Relation of atrial electromechanical delay to P-wave dispersion on surface ECG using vector velocity imaging in patients with hypertrophic cardiomyopathy

Predicting the Propensity of Atrial Cardiopathy and Paroxysmal Atrial Fibrillation in Patients with Embolic Stroke of Undetermined Source (ESUS)

BACKGROUND

There is still a significant population of patients with embolic stroke of Undetermined Source (ESUS) whose specific attributable cause of the stroke remains unknown.

OBJECTIVES

Our research aimed to assess clinical, electrocardiogram, laboratory, and echocardiographic parameters that may predict the propensity of paroxysmal atrial fibrillation (PAF).

METHODS

We enrolled seventy-five ESUS patients who were in sinus rhythm at the time of stroke diagnosis to undergo in-hospital 7-day Holter monitoring, testing for Pro-BNP, and a standard echocardiographic examination. For statistical analysis, a P-value < 0.05 was considered significant.

RESULTS

The average age of the 75 ESUS patients was 58 years old. 60% of the patients were male, and the most prevalent concomitant condition was hypertension (53.3%). Forty patients had atrial cardiopathy, and 15 patients had PAF episodes. Hypertension and the E/e- > 12 were independent predictors of atrial cardiopathy, with p-values of 0.001 and 0.02, respectively. In patients with atrial cardiopathy, multivariable regression analysis was performed; PTFV > 5000 Mv.ms, LA volume index > 34 ml/m2, and ejection fraction < 45% were significant independent predictors of AF with significant p values of 0.001, < 0.001, and 0.001 respectively.

CONCLUSIONS

In ESUS patients, atrial cardiopathy was prevalent. Hypertension and an E/e- ratio greater than 12 were independent predictors for it. Multivariable regression analysis identified PTFV1 > 5000 mV.ms, LA volume index > 34 ml/m2, and ejection fraction < 45% as independent predictors for new-onset atrial fibrillation.

Predicting the Propensity of Atrial Cardiopathy and Paroxysmal Atrial Fibrillation in Patients with Embolic Stroke of Undetermined Source (ESUS)

BACKGROUND

There is still a significant population of patients with embolic stroke of Undetermined Source (ESUS) whose specific attributable cause of the stroke remains unknown.

OBJECTIVES

Our research aimed to assess clinical, electrocardiogram, laboratory, and echocardiographic parameters that may predict the propensity of paroxysmal atrial fibrillation (PAF).

METHODS

We enrolled seventy-five ESUS patients who were in sinus rhythm at the time of stroke diagnosis to undergo in-hospital 7-day Holter monitoring, testing for Pro-BNP, and a standard echocardiographic examination. For statistical analysis, a P-value < 0.05 was considered significant.

RESULTS

The average age of the 75 ESUS patients was 58 years old. 60% of the patients were male, and the most prevalent concomitant condition was hypertension (53.3%). Forty patients had atrial cardiopathy, and 15 patients had PAF episodes. Hypertension and the E/e- > 12 were independent predictors of atrial cardiopathy, with p-values of 0.001 and 0.02, respectively. In patients with atrial cardiopathy, multivariable regression analysis was performed; PTFV > 5000 Mv.ms, LA volume index > 34 ml/m2, and ejection fraction < 45% were significant independent predictors of AF with significant p values of 0.001, < 0.001, and 0.001 respectively.

CONCLUSIONS

In ESUS patients, atrial cardiopathy was prevalent. Hypertension and an E/e- ratio greater than 12 were independent predictors for it. Multivariable regression analysis identified PTFV1 > 5000 mV.ms, LA volume index > 34 ml/m2, and ejection fraction < 45% as independent predictors for new-onset atrial fibrillation.

