The effect of Valsalva maneuver on P wave in 12-lead surface electrocardiography in patients with paroxysmal atrial fibrillation

Anterior Mediastinal Mass Causing Intermittent Atrial Fibrillation

Mediastinal masses are a rare finding in the emergency department and typically present with vague chest complaints such as chest discomfort, chest pain, or dyspnea. Rarely do these tumors present with dysrhythmias, and when dysrhythmias are present, they typically arise secondary to endocrine or metabolic effects exerted by the tumor. Here we report a case of a patient who presented to the emergency department with atrial fibrillation with rapid ventricular response, concomitant with a history of recurrent palpitations that were previously aborted with self-induced vagal maneuvers. Upon further investigation, the patient had an anterior mediastinal mass, diagnosed as a thymoma, suspected to be contributing to his presenting dysrhythmia through mass effect.

Valsalva Maneuver and Strain-Related ECG Changes

BACKGROUND

During the four steps of the Valsalva maneuver (VM), opposite changes can be observed in some physiologic parameters. Manifestations of the VM in the electrocardiogram (ECG) have been studied in detail, but there have been few reports comparing VM-related biochemical and hemodynamic changes with a focus on the strain phase of the VM.

OBJECTIVES

We studied strain-related ECG changes during the VM.

PATIENTS AND METHODS

This self-control descriptive study was conducted in 20 healthy male college students aged 20.12 ± 2.23 years. They were well trained to perform the standard VM: maintenance of a 15-second expiratory pressure at 40 mmHg with open glottis. An ECG was continuously recorded in the supine position at (a) rest (before the VM) and at (b) the start and (c) end of strain maintenance in the second phase of the VM. The averages of four successive beats were computed for each set of (a), (b), and (c). Means ± standard errors of the mean were used for comparison.

RESULTS

Following the VM, the RR and PR intervals, corrected QT interval (QTc), P wave duration and amplitude, T wave amplitude, and the ratio of T/R amplitudes showed significant changes. The QRS duration and R wave amplitude did not show significant changes.

CONCLUSIONS

The VM caused time and voltage changes in some ECG waves during the strain phase. Alterations in heart or lung volume, electrode-related alterations, and autonomic tone may cause these changes.

Valsalva Maneuver and Strain-Related ECG Changes

BACKGROUND

During the four steps of the Valsalva maneuver (VM), opposite changes can be observed in some physiologic parameters. Manifestations of the VM in the electrocardiogram (ECG) have been studied in detail, but there have been few reports comparing VM-related biochemical and hemodynamic changes with a focus on the strain phase of the VM.

OBJECTIVES

We studied strain-related ECG changes during the VM.

PATIENTS AND METHODS

This self-control descriptive study was conducted in 20 healthy male college students aged 20.12 ± 2.23 years. They were well trained to perform the standard VM: maintenance of a 15-second expiratory pressure at 40 mmHg with open glottis. An ECG was continuously recorded in the supine position at (a) rest (before the VM) and at (b) the start and (c) end of strain maintenance in the second phase of the VM. The averages of four successive beats were computed for each set of (a), (b), and (c). Means ± standard errors of the mean were used for comparison.

RESULTS

Following the VM, the RR and PR intervals, corrected QT interval (QTc), P wave duration and amplitude, T wave amplitude, and the ratio of T/R amplitudes showed significant changes. The QRS duration and R wave amplitude did not show significant changes.

CONCLUSIONS

The VM caused time and voltage changes in some ECG waves during the strain phase. Alterations in heart or lung volume, electrode-related alterations, and autonomic tone may cause these changes.

Prediction of cardiovascular risk by electrocardiographic changes in women with intrahepatic cholestasis of pregnancy

OBJECTIVE

We aimed to investigate P wave characteristics in pregnant women with and without intrahepatic cholestasis of pregnancy (ICP).

METHODS

In this case-control study, including 59 pregnant women with intrahepatic cholestasis and 28 with healthy uncomplicated pregnancies, electrocardiographic maximum (Pmax) and minimum (Pmin) P-wave durations and P-wave dispersion (Pd) parameters were investigated.

RESULTS

While Pmin and Pd values were significantly lower in women both with mild and severe ICP when compared to healthy pregnant women (p < 0.001), there was no significant difference between mild and severe disease groups.

CONCLUSION

Intrahepatic cholestasis predisposes to cardiovascular complications. P-wave durations and Pd constitute a recent contribution to the field of noninvasive electrocardiology. Our data clearly demonstrated that these parameters were significantly altered in pregnant women with ICP when compared to the normal ones. This important association can be used to screen for women with an increased risk to better target counseling on lifestyle modifications and to closer follow-up and management of women with a history of ICP.

P-wave duration changes and dispersion in preeclampsia

OBJECTIVE

The purpose of this research was to study P wave parameters to determine the association between preeclampsia and future cardiovascular risk and to study the possible correlation between P waves and severity of preeclampsia.

