The effects of gender on electrical therapies for the heart: physiology, epidemiology, and access to therapies.

The difference between men and women is clear even just by looking at an electrocardiogram: females present higher resting heart rate, a shorter QRS complex length and greater corrected QT interval. The development of these differences from pubertal age onward suggests that sexual hormones play a key role, although their effect is far from being completely understood. Different incidences between sexes have been reported for many arrhythmias, both ventricular and supraventricular, and also for sudden cardiac death. Moreover, arrhythmias are an important issue during pregnancy, both for diagnosis and treatment. Interestingly, cardiovascular structural and electrophysiological remodelling promoted by exercise training enhances this 'gender effect'. Despite all these relevant issues, we lack gender specific recommendations in the current guidelines for electrical therapies for heart rhythm disorders and heart failure. Even more, we continue to see that fewer women are included in clinical trials and are less referred than men for these treatments.

Electrocardiographic and Electrophysiological Characteristics of Atrial Tachycardia With Early Activation Close to the His-Bundle.

INTRODUCTION: Radiofrequency (RF) ablation of atrial tachycardia (AT) with earliest activation at the His-bundle may be associated with the risk of AV block, and detection of this AT origin using the electrocardiogram (ECG) would be helpful in planning ablation. Aim of this study was to characterize the P-wave morphology and intracardiac electrograms at the successful ablation site for this group of ATs. METHODS: All consecutive patients undergoing ablation for AT with earliest activation at the His-bundle were included. Twelve-lead ECG and intracardiac electrograms were analyzed. RESULTS: A total of 33 patients underwent successful ablation. The P-wave and the PR interval during AT (cycle length 460 ± 88, range 360-670 milliseconds) were significantly shorter compared to sinus rhythm 87 ± 18 vs. 117 ± 23 and 131 ± 37 vs. 170 ± 47 milliseconds, respectively, P < 0.01. In 28 patients (85%), the P-wave was biphasic (-/+) or triphasic (+/-/+) in the precordial leads, especially V4 -V6 , and in 25 patients (76%) it was biphasic (-/+) or triphasic (+/-/+) in the inferior leads. RF was delivered at the following locations: noncoronary aortic cusp (NCC) in 24 patients, antero-septal left atrium in 4, supero-septal right atrium in 3, left coronary cusp in 1, and between the right coronary cusp and the NCC in 1. Atrial bipolar electrograms at the successful ablation site preceded the P-wave by 38 ± 11 (range 10-60) milliseconds, and AT termination was obtained after a mean RF energy time of 10 ± 8 (range 2-31) seconds. CONCLUSION: A characteristic narrow and biphasic (-/+) or triphasic (+/-/+) P-wave in the inferior and precordial leads reliably identifies the group of AT arising from the para-Hisian region.

Usefulness of invasive electrophysiologic testing to stratify the risk of arrhythmic events in asymptomatic patients with Wolff-Parkinson-White pattern: results from a large prospective long-term follow-up study.

OBJECTIVES: The aim of this study was to assess in a large cohort of asymptomatic subjects with Wolff-Parkinson-White (WPW) pattern the usefulness of invasive electrophysiologic testing (EPT) in predicting the occurrence of arrhythmic events over a five-year follow-up. BACKGROUND: Sudden death may be the first clinical manifestation of the WPW syndrome in previously asymptomatic patients. Serial EPTs have been proposed to identify patients at risk. METHODS: A total of 212 consecutive asymptomatic WPW patients were enrolled after a baseline EPT; patients were followed for five years, and 162 patients (115 noninducible and 47 inducible) patients underwent a second EPT. RESULTS: After a mean follow-up of 37.7 months, 33 patients became symptomatic. Of the 115 noninducible patients, 18.2% lost anterograde accessory pathway (AP) conduction, 30% retrograde AP conduction, and only 4 (3.4%) developed symptomatic supraventricular tachycardia (SVT). Of the 47 inducible patients, 25 with sustained atrioventricular reciprocating tachycardia (AVRT) and atrial fibrillation (AF), and 4 with nonsustained AVRT and AF became symptomatic for SVT (n = 21) and AF (n = 8). They were younger, had shorter AP anterograde refractory periods, and multiple APs compared to patients who remained asymptomatic (for all comparisons, p < 0.0001). Of the eight patients with symptomatic episodes of AF and inducible sustained AF, two had a resuscitated cardiac arrest and one died suddenly; all three patients were inducible for AVRT and AF and had multiple APs. CONCLUSIONS: In asymptomatic WPW subjects, EPT may be a valuable tool to stratify the risk of symptomatic and fatal arrhythmic events.