Israel Medical Association Journal

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 ≥ 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.
 

Telemedicine is the application of advanced telecommunication technology for diagnostic, monitoring and therapeutic purposes. It enables data transmission from the patient's whereabouts or his/her primary care provider to a specialized medical call center. Telecardiology is a highly developed medical discipline involving almost every aspect of cardiology, including acute coronary syndromes, arrhythmias, congestive heart failure, sudden cardiac arrest and others. Israel is one of the leading countries in the use of telecardiology, achieving both extended survival, improvement of the patient's quality of life, and significant reduction in health costs. 

Background: Familial dysautonomia is a hereditary disease characterized by dysfunction of the sensory and autonomic nervous systems. Studies in patients with familial dysautonomia have shown that abnormal cardiac autonomic denervation might influence repolarization. Autonomic tone also affects atrial conduction parameters and P-wave dispersion, which are predictive of atrial fibrillation.

Objectives: To examine the possible association of familial dysautonomia with abnormal atrial conduction and P-wave dispersion.

Methods: The study population included 12 patients with familial dysautonomia and age and sex-matched control subjects. All participants underwent a 12-lead electrocardiogram under strict conditions. P-wave lengths and P-wave dispersion were computed from a randomly selected beat and an averaged beat using designated computer software.

Results: There were no statistically significant differences between the groups in minimal, maximal, and average P-wave duration or P-wave dispersion for a randomly selected beat. P-wave dispersion for an averaged beat was also similar. During 6 months follow-up, no supraventricular arrhythmias were documented in either group.

Conclusions: We found that patients with familial dysautonomia had P-wave dispersion parameters not significantly different from those of controls. Further research is required to clarify the effects of dysautonomia on atrial conduction in familial dysautonomia.

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[1] who are at risk of ventricular arrhythmias and sudden death.

Methods: This prospective observational study included 21 patients with HCM: 11 with hypertrophic obstructive cardiomyopathy, 9 with non-obstructive hypertrophic cardiomyopathy, and 1 with apical hypertrophic cardiomyopathy. TWA[2] 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 enrolment 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.

Isolated ventricular non-compaction is a frequently underdiagnosed rare congenital cardiomyopathy. The importance of diagnosing this cardiomyopathy lies especially in asymptomatic patients, screening relatives of index cases in order to focus on their follow-up and searching for criteria warranting prophylactic anticoagulation, implantable cardioverter defibrillator and anti-remodeling drugs such as angiotensin-converting inhibitors. We present the clinical and imaging characteristics of this entity and discuss some of the therapeutic dilemmas involving these patients.
 

Background: Long QT syndrome is an inherited cardiac disease, associated with malignant arrhythmias and sudden cardiac death.

Objectives: To map and identify the gene responsible for LQTS[1] in an Israeli family.

Methods: A large family was screened for LQTS after one of them was successfully resuscitated from ventricular fibrillation. The DNA was examined for suspicious loci by whole genome screening and the coding region of the LQT2 gene was sequenced.

Results: Nine family members, 6 males and 3 females, age (median and interquartile range) 26 years (13, 46), who were characterized by a unique T wave pattern were diagnosed as carrying the mutant gene. The LQTS-causing gene was mapped to chromosome 7 with the A614V mutation. All of the affected members in the family were correctly identified by electrocardiogram. Corrected QT duration was inversely associated with age in the affected family members and decreased with age.
Conclusions: Careful inspection of the ECG can correctly identify LQTS in some families. Genetic analysis is needed to confirm the diagnosis and enable the correct therapy in this disease

Background: Catheter ablation is assuming a larger role in the management of patients with cardiac arrhythmias. Conventional fluoroscopic catheter mapping has limited spatial resolution and involves prolonged fluoroscopy. The non-fluoroscopic electroanatomic mapping technique (CARTO) has been developed to overcome these drawbacks.

Objectives: To report the early and late outcome in patients with different arrhythmias treated with radiofrequency ablation combined with the CARTO mapping and navigation system.

Methods: The study cohort comprised 125 consecutive patients with different cardiac arrhythmia referred to our center from January 1999 to July 2005 for mapping and/or ablation procedures using the CARTO system. Forty patients (32%) had previous failed conventional ablation or mapping procedures and were referred by other centers. The arrhythmia included atrial fibrillation (n=13), atrial flutter (n=38), atrial tachycardia (n=25), ventricular tachycardia (n=24), arrhythmogenic right ventricular dysplasia (n=9), and supraventricular tachycardia (n=16).