STUDY DESIGN

In this case-control study 58 pregnant women with preeclampsia and 30 normal pregnant women were compared by measuring maximum and minimum P-wave durations and P-wave dispersion (Pd) in the late third trimester.

RESULTS

Minimum P wave values were lower and Pd values were higher, both significantly, in the preeclampsia groups than in the control group. In addition, the Pd values of the severe preeclampsia group were higher compared to that of the mild preeclampsia group.

CONCLUSION

Preeclampsia predisposes the patient to future cardiovascular complications including atrial or ventricular arrhythmias, but validated tools to assess the risks are yet not available. P-wave duration and Pd constitute a recent contribution to the field of noninvasive electrocardiology. Our data clearly demonstrated that minimum P wave and Pd values were significantly altered in preeclamptic pregnant women when compared to the controls. This important association can be used to screen women for increased risk in order to better target counseling regardinglifestyle modifications and to follow up and manage women with a history of preeclampsia more closely.

Meta-analysis of p-wave dispersion values in healthy individuals: the influence of clinical characteristics

BACKGROUND

P-wave dispersion (Pd) is an appealing marker for predicting the risk of developing atrial fibrillation. At present, no definitive cutoff value has been determined as to the diagnosis of high-risk patients. Our aims were to evaluate P-wave parameters of healthy subjects published in the literature, determine normal range and weighted means of Pd and P-wave parameters, and investigate the influences of gender, age, and BMI on the weighted results.

METHODS

A systematic search of studies published in PubMed was conducted. Only studies which included control groups of healthy individuals were included.

RESULTS

Of the 657 studies initially identified, 80 were eligible for inclusion. The total number of participants was 6,827. The highest reported Pd values were 58.56 ± 16.24 ms; the lowest were 7 ± 2.7 ms. The weighted mean was 33.46 ± 9.65 ms; weighted median was 32.2 ms. Gender and age were not found to be associated with significant influences on P-wave parameter values. High-normal BMI was not found to be associated with increased P-wave parameter values.

CONCLUSIONS

Pd, Pmax, and Pmin span a wide range of values in healthy individuals. Seemingly, abnormal values were often reported in healthy adults. The high variability of P-wave parameters in healthy individuals, and overlapping of the results with those reported for patients with increased risk for atrial fibrillation, might suggest that this technique has limited sensitivity and specificity. The variability between studies may stem from methodological issues and, therefore, there is a definite need for methodological standardization of Pd measurements.

Comparison of P-wave dispersion in healthy dogs, dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction

BACKGROUND

P-wave dispersion (Pd) is a new ECG index used in human cardiology and veterinary medicine. It is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different ECG leads. So far no studies were performed assessing the importance of P-wave dispersion in dogs.

METHODS

The current study was aimed at determining proper value of Pd in healthy dogs (group I), dogs with chronic valvular disease (group II) and dogs with disturbances of supraventricular conduction (group III). The tests were carried out in 53 healthy dogs, 23 dogs with chronic valvular disease and 12 dogs with disturbances of supraventricular conduction of various breeds, sexes and body weight from 1,5 to 80 kg, aged between 0,5 and 17 years, submitted to the ECG examination. ECG was acquired in dogs in a standing position with BTL SD-8 electrocardiographic device and analyzed once the recording was enlarged. P-wave duration was calculated in 9 ECG leads (I, II, III, aVR, aVL, aVF, V1, V2, V4) from 5 cardiac cycles.

RESULTS

The proper P-wave dispersion in healthy dogs was determined at up to 24 ms. P-wave dispersion was statistically significant increased (p<0.01) in dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction. In dogs with the atrial enlargement the P-wave dispersion is also higher than in healthy dogs, although no significant correlation between the size of left atria and Pd was noticed (p=0.1, r=0,17).

CONCLUSIONS

The P-wave dispersion is a constant index in healthy dogs, that is why it can be used for evaluating P wave change in dogs with chronic valvular disease and in dogs with disturbances of supraventricular conduction.

Instantly Converting Atrial Fibrillation into Sinus Rhythm by a Digital Rectal Exam on a 29-year-Old Male

Vagal maneuvers cause increase in vagal tone, which has been shown to slow many types supraventricular tachycardia, such as atrial fibrillation (AF). However, the conversion of AF to sinus rhythm is usually not associated with vagal manuvers. Thus, AF is classically treated with medication and electrical cardioversion. Here, we present a 29-year-old male with no cardiovascular history and a low atherosclerotic risk profile who developed AF which converted into sinus rhythm immediately after a digital rectal exam. The patient remained asymptomatic after a 3-month follow-up. This implies that the digital rectal exam can be considered as an additional attempt to convert AF to sinus rhythm in AF patients.