Prognostic Importance of Novel Oxygen Desaturation Metrics in Patients With Heart Failure and Central Sleep Apnea.

BACKGROUND: Sleep-disordered breathing, particularly central sleep apnea (CSA), is highly prevalent in heart failure (HF) and an independent prognostic marker. We assessed the hypothesis that an increased hypoxemic burden during sleep may have greater prognostic value than the frequency of apneic and hypopneic episodes. METHODS AND RESULTS: We prospectively conducted overnight cardiorespiratory polygraphy on consecutive HF patients referred to our hospital from 2008 to 2011. We studied CSA defined by an apnea-hypopnea index (AHI) of ≥5 events/h with >75% of all events being central in origin. We determined the AHI, proportion of the sleep time with SpO2 <90% (T90%), and proportion of the recording time that 4% desaturation events occurred (4%POD). We studied 112 HF patients with either systolic or diastolic dysfunction. During a follow-up period of 37 ± 25 months, 32 patients (29%) died. Nonsurvivors had a higher 4%POD compared with survivors (11 ± 6.4% vs 19 ± 13%; P = .001), but did not differ significantly from survivors regarding AHI and T90%. An adjusted logistic regression analysis revealed that the 4%POD was the best independent predictor of mortality. CONCLUSIONS: The 4%POD, a novel metric for the nocturnal hypoxemic burden, is an independent prognostic marker in HF patients affected by CSA.

Beat-to-beat variability of T-wave amplitude for the risk assessment of ventricular tachyarrhythmia in patients without structural heart disease.

AIMS: Increased temporal repolarization lability, assessed by beat-to-beat variability of T-wave amplitude (TAV), has been shown to be associated with ventricular tachyarrhythmia in patients with a variety of clinical conditions. The aim of this study was to test the ability of TAV to identify patients presenting with malignant ventricular arrhythmia and to predict subsequent occurrences. METHODS AND RESULTS: We studied 20 consecutive patients (age 42 ± 15 years, mean ± standard deviation) presenting with ventricular tachyarrhythmia who did not have substantial underlying heart disease and compared them with 40 age- and sex-matched control subjects. The TAV was determined by Holter recording (Ela Medical). Patients with ventricular tachyarrhythmia had a higher maximum value of TAV (max TAV: 38 ± 18 vs. 22 ± 15 µV, P < 0.001) than did the controls. The sensitivity and specificity of max TAV > 22.4 µV for detecting the occurrence of ventricular tachyarrhythmia were 77 and 90%, respectively. During a mean follow-up period of 23 months, three patients had relapses of ventricular tachyarrhythmia. Patients with a recurrence of ventricular tachyarrhythmia had a trend towards a higher max TAV as compared with those who had ventricular tachyarrhythmia but did not relapse (56 ± 23 vs. 36 ± 16 µV, P = 0.061). CONCLUSION: Our results suggest that Holter-derived TAV might be associated with the occurrence and recurrence of ventricular tachyarrhythmia in patients without structural heart disease. Prospective validation will be necessary to assess the potential diagnostic value of the TAV in a large general population.

Eicosapentaenoic acid for the prevention of recurrent atrial fibrillation.

BACKGROUND: n-3 polyunsaturated fatty acids, primarily eicosapentaenoic acid (EPA), has been reported to have antiarrhythmic and antiinflammatory effects. The aim of the present study was to examine whether the combination of antiarrhythmic drugs and EPA reduced the frequency of atrial fibrillation (AF) in patients with paroxysmal AF. METHODS: We studied 50 patients with paroxysmal AF (age, 54 ± 9 years) after excluding the clinical conditions associated with an increased risk of AF. Patients were initially treated with antiarrhythmic drugs for 6 months (the observation period), and thereafter, EPA was added at a dose of 1.8 g/day for 6 months (the intervention period). During a one-year period, patients obtained an ECG recording using a portable device each morning and when arrhythmia-related symptom occurred. The end point was the difference of the AF burden (defined by the days of AF per month) between observation period and intervention period. Plasma EPA and C-reactive protein (CRP) levels were also determined. RESULTS: There was no significant difference in the AF burden before and after intervention (2.6 ± 2.2 days/months vs. 2.5 ± 2.2 days/months, P = 0.45). Although EPA level was significantly increased (42 ± 15 µg/mL to 120 ± 47 µg/mL, P < 0.001), CRP level was unchanged (1.04 ± 0.69 mg/L to 0.96 ± 0.56 mg/L, P = 0.24) following EPA treatment. CONCLUSIONS: Treatment of EPA in combination with antiarrhythmic drugs did not reduce the AF burden or the CRP levels in paroxysmal AF patients who had no evidence of substantial structural heart disease.

Prognostic significance of T-wave amplitude in lead aVR in heart failure patients with narrow QRS complexes.

