[Usefulness of superficial electrocardiogram in the diagnosis of narrow QRS tachycardias: correlation with intracavitary electrocardiograms]

Localization and characterization of atrial depolarization waves on the surface electrocardiogram in dogs with rapid supraventricular tachycardia

BACKGROUND

Supraventricular tachycardias (SVTs), despite having various anatomical substrates and pathophysiological mechanisms, frequently show similar electrocardiographic presentations.

OBJECTIVES

To locate and characterize atrial deflections (ADs) on 12-lead electrocardiograms in dogs with sustained rapid SVT and assess the utility of different electrocardiographic variables in differentiating types of tachycardia.

ANIMALS

Ninety-two dogs with orthodromic atrioventricular reciprocating tachycardia, 17 with atrial flutter, 33 with focal atrial tachycardia recorded and confirmed by electrophysiological study, and 40 dogs with sinus tachycardia.

METHODS

Atrial deflection position on the 12-lead surface electrocardiogram was assessed according to the sequence of intracardiac activation. Its features were evaluated together with the relationship between AD and QRS complex interval (AD-R) and QRS complex and AD interval (R-AD).

RESULTS

Orthodromic atrioventricular reciprocating tachycardia was characterized by an AD-AD interval of 213 ± 30 ms, mean electrical axis (MEA) of AD of -90 (-90/-78)°, R-AD interval of 75 (65-80) ms, and R-AD/AD-R of 0.54 (0.45-0.64). Atrial flutter was characterized by an AD-AD interval of 199 ± 57 ms, MEA of 76° (72/81), R-AD of 120 (72-144) ms, and R-AD/AD-R of 0.81 (0.63-1.13). Focal atrial tachycardia was characterized by an AD-AD interval of 270 ± 38 ms, MEA of 49 (-72/76)°, R-AD of 160 (120-200) ms, and R-AD/AD-R of 1.45 (0.92-1.67). Sinus tachycardia was characterized by an AD-AD interval of 292 ± 31 ms, MEA of 66° (52/73), R-AD of 215 (192-222) ms, and R-AD/AD-R of 2.68 (2.25-3.08).

CONCLUSIONS AND CLINICAL IMPORTANCE

Analyzing AD on 12-lead electrocardiogram is helpful in differentiating the most common SVTs in dogs.

Atrial tachycardia originating from the pulmonary vein: clinical, electrocardiographic, and differential electrophysiologic characteristics

INTRODUCTION AND OBJECTIVES

Although atrial tachycardia (AT) frequently originates in the pulmonary vein, pulmonary vein atrial tachycardia (PV-AT) can be difficult to recognize on an ECG. The aim of this study was to identify clinical and electrophysiologic characteristics specific to PV-AT, including sinus P-wave duration and notching.

METHODS

The study included 87 patients who underwent AT ablation, divided into four groups: those with PV-AT alone (Group 1, n=25), those with PV-AT associated with atrial fibrillation (Group 2, n=18), and those with other forms of left AT (Group 3, n=7) and right AT (Group 4, n=37).

RESULTS

The mean age of patients in Group 1, at 44 + or - 14 years, was less than in Groups 2, 3 and 4, at 57 + or - 9, 58 + or - 12 and 53 + or - 16 years, respectively (P< .05) and the left atrial diameter, at 38 + or - 4 mm, was less than in the other left AT groups: 48 + or - 7 mm in Group 2 and 49 + or - 5 mm in Group 3 (P< .05). Overall, PV-AT was most frequently due to abnormal automaticity or triggered activity (P< .05) and presented with a short cycle length: 289 + or - 45 ms and 280 + or - 48 ms in Groups 1 and 2, respectively, versus 392 + or - 106 ms and 407 + or - 87 ms in Groups 3 and 4, respectively (P< .05). In patients aged <50 years with AT and no underlying heart disease, PV-AT was significantly (P< .05) associated with a P-wave duration > or = 110 ms (sensitivity 68%, specificity 69%) and P-wave notching (sensitivity 79%, specificity 70%).

CONCLUSIONS

Sinus P-wave prolongation and notching in young patients with a rapid AT but without heart disease predicted an origin in the pulmonary vein.

[Incessant atrial tachycardia and a cerebral tumor]

We report the case of an asymptomatic 78-year-old woman in whom incessant atrial tachycardia refractory to many pharmacological treatments appeared. Months after the appearance of atrial tachycardia, clinical neurological symptoms of a cerebral cystic tumor appeared. Treatment of the tumor resolved the rhythm disorder.