Motivation: On the first day of my first clinical clerkship, I was following in rounds during medicine when I was called to read an EKG. The EKG looked normal enough except for this sudden huge depolarization in the middle of the EKG. I did not know what it meant at the time, but I have since learnt to call these beats premature ventricular complexes (PVC). Over time, I also learnt to ignore scattered PVC on an EKG as non-consequential. But, the fact remains that they exist, and some apparently healthy people have more PVC than others. Do PVC reflect heart pathology? The clinical relevance of PVC in apparently healthy athletes was studied and reported a few years ago.
Paper: Long-Term Clinical Significance of Frequent and Complex Ventricular Tachyarrhythmias in Trained Athletes. Biffi, A. et. al. J. Am. Coll. of Card. (2002) 40: 446-52. http://content.onlinejacc.org/cgi/content/full/40/3/446
Methods: The study was conducted at the Institute of Sports Science at Rome, Italy. Between 1984 to 1999, 355 athletes were referred to the institute for either (1) more than 3 PVC on resting 12-lead EKG or (2) history of palpitations. Mean age was 24.8 years (range 14-35). Each of the athletes underwent 24 hour Holter EKG monitoring, cardiovascular exam, echo, and chest x-ray. Some athletes with more frequent PVC underwent further testing. The athletes selected in the study were in most cases highly trained with 70% of the participants competing at the national level. Athletes were followed-up six to twelve months (mean follow-up: 8.4 years).
Results:
Holter Montior Results: The number of PVC varied widely on 24 hour Holter monitor data. The authors divided the participants into three groups: (A) 71 (20%) athletes had between 2000 to 43,000 (!) PVC in 24 hours monitoring (mean: 10,850). 38 of the athletes in this group also had bursts of non-sustained ventricular tachycardia. Only 8 of the 71 complained of palpitations. None lost consciousness. (B) 153 (43.1%) athletes had between 100 to 1,890 PVC in 24 hour monitoring. None had ventricular tachycardia. (C) 131 (36.9%) athletes had between 3 to 98 PVC. None had ventricular tachycardia.
Cardiovascular Abnormalities: Based on echo, EKG, and other indicated invasive testing, the presence of structural abnormalities varied widely among the groups. In group A (more than 2000 PVC/24 hr), 30% had evidence of structural abnormalities. The disorders found were arrhythmogenic right ventricular cardiomyopathy, mitral valve prolapse, myocarditis, and dilated cardiomyopathy. In group B (100-2000 PVC/24 hr), only 3% had evidence of mitral valve prolapse. In group C (<100 PVC/24 hour), no abnormlities were noted.
Follow-up: During follow-up time, one athlete died from sudden cardiac death (he was in group A). Everyone else survived.
Discussion: I think the paper demonstrated very nicely that among patients with PVC, a wide spectrum exists. While just the appearance of PVC did not predict structural pathology, a large number of PVC (>2000/24 hours) was associated with greater prevalence of structural pathology. It is interesting to note, however, that even among athletes with the highest number of PVC, 70% turned out not to have any identifiable structural pathology. On the other hand, many of the structural pathologies identified were serious requiring treatment. One wonders if in longer term follow-up, the group with higher PVC would have increased incidence of cardiovascular diseases or sudden death. Follow-up was too short in the study.
A big weakness of the study is, of course, its generalizability. Given that most patients are neither in their 20s nor playing sports at a competitive level, the conclusions drawn in this study may not be more generalizable, and in other circumstances, PVC may be more predictive of structural pathology. In the group of athletes, the general level of diseases burden is low. In conclusion, however, for a young athlete with a few PVC caught on a screening Holter, the chances of structural pathology is low.
Paper: Long-Term Clinical Significance of Frequent and Complex Ventricular Tachyarrhythmias in Trained Athletes. Biffi, A. et. al. J. Am. Coll. of Card. (2002) 40: 446-52. http://content.onlinejacc.org/cgi/content/full/40/3/446
Methods: The study was conducted at the Institute of Sports Science at Rome, Italy. Between 1984 to 1999, 355 athletes were referred to the institute for either (1) more than 3 PVC on resting 12-lead EKG or (2) history of palpitations. Mean age was 24.8 years (range 14-35). Each of the athletes underwent 24 hour Holter EKG monitoring, cardiovascular exam, echo, and chest x-ray. Some athletes with more frequent PVC underwent further testing. The athletes selected in the study were in most cases highly trained with 70% of the participants competing at the national level. Athletes were followed-up six to twelve months (mean follow-up: 8.4 years).
Results:
Holter Montior Results: The number of PVC varied widely on 24 hour Holter monitor data. The authors divided the participants into three groups: (A) 71 (20%) athletes had between 2000 to 43,000 (!) PVC in 24 hours monitoring (mean: 10,850). 38 of the athletes in this group also had bursts of non-sustained ventricular tachycardia. Only 8 of the 71 complained of palpitations. None lost consciousness. (B) 153 (43.1%) athletes had between 100 to 1,890 PVC in 24 hour monitoring. None had ventricular tachycardia. (C) 131 (36.9%) athletes had between 3 to 98 PVC. None had ventricular tachycardia.
Cardiovascular Abnormalities: Based on echo, EKG, and other indicated invasive testing, the presence of structural abnormalities varied widely among the groups. In group A (more than 2000 PVC/24 hr), 30% had evidence of structural abnormalities. The disorders found were arrhythmogenic right ventricular cardiomyopathy, mitral valve prolapse, myocarditis, and dilated cardiomyopathy. In group B (100-2000 PVC/24 hr), only 3% had evidence of mitral valve prolapse. In group C (<100 PVC/24 hour), no abnormlities were noted.
Follow-up: During follow-up time, one athlete died from sudden cardiac death (he was in group A). Everyone else survived.
Discussion: I think the paper demonstrated very nicely that among patients with PVC, a wide spectrum exists. While just the appearance of PVC did not predict structural pathology, a large number of PVC (>2000/24 hours) was associated with greater prevalence of structural pathology. It is interesting to note, however, that even among athletes with the highest number of PVC, 70% turned out not to have any identifiable structural pathology. On the other hand, many of the structural pathologies identified were serious requiring treatment. One wonders if in longer term follow-up, the group with higher PVC would have increased incidence of cardiovascular diseases or sudden death. Follow-up was too short in the study.
A big weakness of the study is, of course, its generalizability. Given that most patients are neither in their 20s nor playing sports at a competitive level, the conclusions drawn in this study may not be more generalizable, and in other circumstances, PVC may be more predictive of structural pathology. In the group of athletes, the general level of diseases burden is low. In conclusion, however, for a young athlete with a few PVC caught on a screening Holter, the chances of structural pathology is low.
Awesome post....its helping me a lot for enhance my knowledge about PVC Cards
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