American Journal of Emergency Medicine xxx (2013) xxx–xxx
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Case Report
Are those Premature Ventricular Complexes?! Abstract Ventricular parasystole has been known to be a benign rhythm. We present a case of a 53-year-old man with chest pain and ventricular parasystole on electrocardiogram upon initial presentation. He was admitted and found to have normal serial cardiac enzymes and nuclear stress testing. He was discharged home with primary care follow-up. We highlight this case, as ventricular parasystole has been shown to be associated with cardiovascular disease and is a rhythm that should not be ignored. Our review of the literature shows that a thorough cardiovascular investigation should take place when this rhythm is identified. A 53-year-old man with a medical history of hypercholesterolemia presented to the emergency department with a 2-week history of general fatigue. In addition, for the past week, he complained of daily intermittent chest pain at rest without aggravating or alleviating factors. Examination revealed a comfortable appearing gentleman in no acute distress, with the following vital signs: temperature, 37.1°C; pulse, 41 beats per minute; respiratory rate, 18 per minute; blood pressure, 160/ 90 mm Hg; and oxygen saturation, 94% on room air. Chest radiography revealed no evidence of acute disease. Laboratory investigation including basic metabolic panel and complete blood count were normal, and troponin I was negative. Electrocardiogram was initially interpreted to be sinus rhythm at a rate of 71 per minute with frequent premature ventricular complexes. Bedside echocardiogram revealed no structural abnormality and normal function. The patient was treated with aspirin, and he was admitted to the medicine service. Serial cardiac enzymes were negative, and a nuclear stress test showed normal myocardial perfusion at rest and poststress. The poststress global left ventricular function was normal, and the left ventricular ejection fraction was calculated at 61%. Regional wall motion/thickening was normal. Computed tomographic angiography of the chest, abdomen, and pelvis was also performed, which revealed no evidence of aortic dissection. Ventricular parasystole has been defined as a dual rhythm with a ventricular pacemaker that is independent of the baseline sinus rhythm [1]. Diagnostic criteria are outlined in Table. The 12-lead electrocardiogram of the patient (Fig. 1) showed 3 distinct wide-complex beats in a bigeminal pattern. The sinus rate was 68 per minute, and the rate of the wide-complex beats was 40 per minute. The variable coupling interval (N100 milliseconds) between the ectopic focus and sinus beats and interectopic intervals, which are multiples of the parasystolic cycle length (2 × 1.52 seconds; see Fig. 2), is consistent with ventricular parasystole. Analysis of the parasystolic beats revealed a left bundle-branch block–like pattern in lead V1 and an inferior axis in the limb leads. This morphology and precordial transition of the ectopic beat after V3 purport a location of the parasystolic focus in the right ventricular outflow tract. The exact location of the focus is difficult to ascertain without an electrophysiology study. The most common mechanism for such a ventricular ectopy is enhanced
automaticity. In contrast to a parasystolic ventricular beat, an example of ventricular premature beats is shown in Fig. 3. The interectopic intervals between ventricular premature beats are constant (1.6 seconds); however, the coupling interval to the preceding sinus beat remains unchanged (0.44 seconds). The literature supports an association between ventricular parasystole and cardiovascular disease [2-4]. The incidence of ventricular parasystole in the asymptomatic general population has been reported to be very rare (0.13%) [2]. The incidence of ventricular parasystole in patients with acute myocardial infarction has been reported to be 1.7% in 1 study and 4% in another [3,4]. In a case series, 38 of 49 patients with ventricular parasystole had pronounced cardiovascular disease [3]. Another case series formulated an association between ventricular parasystole and ventricular tachycardia [5]. Eighty-six percent of the patients with ventricular parasystole have some form of heart disease along with 0.15% having had evidence of myocardial infarction [2]. Although our patient had a normal nuclear stress test, it must be noted that the sensitivities for nuclear myocardial perfusion imaging range from 84% to 89% [6]. In addition, myocardial infarction and cardiac death after normal exercise nuclear and pharmacological nuclear myocardial perfusion imaging range from 0.65% to 1.78%, which is not negligible [6]. Although ventricular parasystole can be a benign rhythm, our review of the literature has shown that the association of cardiovascular disease associated with this rhythm should not be ignored. Identification of ventricular parasystole should prompt extensive cardiovascular investigation. Randeep Thiara MD Nicholas Nacca MD Department of Emergency Medicine SUNY Upstate Medical University, St Syracuse NY 13202, USA E-mail address: [email protected] Tamas Szombathy MD Department of Internal Medicine SUNY Upstate Medical University, St Syracuse NY 13202, USA http://dx.doi.org/10.1016/j.ajem.2013.11.001 Table Diagnostic criteria for venticular parasystole 1. The presence of various coupling intervals between the ectopic beats and their preceding sinus beats 2. The presence of fusion beats. Fusion beats are synchronous discharges by both pacemakers resulting in fusion QRS complexes 3. The presence of ectopic beats with interectopic intervals all related to one another
0735-6757/$ – see front matter © 2013 Elsevier Inc. All rights reserved.
