Atrial Tachycardia in Patients with Cryptogenic Stroke: Is there a Need For Anticoagulation?

BACKGROUND: Brief episodes of atrial tachycardia are a common finding in the Holter monitor recordings of elderly patients. Episodes of atrial tachycardia may convert to atrial fibrillation. Current guidelines do not recommend anti-coagulant therapy in patients with atrial tachycardia and risk factors for embolism. OBJECTIVES: To assess the incidence of atrial tachycardia in a 24 hour Holter monitor recording of patients admitted to hospital with ischemic stroke. METHODS: The patient cohort included two groups: 134 patients admitted with a diagnosis of ischemic stroke (the study group), and 68 consecutive patients with a diagnosis of syncope (the control group). Both groups used a Holter monitor. RESULTS: There was no difference in the incidence of atrial tachycardia runs between the groups. Patients who suffered a stroke were more likely to be hypertensive (P < 0.05) and more likely to have a CHA2DS2-VASc score of ≥ 3 (P = 0.05). CONCLUSIONS: Atrial tachycardia as recorded on a Holter monitor was not more prevalent in patients presenting with ischemic stroke. The occurrence of atrial tachycardia is not an indication for systemic anticoagulation.

Do ventricular arrhythmias in athletes subside over time?

BACKGROUND: Sudden death in athletes can occur during sport activities and is presumably related to ventricular arrhythmias. OBJECTIVES: To investigate the long-term follow-up ofathletes with ventricular arrhythmias during an exercise test. METHODS: From a database of 56,462 athletes we identified 192 athletes (35 years old who had ventricular arrhythmias during an exercise test. Ninety athletes had > or =3 ventricular premature beats (VPB) (group A) and 102 athletes had ventricular couplets or non-sustained ventricular tachycardia during an exercise test (group B). A control group of 92 athletesfrom without ventricular arrhythmias was randomly seleclted from the database (group C). Of the 192 athletes 39 returnied for a repeat exercise test after a mean follow-up period of 70 +/- 25 months and they constitute the study population. RESULTS: Twelve athletes from group A, 21 fromgroup B and 6 from group C returned for a repeat exercise test. The athletes reached a significantly lower peak heart rate during their follow-up exercise test (P = 0.001). More athletes were engaged in competitive sports during their initialexercise test than in the follow-up test (P = 0.021). Most of theathletes who had VPB and/orventricular couplets and/or NSVT during their initial exercise test had far fewer ventricular arrhythmias in the follow-up exercise test (P = 0.001). CONCLUSIONS: Athletes engaged in competitive sports are more likely to develop ventricular arrhythmias during exercise. These arrhythmias subside over time when athletes are engaged in non-competitive sports.

Does chronic atrial fibrillation induce cardiac remodeling?

AIM: The aim of this study was to compare cardiac structure and function in patients with chronic atrial fibrillation (CAF), as opposed to patients with paroxysmal atrial fibrillation (PAF), and normal control subjects. METHODS AND RESULTS: This study included 83 patients, divided into 3 groups: group A, 32 patients with CAF for ≥6 months; group B, 29 patients in sinus rhythm with a documented history of PAF; and group C, 22 patients without history of atrial fibrillation. Patients with CAF were older (71 years vs. 64 in group B, and 64 in group C). Apart from age, groups were clinically similar. After careful clinical evaluation, comprehensive echocardiography studies were performed including cardiac chambers' size, systolic and diastolic left ventricular function. Left atrium (LA) volume index was significantly larger in CAF than PAF and control patients: 39 ± 13 versus 34 ± 9 versus 25 ± 8 (P < 0.003). Left ventricular ejection fraction was lower in CAF: 53.8 ± 7 versus 61.6 ± 6.7 versus 58.4 ± 5.2% (P < 0.001). Isovolumic relaxation time was shorter in CAF, 65 ± 16 versus 82 ± 21 versus 81 ± 13 msec (P < 0.001). E/Vp was significantly greater in CAF 2.6 ± 0.8 versus 1.7 ± 0.4 versus 1.7 ± 0.5 (P < 0.001). Additional diastolic parameters were also significantly different. CONCLUSION: These findings demonstrate that in patients with CAF structural and functional cardiac changes occur. Patients with CAF as opposed to both normal subjects and patients with PAF have larger left atria and reduced systolic and diastolic left ventricular function.

Reproducibility of microvolt T-wave alternans in patients with coronary artery disease.

