New Onset Atrial Fibrillation in STEMI Patients: Main Prognostic Factors and Clinical Outcome.

The indications for the treatment of patients with known atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) are clear, while less is available about the management of new-onset AF (NOAF) during ST-segment elevation myocardial infarction (STEMI). The aim of this study is to evaluate mortality and clinical outcome of this high-risk subgroup of patients. We analyzed 1455 consecutive patients undergoing PCI for STEMI. NOAF was detected in 102 subjects, 62.7% males, with a mean age of 74.8 ± 10.6 years. The mean ejection fraction (EF) was 43.5 ± 12.1% and the mean atrial volume was increased (58 ± 20.9 mL). NOAF occurred mainly in the peri-acute phase and had a very variable duration (8.1 ± 12.5 min). During hospitalization, all the patients were treated with enoxaparin, but only 21.6% of them were discharged with long term oral anticoagulation. The majority of patients had a CHA2DS2-VASc score >2 and a HAS-BLED score of 2 or 3. The in-hospital mortality was 14.2%, while the 1-year mortality was 17.2% and long-term mortality 32.1% (median follow-up 1820 days). We identified age as an independent predictor of mortality both at short- and long-term follow-ups, while EF was the only independent predictor for in-hospital mortality and arrhythmia duration for 1-year mortality. At the 1-year follow-up, we recorded three ischemic strokes and no bleeding complications.

Arrhythmic event prediction in patients with heart failure and reduced ejection fraction.

AIMS: Implantable cardioverter defibrillator (ICD) is an effective treatment to reduce mortality in patients with symptomatic heart failure and left ventricular ejection fraction (LVEF) 35% or less. LVEF presents a low sensitivity for predicting arrhythmic events. Aim of this study was to identify predictors of sustained ventricular arrhythmias (SVAs), overall and according to the cause of heart failure. METHODS: Single-center, retrospective, cohort study of 193 patients (51 nonischemic and 142 ischemic) with chronic heart failure and LVEF less than 35% who had received ICD for primary prevention of sudden cardiac death. We collected clinical data, echocardiographic parameters and SVAs detected by the ICD. RESULTS: During a median follow-up of 1440 days, 32 (16.2%) patients had SVAs. SVAs incidence was similar in patients with nonischemic (15.6%) and ischemic cause of heart failure (16.9%). Hypertension, diabetes, chronic renal failure, atrial fibrillation, chronic obstructive pulmonary disease, New York Heart Association class at least III were predictors at univariate analysis of SVAs. A clinical score, assigning one point to each of these variables, was associated with a significantly increased risk of SVAs [odds ratio for each point increase = 1.92, 95% confidence interval 1.40-2.65, P < 0.0001, area under the curve (AUC) 0.73], with 72% sensitivity and 60% specificity for a cutoff at least three and remained significant in nonischemic (AUC 0.84) and ischemic (AUC 0.68) patients. CONCLUSION: Our study shows the benefit of ICD implantation in primary prevention and its independency of cause. A simple clinical score, based on comorbidities, identifies patients with more benefits from ICD implantation.

Heart rate turbulence and variability in patients with ventricular arrhythmias.

BACKGROUND: To evaluate the changes in autonomic neural control mechanisms before malignant ventricular arrhythmias, we measured heart rate variability (HRV) and heart rate turbulence (HRT) in patients with ventricular tachycardia or fibrillation (Group I; n=6), non sustained ventricular tachycardia (Group II; n=32), frequent premature ventricular beats (Group III; n=26) and with ICD implantation (Group IV; n=11). METHODS: Time domain parameters of HRV and turbulence onset (TO) and slope (TS) were calculated on 24 hour Holter recordings. Normal values were: SDNN > 70 msec for HRV, TO <0% and TS >2.5 msec/RR-I for HRT. RESULTS: Whereas SDNN was within normal range and similar in all study groups, HRT parameters were significantly different in patients who experienced VT/VF during Holter recording. Abnormal TO and/or TS were present in 100% of Group I patients and only in about 50% of Group II and IV. On the contrary, normal HRT parameters were present in 40-70% of Group II, III and IV patients and none of Group I. CONCLUSIONS: These data suggest that HRT analysis is more suitable than HRV to detect those transient alterations in autonomic control mechanisms that are likely to play a major trigger role in the genesis of malignant cardiac arrhythmias.

Autonomic nervous system and paroxysmal atrial fibrillation: a study based on the analysis of RR interval changes before, during and after paroxysmal atrial fibrillation.

AIMS: To evaluate the presence of an abnormal autonomic modulation before, during and immediately after paroxysmal atrial fibrillation (PAF). METHODS AND RESULTS: We analysed Holter recordings of 65 patients with 110 PAF episodes lasting more then 30 s. Mean RR interval, co-efficient of variation and short-term heart rate variability were measured before, during and after PAF episodes. We observed a significant correlation between the coupling interval and both the cycle length measured from 30 min up to few cycles before PAF onset, and ventricular response. When comparing the heart rate variability (HRV) before and after PAF we observed a significant reduction of the low frequency/high frequency components (LF/HF) ratio (from 6.2+/-7.4 to 3.2+/-4.1). A short-long-short cycle sequence was detectable in 37 PAF onsets associated with a greater incidence of atrial ectopic beats and a greater LF component (62+/-25 vs. 53+/-27 normalised units) in comparison to the remaining episodes. When onsets were divided for a LF/HF ratio cut-off value of > or = 2 to separate episodes with a predominant sympathetic, as opposed to those with a prevailing vagal (LF/HF<2) modulation, we observed opposite changes (from 9.1+/-7.8 to 4+/-3.7 and from 0.8+/-0.5 to 2+/-3.6, respectively) consistent with a recovery of a more physiological sympatho-vagal balance immediately after recovery of sinus rhythm. No changes in co-efficient of variation of ventricular response were detectable before PAF termination. CONCLUSIONS: A predominant sympathetic modulation characterises the majority of PAF onsets whereas a vagal predominance was detectable in about 30% of episodes. These patterns are no longer detectable after recovery of sinus rhythm.

Cardiac autonomic modulation in normal, high-risk, and in vitro fertilization pregnancies during the first trimester.

OBJECTIVES: The purpose of this study was to test the adaptation of autonomic modulation of heart rate in high-risk or in vitro fertilization (IVF) pregnancies during the first trimester. STUDY DESIGN: Thirty-three pregnant women were studied between 6.0 and 12.5 weeks of gestation and were divided into three groups: normal (n=17), high-risk (n=7), and IVF pregnancies (n=9), together with 9 nonpregnant women of comparable age. All subjects underwent a short-term continuous electrocardiographic recording to measure short-term heart rate variability (HRV). RESULTS: Average values of mean R-R interval, total power, and low-frequency (LF) component were similar in nonpregnant and normally pregnant women. The high-frequency (HF) component was only slightly increased in normal pregnant women but no difference was observed in LF/HF ratio. High-risk and IVF pregnancies were characterized by a significant increase in LF component in comparison to normal pregnancies. In pregnancies that had obstetric complications, signs of abnormal autonomic modulation of the sinus node were particularly evident. CONCLUSION: Short-term analysis of HRV in high-risk and IVF pregnancies was significantly different from that observed in normal pregnancies. These differences were more significant in those pregnancies later complicated by an adverse outcome, suggesting an early origin of these pathologic conditions.