Are Prolonged Ventricular Pauses in Atrial Fibrillation a Marker of Poor Prognosis?

BACKGROUND: In patients with atrial fibrillation (AF), the long-term prognosis of long electrocardiographic pauses in the ventricular action is not well studied. METHODS: Consecutive Holter recordings in patients with AF (n = 200) between 2009 and 2011 were evaluated, focusing on pauses of at least 2.5 s. Outcomes of interest were all-cause mortality and pacemaker implantation. RESULTS: Forty-three patients (21.5%) had pauses with a mean of 3.2 s and an SD of 0.9 s. After a median follow-up of 99 months (ranging 89-111), 47% (20/43) of the patients with and 45% (70/157) without pauses were deceased. Pauses of ≥2.5 s did not constitute a risk of increased mortality: HR = 0.75 (95% CI: 0.34-1.66); p = 0.48, neither did pauses of ≥3.0 s: HR = 0.43 (95% CI: 0.06-3.20); p = 0.41. Sixteen percent of patients with pauses underwent pacemaker implantation during follow-up. Only pauses in patients referred to Holter due to syncope and/or dizzy spells were associated with an increased risk of pacemaker treatment: HR = 4.7 (95% CI: 1.4-15.9), p = 0.014, adjusted for age, sex, and rate-limiting medication. CONCLUSION: In patients with AF, prolonged electrocardiographic pauses of ≥2.5 s or ≥3.0 s are not a marker for increased mortality in this real-life clinical study.

Excessive supraventricular ectopic activity and risk of incident atrial fibrillation in a consecutive population referred to ambulatory cardiac monitoring.

BACKGROUND: Excessive supraventricular ectopic activity (ESVEA), defined as ≥720 premature atrial contractions (PAC) per day or any runs of ≥20 PACs, has been proposed as a surrogate marker for paroxysmal atrial fibrillation (PAF). OBJECTIVE: We aimed to estimate the prognostic impact of ESVEA on the future development of PAF in consecutive patients referred to ambulatory cardiac monitoring. METHODS: The cohort consists of a population with comorbidities referred to 48-hour ambulatory electrocardiogram aged 30-98 (n = 1316) between 2009 and 2011. After exclusion of known or current atrial fibrillation (AF) (n = 527) and patients with pacemakers (n = 7), 782 patients were included, with a median follow-up of 8.1 years. Events of incident AF and death were retrieved from patient records. RESULTS: Mean age was 58.6 ± 15.5 years and 56.5% were women. A total of 101 patients had ESVEA at baseline (12.9%). During follow-up, 69 (8.9%) developed incidental AF. Twenty-three patients with ESVEA developed AF (23%). Incidence rate of AF in patients with and without ESVEA was 37.1/1000 person-years and 9.1 per 1000 person-years, respectively (P < .001). ESVEA was associated with incident AF after adjustment for potential confounders in Cox regression analysis (hazard ratio [HR]: 2.39; 95% confidence interval [CI]: 1.40-4.09) and in competing risk analysis with death as competing risk (subdistribution HR: 2.35; 95% CI: 1.30-4.17). CONCLUSION: ESVEA increases the risk of incident AF substantially in a population referred to ambulatory cardiac monitoring.

Prognostic Implications of Level-of-Care at Tertiary Heart Centers Compared With Other Hospitals After Resuscitation From Out-of-Hospital Cardiac Arrest.