BACKGROUND: Microvolt T-wave alternans (MTWA) measures subtle beat-to-beat fluctuations in the T-wave amplitude. It was found to be associated with cardiac electrical instability in patients with ischemic and dilated cardiomyopathy. OBJECTIVES: To investigate the reproducibility of the MTWA test results in patients with ischemic heart disease. METHODS: The study group comprised patients with ischemic heart disease who participated in a rehabilitation program at the Assaf Harofeh Medical Center. MTWA was measured during a bicycle exercise test at the first encounter and repeated after one week. RESULTS: Of the 40 study patients with coronary artery disease, 4 had an indeterminate result and were excluded from the data analysis; 5 had a positive MTWA in the first and second study (14%), 27 had a negative MTWA in the first and second study (75%), and 4 had a negative MTWA in the first study and a positive MTWA in the second study (11%). Overall, there was a correlation between the results of the first and the second study in 89% of the patients (kappa = 0.652, P = 0.0001). CONCLUSIONS: MTWA measurements are reproducible in the short term in patients with coronary artery disease.

The clinical significance of ventricular arrhythmias during an exercise test in non-competitive and competitive athletes.

BACKGROUND: Sudden death in athletes can occur during sport activities and is presumably related to ventricular arrhythmias. There are no guidelines concerning athletes who develop ventricular arrhythmias during an exercise test. It is unclear whether they should be allowed to continue with their competitive activity or not. OBJECTIVES: To investigate the long-term follow-up of athletes with ventricular arrhythmias during an exercise test. METHODS: From a database of 56,462 athletes we identified 192 athletes, less than 35 years old, who had ventricular arrhythmias during an exercise test. Ninety athletes had > or = 3 ventricular premature beats (group A) and 102 athletes had ventricular couplets or non-sustained ventricular tachycardia during an exercise test (group B). A control group of 92 athletes without ventricular arrhythmias was randomly selected from the database (group C). RESULTS: All athletes, except one who died from a dilated cardiomyopathy, were alive during a follow-up period of 70 +/- 25 months. An abnormal echocardiogram was obtained in seven athletes from group A (10%), four from group B (5%), and one from group C (3%) (not significant). An abnormal echocardiogram was more likely to be present in competitive athletes (P = 0.001) and in female athletes (P = 0.01). CONCLUSIONS: Our results showed that ventricular arrhythmias during exercise are more commonly associated with cardiovascular abnormalities in young competitive athletes and in female athletes. When present, they necessitate a thorough investigation and follow-up.

The usefulness of microvolt T-wave alternans in the risk stratification of patients with hypertrophic cardiomyopathy.

BACKGROUND: Patients with hypertrophic cardiomyopathy are prone to ventricular arrhythmias and sudden death. Identifying patients at risk of sudden death is difficult. OBJECTIVES: To determine whether microvolt T-wave alternans detected during exercise or rapid atrial pacing can identify patients with HCM who are at risk of ventricular arrhythmias and sudden death. METHODS: This prospective observational study included 21 patients with HCM: the disease was abstructive in 11, nonobstructive in 9 and apical in 1. TWA was measured while the patients were on anti-arrhythmic medication. RESULTS: TWA was positive in 9 patients (43%) and negative in 12 (57%). Three patients were resuscitated after sudden death before their enrollment in the study and two patients developed ventricular tachycardia and fibrillation respectively during the study period. After combining the endpoint of sudden death from a ventricular arrhythmia and the presence of ventricular arrhythmias on a Holter monitor, there was no significant correlation between the presence of a positive TWA and the presence of ventricular arrhythmias on the Holter monitor or a history of sudden death. CONCLUSION: TWA cannot be used as a non-invasive test for detecting patients with HCM and electrical instability. TWA is not useful for predicting sudden death in patients with HCM.

Characteristics of amplitude-integrated electroencephalogram in premature infants.

The aim of this study is to evaluate and characterize amplitude-integrated electroencephalogram tracings in preterm infants at varying gestational ages. Eighty-six amplitude-integrated electroencephalogram traces (1.5-9 hours in duration each) were recorded in 32 preterm infants (24-41 weeks of postconception age) during the study period (July 1, 2001, through August 31, 2002). A stepwise rather than gradual progression was detected, with the first step at 24 to 30 weeks, the second at 31 to 34 weeks, and the third at 35 to 41 weeks. The cyclic pattern amplitude-integrated electroencephalogram typical of healthy full-term infants was not detected in the first step, which was marked by a very low baseline and a wide continuous band width of up to 98.5 microV, with a mean of 74.2 microV (SD = 23.3). The first appearance of cycles was in the second group (31-34 weeks), with a mean intercycle band width of 38.3 microV (SD = 26.3) and a cycle band width of 51 microV (SD = 18). The third step (35-41 weeks) differed from the second, having a mean intercycle band width of 16 microV (SD = 3.5; P < or = .001), with quite a similar cycle band width of 43.8 microV (SD = 19.2). The number of cycles per hour increased from a mean of 0.44 (SD = 0.33) per hour to 0.58 (SD = 0.25) per hour in the second and third steps, respectively (P < or = .001). Amplitude-integrated electroencephalogram is a feasible and reliable brain-monitoring tool in healthy preterm infants. Its features are age dependency and stepwise progression. Its real-time clinical significance and prognostic value in healthy and sick preterm infants are yet to be determined.