Nils Edvardsson

Prospective study of left ventricular function after radiofrequency ablation of atrioventricular junction in patients with atrial fibrillation.

BACKGROUND--In patients with drug resistant incessant supraventricular tachycardia, radiofrequency induced ablation of the atrioventricular junction and pacemaker implantation have hitherto been considered a treatment of last resort. OBJECTIVE--To assess the short and long term effects of ablation of the atrioventricular junction on systolic and diastolic left ventricular function in patients with atrial fibrillation with and without impaired left ventricular function. PATIENTS--29 patients (19 men; mean age 65 (SD 7) years (range 50-76)) undergoing ablation of the atrioventricular junction for drug refractory atrial fibrillation were examined a mean of 2, 65, and 216 days after ablation of the bundle of His. MAIN OUTCOME MEASURES--Left ventricular ejection fraction and early filling deceleration times (Edec) were assessed by Doppler echocardiography after 1 to 2 hours of ventricular pacing at a rate of 80 beats/minute. RESULTS--In 14 patients with a left ventricular ejection fraction < 50% left ventricular ejection fraction increased significantly from 32% (11%) to 39% (11%) (65 days) and 45% (11%) (216 days) (P < 0.001); Edec increased from 142 (46) ms to 169 (57) ms (65 days) and 167 (56) ms (216 days) (P < 0.05). In 15 patients with an ejection fraction > or = 50% at the initial examination no significant change in systolic function was observed. CONCLUSIONS--In patients with left ventricular dysfunction long term improvement of systolic and diastolic left ventricular function was seen after ablation of the atrioventricular junction for rate control of atrial fibrillation. This procedure had no adverse effects on normal left ventricular function.

Role of the CHADS2 Score in Acute Coronary Syndromes: Risk of Subsequent Death or Stroke in Patients With and Without Atrial Fibrillation

BACKGROUND Atrial fibrillation (AF) is common in patients with acute coronary syndromes (ACS). We aimed to describe the value of the CHADS(2) (congestive heart failure, hypertension, age ≥ 75 years, diabetes, prior stroke or transient ischemic attack) score as a risk assessment tool for mortality and stroke in patients with ACS, irrespective of the presence or absence of AF. METHODS Consecutive patients with ACS admitted to the coronary care unit were prospectively included in a risk stratification study. We calculated the CHADS(2) scores from the data collected at admission, and all patients were followed until January 1, 2007, or death. RESULTS Of 2,335 patients with ACS in this study, 442 (age 71 ± 8 years, 142 women) had AF. Their mean CHADS(2) score was 1.6 ± 1.4 vs 1.0 ± 1.1 in patients without AF (P < .0001). The all-cause mortality at 10 years was strongly associated with the CHADS(2) score in patients with AF (hazard ratio [HR] and 95% CI per unit increase in the six-grade CHADS(2) score, 1.21 [1.07-1.36]; P = .002), but the same association was also present in patients without AF (HR 1.38 [1.28-1.48], P < .0001), after adjustment for potential confounders. The more complicated GRACE (Global Registry of Acute Coronary Events) risk score provided a better prediction for short- and long-term mortality than the simpler CHADS(2) score (P < .0001). Hospitalization for stroke was significantly associated with the CHADS(2) score in patients without AF (but not in those with AF) after adjustment (HR 1.46 [1.27-1.68], P < .0001). CONCLUSIONS In patients with ACS, AF is associated with poor prognosis. The CHADS(2) score developed for AF has even greater prognostic value in patients who do not have AF, and it may help to identify patients with high risk for subsequent stroke or death and a need for optimization of risk-reducing treatment.

Effect of New Versus Known Versus No Atrial Fibrillation on 30-Day and 10-Year Mortality in Patients With Acute Coronary Syndrome

Coronary artery disease promotes the development of atrial fibrillation (AF). The aim of this study was to determine short- and long-term mortality in patients with acute coronary syndromes (ACS) and AF, depending on the AF presentation. A total of 2,335 consecutive patients with ACS were included. AF was classified as known persistent or permanent AF, known paroxysmal AF, new AF at admission, and new AF during hospitalization for ACS. Four hundred forty-two patients had any AF: 54 with known persistent or permanent AF, 150 with known paroxysmal AF, 54 with new AF at admission, and 184 with new AF during hospitalization. Statistically significant differences among subgroups related to previous heart failure (p <0.0001), stroke (p = 0.04), myocardial infarction (p <0.0001), angina pectoris (p <0.0001), hypercholesterolemia (p = 0.007), coronary artery bypass grafting (p <0.0001), and percutaneous coronary intervention (p = 0.03) were observed. Thirty-day mortality differed among the subgroups (p = 0.02) and was lowest in patients with known paroxysmal AF (7.3%). Ten-year mortality ranged from 53% to 78% among the subgroups. There were 5 predictors of long-term mortality across the subgroups: age (hazard ratio [HR] 1.06, 95% confidence interval [CI] 1.04 to 1.09, p <0.0001), previous myocardial infarction (HR 1.4, 95% CI 1.0 to 1.8, p = 0.04), heart failure (HR 1.8, 95% CI 1.3 to 2.4, p = 0.0002), diabetes (HR 1.7, 95% CI 1.2 to 2.2, p = 0.0005), and smoking (HR 1.7, 95% CI 1.2 to 2.3, p = 0.001). In conclusion, patient characteristics and 30-day mortality differed significantly among the subgroups, but long-term mortality did not. Any AF associated with ACS almost doubled the long-term mortality risk. AF in patients with ACS should therefore be regarded as an important risk factor irrespective of its presentation.