Please cite this article as: Thiara R, et al, Are those Premature Ventricular Complexes?!, Am J Emerg Med (2013), http://dx.doi.org/10.1016/ j.ajem.2013.11.001
2
R. Thiara et al. / American Journal of Emergency Medicine xxx (2013) xxx–xxx
Fig. 1. 12 lead electrocardiogram showing Ventricular Parasystole.
Fig. 2. Rhythm strip showing Ventricular Parasystole.
Fig. 3. Rhythm strip showing Premature Ventricular Complexes.
References [1] Schamroth L. Ventricular parasystole with slow manifest ectopic discharge. Heart 1962;24.6:731–7 [Print]. [2] Chung E. Parasystole. Prog Cardiovasc Dis 1968;11.1:64–81 [Print]. [3] Salazar J, McKendrick CS. Ventricular parasystole. Heart 1970;32.3:377–85 [Print].
[4] Baxter R. Comparison of ventricular parasystole with other dysrhythmias after acute myocardial infarction. Am Heart J 1974;88.4:443–8 [Print]. [5] Itoh E, Aizawa Y, Washizuka T, Uchiyama H, Kitazawa H, Kusano Y, et al. Two cases of ventricular parasystole associated with ventricular tachycardia. Pacing Clin Electrophysiol 1996;19.3:370–3 [Print]. [6] Arbab-Zadeh A. Stress testing and non-invasive coronary angiography in patients with suspected coronary artery disease: time for a new paradigm. Heart International 2012;7:e2:4–13 [Print].
Please cite this article as: Thiara R, et al, Are those Premature Ventricular Complexes?!, Am J Emerg Med (2013), http://dx.doi.org/10.1016/ j.ajem.2013.11.001
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Case Report
Are those Premature Ventricular Complexes?! Abstract Ventricular parasystole has been known to be a benign rhythm. We present a case of a 53-year-old man with chest pain and ventricular parasystole on electrocardiogram upon initial presentation. He was admitted and found to have normal serial cardiac enzymes and nuclear stress testing. He was discharged home with primary care follow-up. We highlight this case, as ventricular parasystole has been shown to be associated with cardiovascular disease and is a rhythm that should not be ignored. Our review of the literature shows that a thorough cardiovascular investigation should take place when this rhythm is identified. A 53-year-old man with a medical history of hypercholesterolemia presented to the emergency department with a 2-week history of general fatigue. In addition, for the past week, he complained of daily intermittent chest pain at rest without aggravating or alleviating factors. Examination revealed a comfortable appearing gentleman in no acute distress, with the following vital signs: temperature, 37.1°C; pulse, 41 beats per minute; respiratory rate, 18 per minute; blood pressure, 160/ 90 mm Hg; and oxygen saturation, 94% on room air. Chest radiography revealed no evidence of acute disease. Laboratory investigation including basic metabolic panel and complete blood count were normal, and troponin I was negative. Electrocardiogram was initially interpreted to be sinus rhythm at a rate of 71 per minute with frequent premature ventricular complexes. Bedside echocardiogram revealed no structural abnormality and normal function. The patient was treated with aspirin, and he was admitted to the medicine service. Serial cardiac enzymes were negative, and a nuclear stress test showed normal myocardial perfusion at rest and poststress. The poststress global left ventricular function was normal, and the left ventricular ejection fraction was calculated at 61%. Regional wall motion/thickening was normal. Computed tomographic angiography of the chest, abdomen, and pelvis was also performed, which revealed no evidence of aortic dissection. Ventricular parasystole has been defined as a dual rhythm with a ventricular pacemaker that is independent of the baseline sinus rhythm [1]. Diagnostic criteria are outlined in Table. The 12-lead electrocardiogram of the patient (Fig. 1) showed 3 distinct wide-complex beats in a bigeminal pattern. The sinus rate was 68 per minute, and the rate of the wide-complex beats was 40 per minute. The variable coupling interval (N100 milliseconds) between the ectopic focus and sinus beats and interectopic intervals, which are multiples of the parasystolic cycle length (2 × 1.52 seconds; see Fig. 2), is consistent with ventricular parasystole. Analysis of the parasystolic beats revealed a left bundle-branch block–like pattern in lead V1 and an inferior axis in the limb leads. This morphology and precordial transition of the ectopic beat after V3 purport a location of the parasystolic focus in the right ventricular outflow tract. The exact location of the focus is difficult to ascertain without an electrophysiology study. The most common mechanism for such a ventricular ectopy is enhanced