Results: During the study period, a total of 125 patients (mean age 49 ± 19 years, 59% males) underwent electrophysiological study and electroanatomic mapping of the heart chambers. Supraventricular arrhythmias were identified in 92 patients (73 %) and ventricular arrhythmias in 33 (27%). Acute and late success rates, defined as termination of the arrhythmia without anti-arrhythmic drugs, were 87% and 76% respectively. One patient (0.8%) developed a clinically significant complication.

Conclusions: The CARTO system advances our understanding of arrhythmias, and increases the safety, efficacy and efficiency of radiofrequency ablation.

Background: The significance of arrhythmia occurring after successful recanalization of an occluded artery during treatment following primary percutaneous coronary intervention for ST-segment elevation myocardial infarction is controversial.

Objectives: To study the association of reperfusion arrhythmia with short and long-term survival.

Methods: We used a prospective registry of consecutive STEMI[1] patients undergoing PPCI[2]. Patients with an impaired epicardial flow (TIMI flow grade < 3) at the end of the procedure were excluded.

Results: Of the 688 patients in the study group, 22% were women. Mean (± SD) age of the cohort was 61 (± 14) years and frequent co-morbidities included diabetes mellitus (25%), dyslipidemia (55%), hypertension (43%) and smoking (41%). RA[3] was recorded in 200 patients (29%). Patients with RA had lower rates of diabetes (16% vs. 30%, P < 0.01) and hypertension (48% vs. 62%, P < 0.01), and a shorter median pain-to-balloon time (201 vs. 234 minutes, P < 0.01) than patients without RA. Thirty day mortality was 3.7% and 8.3% for patients with and without RA, respectively (P = 0.04). After controlling for age, gender and pain-to-balloon time the hazard ratio for mortality for patients with RA during a median follow-up period of 466 days was 0.46 (95% confidence interval 0.23–0.92).

Conclusions: The occurrence of RA immediately following PPCI for acute STEMI is associated with better clinical characteristics and identifies a subgroup with a particularly favorable prognosis.

Objective: To identify risk factors and associated conditions that may cause TdP[1] in patients on chronic amiodarone treatment.

Methods: We reviewed the data of six consecutive patients on chronic amiodarone treatment who were admitted to the intensive cardiac care unit due to syncope and TdP.

Results: The patients’ median age was 73.5 years, and five were women. Concomitantly, loratadine was given to two patients and trazodone to one patient. Associated and attributing conditions to the development of TdP were hypokalemia in three patients, drug-induced bradycardia in one and reduced left ventricular function in four.

Conclusions: TdP associated with chronic amiodarone treatment may occur when amiodarone is co-administered with drugs that may potentially prolong QT interval. Additional risk factors for amiodarone-associated TdP include female gender, hypokalemia, reduced left ventricular function and bradycardia.

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[1] TdP = torsade de pointes

Background: Anemia is a known risk factor for ischemic heart disease. Based on knowledge of the physiologic role of oxygen delivery to the myocardium, anemia may be a cause of more severe cardiovascular diseases or a marker of other processes occurring in the body that induce more severe disease.

Objectives: To investigate the relationship between anemia and the clinical picture of IHD[1], including manifestations, severity and complications.

Methods: The population studied comprised 417 similarly aged patients with IHD and anemia. The patients were categorized into subgroups of IHD according to disease severity: namely, angina pectoris, acute ischemia, acute myocardial infarction, congestive heart failure or cardiac arrhythmias. Two populations served as control groups: patients with anemia but no IHD (C-I) and patients with IHD without anemia (C-II). A standard anemia workup was conducted in all patients with IHD and anemia and a correlation was made between the hematologic parameters and the manifestations and complications of IHD.

Results: The common presenting symptom was chest pain in the study group and in C-II (94% and 86% respectively) and weakness (90%) in C-I. Patients with IHD and anemia tended to suffer from a more advanced degree of IHD (80%) compared to patients with IHD alone who had milder disease (46%). Hematologic values including hemoglobin, mean cell volume, serum iron and total iron binding capacity correlated inversely with disease severity among anemic patients with IHD. There were significant differences between the study group and C-II regarding CHF[2] (31% and 18% respectively) and arrhythmias (41% and 16% respectively). The mortality rate was higher in patients with IHD and anemia than in patients with IHD alone (13% and 4% respectively).

Conclusions: Anemia is a significant risk factor in IHD. It correlates with advanced IHD, CHF, rhythm disturbance and higher mortality rate. An aggressive therapeutic and preventive approach might improve the outcome of this disease.