BACKGROUND: Studies have found higher survival rates after out-of-hospital cardiac arrest and admission to tertiary heart centers. The aim was to examine the level-of-care at tertiary centers compared with nontertiary hospitals and the association with outcome after out-of-hospital cardiac arrest. METHODS AND RESULTS: Consecutive out-of-hospital cardiac arrest patients (n=1078) without ST-segment-elevation myocardial infarction admitted to tertiary centers (54%) and nontertiary hospitals (46%) were included (2002-2011). Patient charts were reviewed focusing on level-of-care and comorbidity. Survival to discharge differed significantly with 45% versus 24% of patients discharged alive (P<0.001), and after adjustment for prognostic factors admissions to tertiary centers were still associated with lower 30-day mortality (hazard ratio, 0.78 [0.64-0.96; P=0.02]), independent of comorbidity. The adjusted odds of predefined markers of level-of-care were higher in tertiary centers: admission to intensive care unit (odds ratio [OR], 1.8 [95% confidence interval, 1.2-2.5]), temporary pacemaker (OR, 6.4 [2.2-19]), vasoactive agents (OR, 1.5 [1.1-2.1]), acute (<24 hours) and late coronary angiography (OR, 10 [5.3-22] and 3.8 [2.5-5.7]), neurophysiological examination (OR, 1.8 [1.3-2.6]), and brain computed tomography (OR, 1.9 [1.4-2.6]), whereas no difference in therapeutic hypothermia was noted. Patients at tertiary centers were more often consulted by a cardiologist (OR, 8.6 [5.0-15]), had an echocardiography (OR, 2.8 [2.1-3.7]), and survivors more often had implantable cardioverter defibrillator's implanted (OR, 2.1 [1.2-3.6]). CONCLUSIONS: Admissions to tertiary centers were associated with significantly higher survival after out-of-hospital cardiac arrest in patients without ST-segment-elevation myocardial infarction in the Copenhagen area even after adjustment for prognostic factors including comorbidity. Level-of-care seems higher in tertiary centers both in the early phase, during the intensive care unit admission, and in the workup before discharge. The varying level-of-care may contribute to the survival difference; however, differences in comorbidity do not seem to matter significantly.

Diastolic dysfunction after an acute myocardial infarction in patients with antecedent hypertension.

OBJECTIVE: We sought to assess changes in the left ventricular systolic and diastolic function in patients with antecedent hypertension and an acute myocardial infarction. METHODS: A group of 38 patients with antecedent hypertension and acute myocardial infarction were compared with an age-matched nonhypertensive control group. There was a 30-day follow-up. Outcome measures were left ventricular volumes and ejection fraction, systolic velocities, and strain. Diastolic function was assessed by mitral inflow combined with tissue velocities of the mitral ring. RESULTS: Patients with antecedent hypertension did not experience any regression in the E/E' ratio (16.5 +/- 7.5 vs 17.1 +/- 9.0, P = not significant) or increase in the E'/A' ratio (0.76 +/- 0.5 vs 0.84 +/- 0.6, P = not significant) compared with significant improvements in E/E' ratio (18.9 +/- 8.7 vs 12.8 +/- 7.4, P < .01) and E'/A' ratio (0.76 +/- 0.5 vs 1.1 +/- 0.7, P < .01) in the control group. This was found despite similar changes ejection fraction, volumes, and systolic strain. CONCLUSIONS: Patients with antecedent hypertension have incomplete improvement of the diastolic function compared with control subjects despite comparable left ventricular volumes and ejection fraction after an acute myocardial infarction.

No beneficial effects of coronary thrombectomy on left ventricular systolic and diastolic function in patients with acute S-T elevation myocardial infarction: a randomized clinical trial.

OBJECTIVE: We sought to evaluate the effect of acute coronary thrombectomy, as adjunctive treatment to primary percutaneous coronary intervention, on the systolic and diastolic left ventricular function, in patients with acute S-T elevation myocardial infarction. METHODS: In a prospective randomized study, patients with acute S-T elevation myocardial infarction were randomized to treatment with primary percutaneous coronary intervention with or without thrombectomy. Outcome measures were left ventricular volumes and ejection fraction in addition to systolic long-axis function, estimated from the tissue Doppler systolic velocities of the mitral ring. Diastolic function was assessed by mitral inflow and diastolic velocities of the mitral ring movement. RESULTS: Of the 215 patients included, 172 patients (80%) had a 30-day follow-up. There were no significant differences in ejection fraction between groups during follow-up (thrombectomy at baseline 47 +/- 14% vs 47 +/- 14% at follow-up, control group at baseline 48 +/- 11% vs 51 +/- 12% at follow-up, P = not significant). Systolic velocities were significantly higher in the control group at follow-up (thrombectomy, at baseline, 6.5 +/- 1.9 vs 6.3 +/- 1.8 cm/s at follow-up; control group, at baseline, 6.5 +/- 1.9 vs 7.0 +/- 1.9 cm/s at follow-up; P < .05). There were no significant differences in diastolic function between the two groups. CONCLUSION: Thrombectomy had no beneficial effect on the left ventricular function in patients with acute S-T elevation myocardial infarction.