BACKGROUND: Prolonged duration of the QRS complex is a prognostic marker in patients with heart failure (HF), whereas electrocadiographic markers in HF with narrow QRS complex remain unclear. We evaluated the prognostic value of the T-wave amplitude in lead aVR in HF patients with narrow QRS complexes. METHODS: We examined 331 patients who were admitted to our hospital for worsening HF (68 ± 15 years, mean ± standard deviation) from January 2000 to October 2004 who had sinus rhythm and QRS complex <120 ms. The patients were categorized into three groups according to the peak T-wave amplitude from baseline in lead aVR: negative (<-0.1 mV; n = 209, 63%), flat (-0.1-0.1 mV; n = 64, 19%), and positive (>0.1 mV; n = 58, 18%). RESULTS: During a mean follow-up of 33 months, 113 (34%) patients had all-cause death, the primary end point. After adjusting for clinical covariates, flat T wave (hazard ratio [HR] 1.86, 95% confidence interval [CI] 1.42-2.46), and positive T wave (HR 6.76, 95% CI 3.92-11.8) were independent predictors of mortality, when negative T wave was considered a reference. CONCLUSIONS: As the peak T-wave amplitude in lead aVR becomes less negative, there was a progressive increase in mortality. The T wave in lead aVR provides prognostic information for risk stratification in HF patients with narrow QRS complexes.

Major bleeding complications related to combined antithrombotic therapy in atrial fibrillation patients 12 months after coronary artery stenting.

BACKGROUND AND PURPOSE: Many patients with atrial fibrillation (AF) and coronary artery stent deployment are given both antiplatelet drug and warfarin. Little information is available as to the relationship between the antithrombotic therapies in the late phase after stenting and the clinical outcomes of these patients. We examined the clinical outcomes of AF patients 12 months after coronary artery stenting. METHODS: We retrospectively examined 146 patients and classified them into three groups according to the antithrombotic therapies [dual antiplatelet therapy (DAPT), single antiplatelet therapy (SAPT) plus warfarin, and DAPT plus warfarin] 12 months after stenting. We defined the primary endpoint as Thrombolysis in Myocardial Infarction major bleeding and the secondary endpoint as a composite of adverse events (CAE: all-cause death, nonfatal myocardial infarction, intracranial bleeding, and cerebral infarction). RESULTS: During a median follow-up of 37 months, major bleeding and CAE were observed in 14 (9.6%) and 46 (31.5%) patients, respectively. DAPT plus warfarin was an independent risk factor for major bleeding in a multivariate Cox hazard regression model after adjustment for age, gender, and the type of AF (hazard ratio: 4.20; 95% confidence interval: 1.13-17.27; p=0.033). No significant clinical variables were found for CAE. CONCLUSIONS: Prolonged use of DAPT with warfarin significantly increases the risk of major bleeding in AF patients after coronary artery stenting. Individualized antithrombotic treatment is required in these patients to prevent major bleeding.

Central sleep apnoea and inflammation are independently associated with arrhythmia in patients with heart failure.

AIMS: We examined whether the severity of central sleep apnoea (CSA) and the level of C-reactive protein are associated with the prevalence and complexity of arrhythmias, and whether these factors contribute to increased risk of nocturnal sudden death. METHODS AND RESULTS: We prospectively examined 178 patients (age 70 ± 1 years) who were admitted to our hospital due to worsening heart failure. We recorded a simultaneous overnight cardiorespiratory polygraph and Holter ECG. Obstructive sleep apnoea was excluded and patients were dichotomized based on the median value of the central apnoea index (CAI) of 7.5/h. The prevalence and complexity of arrhythmias were compared between daytime (06:00 h to 15:00 h) and night-time (21:00 h to 06:00 h). A multivariate logistic regression analysis revealed that the CAI was associated with prevalence of atrial fibrillation (AF) [odds ratio 1.03, 95% confidence interval (CI) 1.02-2.51)] and sinus pause during the night-time period (1.12, 95% CI 1.08-1.35). The CAI and C-reactive protein were independently associated with non-sustained ventricular tachycardia during both daytime (1.22, 95% CI 1.00-6.92; and 5.82, 2.58-56.1, respectively) and night-time periods (3.57, 95% CI 1.06-13.1; and 10.7, 3.30-44.4, respectively). During a mean follow-up period of 22 months, 30 (17%) patients had cardiovascular deaths and the CSA was an independent predictor (hazard ratio 1.29, 95% CI 1.16-2.32); only 5 (2.8%) of them died due to ventricular tachyarrhythmia, occurring during wakefulness. CONCLUSIONS: We demonstrated that the severity of CSA and C-reactive protein levels are independently associated with the prevalence and complexity of arrhythmias. CSA was associated with increased mortality risk, but it was not related directly to nocturnal death due to ventricular tachyarrhythmia.