Analysis of initial rhythm, witnessed status and delay to treatment among survivors of out-of-hospital cardiac arrest in Sweden

Background The characteristics of patients who survive out-of-hospital cardiac arrest (OHCA) are incompletely known. The characteristics of survivors of OHCA during a period of 16 years in Sweden are described. Methods All the patients included in the Swedish Cardiac Arrest Registry between 1992 and 2007 in whom cardiopulmonary resuscitation was attempted and who were alive after 1 month were included in the survey. Results In all, 2432 survivors were registered. Information on initial rhythm at their first ECG recording was missing in 11%. Of the remaining 2165 survivors, 80% had a shockable rhythm and 20% had a non-shockable rhythm. Only a minority with a shockable rhythm among the bystander-witnessed cases were defibrillated within 5 min after cardiac arrest. This proportion did not change during the entry period. Among survivors found in a non-shockable rhythm, the majority were bystander-witnessed cases and a few had a delay from cardiac arrest to ambulance arrival of <5 min. Of all survivors, more women (27%) than men (18%) were found in a non-shockable rhythm (p<0.0001). During the 16 years in which the register was used for this study, the proportion of survivors found in a shockable rhythm did not change significantly. The cerebral performance categories score indicated better cerebral function among patients found in a shockable rhythm than in those found in a non-shockable rhythm. Conclusion Among survivors of OHCA, a substantial proportion was found in a non-shockable rhythm and this occurred more frequently in women than in men. The proportion of survivors found in a shockable rhythm has not changed markedly over time. Survivors found in a shockable rhythm had a better cerebral performance than survivors found in a non-shockable rhythm. The proportion of survivors who were bystander-witnessed and found in a shockable rhythm and defibrillated early is still remarkably low.

Vectorcardiography shows cardiac memory and repolarization heterogeneity after ablation of accessory pathways not apparent on ECG

BACKGROUND Pacing induced cardiac memory is an established phenomenon, but following successful WPW ablation, cardiac memory was present on ECG in variable proportions of patients depending on accessory pathway (AP) location. We hypothesized that vectorcardiography (VCG), which is more sensitive than ECG, would show cardiac memory after WPW ablation independent of AP location. METHODS Thirty-six patients were followed after successful AP ablation, 11 with overt posteroseptal (PS), 13 with overt left-sided (LS) and 12 with concealed APs (controls). VCGs were recorded the day before and after the procedure, ≥ once/week for 6-8 weeks and after ≥ 3 months. T vector and T-vector loop parameters were analyzed and compared. RESULTS After ablation of overt APs, there was a correlation between the directions of the preexcited maximum QRS-vector and the post-ablation maximum T-vector, confirming the presence of cardiac memory. Ablation of overt APs was followed by cardiac memory apparent in different directions. Thus, ablation of PS APs was followed by most pronounced changes in T-vector elevation and LS APs with significant changes only in T-vector azimuth. Cardiac memory disappeared within a month in > 80% of cases. Furthermore, T-vector loop morphology changes suggested a period of repolarization heterogeneity immediately after ablation of overt APs. CONCLUSIONS According to VCG analysis cardiac memory was present after ablation of overt APs independent of location as consistently as after ventricular pacing, and disappeared within a similar time frame during normal ventricular activation. In addition, signs of transient repolarization heterogeneity were observed after ablation of overt APs.

The signal-averaged electrocardiogram before and after electrical cardioversion of persistent atrial fibrillation—implications of the sudden change in rhythm

BACKGROUND Atrial fibrillation (AF), electrical cardioversion (direct current, or DC) shock energy, and a sudden change to sinus rhythm (SR) might all influence the interpretation of the signal-averaged electrocardiogram (SAECG) as risk markers of ventricular tachyarrhythmia. METHODS The SAECG was recorded in 82 patients with persistent AF before and 2 hours after DC and analyzed for ventricular late potentials (LPs) and spectral turbulence. RESULTS Sixty-nine patients (84%) obtained SR. Their mean (SD) heart rate decreased by 22 (20) beats/min, and the QTcF interval was significantly prolonged, 17 (38) milliseconds, as was the filtered QRS duration, 1.1 (4.7) milliseconds (40 Hz). The proportion of LP positivity (20%) did not change with the change in rhythm. Eight of 60 spectral turbulence-negative patients before DC became positive after DC (P = .01). The change in SAECG variables did not correlate significantly with the amount of energy delivered at DC. CONCLUSION The LP analysis provided similar results in AF and SR, whereas the spectral turbulence analysis was more abnormal in SR. The electrical shock itself did not seem to explain this phenomenon.