTS: The NTproBNP level was higher in the 49 patients (70%) with a final diagnosis of HF (P = .006); the area under the ROC curve was 0.72 (0.60-0.82). The optimum diagnostic cut-off value was 900 pg/mL, which had an accuracy of 87%, a sensitivity of 98%, and a negative predictive value of 92%. The NTproBNP level was significantly higher in the 6 patients (9%) who died during hospitalization (P = .009); the area under the ROC curve was 0.87 (0.76-0.93) and the optimum cut-off value for predicting death was 5500 pg/mL, which had an accuracy of 77%, a sensitivity of 100%, and a positive likelihood ratio of 4.2. CONCLUSIONS: In patients with severe dyspnea and an uncertain diagnosis of HF, an NTproBNP level < 900 pg/mL helps exclude the presence of HF, whereas a NTproBNP level > 5500 pg/mL identifies patients at an increased risk of death.

[Functional assessment of patients with hypertrophic cardiomyopathy by maximal oxygen consumption]. / Evaluación funcional de los pacientes con miocardiopatía hipertrófica mediante análisis del consumo de oxígeno máximo.

INTRODUCTION AND OBJECTIVES: Differences between anatomical severity and clinical manifestations are frequent in patients with hypertrophic cardiomyopathy. Our objective was to assess functional capacity in a consecutive group of patients with hypertrophic cardiomyopathy measuring exercise aerobic parameters, as well as clinical and echocardiographic variables. PATIENTS AND METHOD: We studied 98 consecutive patients with hypertrophic cardiomyopathy. All patients underwent both echocardiographic and cardiopulmonary exercise testing. The control group consisted of 22 untrained persons. We studied exercise capacity by analyzing maximal oxygen consumption and aerobic functional capacity, among other variables. RESULTS: Patients with hypertrophic cardiomyopathy attained significantly lower maximal oxygen consumption values than controls (24.1 5.9 vs 36.4 5.9 ml/kg/min; p = 0.0001). Maximal aerobic capacity was significantly different among patients with NYHA functional capacity class I, II or III (78.9 13.5%; 71.9 14.7%; 63.9 15.7%; p = 0.009). However, considerable overlap was found between groups in maximal aerobic capacity. Functional impairment was greater in patients with left ventricular thickness > 20 mm, ejection fraction < 50%, left atrial dimension > 45 mm and pseudonormal or restrictive transmitral flow pattern. CONCLUSIONS: Patients with hypertrophic cardiomyopathy show significant functional impairment, which is difficult to detect from their clinical manifestations. Optimal assessment requires cardiopulmonary exercise testing.

[Addition of an angiotensin II receptor blocker to maximal dose of ACE inhibitors in heart failure]. / Adición de un ARAII al tratamiento con dosis máximas de IECA en la insuficiencia cardíaca.

In heart failure, the benefits of adding angiotensin-receptor blockade to ACE inhibitors have been studied only with submaximal doses of ACE inhibitors. We included 20 patients (LVEF 24 7%, NYHA II-III), with no clinical or therapeutic variations in the previous three months, who were receiving maximal doses of ACE inhibitors. We added losartan 50 mg once a day. At six months, SBP decreased (115 8 vs. 106 9 mmHg; p = 0.001), LVEF increased (24.4 7 vs. 34.1 7%; p < 0.001), ventricular end-diastolic volumes decreased (220 58 vs 190 46 ml; p = 0.007), and SPAP decreased (43 8 vs. 35 7 mmHg; p < 0.001). Seven patients improved one degree on the NYHA scale (p = 0.004), but VO2max did not change (20.8 5.2 vs. 21.8 5.0 ml/kg/min, p = 0.120). Plasma levels of norepinephrine, at rest and maximal exercise, brain natriuretic peptide, and renin were similar. After maximum ACE inhibitor doses, the addition of losartan is safe and associated with an improvement in ventricular function and NYHA functional class, but with no change in neurohormonal status.