Electrocardiographic abnormalities in patients with cardiomyopathies

Abnormalities in impulse generation and transmission are among the first signs of cardiac remodeling in cardiomyopathies. Accordingly, 12-lead electrocardiogram (ECG) of patients with cardiomyopathies may show multiple abnormalities. Some findings are suggestive of specific disorders, such as the discrepancy between QRS voltages and left ventricular (LV) mass for cardiac amyloidosis or the inverted T waves in the right precordial leads for arrhythmogenic cardiomyopathy. Other findings are less sensitive and/or specific, but may orient toward a specific diagnosis in a patient with a specific phenotype, such as an increased LV wall thickness or a dilated LV. A "cardiomyopathy-oriented" mindset to ECG reading is important to detect the possible signs of an underlying cardiomyopathy and to interpret correctly the meaning of these alterations, which differs in patients with cardiomyopathies or other conditions.

Vectorial theory surpasses the local theory in explaining the origin of P-wave dispersion

BACKGROUND

Local theory and the vectorial theory are used to explain the origin of P-wave dispersion (PWD). There are no previous studies that analyze both at the same time.

OBJECTIVES

We set out to determine the implication of local and vectorial theories in the origin of PWD.

METHODS

Cross-sectional study in 153 randomly selected patients aged 18-70 years, undergoing electrophysiological study. Inhomogeneous atrial conduction was evaluated by atrial electrogram dispersion in terms of duration (EGM_durdis) and morphology (EGM_morph dis). P-distal coronary sinus interval (P-DCS) was also measured. P-wave was measured twice, firstly at a calibration of 20 mm/mV and a sweep speed of 50 mm/s, enhancement 10× (basic measurement [BM]), and second time at sweep speed of 150 mm/s, enhancement 80-160× (high precision measurement [HPM]).

RESULTS

PWD with BM was 48 ms [36-54 ms] while with HPM it was 4 ms [0-10 ms], p < 0.001. With BM, maximum and minimum P- wave duration presented a moderate correlation (r = 0.342; p < 0.001), using HPM it becomes strong (r = 0.750; p < 0.001). In cases with P-DCS < 80 ms (r = 0.965; p < 0.001), but not with P-DCS ≥ 80 ms (r = 0.649; p < 0.001), the previous correlation became almost perfect with HPM. EGM_durdis and EGM_morphdis were weak but significantly correlated with PWD. This correlation became moderate in patients with P-DCS ≥ 80 ms and disappeared in those with P-DCS, using BM and HPM.

CONCLUSION

Vectorial theory explains almost entirely the PWD phenomenon. Inhomogeneous conduction could be an additional mechanism to explain PWD, but its contribution is small.

Relation of atrial electromechanical delay to P-wave dispersion on surface ECG using vector velocity imaging in patients with hypertrophic cardiomyopathy

OBJECTIVES

Heterogeneity of structural and electrophysiologic properties of atrial myocardium is common characteristic in hypertrophic cardiomyopathy (HCM). We assessed the dispersion of atrial refractoriness on surface ECG using P-wave dispersion (PWD) and its relation to atrial electromechanical functions using vector velocity imaging (VVI) in HCM population.

METHODS

Seventy-nine HCM patients (mean age: 43.7 ± 13 years, 67% male) were compared with 25 healthy individuals as control. P-wave durations, Pmax and Pmin , P-wave dispersion (PWD), and P terminal force (PTF) were measured from 12-lead ECG. LA segmental delay (TTP-d) and dispersion (TTP-SD) of electromechanical activation were derived from atrial strain rate curves.

RESULTS

HCM patients had longer PR interval, PW duration, higher PWD, PTF, QTc compared to control (p < .001). HCM patients were classified according to presence of PWD into two groups, group I with PWD > 46 ms (n = 25) and group II PWD ≤ 46 ms (n = 54). Group I showed higher prevalence of female gender, higher PTF, QTc interval, left ventricular outflow tract (LVOT) obstruction, p < .01, LVOT gradient (p < .001), LV mass index (p < .01), E/E' (p < .01), and severe mitral regurgitation (p < .001). Moreover, PWD was associated with increased atrial electromechanical delay (TTP-d) and LA mechanical dyssynchrony (TTP-SD), p < .001. LA segmental delay and dispersion of electromechanical activation were distinctly higher among HCM patient.

CONCLUSION

PWD is simple ECG criterion, and it is associated with more severe HCM phenotype and LA electromechanical delay while PTF is linked only to atrial remodeling.