automaticity. In contrast to a parasystolic ventricular beat, an example of ventricular premature beats is shown in Fig. 3. The interectopic intervals between ventricular premature beats are constant (1.6 seconds); however, the coupling interval to the preceding sinus beat remains unchanged (0.44 seconds). The literature supports an association between ventricular parasystole and cardiovascular disease [2-4]. The incidence of ventricular parasystole in the asymptomatic general population has been reported to be very rare (0.13%) [2]. The incidence of ventricular parasystole in patients with acute myocardial infarction has been reported to be 1.7% in 1 study and 4% in another [3,4]. In a case series, 38 of 49 patients with ventricular parasystole had pronounced cardiovascular disease [3]. Another case series formulated an association between ventricular parasystole and ventricular tachycardia [5]. Eighty-six percent of the patients with ventricular parasystole have some form of heart disease along with 0.15% having had evidence of myocardial infarction [2]. Although our patient had a normal nuclear stress test, it must be noted that the sensitivities for nuclear myocardial perfusion imaging range from 84% to 89% [6]. In addition, myocardial infarction and cardiac death after normal exercise nuclear and pharmacological nuclear myocardial perfusion imaging range from 0.65% to 1.78%, which is not negligible [6]. Although ventricular parasystole can be a benign rhythm, our review of the literature has shown that the association of cardiovascular disease associated with this rhythm should not be ignored. Identification of ventricular parasystole should prompt extensive cardiovascular investigation. Randeep Thiara MD Nicholas Nacca MD Department of Emergency Medicine SUNY Upstate Medical University, St Syracuse NY 13202, USA E-mail address: [email protected] Tamas Szombathy MD Department of Internal Medicine SUNY Upstate Medical University, St Syracuse NY 13202, USA http://dx.doi.org/10.1016/j.ajem.2013.11.001 Table Diagnostic criteria for venticular parasystole 1. The presence of various coupling intervals between the ectopic beats and their preceding sinus beats 2. The presence of fusion beats. Fusion beats are synchronous discharges by both pacemakers resulting in fusion QRS complexes 3. The presence of ectopic beats with interectopic intervals all related to one another
0735-6757/$ – see front matter © 2013 Elsevier Inc. All rights reserved.
Please cite this article as: Thiara R, et al, Are those Premature Ventricular Complexes?!, Am J Emerg Med (2013), http://dx.doi.org/10.1016/ j.ajem.2013.11.001
2
R. Thiara et al. / American Journal of Emergency Medicine xxx (2013) xxx–xxx
Fig. 1. 12 lead electrocardiogram showing Ventricular Parasystole.
Fig. 2. Rhythm strip showing Ventricular Parasystole.
Fig. 3. Rhythm strip showing Premature Ventricular Complexes.
References [1] Schamroth L. Ventricular parasystole with slow manifest ectopic discharge. Heart 1962;24.6:731–7 [Print]. [2] Chung E. Parasystole. Prog Cardiovasc Dis 1968;11.1:64–81 [Print]. [3] Salazar J, McKendrick CS. Ventricular parasystole. Heart 1970;32.3:377–85 [Print].
[4] Baxter R. Comparison of ventricular parasystole with other dysrhythmias after acute myocardial infarction. Am Heart J 1974;88.4:443–8 [Print]. [5] Itoh E, Aizawa Y, Washizuka T, Uchiyama H, Kitazawa H, Kusano Y, et al. Two cases of ventricular parasystole associated with ventricular tachycardia. Pacing Clin Electrophysiol 1996;19.3:370–3 [Print]. [6] Arbab-Zadeh A. Stress testing and non-invasive coronary angiography in patients with suspected coronary artery disease: time for a new paradigm. Heart International 2012;7:e2:4–13 [Print].
Please cite this article as: Thiara R, et al, Are those Premature Ventricular Complexes?!, Am J Emerg Med (2013), http://dx.doi.org/10.1016/ j.ajem.2013.11.001
