Cannon A wave validation as a diagnostic tool in paroxysmal supraventricular tachycardias

OBJECTIVE

The presence of cannon A waves, the so called "frog sign", has traditionally been considered diagnostic of atrioventricular nodal re-entrant tachycardia (AVNRT). Nevertheless, it has never been systematically evaluated. The aim of this study is to assess the independent diagnostic utility of cannon A waves in the differential diagnosis of supraventricular tachycardias (SVTs).

METHODS

We prospectively included 100 patients who underwent an electrophysiology (EP) study for SVT. The right jugular venous pulse was recorded during the study. In 61 patients, invasive central venous pressure (CVP) was registered as well. CVP increase is thought to be related with the timing between atria and ventricle depolarization; two groups were prespecified, the short VA interval tachycardias (including typical AVNRT and atrioventricular reciprocating tachycardia (AVRT) mediated by a septal accessory pathway) and the long VA interval tachycardias (including atypical AVNRT and AVRT mediated by a left free wall accessory pathway).

RESULTS

The relationship between cannon A waves and AVNRT did not reach the statistical significance (OR: 3.01; p = .058); On the other hand, it was clearly associated with the final diagnosis of a short VA interval tachycardia (OR: 10.21; p < .001). CVP increase showed an inversely proportional relationship with the VA interval during tachycardia (b = -.020; p < .001). CVP increase was larger in cases of AVNRT (4.0 mmHg vs. 1.2 mmHg; p < .001) and short VA interval tachycardias (3.9 mmHg vs. 1.2 mmHg; p < .001).

CONCLUSION

The presence of cannon A waves is associated with the final diagnosis of short VA interval tachycardias.

Circadian Rhythm of Deaths in a Cardiology Department: A Five-Year Analysis

BACKGROUND

Previous studies have described a circadian pattern of death from cardiovascular causes with a morning peak. Our aim is to describe the daytime oscillations in mortality in hospitalized patients with cardiovascular diseases.

METHODS

Our retrospective registry including all patients who died in the Cardiology Department, including the cardiac intensive care unit, Madrid, Spain.

RESULTS

From a total of 500 patients, time of death was registered in 373 (74.6%), which are the focus of our study; 354 (70.8%) died in the cardiac intensive care unit and 146 (29.2%) in the conventional ward. Mean age was 74.2 ± 13.1 years, and 239 (64.1%) were male. Cardiovascular causes were the leading cause of death (308 patients; 82.6%). Mortality followed a circadian biphasic pattern with a peak at dawn (00.00-05.59 a.m.: 104 patients [27.9%]) and in the afternoon (12.00-17.59 p.m.: 135 patients [36.2%]), irrespective of the cause of death. The peak of mortality occurred in the afternoon (12.00-17.59 p.m.) in the case of cardiovascular mortality (119 deaths [38.6%]) and in the evening (18.00-23.59 p.m.) for non-cardiovascular deaths (21 deaths [32.3%], p = 0.03). This pattern was present regardless from the place of death (conventional ward or cardiac intensive care unit) and also throughout the four seasons.

CONCLUSIONS

Mortality in hospitalized patients with cardiovascular diseases follows a circadian biphasic pattern.